Bryant Furnace 315AAV User Manual

315AAV/JAV  
VARIABLE--SPEED, INDUCED--COMBUSTION DELUXE  
4--WAY MULTIPOISE GAS FURNACE  
Installation, Start--up, Operating and  
Service and Maintenance Instructions  
Series 150/F  
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . 2  
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
CODES AND STANDARDS . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
General Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Combustion and Ventilation Air . . . . . . . . . . . . . . . . . . . . . . 4  
Duct Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Acoustical Lining and Fibrous Glass Duct . . . . . . . . . . . . . . . 4  
Gas Piping and Gas Pipe Pressure Testing . . . . . . . . . . . . . . . 4  
Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
ELECTRICAL CONNECTION . . . . . . . . . . . . . . . . . . . . . . . 20  
ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
VENTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
START--UP, ADJUSTMENT, AND SAFETY CHECK . . . . . 34  
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34  
Start--Up Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37  
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37  
Check Safety Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45  
Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46  
SERVICE AND MAINTENANCE PROCEDURES . . . . . . . 46  
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46  
Care and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47  
Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52  
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56  
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56  
Accessory List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59  
PARTS REPLACEMENT INFORMATION GUIDE . . . . . . . 60  
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS  
PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
LOCATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5  
AIR FOR COMBUSTION AND VENTILATION . . . . . . . . . 8  
Outdoor Combustion Air Method . . . . . . . . . . . . . . . . . . . . 9  
The Standard Method: . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Combination of Indoor and Outdoor Air . . . . . . . . . . . . . 10  
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Bottom Return Air Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Side Return Air Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Leveling Legs (If Desired) . . . . . . . . . . . . . . . . . . . . . . . . 11  
Bottom Return Air Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Suspended Furnace Support . . . . . . . . . . . . . . . . . . . . . . . 11  
Platform Furnace Support . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Roll--Out Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12  
Bottom Return Air Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . 12  
Side Return Air Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12  
Filter Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
AIR DUCTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Ductwork Acoustical Treatment . . . . . . . . . . . . . . . . . . . . 13  
Supply Air Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Upflow and Horizontal Furnaces . . . . . . . . . . . . . . . . . . . 14  
Downflow Furnaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Return Air Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
Downflow Furnaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
Upflow and Horizontal Furnaces . . . . . . . . . . . . . . . . . . . 18  
GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
ISO 9001:2000  
REGISTERED  
G
F
E
N
I
D
C
D
E
E
R
NOTE: Read the entire instruction manual before starting the  
installation.  
Portions of the text and tables are reprinted from NFPA 54/ANSI  
Z223.1--2009E, with permission of National Fire Protection  
Association, Quincy, MA 02269 and American Gas Association,  
Washington DC 20001. This reprinted material is not the  
complete and official position of the NFPA or ANSI on the  
referenced subject, which is represented only by the standard in  
its entirety.  
1
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A10269  
Fig. 1 -- Clearances to Combustibles  
3
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only the NFGC, contact the American Gas Association, 400 N.  
Capitol Street, N.W., Washington, DC 20001 (www.AGA.org.) .  
Combustion and Ventilation Air  
INTRODUCTION  
The Series 150/F 4--way multipoise Category I fan--assisted  
furnace is CSA (formerly A.G.A. and C.G.A.) design--certified. A  
Category I fan--assisted furnace is an appliance equipped with an  
integral mechanical means to either draw or force products of  
combustion through the combustion chamber and/or heat  
exchanger. The furnace is factory--shipped for use with natural  
gas. This furnace is not approved for installation in mobile  
homes, recreational vehicles, or outdoors.  
Section 9.3 NFPA 54/ANSI Z223.1--2009, Air for Combustion  
and Ventilation .  
Duct Systems  
Air Conditioning Contractors Association (ACCA) Manual D,  
Sheet Metal and Air Conditioning Contractors National  
Association (SMACNA), or American Society of Heating,  
Refrigeration, and Air Conditioning Engineers (ASHRAE) 2001  
Fundamentals Handbook Chapter 34 or 2000 HVAC Systems  
and Equipment Handbook Chapters 9 and 16.  
80 / 27 C  
Acoustical Lining and Fibrous Glass Duct  
Current edition of SMACNA and NFPA 90B as tested by UL  
Standard 181 for Class I Rigid Air Ducts  
Gas Piping and Gas Pipe Pressure Testing  
NFPA 54/ANSI Z223.1--2009 ; chapters 5, 6, and 7 and National  
Plumbing Codes .  
Electrical Connections  
National Electrical Code (NEC) ANSI/NFPA70--2008 .  
Venting  
60 / 16 C  
NFPA 54/ANSI Z223.1--2009; chapters 12 and 13.  
ELECTROSTATIC DISCHARGE (ESD)  
PRECAUTIONS PROCEDURE  
A06745  
Fig. 2 -- Return Air Temperature  
This furnace is designed for minimum continuous return--air  
temperature of 60_F (15_C) db or intermittent operation down to  
55_F (13_C)db such as when used with a night setback  
thermostat. Return--air temperature must not exceed 80_F (27_C)  
db. Failure to follow these return--air temperature limits may  
affect reliability of heat exchangers, motors, and controls. (See  
Fig. 2.)  
For accessory installation details, refer to the applicable  
instruction literature.  
NOTE: Remove all shipping brackets and materials before  
!
CAUTION  
FURNACE RELIABILITY HAZARD  
Failure to follow this caution may result in unit component  
damage.  
Electrostatic discharge can affect electronic components.  
Take precautions during furnace installation and servicing  
to protect the furnace electronic control. Precautions will  
prevent electrostatic discharges from personnel and hand  
tools which are held during the procedure. These  
precautions will help to avoid exposing the control to  
electrostatic discharge by putting the furnace, the control,  
and the person at the same electrostatic potential.  
operating the furnace.  
CODES AND STANDARDS  
Follow all national and local codes and standards in addition  
to these instructions. The installation must comply with  
regulations of the serving gas supplier, local building, heating,  
plumbing, and other codes. In absence of local codes, the  
installation must comply with the national codes listed below and  
all authorities having jurisdiction.  
1. Disconnect all power to the furnace. Multiple disconnects  
may be required. DO NOT TOUCH THE CONTROL OR  
ANY WIRE CONNECTED TO THE CONTROL PRIOR  
TO  
DISCHARGING  
YOUR  
BODY’S  
ELECTROSTATIC CHARGE TO GROUND.  
In the United States, follow all codes and standards for the  
following:  
2. Firmly touch the clean, unpainted, metal surface of the fur-  
nace chassis which is close to the control. Tools held in a  
person’s hand during grounding will be satisfactorily dis-  
charged.  
Safety  
NFPA 54/ANSI Z223.1--2009 and the Installation Standards,  
Warm Air Heating and Air Conditioning Systems ANSI/NFPA  
90B .  
3. After touching the chassis, you may proceed to service the  
control or connecting wires as long as you do nothing to  
recharge your body with static electricity (for example;  
DO NOT move or shuffle your feet, do not touch un-  
grounded objects, etc.).  
General Installation  
Current edition of the NFGC and the NFPA 90B. For copies,  
contact the National Fire Protection Association Inc.,  
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5.1  
[130.5]  
2 1/16  
[51.6]  
1.7  
[43.5]  
C
Ø7/8  
[22.2]  
ACCESSORY (2)  
8 5/8  
[219]  
6 13/16  
[172.3]  
5 7/8  
1 15/16  
[49.2]  
[148.5] 5 5/8  
AIR FLOW  
AIR FLOW  
[143.3]  
2 5/16  
5 7/16  
[138.5]  
5 15/16  
[150.7]  
5 1/2  
[140.3]  
3 7/16  
[86.8]  
5 7/8  
[148.5]  
[59]  
A
B
19  
[481.7]  
OUTLET  
1 15/16  
[49.2]  
AIR FLOW  
TOP OFF CASING  
TOP OF CASING  
Ø1/2  
4 13/16  
[122.2]  
Ø7/8  
[22.2]  
JUNCTION BOX  
LOCATION  
Ø7/8  
[22.2]  
[12.7]  
7 13/16  
[197.8]  
8 7/16  
[213.5]  
9 11/16  
[245.4]  
THERMOOSTATT WWIRE ENTRY  
9 9/16  
[243.3]  
ACCESSORY  
11 7/16  
[290.7]  
Ø1 3/4  
9 7/8  
[250.7]  
[44.5]  
GAS ENTRY  
Ø7/8  
[22.2]  
27 3/4  
[704.7]  
Ø1/2  
[12.7]  
J.BOX PPROVISION  
Ø7/8  
Ø1 3/4  
27 3/4  
[704.7]  
29 9/16  
[750.7]  
[44.5]  
THERMOSTAT WWIRE EENTRY  
[22.2]  
ACCESSORY  
GAS ENTRY  
33 1/4  
[843.9]  
14 7/8  
Ø7/8  
[337.3]  
[22.2]  
(BOTH SIDES)  
ACCESSORY  
Ø7/8  
[22.2]  
ACCESSORY  
KNOCK OOUTS FOR  
VENTING(5  
PLACES)  
21.6  
6.1  
[155.7]  
1 1/4  
D
3/4  
[19.1]  
[549.5]  
[31.8]  
22 1/16  
1
BOTTOM RRETURN  
WIDTH  
BOTTOM IINLET  
[560]  
[25.4]  
28.39  
SIDE INLET  
(BOTH SIDES)  
[721.2]  
29  
[736.9]  
A10290  
NOTES:  
1. Two additional 7/8---in. (22 mm) diameter holes are located in the top plate.  
2. Minimum return---air openings at furnace, based on metal duct. If flex duct is used, see flex duct manufacturer’s recommendations for equivalent diameters.  
a. For 800 CFM---16---in. (406 mm) round or 14 1/2 x 12---in. (368 x 305 mm) rectangle.  
b. For 1200 CFM---20---in. (508 mm) round or 14 1/2 x 19 1/2---in. (368 x 495 mm) rectangle.  
c. For 1600 CFM---22---in. (559 mm) round or 14 1/2 x 22 1/16---in. (368 x 560mm) rectangle.  
d. For airflow requirements above 1800 CFM, see Air Delivery table in Product Data literature for specific use of single side inlets. The use of both side inlets,  
a combination of 1 side and the bottom, or the bottom only will ensure adequate return air openings for airflow requirements above 1800 CFM.  
Fig. 3 -- Dimensional Drawing  
Table 1 – Dimensions -- In. (mm)  
C
A
B
D
VENT  
CONNECTION  
SIZE  
ACCESSORY  
FILTER MEDIA  
CABINET SIZE  
TOP AND  
BOTTOM FLUE  
COLLAR  
SHIP WT.  
LB (KG)  
FURNACE SIZE  
CABINET  
WIDTH  
OUTLET  
WIDTH  
BOTTOM  
INLET WIDTH  
070---12/036070  
090---16/048090  
110---20/060110  
135---22/066135  
155---22/066155  
14---3/16 (360)  
17---1/2 (445)  
21 (533)  
24---1/2 (622)  
24---1/2 (622)  
12---9/16 (319)  
15---7/8 (403)  
19---3/8 (492)  
22---7/8 (581)  
22---7/8 (581)  
9---5/16 (237)  
11---9/16 (294)  
13---5/16 (338)  
15---1/16 (383)  
15---1/16 (383)  
12---11/16 (322)  
16 (406)  
19---1/2 (495)  
23 (584)  
4 (102)  
4 (102)  
4 (102)  
4 (102)†  
4 (102)†  
115 (52)  
130 (59)  
155 (70)  
166 (75)  
175 (79)  
16 (406)  
16 (406)  
20 (508)  
24 (610)  
24 (610)  
23 (584)  
*135 and 155 size furnaces require a 5 or 6---in. (127 or 152 mm) vent. Use a vent adapter between furnace and vent stack. See Installation Instructions for  
complete installation requirements.  
4. If you touch ungrounded objects (and recharge your body  
LOCATION  
with static electricity), firmly touch a clean, unpainted  
GENERAL  
metal surface of the furnace again before touching control  
This multipoise furnace is shipped in packaged configuration.  
or wires.  
Some assembly and modifications are required when used in any  
5. Use this procedure for installed and uninstalled (ungroun-  
of the four applications shown in Fig. 4.  
ded) furnaces.  
6. Before removing a new control from its container, dis-  
NOTE:  
For high--altitude installations, the high--altitude  
charge your body’s electrostatic charge to ground to pro-  
tect the control from damage. If the control is to be in-  
stalled in a furnace, follow items 1 through 4 before  
bringing the control or yourself in contact with the fur-  
nace. Put all used and new controls into containers before  
touching ungrounded objects.  
conversion kit MUST be installed at or above 5500 ft. (1676 M)  
above sea level. Obtain high--altitude conversion kit from your  
area authorized distributor.  
7. An ESD service kit (available from commercial sources)  
may also be used to prevent ESD damage.  
5
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THE BLOWER IS  
LOCATED BELOW THE  
BURNER SECTION, AND  
CONDITIONED AIR IS  
DISCHARGED UPWARD.  
THE BLOWER IS LOCATED  
TO THE RIGHT OF THE  
BURNER SECTION, AND  
AIR CONDITIONED AIR IS  
DISCHARGED TO THE LEFT.  
THE BLOWER IS  
THE BLOWER IS  
LOCATED ABOVE THE  
BURNER SECTION, AND  
CONDITIONED AIR IS  
DISCHARGED DOWNWARD  
LOCATED TO THE LEFT  
OF THE BURNER SECTION,  
AND CONDITIONED AIR IS  
DISCHARGED TO THE RIGHT.  
A02097  
Fig. 4 -- Multipoise Orientations  
This furnace must:  
If air is exposed to the following substances, it should not be used  
for combustion air, and outdoor air may be required for  
combustion:  
S
be installed so the electrical components are protected  
from water.  
S
S
S
S
S
S
S
S
S
S
S
S
S
Permanent wave solutions  
S
not be installed directly on any combustible material  
other than wood flooring (refer to SAFETY  
CONSIDERATIONS).  
Chlorinated waxes and cleaners  
Chlorine based swimming pool chemicals  
Water softening chemicals  
S
S
be located close to the chimney or vent and attached to  
an air distribution system. Refer to Air Ducts section.  
De--icing salts or chemicals  
be provided ample space for servicing and cleaning.  
Always comply with minimum fire protection clear-  
ances shown on the furnace clearance to combustible  
construction label.  
Carbon tetrachloride  
Halogen type refrigerants  
Cleaning solvents (such as perchloroethylene)  
Printing inks, paint removers, varnishes, etc.  
Hydrochloric acid  
!
WARNING  
CARBON MONOXIDE POISONING / COMPONENT  
DAMAGE HAZARD  
Cements and glues  
Antistatic fabric softeners for clothes dryers  
Masonry acid washing materials  
Failure to follow this warning could result in personal injury  
or death and unit component damage.  
Corrosive or contaminated air may cause failure of parts  
containing flue gas, which could leak into the living space.  
Air for combustion must not be contaminated by halogen  
compounds, which include fluoride, chloride, bromide, and  
iodide. These elements can corrode heat exchangers and  
shorten furnace life. Air contaminants are found in aerosol  
sprays, detergents, bleaches, cleaning solvents, salts, air  
fresheners, and other household products. Do not install  
furnace in a corrosive or contaminated atmosphere. Make  
sure all combustion and circulating air requirements are met,  
in addition to all local codes and ordinances.  
All fuel--burning equipment must be supplied with air for fuel  
combustion. Sufficient air must be provided to avoid negative  
pressure in the equipment room or space. A positive seal must be  
made between the furnace cabinet and the return--air duct to  
prevent pulling air from the burner area and from draft safeguard  
opening.  
!
WARNING  
FIRE, INJURY OR DEATH HAZARD  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
The following types of furnace installations may require  
OUTDOOR AIR for combustion due to chemical exposures:  
When the furnace is installed in a residential garage, the  
burners and ignition sources must be located at least 18 in.  
(457 mm) above the floor. The furnace must be located or  
protected to avoid damage by vehicles. When the furnace is  
installed in a public garage, airplane hangar, or other  
building having a hazardous atmosphere, the furnace must  
be installed in accordance with the NFPA 54/ANSI  
Z223.1--2009 . (See Fig. 5.)  
S
S
S
S
S
Commercial buildings  
Buildings with indoor pools  
Laundry rooms  
Hobby or craft rooms, and  
Chemical storage areas  
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!
CAUTION  
PERSONAL INJURY AND/OR PROPERTY  
DAMAGE HAZARD  
Improper use or installation of this furnace may result in  
premature furnace component failure. This gas furnace may  
be used for heating buildings under construction provided  
that:  
--The furnace is permanently installed with all electrical  
wiring, piping, venting and ducting installed according to  
these installation instructions. A return air duct is provided,  
sealed to the furnace casing, and terminated outside the  
space containing the furnace. This prevents a negative  
pressure condition as created by the circulating air blower,  
18-IN. (457.2 mm)  
MINIMUM TO BURNERS  
causing  
a
flame rollout and/or drawing combustion  
products into the structure.  
A93044  
Fig. 5 -- Installation in a Garage  
--The furnace is controlled by a thermostat. It may not be  
“hot wired” to provide heat continuously to the structure  
without thermostatic control.  
--Clean outside air is provided for combustion. This is to  
minimize the corrosive effects of adhesives, sealers and  
other construction materials. It also prevents the  
entrainment of drywall dust into combustion air, which can  
cause fouling and plugging of furnace components.  
!
WARNING  
FIRE HAZARD  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
--The temperature of the return air to the furnace is  
maintained between 55_F (13_C) and 80_F (27_C), with  
no evening setback or shutdown. The use of the furnace  
while the structure is under construction is deemed to be  
intermittent operation per our installation instructions.  
Do not install the furnace on its back or hang furnace with  
control compartment facing downward. Safety control  
operation will be adversely affected. Never connect  
return--air ducts to the back of the furnace. (See Fig. 6.)  
--The air temperature rise is within the rated rise range on  
the furnace rating plate, and the gas input rate has been set  
to the nameplate value. --The filters used to clean the  
circulating air during the construction process must be  
either changed or thoroughly cleaned prior to occupancy.  
LOCATION RELATIVE TO COOLING EQUIPMENT  
The cooling coil must be installed parallel with, or on the  
downstream side of the unit to avoid condensation in the heat  
exchangers. When installed parallel with the furnace, dampers or  
other flow control must prevent chilled air from entering the  
furnace. If the dampers are manually operated, they must be  
equipped with means to prevent operation of either unit unless  
the damper is in the full--heat or full--cool position.  
--The furnace, ductwork and filters are cleaned as necessary  
to remove drywall dust and construction debris from all  
HVAC system components after construction is completed.  
--Verify proper furnace operating conditions including  
ignition, gas input rate, air temperature rise, and venting  
according to these installation instructions.  
A02054  
Fig. 6 -- Prohibit Installation on Back  
7
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Table 2 – Minimum Free Area Required for Each Combustion Air opening of Duct to Outdoors  
TWO HORIZONTAL DUCTS  
(1 SQ. IN./2,000 BTUH) (1,100 SQ. MM/KW)  
SINGLE DUCT OR OPENING  
(1 SQ. IN./3,000 BTUH) (734 SQ. MM/KW)  
TWO OPENINGS OR VERTICAL DUCTS  
(1 SQ. IN./4,000 BTUH) (550 SQ. MM/KW)  
FURNACE  
INPUT  
(BTUH)  
Free Area of Opening  
and Duct  
Sq. In. (Sq. mm)  
Round Duct  
Dia.  
In. (mm)  
Free Area of Opening  
and Duct  
Sq. In. (Sq. mm)  
Round Duct  
Dia.  
In. (mm)  
Free Area of Opening  
and Duct  
Sq. In. (Sq. mm)  
Round Duct  
Dia.  
In. (mm)  
44,000  
66,000  
88,000  
110,000  
132,000  
154,000  
22 (14194)  
33 (21290)  
44 (28387)  
55 (35484)  
66 (42580)  
77 (49677)  
6 (152)  
7 (178)  
8 (203)  
9 (229)  
10 (254)  
10 (254)  
14.7 (9484)  
22 (14193)  
29.3 (18903)  
36.7 (23677)  
44 (28387)  
5 (127)  
6 (152)  
7 (178)  
7 (178)  
8 (203)  
9 (229)  
11 (7096)  
16.5 (10645)  
22 (14193)  
27.5 (17742)  
33 (21290)  
38.5 (24839)  
4 (102)  
5 (127)  
6 (152)  
6 (152)  
7 (178)  
8 (203)  
51.3 (33096)  
EXAMPLES: Determining Free Area  
FURNACE  
WATER HEATER  
30,000  
TOTAL INPUT  
110,000  
66,000  
88,000  
+
+
+
=
=
=
(140,000 divided by 4,000)  
(106,000 divided by 3,000)  
(118,000 divided by 2,000)  
=
=
=
35.0 Sq. In. for each two Vertical Ducts or Openings  
35.3 Sq. In. for a Single Duct or Opening  
40,000  
30,000  
59.0 Sq. In. for each of two Horizontal Ducts  
Table 3 – Minimum Space Volumes for 100% Combustion, Ventilation, and Dilution from Indoors  
OTHER THAN FAN-ASSISTED TOTAL  
(1,000’S BTUH GAS INPUT RATE)  
FAN-ASSISTED TOTAL  
(1,000’S BTUH GAS INPUT RATE)  
30  
40  
50  
44  
66  
88  
110  
132  
154  
ACH  
0.60  
0.50  
0.40  
0.30  
0.20  
3
3
Space Volume Ft (M )  
1,650  
1,050  
(29.7)  
1,400  
(39.6)  
1,750  
(49.5)  
1,100  
(31.1)  
2,200  
(62.2)  
2,750  
(77.8)  
3,300  
(93.4)  
3,850  
(109.0)  
(46.7)  
1,260  
(35.6)  
1,680  
(47.5)  
2,100  
(59.4)  
1,320  
(37.3)  
1,980  
(56.0)  
2,640  
(74.7)  
3,300  
(93.4)  
3,960  
(112.1)  
4,620  
(130.8)  
1,575  
(44.5)  
2,100  
(59.4)  
2,625  
(74.3)  
1,650  
(46.7)  
2,475  
(70.0)  
3,300  
(93.4)  
4,125  
(116.8)  
4,950  
(140.1)  
5,775  
(163.5)  
2,100  
(59.4)  
2,800  
(79.2)  
3,500  
(99.1)  
2,200  
(62.2)  
3,300  
(93.4)  
4,400  
(124.5)  
5,500  
(155.7)  
6,600  
(186.8)  
7,700  
(218.0)  
3,150  
(89.1)  
4,200  
(118.9)  
3,300  
(93.4)  
4,950  
(140.1)  
6,600  
(186.8)  
8,250  
(233.6)  
9,900  
(280.3)  
11,550  
(327.0)  
5,250 (148.6)  
6,300  
8,400  
10,500  
(297.3)  
6,600  
9,900  
13,200  
(373.7)  
16,500  
(467.2)  
19,800  
(560.6)  
23,100  
(654.1)  
0.10  
0.00  
(178.3)  
(237.8)  
(186.8)  
(280.3)  
NP  
NP  
NP  
NP  
NP  
NP  
NP  
NP  
NP  
NP = Not Permitted  
AIR FOR COMBUSTION AND  
VENTILATION  
Provisions for adequate combustion, ventilation, and dilution air  
must be provided in accordance with:  
!
WARNING  
CARBON MONOXIDE POISONING HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
S
U.S. Installations: Section 9.3 of the NFPA 54/ANSI  
Z223.1--2009 , Air for Combustion and Ventilation and  
applicable provisions of the local building codes.  
The operation of exhaust fans, kitchen ventilation fans,  
clothes dryers, attic exhaust fans or fireplaces could create a  
NEGATIVE PRESSURE CONDITION at the furnace.  
Make--up air MUST be provided for the ventilation devices,  
in addition to that required by the furnace. Refer to the  
Carbon Monoxide Poisoning Hazard warning in the venting  
section of these instructions to determine if an adequate  
amount of make--up air is available.  
!
CAUTION  
FURNACE CORROSION HAZARD  
Failure to follow this caution may result in furnace damage.  
Air for combustion must not be contaminated by halogen  
compounds, which include fluoride, chloride, bromide, and  
iodide. These elements can corrode heat exchangers and  
shorten furnace life. Air contaminants are found in aerosol  
sprays, detergents, bleaches, cleaning solvents, salts, air  
fresheners, and other household products.  
The requirements for combustion and ventilation air depend upon  
whether or not the furnace is located in a space having a volume  
of at least 50 cubic feet per 1,000 Btuh input rating for all gas  
appliances installed in the space.  
S
Spaces having less than 50 cubic feet per 1,000 Btuh  
require the OUTDOOR COMBUSTION AIR  
METHOD.  
8
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1 SQ IN.  
PER 4000  
BTUH*  
CIRCULATING AIR  
DUCTS  
DUCTS  
TO  
OUTDOORS  
VENT THROUGH ROOF  
12" MAX(305mm)  
(305mm)  
12MAX  
D
12  
(305mm)  
MAX  
1 SQ IN.  
PER 2000  
BTUH*  
VENT  
B
1 SQ IN.  
THROUGH  
ROOF  
F
PER 1000  
1 SQ IN.  
PER  
BTUH* IN DOOR  
OR WALL  
4000  
BTUH*  
UNCONFINED  
SPACE  
INTERIOR  
HEATED  
SPACE  
DUCTS  
TO  
OUTDOORS  
6" MIN (152mm)  
(FRONT)Ü  
1 SQ IN.  
1 SQ IN.  
PER  
PER 1000  
BTUH* IN DOOR  
OR WALL  
4000  
BTUH*  
1 SQ IN.  
PER 2000  
BTUH*  
E
G
A
12″  
MAX  
12" MAX  
(305mm)  
(305mm)  
(305mm)  
12MAX  
C
12MAX  
(305mm)  
CIRCULATING AIR DUCTS  
CIRCULATING AIR DUCTS  
DUCT  
TO  
OUTDOORS  
1 SQ IN.  
PER 4000  
BTUH*  
* Minimum opening size is 100 sq in. (64516 sq. mm)with minimum dimensions  
of 3 in. (76 mm)  
*Minimum dimensions of 3---in. (76 mm).  
NOTE: Use any of the following combinations of openings:  
† Minimum of 3 in. (76 mm) when type-B1 vent is used.  
A & B C & D D & E F & G  
A03175  
Fig. 8 -- Air for Combustion, Ventilation, and Dilution from  
Indoors  
A03174  
Fig. 7 -- Air for Combustion, Ventilation, and Dilution for  
Outdoors  
The opening shall commence within 12 in. (300 mm) of the  
ceiling. Appliances in the space shall have clearances of at least 1  
in. (25 mm) from the sides and back and 6 in. (150 mm) from the  
front. The opening shall directly communicate with the outdoors  
or shall communicate through a vertical or horizontal duct to the  
outdoors or spaces (crawl or attic) that freely communicate with  
the outdoors.  
Indoor Combustion AirE NFPA & AGA  
Standard and Known--Air--Infiltration Rate Methods  
Indoor air is permitted for combustion, ventilation, and dilution,  
if the Standard or Known--Air--Infiltration Method is used.  
S
Spaces having at least 50 cubic feet per 1,000 Btuh  
may use the INDOOR COMBUSTION AIR,  
STANDARD or KNOWN AIR INFILTRATION  
METHOD.  
Outdoor Combustion Air Method  
1. Provide the space with sufficient air for proper combus-  
tion, ventilation, and dilution of flue gases using perman-  
ent horizontal or vertical duct(s) or opening(s) directly  
communicating with the outdoors or spaces that freely  
communicate with the outdoors.  
2. Fig. 7 illustrates how to provide TWO OUTDOOR  
OPENINGS, one inlet and one outlet combustion and  
ventilation air opening, to the outdoors.  
!
WARNING  
e. One opening MUST commence within 12 in. (300  
mm) of the ceiling and the second opening MUST  
commence within 12 in. (300 mm) of the floor.  
CARBON MONOXIDE POISONING HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
f. Size openings and ducts per Fig. 7 and Table 2.  
Many homes require air to be supplied from outdoors  
for furnace combustion, ventilation, and dilution of flue  
gases.  
g. TWO HORIZONTAL DUCTS require 1 sq. in. (645  
2
sq. mm) of free area per 2,000 Btuh (1,100 mm /kW)  
of combined input for all gas appliances in the space  
per Fig. 7 and Table 2.  
The furnace combustion air supply must be provided in  
accordance with this instruction manual.  
h. TWO OPENINGS OR VERTICAL DUCTS require 1  
sq. in. (645 sq. mm) of free area per 4,000 Btuh (550  
2
mm /kW) for combined input of all gas appliances in  
The Standard Method:  
the space per Fig. 7 and Table 2.  
1. The space has no less volume than 50 cubic feet per 1,000  
Btuh of the maximum input ratings for all gas appliances  
installed in the space and  
2. The air infiltration rate is not known to be less than 0.40  
air changes per hour (ACH).  
3. ONE OUTDOOR OPENING requires:  
a. 1 sq. in. (645 sq. mm) of free area per 3,000 Btuh  
2
(734 mm /kW) for combined input of all gas appli-  
ances in the space per Table 2 and  
b. Not less than the sum of the areas of all vent connect-  
ors in the space.  
The Known Air Infiltration Rate Method shall be used, if the  
infiltration rate is known to be:  
1. Less than 0.40 ACH and  
2. Equal to or greater than 0.10 ACH  
9
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Infiltration rates greater than 0.60 ACH shall not be used. The  
minimum required volume of the space varies with the number of  
ACH and shall be determined per Table 3 or Equations 1 and 2.  
Determine the minimum required volume for each appliance in  
the space and add the volumes together to get the total minimum  
required volume for the space.  
plates and floors, between wall--ceiling joints, between  
wall panels, at penetrations for plumbing, electrical  
and gas lines, etc.  
Combination of Indoor and Outdoor Air  
1. Indoor openings shall comply with the Indoor Combus-  
tion Air Method below and,  
2. Outdoor openings shall be located as required in the Out-  
door Combustion Air Method mentioned previously and,  
Table 3 -- Minimum Space Volumes were determined by using  
the following equations from the National Fuel Gas Code ANSI  
Z223.1--2009/NFPA 54--2009, 9.3.2.2:  
3. Outdoor openings shall be sized as follows:  
1. For other than fan--assisted appliances, such as a draft  
hood--equipped water heater:  
a. Calculate the Ratio of all Indoor Space volume divided  
by required volume for Indoor Combustion Air  
Method below.  
b. Outdoor opening size reduction Factor is 1 minus the  
Ratio in a. above.  
21ft3  
I other  
ACH 1000 Btu/hr  
Volume  
=
Other  
c. Minimum size of Outdoor openings shall be the size  
required in Outdoor Combustion Air Method above  
multiplied by reduction Factor in b. above. The min-  
imum dimension of air openings shall be not less than  
3 in. (80 mm).  
A04002  
2. For fan--assisted appliances such as this furnace:  
15ft3  
I fan  
Volume  
=
INSTALLATION  
UPFLOW INSTALLATION  
Fan  
ACH 1000 Btu/hr  
A04003  
Bottom Return Air Inlet  
If: Iother = combined input of all other than fan--assisted  
appliances in Btuh/hr  
These furnaces are shipped with bottom closure panel installed in  
bottom return--air opening. Remove and discard this panel when  
bottom return air is used. To remove bottom closure panel,  
perform the following:  
Ifan = combined input of all fan--assisted appliances in Btuh/hr  
ACH = air changes per hour (ACH shall not exceed 0.60.)  
1. Tilt or raise furnace and remove 2 screws holding bottom  
filler panel. (See Fig. 9.)  
The following requirements apply to the Standard Method and  
to the Known Air Infiltration Rate Method.  
2. Rotate bottom filler panel downward to release holding  
tabs.  
1. Adjoining rooms can be considered part of a space if:  
a. There are no closeable doors between rooms.  
3. Remove bottom closure panel.  
4. Reinstall bottom filler panel and screws.  
Side Return Air Inlet  
b. Combining spaces on same floor level. Each opening  
2
shall have free area of at least 1 in. /1,000 Btuh (2,000  
2
mm /kW) of the total input rating of all gas appliances  
2
2
in the space, but not less than 100 in. (0.06 m ). One  
opening shall commence within 12 in. (300 mm) of  
the ceiling and the second opening shall commence  
within 12 in. (300 mm) of the floor. The minimum  
dimension of air openings shall be at least 3 in. (80  
mm). (See Fig. 8.)  
These furnaces are shipped with bottom closure panel installed in  
bottom return--air opening. This panel MUST be in place when  
only side return air is used.  
c. Combining space on different floor levels. The  
volumes of spaces on different floor levels shall be  
considered as communicating spaces if connected by  
one or more permanent openings in doors or floors  
Bottom  
Closure Panel  
2
having free area of at least 2 in. /1,000 Btuh (4,400  
2
mm /kW) of total input rating of all gas appliances.  
2. An attic or crawlspace may be considered a space that  
freely communicates with the outdoors provided there are  
adequate permanent ventilation openings directly to out-  
Bottom Filler Panel  
2
doors having free area of at least 1--in. /4,000 Btuh of total  
A10273  
input rating for all gas appliances in the space.  
Fig. 9 -- Removing Bottom Closure Panel  
3. In spaces that use the Indoor Combustion Air Method,  
infiltration should be adequate to provide air for combus-  
tion, permanent ventilation and dilution of flue gases.  
However, in buildings with unusually tight construction,  
additional air MUST be provided using the methods de-  
scribed in the Outdoor Combustion Air Method section.  
NOTE: Side return--air openings can be used in UPFLOW and  
most HORIZONTAL configurations. Do not use side return--air  
openings in DOWNFLOW configuration.  
Leveling Legs (If Desired)  
4. Unusually tight construction is defined as Construction  
with:  
In upflow position with side return inlet(s), leveling legs may be  
used. (See Fig. 10.) Install field--supplied, 5/16 X 1--1/2 in. (8 X  
38 mm) (max) corrosion--resistant machine bolts, washers and  
nuts.  
a. Walls and ceilings exposed to the outdoors have a con-  
tinuous, sealed vapor barrier. Openings are gasketed or  
sealed and  
b. Doors and openable windows are weatherstripped and  
c. Other openings are caulked or sealed. These include  
joints around window and door frames, between sole  
10  
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5/  
NOTE: It is recommended that the perforated supply--air duct  
flanges be completely folded over or removed from furnace when  
installing the furnace on a factory--supplied cased coil or coil box.  
To remove the supply--air duct flange, use wide duct pliers or  
hand seamers to bend flange back and forth until it breaks off. Be  
careful of sharp edges. (See Fig. 14.)  
16  
(8mm)  
(8mm)  
16″  
5/  
1 3/4  
(44mm)  
Bottom Return Air Inlet  
These furnaces are shipped with bottom closure panel installed in  
bottom return--air opening. Remove and discard this panel when  
bottom return air is used. To remove bottom closure panel,  
perform the following:  
1 3/4  
(44mm)  
1. Tilt or raise furnace and remove 2 screws holding bottom  
filler panel. (See Fig. 9.)  
(8mm)  
5/16″  
2. Rotate bottom filler panel downward to release holding  
tabs.  
3. Remove bottom closure panel.  
4. Reinstall bottom filler panel and screws.  
HORIZONTAL INSTALLATION  
(8mm)  
5/  
16″  
(44mm)1 3/  
1 3/  
4
4
(44mm)  
!
WARNING  
A89014  
FIRE, EXPLOSION, AND CARBON MONOXIDE  
POISONING HAZARD  
Fig. 10 -- Leveling Legs  
Failure to follow this warning could result in personal  
injury, death, or property damage.  
NOTE: Bottom closure must be used when leveling legs are  
used. It may be necessary to remove and reinstall bottom closure  
panel to install leveling legs. To remove bottom closure panel, see  
Item 1 in Bottom Return Air Inlet section in Step 1 above.  
Do not install the furnace on its back or hang furnace with  
control compartment facing downward. Safety control  
operation will be adversely affected. Never connect  
return--air ducts to the back of the furnace.  
To install leveling legs:  
1. Position furnace on its back. Locate and drill a hole in  
each bottom corner of furnace. (See Fig. 10.)  
The furnace can be installed horizontally in an attic or crawlspace  
on either the left--hand (LH) or right--hand (RH) side. The furnace  
can be hung from floor joists, rafters or trusses or installed on a  
non--combustible platform, blocks, bricks or pad.  
2. For each leg, install nut on bolt and then install bolt with  
nut in hole. (Install flat washer if desired.)  
3. Install another nut on other side of furnace base. (Install  
flat washer if desired.)  
4. Adjust outside nut to provide desired height, and tighten  
inside nut to secure arrangement.  
Suspended Furnace Support  
The furnace may be supported under each end with threaded rod,  
angle iron or metal plumber’s strap as shown. (See Fig. 15 and  
16.) Secure angle iron to bottom of furnace as shown.  
Heavy--gauge sheet metal straps (plumber’s straps) may be used  
to suspend the furnace from each bottom corner. To prevent  
screws from pulling out, use 2 #8 x in. screws into the side and 2  
#8 x in. screws in the bottom of the furnace casing for each strap.  
(See Fig. 15 and 16.)  
5. Reinstall bottom closure panel if removed.  
DOWNFLOW INSTALLATION  
NOTE: For downflow applications, this furnace is approved for  
use on combustible flooring when any one of the following 3  
accessories are used:  
S
S
Special Base, KGASB  
If the screws are attached to ONLY the furnace sides and not the  
bottom, the straps must be vertical against the furnace sides and  
not pull away from the furnace sides, so that the strap attachment  
screws are not in tension (are loaded in shear) for reliable support.  
Cased Coil Assembly Part No. CNPV, CNRV, CAP, or  
CAR  
S
Coil Box Part No. KCAKC  
Platform Furnace Support  
1. Determine application being installed from Table 4.  
2. Construct hole in floor per Table 4 and Fig. 11.  
Construct working platform at location where all required furnace  
clearances are met. (See Fig. 2 and 17.) For furnaces with 1--in.  
(25 mm) clearance requirement on side, set furnace on  
non--combustible blocks, bricks or angle iron. For crawlspace  
installations, if the furnace is not suspended from the floor joists,  
the ground underneath furnace must be level and the furnace set  
on blocks or bricks.  
3. Construct plenum to dimensions specified in Table 4 and  
Fig. 11.  
4. If downflow subbase, KGASB is used, install as shown in  
Fig. 12. If Coil Assembly Part No. CPVP, CAPMP or  
CNPVP Coil Box Part No. KCAKC is used, install as  
shown in Fig. 13.  
11  
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FURNACE  
(OR COIL CASING  
WHEN USED)  
A
COMBUSTIBLE  
FLOORING  
PLENUM  
OPENING  
B
D
DOWNFLOW  
SUBBASE  
FLOOR  
OPENING  
C
SHEET METAL  
PLENUM  
FLOOR  
OPENING  
A96285  
A96283  
Fig. 12 -- Furnace, Plenum, and Subbase Installed on a  
Combustible Floor  
Fig. 11 -- Floor and Plenum Opening Dimensions  
Roll--Out Protection  
Provide a minimum 17--3/4--in. X 22--in. (451 X 559 mm) piece  
of sheet metal for flame roll--out protection in front of burner area  
for furnaces closer than 12--in. (305 mm) above the combustible  
deck or suspended furnaces closer than 12--in. (305 mm) to joists.  
The sheet metal MUST extend underneath the furnace casing by  
1--in. (25 mm)with the door removed.  
FURNACE  
APPROVED  
COIL ASSEMBLY  
OR  
COIL BOX  
The bottom closure panel on furnaces of widths 17--1/2--in. (445  
mm) and larger may be used for flame roll--out protection when  
bottom of furnace is used for return air connection. See Fig. 17  
for proper orientation of roll--out shield.  
COMBUSTIBLE  
FLOORING  
Bottom Return Air Inlet  
These furnaces are shipped with bottom closure panel installed in  
bottom return--air opening. Remove and discard this panel when  
bottom return air is used. To remove bottom closure panel,  
perform the following:  
SHEET METAL  
PLENUM  
FLOOR  
OPENING  
1. Tilt or raise furnace and remove two screws holding bot-  
tom filler panel. (See Fig. 9.)  
2. Rotate bottom filler panel downward to release holding  
tabs.  
3. Remove bottom closure panel.  
4. Reinstall bottom filler panel and screws.  
Side Return Air Inlet  
These furnaces are shipped with bottom closure panel installed in  
bottom return--air opening. This panel MUST be in place when  
side return air inlet(s) are used without a bottom return air inlet.  
A08556  
Fig. 13 -- Furnace, Plenum, and Coil Assembly or Coil Box  
Installed on a Combustible Floor  
Not all horizontal furnaces are approved for side return air  
connections (See Fig. 20.)  
12  
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Table 4 – Opening Dimensions -- In. (mm)  
PLENUM OPENING  
FURNACE  
CASING  
WIDTH  
FLOOR OPENING  
APPLICATION  
A
B
C
D
IN. (mm)  
Upflow Applications on Combustible or Noncombustible Floor-  
ing (KGASB subbase not required)  
12---11/16  
(322)  
21---5/8  
(549)  
19  
(483)  
19  
(483)  
13---5/16  
(338)  
22---1/4  
(565)  
Downflow Applications on Noncombustible Flooring (KGASB  
subbase not required)  
12---9/16  
(319)  
13---3/16  
(335)  
19---5/8  
(498)  
14–3/16  
(360)  
Downflow applications on combustible flooring (KGASB sub-  
base required)  
11---13/16  
(284)  
13---7/16  
(341)  
20---5/8  
(600)  
Downflow Applications on Combustible Flooring with CNPV,  
CNRV, CAR or CAP Coil Assembly or KCAKC coil box (KGASB  
subbase not required)  
12---5/16  
(319)  
19  
13---5/16  
(338)  
20  
(483)  
(508)  
Upflow Applications on Combustible or Noncombustible Floor-  
ing (KGASB subbase not required)  
16  
(406)  
21---5/8  
(549)  
19  
(483)  
19  
(483)  
16---5/8  
(422)  
22---1/4  
(565)  
Downflow Applications on Noncombustible Flooring (KGASB  
subbase not required)  
15---7/8  
(403)  
16---1/2  
(419)  
19---5/8  
(498)  
17–1/2  
(445)  
Downflow applications on combustible flooring (KGASB sub-  
base required)  
15---1/8  
(384)  
16---3/4  
(425)  
20---5/8  
(600)  
Downflow Applications on Combustible Flooring with CNPV,  
CNRV, CAR or CAP Coil Assembly or KCAKC coil box (KGASB  
subbase not required)  
15---1/2  
(394)  
19  
16---1/2  
(419)  
20  
(483)  
(508)  
Upflow Applications on Combustible or Noncombustible Floor-  
ing (KGASB subbase not required)  
19---1/2  
(495)  
21---5/8  
(549)  
19  
(483)  
19  
(483)  
20---1/8  
(511)  
20  
(508)  
20---1/4  
(514)  
22---1/4  
(565)  
Downflow Applications on Noncombustible Flooring (KGASB  
subbase not required)  
19---3/8  
(492)  
19---5/8  
(498)  
21  
(533)  
Downflow applications on combustible flooring (KGASB sub-  
base required)  
18---5/8  
(473)  
20---5/8  
(600)  
Downflow Applications on Combustible Flooring with CNPV,  
CNRV, CAR or CAP Coil Assembly or KCAKC coil box (KGASB  
subbase not required)  
19  
19  
20  
20  
(483)  
(483)  
(508)  
(508)  
Upflow Applications on Combustible or Noncombustible Floor-  
ing (KGASB subbase not required)  
23  
(584)  
21---1/8  
(537)  
19  
(483)  
19  
(483)  
23---5/8  
(600)  
22---1/4  
(565)  
Downflow Applications on Noncombustible Flooring (KGASB  
subbase not required)  
22---7/8  
(581)  
23---1/2  
(597)  
19---5/8  
(498)  
24---1/2  
(622)  
Downflow applications on Combustible flooring (KGASB sub-  
base required)  
22---1/8  
(562)  
23---3/4  
(603)  
20---5/8  
(600)  
Downflow Applications on Combustible Flooring with CNPV,  
CNRV, CAR or CAP Coil Assembly or KCAKC coil box (KGASB  
subbase not required)  
22---1/2  
(572)  
19  
(483)  
23---1/2  
(597)  
20  
(508)  
Filter Arrangement  
the supply ducts carry air circulated by the furnace to areas  
outside the space containing the furnace, the return air shall also  
be handled by duct(s) sealed to the furnace casing and  
terminating outside the space containing the furnace.  
!
WARNING  
CARBON MONOXIDE POISONING HAZARD  
Secure ductwork with proper fasteners for type of ductwork used.  
Seal supply-- and return--duct connections to furnace with code  
approved tape or duct sealer.  
Failure to follow this warning could result in personal  
injury, or death.  
Never operate a furnace without a filter or with filter access  
door removed.  
NOTE: Flexible connections should be used between ductwork  
and furnace to prevent transmission of vibration.  
Ductwork passing through unconditioned space should be  
insulated to enhance system performance. When air conditioning  
is used, a vapor barrier is recommended.  
Maintain a 1--in. (25 mm) clearance from combustible materials  
to supply air ductwork for a distance of 36--in. (914 mm)  
horizontally from the furnace. See NFPA 90B or local code for  
further requirements.  
There are no provisions for an internal filter rack in these  
furnaces. A field--supplied accessory external filter rack is  
required.  
Refer to the instructions supplied with the external filter rack for  
assembly and installation options.  
AIR DUCTS  
Ductwork Acoustical Treatment  
General Requirements  
NOTE: Metal duct systems that do not have a 90 degree elbow  
and 10 ft. (3 M) of main duct to the first branch take--off may  
require internal acoustical lining. As an alternative, fibrous  
ductwork may be used if constructed and installed in accordance  
with the latest edition of SMACNA construction standard on  
fibrous glass ducts. Both acoustical lining and fibrous ductwork  
shall comply with NFPA 90B as tested by UL Standard 181 for  
Class 1 Rigid air ducts.  
The duct system should be designed and sized according to  
accepted national standards such as those published by: Air  
Conditioning Contractors Association (ACCA), Sheet Metal and  
Air Conditioning Contractors National Association (SMACNA)  
or American Society of Heating, Refrigerating and Air  
Conditioning Engineers (ASHRAE) or consult The Air Systems  
Design Guidelines reference tables available from your local  
distributor. The duct system should be sized to handle the  
required system design CFM at the design external static pressure.  
The furnace airflow rates are provided in Table 5--Air  
Delivery--CFM (With Filter). When a furnace is installed so that  
13  
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Supply Air Connections  
NOTE: For horizontal applications, the top most flange may be  
bent past 90_ to allow the evaporator coil to hang on the flange  
temporarily while the remaining attachment and sealing of the  
coil are performed.  
For a furnace not equipped with a cooling coil, the outlet duct  
shall be provided with a removable access panel. This opening  
shall be accessible when the furnace is installed and shall be of  
such a size that the heat exchanger can be viewed for possible  
openings using light assistance or a probe can be inserted for  
sampling the air stream. The cover attachment shall prevent leaks.  
Downflow Furnaces  
Connect supply--air duct to supply--air outlet on furnace. Bend  
flange inward past 90_ with wide duct pliers (See Fig. 14.) The  
supply--air duct must be connected to ONLY the furnace supply  
outlet or air conditioning coil casing (when used). When installed  
on combustible material, supply--air duct must be connected to  
Upflow and Horizontal Furnaces  
Connect supply--air duct to flanges on furnace supply--air outlet.  
Bend flange upward to 90_ with wide duct pliers. (See Fig. 14.)  
The supply--air duct must be connected to ONLY the furnace  
supply--outlet--air duct flanges or air conditioning coil casing  
(when used). DO NOT cut main furnace casing side to attach  
supply air duct, humidifier, or other accessories. All accessories  
MUST be connected to duct external to furnace main casing.  
ONLY the factory--approved accessory subbase, or  
a
factory--approved air conditioning coil casing. DO NOT cut main  
furnace casing to attach supply side air duct, humidifier, or other  
accessories. All accessories MUST be connected to duct external  
to furnace casing.  
UPFLOW  
DOWNFLOW  
HORIZONTAL  
90°  
90°  
YES  
YES  
YES  
YES  
YES  
YES  
120°  
120°  
120°  
MIN  
MIN  
MIN  
NO  
NO  
NO  
A02020  
Fig. 14 -- Duct Flanges  
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1
/
4" (6mm) THREADED ROD  
4 REQ.  
OUTER DOOR  
ASSEMBLY  
SECURE ANGLE  
IRON TO BOTTOM  
OF FURNACE WITH  
3 #8 x3/4" (19mm) SCREWS  
TYPICAL FOR 2 SUPPORTS  
8" (203mm) MIN  
FOR DOOR REMOVAL  
1” (25mm) SQUARE, 1-1/4”x1-1/4”x1/8” (32x32x3mm)  
ANGLE IRON OR UNI-STRUT MAY BE USED  
(2) HEX NUTS, (2) WASHERS & (2) LOCK WASHERS  
REQ. PER ROD  
A10130  
Fig. 15 -- Horizontal Unit Suspension  
METHOD 2  
USE (4) #8 x 3/4 (19 mm) SHEET  
METAL SCREWS FOR EACH  
STRAP. THE STRAPS  
SHOULD BE VERTICAL  
AGAINST THE FURNACE  
SIDES AND NOT PULL AWAY  
FROM THE FURNACE  
SIDES.  
METHOD 1  
FOLD ALL STRAPS UNDER  
FURNACE AND SECURE WTH  
(4) #8 x 3/4 (19 mm) SHEET METAL SCREWS  
(2 SCREWS IN SIDE AND 2 SCREWS  
IN BOTTOM).  
A10131  
Fig. 16 -- Horizontal Suspension with Straps  
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LINE CONTACT ONLY PERMISSIBLE BETWEEN  
LINES FORMED BY INTERSECTIONS OF  
THE TOP AND TWO SIDES OF THE FURNACE  
JACKET AND BUILDING JOISTS,  
STUDS, OR FRAMING.  
17 3/4  
4 3/4  
(451mm)OVERALL  
(121mm) UNDER DOOR  
1(25mm) UNDER FURNACE  
GAS  
ENTRY  
TYPE-B  
VENT  
EXTEND OUT 12(305mm)  
FROM FACE OF DOOR  
(152mm)  
*
IN  
M
6
30-IN. (762mm)  
MIN WORK AREA  
* WHEN USED WITH  
SINGLE WALL VENT  
CONNECTIONS  
17 3/4  
(451mm)  
SHEET  
METAL  
22  
EQUIPMENT MANUAL  
SHUT-OFF GAS VALVE  
SEDIMENT  
TRAP  
UNION  
A10164  
Fig. 17 -- Typical Attic Installation  
A02075  
Fig. 18 -- Upflow Return Air Configurations and Restrictions  
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A02163  
Fig. 19 -- Downflow Return Air Configurations and Restrictions  
A02162  
Fig. 20 -- Horizontal Return Air Configurations and Restrictions  
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Table 5 – Air Delivery -- CFM (With Filter)*  
External  
Static  
External Static Pressure (ESP) (IN. W.C.)  
CFM  
Pressure  
Range*  
(In. W.C.)  
Airflow  
Setting  
Unit Size  
Operating Mode  
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.7  
0.8  
0.9  
1
070---12  
††  
AIRFLOW (CFM)  
725  
Low Heat  
High Heat  
735 (615)†  
1180  
0---0.50  
0 --- 1 . 0  
735  
735  
735  
735  
1160 1165 1175 1180 1180 1180 1180 1180 1180 1175  
(1060)†  
525  
††  
††  
1 --- 1 / 2 --- To n C o o li n g  
2 --- To n A / C C o o li n g  
2 --- 1 / 2 --- To n A / C C o o li n g  
3 --- To n A / C C o o li n g  
3 --- 1 / 2 --- To n A / C C o o li n g  
Maximum  
0---0.50‡  
0---0.50‡  
0---1.0‡  
0---1.0‡  
0 --- 1 . 0  
515  
690  
875  
500  
680  
875  
500  
675  
875  
490  
680  
870  
485  
675  
865  
700  
875  
855  
850  
835  
825  
820  
1050  
1050 1050 1050 1050 1050 1050 1045 1035 1020 1000  
1220 1225 1225 1225 1225 1220 1205 1190 1185 1170  
1395 1400 1400 1400 1395 1385 1370 1340 1300 1245  
1225  
1400  
0 --- 1 . 0  
090---16  
Low Heat  
High Heat  
985 (825)†  
1210  
(1090)†  
525  
0 --- 1 . 0  
0 --- 1 . 0  
950  
970  
985  
985  
985  
985  
985  
985  
985  
980  
1190 1205 1210 1210 1210 1210 1210 1210 1210 1200  
††  
††  
1 --- 1 / 2 --- To n A / C C o o li n g  
2 --- To n A / C C o o li n g  
2 --- 1 / 2 --- To n A / C C o o li n g  
3 --- To n A / C C o o li n g  
3 --- 1 / 2 --- To n A / C C o o li n g  
4 --- To n A / C C o o li n g  
Maximum  
0---0.50‡  
0---0.50‡  
0---1.0‡  
0---1.0‡  
0 --- 1 . 0  
0 --- 1 . 0  
0 --- 1 . 0  
525  
680  
815  
520  
680  
845  
525  
680  
845  
495  
675  
855  
475  
670  
850  
700  
875  
1050  
1225  
1400  
1600  
850  
845  
835  
820  
805  
1005 1005 1015 1035 1040 1040 1035 1030 1025 1010  
1190 1200 1200 1205 1205 1215 1205 1200 1185 1170  
1350 1370 1390 1390 1400 1390 1380 1380 1360 1340  
1595 1600 1600 1600 1595 1555 1505 1465 1430 1390  
110---20***  
1320  
(1110)†  
1475  
(1330)†  
700  
Low Heat  
High Heat  
0 --- 1 . 0  
0 --- 1 . 0  
1275 1295 1315 1320 1320 1320 1320 1320 1320 1315  
1460 1465 1475 1475 1475 1475 1475 1475 1465 1465  
††  
††  
††  
2 --- To n A / C C o o li n g  
2 --- 1 / 2 --- To n A / C C o o li n g  
3 --- To n A / C C o o li n g  
3 --- 1 / 2 --- To n A / C C o o li n g  
4 --- To n A / C C o o li n g  
5 --- To n A / C C o o li n g  
6 --- To n A / C C o o li n g  
Maximum  
0---0.50‡  
0---0.50‡  
0---0.50‡  
0---1.0‡  
0---1.0‡  
0---1.0‡  
0 --- 1 . 0  
700  
875  
700  
875  
700  
875  
700  
875  
700  
875  
875  
1050  
1225  
1400  
1750  
2100  
2200  
1050 1050 1050 1050 1050  
1225 1225 1225 1225 1225 1225 1225 1225 1225 1225  
1400 1400 1400 1400 1400 1400 1400 1400 1400 1400  
1750 1750 1750 1750 1750 1750 1750 1750 1740 1725  
2100 2100 2100 2100 2090 2075 2055 2040 2005 1970  
2200 2190 2190 2180 2155 2145 2125 2100 2080 2020  
0 --- 1 . 0  
135---22  
1700  
(1430)†  
1915  
(1725)†  
700  
Low Heat  
High Heat  
0 --- 1 . 0  
0 --- 1 . 0  
1700 1700 1700 1700 1700 1695 1700 1695 1685 1670  
1900 1905 1915 1915 1915 1915 1915 1915 1915 1915  
††  
††  
††  
2 --- To n A / C C o o li n g  
2 --- 1 / 2 --- To n A / C C o o li n g  
3 --- To n A / C C o o li n g  
3 --- 1 / 2 --- To n A / C C o o li n g  
4 --- To n A / C C o o li n g  
5 --- To n A / C C o o li n g  
6 --- To n A / C C o o li n g  
Maximum  
0---0.50‡  
0---0.50‡  
0---0.50‡  
0---1.0‡  
0---1.0‡  
0---1.0‡  
0 --- 1 . 0  
700  
870  
700  
870  
700  
865  
700  
865  
665  
865  
875  
1050  
1225  
1400  
1750  
2100  
2200  
1010 1030 1050 1050 1050  
1155 1180 1200 1210 1220 1225 1225 1225 1225 1225  
1395 1400 1400 1400 1400 1400 1400 1390 1375 1355  
1740 1750 1750 1750 1735 1740 1735 1730 1715 1700  
2075 2085 2090 2100 2100 2100 2090 2080 2055 2025  
2180 2195 2200 2200 2200 2200 2185 2165 2140 2095  
0 --- 1 . 0  
155---22  
1715  
(1440)†  
1970  
(1775)†  
700  
Low Heat  
High Heat  
0 --- 1 . 0  
0 --- 1 . 0  
1715 1715 1715 1715 1715 1705 1710 1705 1705 1695  
1955 1965 1965 1970 1970 1970 1970 1970 1970 1960  
††  
††  
††  
2 --- To n A / C C o o li n g  
2 --- 1 / 2 --- To n A / C C o o li n g  
3 --- To n A / C C o o li n g  
3 --- 1 / 2 --- To n A / C C o o li n g  
4 --- To n A / C C o o li n g  
5 --- To n A / C C o o li n g  
6 --- To n A / C C o o li n g  
Maximum  
0---0.50‡  
0---0.50‡  
0---0.50‡  
0---1.0‡  
0---1.0‡  
0---1.0‡  
0 --- 1 . 0  
700  
865  
700  
875  
700  
875  
700  
865  
680  
865  
875  
1050  
1225  
1400  
1750  
2100  
2200  
1015 1020 1035 1045 1050  
1160 1185 1215 1225 1225 1225 1225 1225 1225 1225  
1385 1400 1400 1400 1400 1400 1395 1395 1380 1360  
1745 1750 1750 1750 1745 1740 1745 1745 1740 1735  
2055 2070 2080 2085 2095 2100 2100 2100 2090 2065  
2175 2190 2200 2200 2200 2200 2200 2200 2180 2160  
0 --- 1 . 0  
*Actual external static pressure (ESP) can be determined by using the fan laws (CFM 2 proportional to ESP); such as, a system with 1180 CFM  
at 0.5 ESP would operate at cooling airflow of 1050 CFM at 0.4 ESP and low---heating airflow of 735 CFM at 0.19 ESP.  
{Comfort airflow values are shown in parenthesis. Comfort airflow is selected when the low---heat rise adjustment switch (SW1---3) is OFF and  
the comfort/efficiency switch (SW1---4) is ON.  
}Ductwork must be sized for high---heating CFM within the operational range of ESP.  
{{Operation within the blank areas of the chart is not recommended because high---heat operation will be above 1.0 ESP.  
***All airflow on 110 size furnace are 5% less on side return only installations.  
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Return Air Connections  
NOTE: In the state of Massachusetts:  
1. Gas supply connections MUST be performed by a li-  
censed plumber or gas fitter.  
2. When flexible connectors are used, the maximum length  
shall not exceed 36 in. (915 mm).  
!
WARNING  
FIRE HAZARD  
3. When lever handle type manual equipment shutoff valves  
are used, they shall be T--handle valves.  
A failure to follow this warning could cause personal injury,  
death and/or property damage.  
4. The use of copper tubing for gas piping is NOT approved  
by the state of Massachusetts.  
Never connect return--air ducts to the back of the furnace.  
Follow instructions below.  
Refer to Table 6 for recommended gas pipe sizing. Risers must be  
used to connect to furnace and to meter. Support all gas piping  
with appropriate straps, hangers, etc. Use a minimum of 1 hanger  
every 6 ft. (1.8 M). Joint compound (pipe dope) should be  
applied sparingly and only to male threads of joints. Pipe dope  
must be resistant to the action of propane gas.  
Downflow Furnaces  
The return--air duct must be connected to return--air opening  
(bottom inlet) as shown in Fig. 3. DO NOT cut into casing sides  
(left or right). Side opening is permitted for only upflow and  
certain horizontal furnaces. Bypass humidifier connections  
should be made at ductwork or coil casing sides exterior to  
furnace. (See Fig. 19.)  
Table 6 – Maximum Capacity of Pipe  
NOMINAL  
IRON PIPE  
SIZE  
LENGTH OF PIPE --- FT (M)  
INTERNAL  
DIA.  
IN. (MM)  
Upflow and Horizontal Furnaces  
10  
20  
30  
40  
50  
(3.0)  
(6.0)  
(9.1)  
(12.1)  
(15.2)  
IN. (MM)  
The return--air duct must be connected to bottom, sides (left or  
right), or a combination of bottom and side(s) of main furnace  
casing as shown in Fig. 3. Bypass humidifier may be attached  
into unused return air side of the furnace casing. (See Fig. 18 and  
20.) Not all horizontal furnace models are approved for side  
return air connections. (See Fig. 20.)  
1/2 (12.7)  
3/4 (19.0)  
1 ( 25.4)  
0.622(158)  
0.824 (20.9)  
1.049 (26.6)  
175  
360  
680  
120  
250  
465  
97  
82  
73  
200  
375  
170  
320  
151  
285  
1-1/4  
1.380 (35.0)  
1.610 (40.9)  
1400  
2100  
950  
770  
660  
990  
580  
900  
(31.8)  
1-1/2  
(38.1)  
1460  
1180  
GAS PIPING  
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14---In. W.C.) or less and  
a pressure drop of 0.5---In. W.C. (based on a 0.60 specific gravity gas). Ref:  
Table 6 and 9.2 NFGC.  
!
WARNING  
!
FIRE OR EXPLOSION HAZARD  
WARNING  
Failure to follow this warning could result in personal  
injury, death, and/or property damage.  
FIRE OR EXPLOSION HAZARD  
A failure to follow this warning could result in personal  
injury, death, and/or property damage.  
Never purge a gas line into a combustion chamber. Never  
test for gas leaks with an open flame. Use a commercially  
available soap solution made specifically for the detection  
of leaks to check all connections.  
If local codes allow the use of a flexible gas appliance  
connector, always use a new listed connector. Do not use a  
connector which has previously served another gas  
appliance. Black iron pipe shall be installed at the furnace  
gas control valve and extend a minimum of 2--in. (51 mm)  
outside the furnace.  
!
WARNING  
FIRE OR EXPLOSION HAZARD  
Failure to follow this warning could result in personal  
injury, death, and/or property damage.  
!
CAUTION  
Use proper length of pipe to avoid stress on gas control  
manifold and a gas leak.  
FURNACE DAMAGE HAZARD  
Failure to follow this caution may result in furnace damage.  
Connect gas pipe to furnace using a backup wrench to  
avoid damaging gas controls and burner misalignment.  
!
WARNING  
An accessible manual equipment shutoff valve MUST be  
installed external to furnace casing and within 6 ft. (1.8 M) of  
furnace. A 1/8--in. (3 mm) NPT plugged tapping, accessible for  
test gauge connection, MUST be installed immediately upstream  
of gas supply connection to furnace and downstream of manual  
equipment shutoff valve.  
NOTE: The furnace gas control valve inlet pressure tap  
connection is suitable to use as test gauge connection providing  
test pressure DOES NOT exceed maximum 0.5 psig (14--In.  
W.C.) stated on gas control valve. (See Fig. 50.)  
FIRE OR EXPLOSION HAZARD  
Failure to follow this warning could result in personal  
injury, death, and/or property damage.  
Gas valve inlet and/or inlet pipe must remain capped until  
gas supply line is permanently installed to protect the valve  
from moisture and debris. Also, install a sediment trap in the  
gas supply piping at the inlet to the gas valve.  
Gas piping must be installed in accordance with national and  
local codes. Refer to current edition of NFGC in the U.S.  
Installations must be made in accordance with all authorities  
having jurisdiction. If possible, the gas supply line should be a  
separate line running directly from meter to furnace.  
Some installations require gas entry on right side of furnace (as  
viewed in upflow). (See Fig. 21.)  
Install a sediment trap in riser leading to furnace as shown in Fig.  
22. Connect a capped nipple into lower end of tee. Capped nipple  
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should extend below level of furnace gas controls. Place a ground  
joint union between furnace gas control valve and exterior  
manual equipment gas shutoff valve.  
ELECTRICAL CONNECTIONS  
!
WARNING  
A 1/8--in. (3 mm) NPT plugged tapping, accessible for test gauge  
connection, MUST be installed immediately upstream of gas  
supply connection to furnace and downstream of manual  
equipment shutoff valve.  
Piping should be pressure and leak tested in accordance with the  
current addition of the NFGC in the United States, local, and  
national plumbing and gas codes before the furnace has been  
connected. After all connections have been made, purge lines and  
check for leakage at furnace prior to operating furnace.  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
Blower access panel door switch opens 115--v power to  
control. No component operation can occur. Do not  
bypass or close switch with panel removed.  
If pressure exceeds 0.5 psig (14--In. W.C.), gas supply pipe must  
be disconnected from furnace and capped before and during  
supply pipe pressure test. If test pressure is equal to or less than  
0.5 psig (14--In. W.C.), turn off electric shutoff switch located on  
furnace gas control valve and accessible manual equipment  
shutoff valve before and during supply pipe pressure test. After  
all connections have been made, purge lines and check for  
leakage at furnace prior to operating furnace.  
See Fig. 25 for field wiring diagram showing typical field 115--v  
wiring. Check all factory and field electrical connections for  
tightness.  
Field--supplied wiring shall conform with the limitations of 63_F  
(33_C) rise.  
!
WARNING  
The gas supply pressure shall be within the maximum and  
minimum inlet supply pressures marked on the rating plate with  
the furnace burners ON and OFF.  
ELECTRICAL SHOCK AND FIRE HAZARD  
Failure to follow this warning could result in personal  
injury, death, or property damage.  
The cabinet MUST have an uninterrupted or unbroken  
ground according to NEC ANSI/NFPA 70--2008 or local  
codes to minimize personal injury if an electrical fault  
should occur. This may consist of electrical wire, conduit  
approved for electrical ground or a listed, grounded power  
cord (where permitted by local code) when installed in  
accordance with existing electrical codes. Refer to the  
power cord manufacturer’s ratings for proper wire gauge.  
Do not use gas piping as an electrical ground.  
2(51mm)  
Street Elbow  
A08551  
!
Fig. 21 -- Burner and Manifold  
CAUTION  
FURNACE MAY NOT OPERATE HAZARD  
Failure to follow this caution may result in intermittent  
furnace operation.  
GAS  
SUPPLY  
MANUAL  
SHUTOFF  
VALVE  
Furnace control must be grounded for proper operation or  
else control will lock out. Control must remain grounded  
through green/yellow wire routed to gas valve and manifold  
bracket screw.  
(REQUIRED)  
SEDIMENT  
TRAP  
UNION  
115--V Wiring  
Verify that the voltage, frequency, and phase correspond to that  
specified on unit rating plate. Also, check to be sure that service  
provided by utility is sufficient to handle load imposed by this  
equipment. Refer to rating plate or Table 7 for equipment  
electrical specifications.  
U.S. Installations: Make all electrical connections in accordance  
with National Electrical Code (NEC) ANSI/NFPA 70--2008 and  
any local codes or ordinances that might apply.  
A02035  
Fig. 22 -- Typical Gas Pipe Arrangement  
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Table 7 – Electrical Data  
OPERATING  
V O LT S ---  
H E R T Z ---  
PHASE  
115 --- 60 --- 1  
115 --- 60 --- 1  
115 --- 60 --- 1  
115 --- 60 --- 1  
115 --- 60 --- 1  
UNIT  
MAX. UNIT  
AMPACITY  
AMPS  
MIN.  
WIRE  
FURNACE  
SIZE  
MAX. WIRE  
MAX. FUSE OR  
VOLTAGE RANGE  
L E N G T H --- F T ( M ) } CKT BKR AMPS {  
#
GAUGE  
Max.  
127  
127  
127  
127  
127  
Min.  
104  
104  
104  
104  
104  
070---12/036070  
090---16/048090  
110---20/060110  
135---22/066135  
155---22/066155  
9.0  
9.6  
11.99  
12.56  
19.33  
19.13  
19.23  
30 (9.0)  
29 (8.8)  
29 (8.8)  
30 (9.0)  
29 (8.8)  
15  
15  
20  
20  
20  
14  
14  
12  
12  
12  
15.1  
14.9  
15.0  
* Permissible limits of the voltage range at which the unit operates satisfactorily.  
# Unit ampacity = 125 percent of largest operating component’s full load amps plus 100 percent of all other potential operating components’ (EAC, humidifier,  
etc.) full load amps.  
{Time---delay type is recommended.  
}Length shown is as measured 1 way along wire path between furnace and service panel for maximum 2 percent voltage drop.  
!
Factory  
Installed  
WARNING  
FIRE HAZARD  
Failure to follow this warning could result in personal  
injury, death, or property damage.  
Alternate  
Location  
Do not connect aluminum wire between disconnect  
switch and furnace. Use only copper wire.  
Use a separate, fused branch electrical circuit with a properly  
sized fuse or circuit breaker for this furnace. See Table 7 for wire  
size and fuse specifications. A readily accessible means of  
electrical disconnect must be located within sight of the furnace.  
NOTE: Proper polarity must be maintained for 115--v wiring. If  
polarity is incorrect, control LED status indicator light will flash  
rapidly and furnace will NOT operate.  
A10291  
Fig. 23 -- Relocating J--Box  
J--Box Relocation  
NOTE: If factory location of J--Box is acceptable, go to next  
section (ELECTRICAL CONNECTION to J--Box).  
1. Select and remove a hole knockout in the casing where the  
electrical box is to be installed.  
NOTE: On 14--in. (356 mm) wide casing models, the J--Box  
shall not be relocated to other side of furnace casing when the  
vent pipe is routed within the casing.  
NOTE: Check that duct on side of furnace will not interfere with  
installed electrical box.  
2. Remove the desired electrical box hole knockout and posi-  
tion the hole in the electrical box over the hole in the fur-  
nace casing.  
1. Remove and save two screws holding J--Box. (See Fig.  
23.)  
NOTE: The J--Box cover need not be removed from the J--Box  
in order to move the J--Box. Do NOT remove green ground  
screw inside J--Box. (See Fig. 23.)  
3. Fasten the electrical box to casing by driving two field--  
supplied screws from inside electrical box into casing  
steel.  
2. Cut wire tie on loop in furnace wires attached to J--Box.  
3. Move J--Box to desired location.  
4. Remove and save two screws holding J--Box. (See Fig.  
23.)  
4. Fasten J--Box to casing with the two screws removed in  
Step 1.  
5. Route J--Box wires within furnace away from sharp edges,  
rotating parts and hot surfaces.  
5. Pull furnace power wires out of 1/2--in. (12 mm) diameter  
hole in J--Box. Do not loosen wires from strain--relief  
wire--tie on outside of J--Box.  
6. Route furnace power wires through holes in casing and  
electrical box and into electrical box.  
Electrical Connection to J--Box  
7. Pull field power wires into electrical box.  
8. Remove cover from furnace J--Box.  
Electrical Box on Furnace Casing Side (See Fig. 24.)  
9. Route field ground wire through holes in electrical box  
and casing, and into furnace J--Box.  
!
WARNING  
10. Reattach furnace J--Box to furnace casing with screws re-  
moved in Step 4.  
11. Secure field ground wire to J--Box green ground screw.  
FIRE OR ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal  
injury, death, or property damage.  
12. Complete electrical box wiring and installation. Connect  
line voltage leads as shown in Fig. 24. Use best practices  
(NEC in U.S. for wire bushings, strain relief, etc.  
If field--supplied manual disconnect switch is to be mounted  
on furnace casing side, select a location where a drill or  
fastener cannot damage electrical or gas components.  
13. Reinstall cover to J--Box. Do not pinch wires between  
cover and bracket.  
21  
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2. Route BX cable into 7/8--in. (22 mm) diameter hole in  
J--Box.  
3. Secure BX cable to J--Box bracket with connectors ap-  
proved for the type of cable used.  
4. Secure field ground wire to green ground screw on J--Box  
bracket.  
5. Connect line voltage leads as shown in Fig. 25.  
6. Reinstall cover to J--Box. Do not pinch wires between  
cover and bracket.  
24--V Wiring  
Make field 24--v connections at the 24--v terminal strip. (See Fig.  
25 -- 34.) Connect terminal Y/Y2 as shown in Fig. 27--34 for  
proper cooling operation. Use only AWG No. 18, color--coded,  
copper thermostat wire.  
The 24--v circuit contains an automotive--type, 3--amp. fuse  
located on the control. Any direct shorts during installation,  
service, or maintenance could cause this fuse to blow. If fuse  
replacement is required, use ONLY a 3--amp. fuse of identical  
size.  
ACCESSORIES  
1. Electronic Air Cleaner (EAC)  
Connect an accessory Electronic Air Cleaner (if used) us-  
ing 1/4--in female quick connect terminals to the two male  
1/4--in quick--connect terminals on the control board  
marked EAC--1 and EAC--2. The terminals are rated for  
115VAC, 1.0 amps maximum and are energized during  
blower motor operation. (See Fig. 26.)  
2. Humidifier (HUM)  
A10141  
Connect an accessory 24 VAC, 0.5 amp. maximum hu-  
midifier (if used) to the 1/4--in male quick--connect HUM  
terminal and COM--24V screw terminal on the control  
board thermostat strip. The HUM terminal is energized  
when blower is energized in heating. (See Fig. 26.)  
Fig. 24 -- Field--Supplied Electrical Box on Furnace Casing  
Power Cord Installation in Furnace J--Box  
NOTE: Power cords must be able to handle the electrical  
requirements listed in Table 6. Refer to power cord  
manufacturer’s listings.  
NOTE: DO NOT connect furnace control HUM terminal to  
HUM (humidifier) terminal on Thermidistat, Zone Controller or  
similar device. See ThermidistatE, Zone Controller, thermostat,  
or controller manufacturer’s instructions for proper connection.  
1. Remove cover from J--Box.  
2. Route listed power cord through 7/8--in. (22 mm) diameter  
hole in J--Box.  
VENTING  
3. Secure power cord to J--Box bracket with a strain relief  
bushing or a connector approved for the type of cord used.  
4. Secure field ground wire to green ground screw on J--Box  
bracket.  
The furnace shall be connected to a listed factory built chimney  
or vent, or a clay--tile lined masonry or concrete chimney. Venting  
into an unlined masonry chimney or concrete chimney is  
prohibited.  
5. Connect line voltage leads as shown in Fig. 25.  
When an existing Category I furnace is removed or replaced, the  
original venting system, may no longer be sized to properly vent  
the attached appliances. An improperly sized Category I venting  
system could cause the formation of condensate in the furnace  
and vent, leakage of condensate and combustion products, and  
spillage of combustion products into the living space.  
6. Reinstall cover to J--Box. Do not pinch wires between  
cover and bracket.  
BX Cable Installation in Furnace J--Box  
1. Remove cover from J--Box.  
22  
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FIELD 24-VOLT WIRING  
FIELD 115-, 208/230-, 460-VOLT WIRING  
FACTORY 24-VOLT WIRING  
FACTORY 115-VOLT WIRING  
NOTE 2  
1-STAGE  
THERMOSTAT  
TERMINALS  
W
C
Y
R
G
FIVE  
WIRE  
FIELD-SUPPLIED  
FUSED DISCONNECT  
THREE-WIRE  
HEATING-  
ONLY  
208/230- OR  
460-VOLT  
THREE  
PHASE  
W2  
BLK  
BLK  
COM  
W/W1  
WHT  
WHT  
208/230-  
VOLT  
SINGLE  
PHASE  
GND  
NOTE 1  
Y/Y2  
115-VOLT FIELD- JUNCTION  
SUPPLIED  
FUSED  
BOX  
R
G
GND  
CONTROL  
BOX  
CONDENSING  
UNIT  
DISCONNECT  
24-VOLT  
TERMINAL  
BLOCK  
NOTES: 1. Connect Y/Y2-terminal as shown for proper operation.  
2. Some thermostats require a "C" terminal connection as shown.  
3. If any of the original wire, as supplied, must be replaced, use  
same type or equivalent wire.  
FURNACE  
A95236  
Fig. 25 -- Field Wiring Diagram  
USER INTERFACE  
OR ADVANCED  
PRODUCT  
CONTINUOUS FAN  
(CF) AIRFLOW  
SETUP SWITCHES  
SW4 SETUP  
SWITCHES  
OAT  
CONNECTOR  
MODEL PLUG  
MONITOR  
CONNECTOR  
CONNECTOR  
SW1 SETUP  
SWITCHES AND  
BLOWER OFF-  
DELAY  
AIR CONDITIONING  
(A/C) AIRFLOW  
SETUP SWITCHES  
HUMIDIFIER  
TERMINAL (24-VAC  
0.5 AMP MAX.  
ACRDJ – AIR  
CONDITIONING  
RELAY DISABLE  
JUMPER  
24-V THERMOSTAT  
TERMINALS  
FLASH  
UPGRADE  
CONNECTOR  
(FACTORY  
ONLY)  
STATUS AND COMM  
LED LIGHTS  
PL3 – ECM BLOWER  
HARNESS  
3-AMP FUSE  
CONNECTOR  
TRANSFORMER 24-VAC  
CONNECTIONS  
BOARD SERIAL  
NUMBER  
115-VAC (L2) NEUTRAL  
CONNECTIONS  
EAC-1 TERMINAL  
(115 -VAC 1.0 AMP MAX.)  
PL1 – LOW VOLTAGE MAIN  
HARNESS CONNECTOR  
115-VAC (L1) LINE  
VOLTAGE CONNECTIONS  
PL2 – HOT SURFACE  
IGNITER INDUCER  
MOTOR CONNECTOR  
EXAMPLE:  
V14 HK42FZ022 3410  
SOFTWARE  
VERSION  
NUMBER  
PA RT  
NUMBER  
DATE  
CODE  
A10286  
Fig. 26 -- Variable Speed Furnace Control for ECM Blower Motor  
23  
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!
WARNING  
CARBON MONOXIDE POISONING HAZARD  
Failure to follow the steps outlined below for each  
appliance connected to the venting system being placed into  
operation could result in carbon monoxide poisoning or  
death.  
The following steps shall be followed for each appliance  
connected to the venting system being placed into  
operation, while all other appliances connected to the  
venting system are not in operation:  
1. Seal any unused openings in venting system.  
2. Inspect the venting system for proper size and  
horizontal pitch, as required in the National Fuel Gas  
Code, NFPA 54/ANSI Z223.1--2009 and these  
instructions. Determine that there is no blockage or  
restriction, leakage, corrosion and other deficiencies,  
which could cause an unsafe condition.  
3. As far as practical, close all building doors and  
windows and all doors between the space in which  
the appliance(s) connected to the venting system are  
located and other spaces of the building.  
4. Close fireplace dampers.  
A00275  
5. Turn on clothes dryers and any appliance not  
connected to the venting system. Turn on any  
exhaust fans, such as range hoods and bathroom  
exhausts, so they are operating at maximum speed.  
Do not operate a summer exhaust fan.  
6. Follow the lighting instructions. Place the appliance  
being inspected into operation. Adjust the thermostat  
so appliance is operating continuously.  
Fig. 27 -- Two--Stage Furnace with Single--Speed  
Air Conditioner  
!
WARNING  
CARBON MONOXIDE POISONING HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
7. Test for spillage from draft hood equipped  
appliances at the draft hood relief opening after 5  
minutes of main burner operation. Use the flame of a  
match or candle.  
Do not bypass the draft safeguard switch, as an unsafe  
condition could exist which must be corrected.  
8. If improper venting is observed during any of the  
above tests, the venting system must be corrected in  
accordance with the National Fuel Gas Code, NFPA  
54/ANSI Z223.1--2009.  
1. If a vent (common or dedicated) becomes blocked, the fur-  
nace will be shut off by the draft safeguard switch located  
on the vent elbow.  
9. After it has been determined that each appliance  
connected to the venting system properly vents when  
tested as outlined above, return doors, windows,  
exhaust fans, fireplace dampers and any other  
gas--fired burning appliance to their previous  
conditions of use.  
2. Two--stage furnaces require Type B vent connectors out-  
side the casing in all configurations. Single wall vent con-  
nector may be used inside the furnace casing with the  
transition to Type B vent outside the furnace casing. Size  
the connector so that the FAN--Min vent connector capa-  
city is equal to or lower than the low fire rate of the fur-  
nace and the FAN--Max vent connector capacity is equal  
to or higher than the furnace high fire rate.  
Vent system or vent connectors may need to be resized. Vent  
systems or vent connectors must be sized to approach minimum  
size as determined using appropriate table found in the current  
edition of NFGC.  
3. Do not vent this Category I furnace into a single wall ded-  
icated or common vent. The dedicated or common vent is  
considered to be the vertical portion of the vent system  
that terminates outdoors.  
4. Vent connectors serving Category I furnaces shall not be  
connected into any portion of a mechanical draft system  
operating under positive pressure.  
5. Do not vent this appliance with any solid fuel burning ap-  
pliance.  
6. Category I furnaces must be vented vertically or nearly  
vertically unless equipped with a listed mechanical venter.  
See SIDEWALL VENTING section.  
General Venting Requirements  
Follow all safety codes for proper vent sizing and installation  
requirements, including local building codes, the National Fuel  
Gas Code NFPA 54/ANSI Z223.1--2009 (NFGC), Parts 12 and  
13 in the United States, the local building codes, and furnace and  
vent manufacturers’ instructions.  
The following information and warning must be considered in  
addition to the requirements defined in the NFGC.  
7. Do not vent this appliance into an unlined masonry chim-  
ney. Refer to Chimney Inspection Chart, Fig. 35.  
24  
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See notes 2, 5, 8, 10, 11 and 12  
on the page following these figures  
See notes 1, 2, 3, 4, 6, 8, 9, 10, 12, 13 and 15  
on the page following these figures  
A03179  
A03178  
Fig. 28 -- Two--Stage Furnace with Two--Speed Air Condi-  
tioner  
Fig. 30 -- Two--Stage Furnace with Two--Speed Heat Pump  
(Dual Fuel)  
See notes 1, 2, 4, 11, 14, 15, and 16  
on the page following these figures  
See notes 1, 2, 4, 6, 7, 9, 10, 11, and 15  
on the page following these figures  
A03180  
A03181  
Fig. 29 -- Two--Stage Furnace with Single--Speed Heat Pump  
(Dual Fuel)  
Fig. 31 -- Dual--Fuel Thermostat with Two--Stage Furnace  
and Single--Speed Heat Pump  
25  
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7
See notes 2, 11, and 12 on the  
page following these figures  
See notes 1, 2, 3, 4, 12, 13, 14, 15, and 17  
on the page following these figures  
A03182  
A03183  
Fig. 32 -- Dual--Fuel Thermostat with Two--Stage Furnace  
and Two--Speed Heat Pump  
Fig. 33 -- Two--Stage Thermostat with Two--Stage Furnace  
and Two--Speed Air Conditioner  
See notes 1 and 2 on the page  
following these figures  
A03184  
Fig. 34 -- Single--Stage Thermostat with Two--Stage Furnace and Two--Speed Air Conditioner  
26  
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NOTES FOR FIGURES 27 -- 34  
1. Heat pump MUST have a high pressure switch for dual fuel applications.  
2. Refer to outdoor equipment Installation Instructions for additional information and setup procedure.  
3. If the heat pump date code is 1501E or earlier, select the “ZONE” position on the two--speed heat pump control. Heat pumps having  
date codes 1601E and later do not have or require a “ZONE” selection.  
4. Outdoor Air Temperature Sensor must be attached in all dual fuel applications.  
5. Dip switch No. 1 on Thermidistat should be set in OFF position for air conditioner installations. This is factory default.  
6. Dip switch No. 1 on Thermidistat should be set in ON position for heat pump installations.  
7. Dip switch No. 2 on Thermidistat should be set in OFF position for single--speed compressor operation. This is factory default.  
8. Dip switch No. 2 on Thermidistat should be set in ON position for two--speed compressor operation.  
9. Configuration Option No. 10 “Dual Fuel Selection” must be turned ON in all dual fuel applications.  
10. NO connection should be made to the furnace HUM terminal when using a Thermidistat.  
11. Optional connection: If wire is connected, dip switch SW1--2 on furnace control should be set in ON position to allow Thermidistat/  
Thermostat to control furnace staging.  
12. Optional connection: If wire is connected, ACRDJ jumper on furnace control should be removed to allow Thermidistat/Thermostat to  
control outdoor unit staging.  
13. Furnace must control its own high--stage heating operation via furnace control algorithm.  
14. The RVS Sensing terminal “L” should not be connected. This is internally used to sense defrost operation.  
15. DO NOT SELECT the “FURNACE INTERFACE” or “BALANCE POINT” option on the two--speed heat pump control board. This  
is controlled internally by the Thermidistat/Dual Fuel Thermostat.  
16. Dip switch D on Dual Fuel Thermostat should be set in OFF position for single--speed compressor operation. This is factory default.  
17. Dip switch D on Dual Fuel Thermostat should be set in ON position for two--speed compressor operation.  
27  
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A10133  
Fig. 35 -- Chimney Inspection Chart  
28  
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Masonry Chimney Requirement  
Relining with a listed metal liner or Type--B vent is considered to  
be a vent--in--a--chase.  
If a metal liner or Type--B vent is used to line a chimney, no other  
appliance shall be vented into the annular space between the  
chimney and the metal liner.  
NOTE: These furnaces are CSA design--certified for use in  
exterior tile--lined masonry chimneys with a factory accessory  
Chimney Adapter Kit. Refer to the furnace rating plate for correct  
kit usage. The Chimney Adapter Kits are for use with ONLY  
furnaces having a Chimney Adapter Kit number marked on the  
furnace rating plate.  
Exterior Masonry Chimney FAN + NAT  
Installations with Type--B Double--Wall Vent  
Connectors ENFPA & AGA  
Table 8 – Combined Appliance Maximum Input  
Rating in Thousands of Btuh per Hour  
If a clay tile--lined masonry chimney is being used and it is  
exposed to the outdoors below the roof line, relining might be  
required. Chimneys shall conform to the Standard for Chimneys,  
Fireplaces, Vents, and Solid Fuel Burning Appliances  
ANSI/NFPA 211--2009 in the United States and must be in good  
condition.  
INTERNAL AREA OF CHIMNEY  
SQ. IN. (SQ. MM)  
VENT HEIGHT  
FT (M)  
12  
(7741)  
19  
28  
(18064)  
38  
(12258)  
(24516)  
U.S.A.--Refer to Sections 13.1.8 and 13.2.20 of the NFPA  
54/ANSI Z223.1--2009 or the authority having jurisdiction to  
determine whether relining is required. If relining is required, use  
a properly sized listed metal liner, Type--B vent, or a listed  
alternative venting design.  
6 (1.8)  
8 (2.4)  
10 (3.0)  
15 (4.5)  
20 (6.0)  
30 (9.1)  
74  
80  
84  
NR  
NR  
NR  
119  
130  
138  
152  
NR  
178  
193  
207  
233  
250  
NR  
257  
279  
299  
334  
368  
404  
NR  
NOTE:  
See the NFPA 54/ANSI Z223.1--2009 13.1.9 and  
Appliance Application Requirements  
13.2.20 regarding alternative venting design and the exception,  
which cover installations such as our Chimney Adapter Kits  
which are listed for use with these furnaces. See Table 17 for  
accessory listing.  
Appliance operation has a significant impact on the performance  
of the venting system. If the appliances are sized, installed,  
adjusted, and operated properly, the venting system and/or the  
appliances should not suffer from condensation and corrosion.  
The venting system and all appliances shall be installed in  
accordance with applicable listings, standards, and codes.  
The Chimney Adapter Kit is a listed alternative venting system  
for these furnaces. See the kit instructions for complete details.  
This furnace is permitted to be vented into a clay tile--lined  
masonry chimney that is exposed to the outdoors below the roof  
line, provided:  
The furnace should be sized to provide 100 percent of the design  
heating load requirement plus any margin that occurs because of  
furnace model size capacity increments. Heating load estimates  
can be made using approved methods available from Air  
Conditioning Contractors of America (Manual J); American  
Society of Heating, Refrigerating, and Air--Conditioning  
Engineers; or other approved engineering methods. Excessive  
oversizing of the furnace could cause the furnace and/or vent to  
fail prematurely.  
When a metal vent or metal liner is used, the vent must be in  
good condition and be installed in accordance with the vent  
manufacturer’s instructions.  
To prevent condensation in the furnace and vent system, the  
following precautions must be observed:  
1. Vent connector is Type--B double--wall, and  
2. This furnace is common vented with at least 1 draft hood  
equipped appliance, and  
3. The combined appliance input rating is less than the max-  
imum capacity given in Table 8, and  
4. The input rating of each space heating appliance is greater  
than the minimum input rating given in Table 9 for the  
local 99% Winter Design Temperature. Chimneys having  
internal areas greater than 38 sq. in. (24516 sq. mm) re-  
quire furnace input ratings greater than the input ratings of  
these furnaces. See footnote at bottom of Table 9, and  
5. The authority having jurisdiction approves.  
1. The return--air temperature must be at least 60_F db except  
for brief periods of time during warm--up from setback at  
no lower than 55_F (13_C) db or during initial start--up  
from a standby condition.  
If all of these conditions cannot be met, an alternative venting  
design shall be used, such as the listed chimney adapter kit with a  
furnace listed for use with the kit, a listed chimney--lining system,  
or a Type--B common vent.  
2. Adjust the gas input rate per the installation instructions.  
Low gas input rate causes low vent gas temperatures, caus-  
ing condensation and corrosion in the furnace and/or vent-  
ing system. Derating is permitted only for altitudes above  
2000 Ft. (610 M).  
Inspections before the sale and at the time of installation will  
determine the acceptability of the chimney or the need for repair  
and/or (re)lining. Refer to the Fig. 33 to perform a chimney  
inspection. If the inspection of a previously used tile--lined  
chimney:  
3. Adjust the air temperature rise to the midpoint of the rise  
range or slightly above. Low air temperature rise can cause  
low vent gas temperature and potential for condensation  
problems.  
a. Shows signs of vent gas condensation, the chimney  
should be relined in accordance with local codes and  
the authority having jurisdiction. The chimney should  
be relined with a listed metal liner, Type--B vent, or a  
listed chimney adapter kit shall be used to reduce con-  
densation. If a condensate drain is required by local  
code, refer to the NFPA 54/ANSI Z223.1--2009, Sec-  
tion 12.10 for additional information on condensate  
drains.  
4. Set the thermostat heat anticipator or cycle rate to reduce  
short cycling.  
!
CAUTION  
BURN HAZARD  
b. Indicates the chimney exceeds the maximum permiss-  
ible size in the tables, the chimney should be rebuilt or  
relined to conform to the requirements of the equip-  
ment being installed and the authority having jurisdic-  
tion.  
Failure to follow this caution may result in personal injury.  
Hot vent pipe is within reach of small children when  
installed in downflow position.  
See the following instruction.  
A chimney without a clay tile liner, which is otherwise in good  
condition, shall be rebuilt to conform to ANSI/NFPA 211 or be  
lined with a UL listed metal liner or UL listed Type--B vent.  
29  
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Table 9 – Minimum Allowable Input Rating of  
Additional Venting Requirements  
Space--Heating Appliance in Thousands of Btuh per Hour  
A 4--in. (102 mm) round vent elbow is supplied with the furnace.  
A 5--in. (127 mm) or 6-- in. (152 mm) vent connector may be  
required for some model furnaces. A field--supplied 4--in. (102  
mm) to 5--in. (127 mm) or 4--in. (102 mm) to 6--in. (152 mm)  
sheet metal increaser fitting is required when 5--in. (127 mm) or  
6--in. (152 mm) vent connector is used. See Fig. 36 -- 48, Venting  
Orientation for approved vent configurations.  
INTERNAL AREA OF CHIMNEY  
VENT HEIGHT  
FT. (M)  
SQ. IN. (SQ. MM)  
19 28  
(12258) 18064)  
12  
(7741)  
38  
(24516)  
Local 99% Winter Design Temperature: 17 to 26 degrees F  
6
8
10  
15  
20  
30  
0
52  
NR  
NR  
NR  
NR  
55  
74  
90  
NR  
NR  
NR  
99  
141  
154  
169  
212  
258  
362  
NOTE: Vent connector length for connector sizing starts at  
furnace vent elbow. The 4--in. (102 mm) vent elbow is shipped  
for upflow configuration and may be rotated for other positions.  
Remove the three screws that secure vent elbow to furnace, rotate  
furnace vent elbow to position desired, reinstall screws. The  
factory--supplied vent elbow does NOT count as part of the  
number of vent connector elbows.  
111  
125  
167  
212  
NR  
Local 99% Winter Design Temperature: 5 to 16 degrees F*  
6
8
10  
15  
20  
30  
NR  
NR  
NR  
NR  
NR  
NR  
78  
94  
111  
NR  
NR  
NR  
121  
135  
149  
193  
NR  
166  
182  
198  
247  
293  
377  
The vent connector can exit the furnace through one of five  
locations on the casing.  
!
CAUTION  
NR  
Local 99% Winter Design Temperature: ---10 to 4 degrees F*  
CUT HAZARD  
6
8
10  
15  
20  
30  
NR  
NR  
NR  
NR  
NR  
NR  
NR  
NR  
NR  
NR  
NR  
NR  
145  
159  
175  
NR  
NR  
NR  
196  
213  
231  
283  
333  
NR  
Failure to follow this caution may result in personal injury.  
Sheet metal parts may have sharp edges or burrs. Use care  
and wear appropriate protective clothing, safety glasses and  
gloves when handling parts, and servicing furnaces.  
Local 99% Winter Design Temperature: ---11 degrees F or  
lower  
1. Attach the single wall vent connector to the furnace vent  
elbow, and fasten the vent connector to the vent elbow  
with at least two field--supplied, corrosion--resistant, sheet  
metal screws located 180_ apart.  
Not recommended for any vent configuration.  
*The 99.6% heating (db) temperatures found in the 1997 or 2001  
ASHRAE Fundamentals Handbook, Climatic Design Information chapter,  
Table 1A (United States) and 2A (Canada) or the 2005 ASHRAE Funda-  
mentals handbook, Climatic Design Information chapter, and the CD---  
ROM included with the 2005 ASHRAE Fundamentals Handbook.  
NOTE: An accessory flue extension is available to extend from  
the furnace elbow to outside the furnace casing. See Table 17 for  
accessory listing. If flue extension is used, fasten the flue  
extension to the vent elbow with at least two field--supplied,  
corrosion--resistant, sheet metal screws located 180_ apart. Fasten  
the vent connector to the flue extension with at least two  
field--supplied, corrosion resistant sheet metal screws located  
180_ apart.  
Air for combustion must not be contaminated by halogen  
compounds which include chlorides, fluorides, bromides, and  
iodides. These compounds are found in many common home  
products such as detergent, paint, glue, aerosol spray, bleach,  
cleaning solvent, salt, and air freshener, and can cause corrosion  
of furnaces and vents. Avoid using such products in the  
combustion--air supply. Furnace use during construction of the  
building could cause the furnace to be exposed to halogen  
compounds, causing premature failure of the furnace or venting  
system due to corrosion.  
2. Vent the furnace with the appropriate connector as shown  
in Fig. 36 -- 48.  
3. Determine the correct location of the knockout to be re-  
moved.  
4. Use a hammer and screwdriver to strike a sharp blow  
between the tie points and work the slug back and forth  
until the slug breaks free.  
Vent dampers on any appliance connected to the common vent  
can cause condensation and corrosion in the venting system. Do  
not use vent dampers on appliances common vented with this  
furnace.  
An accessory Vent Guard Kit is REQUIRED for downflow  
applications for use where the vent exits through the lower  
portion of the furnace casing. Refer to the Vent Guard Kit  
Instructions for complete details. See Table 17 for accessory  
listing.  
30  
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SEE NOTES: 1,2,4,7,8,9  
on the page following  
these figures  
SEE NOTES:1,2,3,4,5,7,8,9  
on the page following  
these figures  
A03208  
A03210  
Fig. 36 -- Upflow Application -- Vent Elbow Up  
Fig. 38 -- Downflow Application -- Vent Elbow Up then Left  
SEE NOTES: 1,2,4,5,7,8,9  
on the page following  
these figures  
SEE NOTES: 1,2,3,4,7,8,9  
on the pages following  
these figures  
A03209  
A03211  
Fig. 37 -- Upflow Application -- Vent Elbow Right  
Fig. 39 -- Downflow Application -- Vent Elbow Up  
31  
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SEE NOTES: 1,2,4,7,8,9 on the page  
following these figures  
A03213  
Fig. 42 -- Horizontal Left Application -- Vent Elbow Left  
SEE NOTES: 1,2,4,5,6,7,8,9,10  
on the page following these figures  
A03207  
Fig. 40 -- Downflow Application -- Vent Elbow Left then Up  
SEE NOTES: 1,2,4,5,7,8,9 on the page  
following these figures  
A03214  
Fig. 43 -- Horizontal Left Application -- Vent Elbow Right  
then Up  
SEE NOTES:1,2,3,4,5,7,8,9  
on the page following  
these figures.  
SEE NOTES: 1,2,4,7,8,9 on the page  
following these figures  
A03212  
A03218  
Fig. 41 -- Downflow Application -- Vent Elbow Up then Right  
Fig. 44 -- Horizontal Right Application -- Vent Elbow Right  
32  
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SEE NOTES: 1,2,4,5,7,8,9 on the page  
following these figures  
SEE NOTES: 1,2,4,5,7,8,9 on the page  
following these figures  
A03215  
A03219  
Fig. 45 -- Horizontal Left Application -- Vent Elbow Up  
Fig. 47 -- Horizontal Right Application -- Vent Elbow Left  
then Up  
SEE NOTES: 1,2,4,5,7,8,9  
SEE NOTES: 1,2,4,5,7,8,9 on the page  
following these figures  
A02068  
A03216  
Fig. 48 -- Horizontal Right Application--Vent Elbow Left  
Fig. 46 -- Horizontal Left Application -- Vent Elbow Right  
VENTING NOTES FOR FIG. 36 -- 48  
1. For common vent, vent connector sizing and vent material: United States----use the NFGC.  
2. Immediately increase to 5--in. (102 mm) or 6--in. (152 mm) vent connector outside furnace casing when 5--in. (127 mm) vent  
connector is required, refer to Note 1 above.  
3. Side outlet vent for upflow and downflow installations must use Type B vent immediately after exiting the furnace, except when  
factory--approved Downflow Vent Guard Kit is used in the downflow position. See Table 17 for accessory listing.  
4. Type--B vent where required, refer to Note 1 above.  
5. A 4--in.(102 mm) single--wall (26 ga. min.) vent must be used inside furnace casing and when the factory--approved Downflow Vent  
Guard Kit is used external to the furnace. See Table 17 for accessory listing.  
6. Accessory Downflow Vent Guard Kit required in downflow installations with lower vent configuration. See Table 17 for accessory  
listing.  
7. Chimney Adapter Kit may be required for exterior masonry chimney applications. Refer to Chimney Adapter Kit for sizing and  
complete application details. See Table 17 for accessory listing.  
8. Secure vent connector to furnace elbow with (2) corrosion--resistant sheet metal screws, spaced approximately 180_ apart.  
9. Secure all other single wall vent connector joints with (3) corrosion resistant screws spaced approximately 120_ apart. Secure Type--B  
vent connectors per vent connector manufacturer’s recommendations.  
10. The total height of the vent and connector shall be at least seven feet for the 154,000 Btuh gas input rate model when installed in a  
downflow application with furnace elbow turned to left side with the connector elbow outside furnace casing pointing upward. (See  
Fig. 38.)  
33  
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Caution!! For the following applications, use the minimum vertical heights as specified below.  
For all other applications, follow exclusively the National Fuel Gas Code.  
MIN. VENT  
DIAMETER  
IN. (mm)*  
MIN. VERTICAL VENT  
FURNACE  
ORIENTATION  
VENT ORIENTATION  
FURNACE INPUT  
(BTUH/HR)  
HEIGHT  
FT. (M)**  
Vent elbow left, then up  
Downflow  
Horizontal Left  
Horizontal Left  
Horizontal Left  
Downflow  
154,000 132,000 110,000  
154,000 132,000  
154,000 132,000  
154,000  
5 (127)  
5 (127)  
5 (127)  
5 (127)  
5 (127)  
5 (127)  
12 (3.6)  
7 (2.1)  
7 (2.1)  
7 (2.1)  
10 (3.0)  
10 (3.0)  
Fig. 36  
Vent elbow right, then up  
Fig. 39  
Vent Elbow up  
Fig. 40  
Vent elbow right  
Fig. 41  
Vent elbow up then left  
Fig. 34  
Vent elbow up, then right  
Fig. 37  
110,000  
Downflow  
110,000  
NOTE: All vent configurations must also meet National Fuel Gas Code venting requirements NFGC.  
*4---in. (102 mm) inside casing or vent guard  
**Including 4 in. (102 mm) vent section(s)  
The horizontal portion of the venting system shall slope upwards  
not less than 1/4--in. per linear ft. (21 mm/m) from the furnace to  
the vent and shall be rigidly supported every 5 ft. (1.5 M) or less  
with metal hangers or straps to ensure there is no movement after  
installation.  
3. Gas supply pressure to the furnace must be greater than  
4.5--In. W.C. (0.16 psig ) but not exceed 14--In. W.C. (0.5  
psig).  
4. Check all manual--reset switches for continuity.  
5. Replace blower compartment door. Door must be in place  
to operate furnace.  
Sidewall Venting  
This furnace is not approved for direct sidewall horizontal  
venting.  
6. Setup switch descriptions The variable speed furnace con-  
trol has DIP switches to select thermostat staging, blower  
off delay timings, air flow selection and other operational  
or service related functions. (See Fig. 26, 53 and Table  
10.)  
Per section 12.4.3 of the NFPA 54/ANSI Z223.1--2009, any  
listed mechanical venter may be used, when approved by the  
authority having jurisdiction.  
Select the listed mechanical venter to match the Btuh input of the  
furnace being vented. Follow all manufacturer’s installation  
requirements for venting and termination included with the listed  
mechanical venter.  
!
CAUTION  
CUT HAZARD  
START--UP, ADJUSTMENT, AND SAFETY  
Failure to follow this caution may result in personal injury.  
CHECK  
Sheet metal parts may have sharp edges or burrs. Use care  
and wear appropriate protective clothing, safety glasses and  
gloves when handling parts, and servicing furnaces.  
General  
!
WARNING  
REGULATOR COVER SCREW  
FIRE HAZARD  
PLASTIC ADJUST SCREW  
Failure to follow this warning could result in personal injury,  
death or property damage.  
ON/OFF SWITCH  
REGULATOR SPRING  
This furnace is equipped with manual reset limit switches in  
the gas control area. The switches open and shut off power to  
the gas valve, if a flame rollout or overheating condition  
occurs in the gas control area. DO NOT bypass the switches.  
Correct problem before resetting the switches.  
1/2˝ NPT INLET  
HIGH STAGE GAS  
PRESSURE REGULATOR  
ADJUSTMENT  
LOW STAGE  
GAS PRESSURE  
REGULATOR ADJUSTMENT  
INLET  
PRESSURE TAP  
1. Maintain 115--v wiring and ground. Improper polarity will  
result in rapid flashing LED and no furnace operation.  
MANIFOLD  
PRESSURE TAP  
1/2˝ NPT OUTLET  
2. Make thermostat wire connections at the 24--v terminal  
block on the furnace control. Failure to make proper con-  
nections will result in improper operation. (See Fig. 25 --  
34.)  
A04167  
Fig. 49 -- Redundant Automatic Gas Control Valve  
34  
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Start--Up Procedures  
!
WARNING  
FIRE AND EXPLOSION HAZARD  
Failure to follow this warning could cause personal injury,  
death or property damage.  
Never test for gas leaks with an open flame. Use a  
commercially available soap solution made specifically for  
detection of leaks to check all connections.  
BURNER  
ORIFICE  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
A93059  
Failure to follow this warning could result in personal  
injury, or death.  
Fig. 50 -- Orifice Hole  
Blower access door switch opens 115--v power to control.  
No component operation can occur unless switch is closed.  
Caution must be taken when manually closing this switch  
for service purposes.  
1. Purge gas lines after all connections have been made.  
2. Check gas lines for leaks.  
THERMOSTAT SUBBASE  
TERMINALS WITH  
3. To Begin Component Self--Test:  
Remove Blower Access Door. Disconnect the thermostat  
R lead from furnace control board. Manually close blower  
door switch. Turn Setup DIP switch SW1--6 ON. (See Fig.  
26, 53 and Table 10.)  
THERMOSTAT REMOVED  
(ANITICIPATOR, CLOCK, ETC.,  
MUST BE OUT OF CIRCUIT.)  
HOOK-AROUND  
AMMETER  
NOTE: The furnace control allows all components, except the  
gas valve, to be run for short period of time. This feature helps  
diagnose a system problem in case of a component failure.  
Component test feature will not operate if any thermostat signal is  
present at the control.  
R
Y
W
G
Refer to service label attached to furnace or See Fig. 52.  
Component test sequence is as follows:  
a. Inducer motor starts on high--speed and continues to  
run until Step d. of component test sequence.  
b. Hot surface igniter is energized for 15 sec., then off.  
c. Blower motor operates for 15 sec.  
10 TURNS  
d. Inducer motor goes to low--speed for 10 sec., then  
stops.  
e. After component test is completed, one or more status  
codes (11, 25, or 41) will flash. See component test  
section of service label (Fig. 52) in furnace for explan-  
ation of status codes.  
FROM UNIT 24-V  
CONTROL TERMINALS  
0.5 AMPS FOR THERMOSTAT  
5.0 AMPS ON AMMETER  
=
EXAMPLE:  
ANTICIPATOR SETTING  
NOTE: To repeat component test, turn setup switch SW1--6  
10 TURNS AROUND JAWS  
OFF, then back ON.  
A96316  
4. Turn setup DIP switch SW1--6 OFF. Reconnect R lead to  
furnace control board, release blower door switch and re-  
install blower access door.  
Fig. 51 -- Amp. Draw Check with Ammeter  
5. Operate furnace per instruction on inner door.  
6. Verify furnace shut down by lowering thermostat setting  
below room temperature.  
7. Verify furnace restarts by raising thermostat setting above  
room temperature.  
35  
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Table 10 – Furnace Setup Switch Description  
SETUP SWITCH  
NO.  
NORMAL  
POSITION  
SWITCH NAME  
DESCRIPTION OF USE  
Turn ON to retrieve up to 7 stored status codes for troubleshooting as-  
sistance when R thermostat lead is disconnected.  
Allows 2---stage operation with a single stage thermostat. Turn ON when  
using 2 stage thermostat to allow Low Heat operation when R to W/W1  
closes and High Heat operation when R to W/W1 and W2 close.  
Turn ON to increase Low Heat airflow by 18 percent. This compensates  
for increased return air temperature caused with bypass humidifier.  
Turn ON to decrease Low Heat airflow by 16 percent and High Heat  
airflow 10 percent for maximum comfort.  
Turn ON for 400 CFM per ton. Turn OFF for 350 CFM per ton.  
Turn ON to initiate Component Self---Test for troubleshooting assistance  
when R thermostat lead is disconnected. Turn OFF when Self---Test is  
completed.  
SW 1 --- 1  
SW 1 --- 2  
SW 1 --- 3  
Status Code Recovery  
OFF  
Adaptive Heat Mode  
OFF  
OFF  
Low Heat Rise Adjust  
Comfort/Efficiency Ad-  
justment  
CFM per ton adjust  
SW 1 --- 4  
SW 1 --- 5  
ON  
OFF  
SW 1 --- 6  
Component Self---Test  
OFF  
Control blower Off Delay time. Used in conjunction with SW1---8. See  
SW 1 --- 7  
SW 1 --- 8  
Blower OFF delay  
Blower OFF delay  
ON or OFF  
ON or OFF  
Table 11.  
Control blower Off Delay time. Used in conjunction with SW1---7. See  
Table 11.  
SERVICE  
LED CODE  
STATUS  
If status code recall is needed disconnect the "R" thermostat lead, reset power, and put setup switch "SW1-1" in the ON  
position. To cl ear the status code history put setup switch "SW1-1" in the ON position and jumper thermostat terminals "R",  
"W/W1", and "Y/Y2" simultaneously until status code #11 is flashed.  
CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and SEC-2.  
CONTINUOUS ON - Control has 24VAC power.  
RAPID FLASHING - Line voltage (115VAC) polarity reversed.  
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST DIGIT DETERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY THE NUMBER OF LONG FLASHES.  
11 NO PREVIOUS CODE - Stored status codes are erased automatically after 72  
32 Continued: Check for:  
- Defective inducer motor  
- Low inducer voltage (115 VAC)  
- Inadequate combustion air supply  
- Low inlet gas pressure (if LGPS used)  
COMPONENT TEST  
hours or as specified above.  
12 BLOWER ON AFTER POWER UP (115 VAC or 24 VAC) -Blower runs for 90  
seconds, if unit is powered up during a call for heat (R-W/W1 closed) or  
(R-W/W1 opens) during blower on-delay period.  
- Defective pressure switch  
- Low inducer voltage (115 VAC)  
To initiate the component test sequence, shut  
OFF the room thermostat or disconnect the "R"  
thermostat lead. Reset power and then put setup  
switch "SW1-6" in the ON position to start the  
component test sequence. Once initiated the  
furnace control will turn the inducer ON at high-  
heat speed. The inducer motor will run for the  
entire test. The hot surface igniter and blower  
motor will be turned ON for 15 seconds each.  
When the blower is turned OFF the inducer will  
be switched to low-speed for 10 seconds. When  
the component test is completed one or more of  
the following codes will flash.  
- Disconnected or obstructed pressure tubing  
13 LIMIT CIRCUIT LOCKOUT - Lockout occurs if a limit, draft safeguard, flame  
rollout, or blocked vent switch (if used) is open longer than 3 minutes or 10  
successive limit trips occurred during high-heat. Control will auto reset after  
three hours. Refer to status code #33.  
33 LIMIT CIRCUIT FAULT - Indicates a limit, draft safeguard, flame rollout, or  
blocked vent switch (if used) is open or the furnace is operating in high-heat  
only mode due to 2 successive low heat limit trips. Blower will run for 4  
minutes or until open switch remakes whichever is longer. If open longer  
than 3 minutes, code changes to lockout #13. If open less than 3 minutes  
status code #33 continues to flash until blower shuts off. Flame rollout switch  
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to status  
code #34.  
15 BLOWER MOTOR LOCKOUT - Indicates the blower failed to reach 250 RPM or  
the blower failed to communicate within 30 seconds after being turned ON in two  
successive heating cycles. Control will auto reset after 3 hours.  
Refer to status code #41.  
and BVSS require manual reset.  
Check for: - Loose blower wheel  
- Restricted vent  
- Proper vent sizing - Excessive wind  
- Dirty filter or restricted duct system  
- Defective switch or connections  
21 GAS HEATING LOCKOUT - Control will NOT auto reset. Check for:  
- Inadequate combustion air supply (Flame Roll-out Switch open)  
34 IGNITION PROVING FAILURE - Control will try three more times before  
lockout #14 occurs. If flame signal lost during blower on-delay period, blower  
will come on for the selected blower off-delay. Check for:  
- Mis-wired gas valve  
-Defective control (valve relay)  
22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is  
de-energized. Inducer will run until fault is cleared. Check for:  
CODE  
DESCRIPTION  
- Leaky gas valve  
- Stuck-open gas valve  
- Oxide buildup on flame sensor (clean with fine steel wool)  
23 PRESSURE SWITCH DID NOT OPEN Check for:  
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal)  
- Manual valve shut-off - Low inlet gas pressure - Control ground continuity  
11  
Indicates the blower motor tested  
OK. Visual check of inducer motor  
and hot surface igniter required.  
SETUP ERROR - Same as code 25 above.  
- Obstructed pressure tubing  
- Pressure switch stuck closed  
24 SECONDARY VOLTAGE FUSE IS OPEN Check for: - Short circuit in secondary  
voltage (24VAC) wiring.  
- Gas valve defective or turned off  
- Flame sensor must not be grounded  
- Inadequate flame carryover or rough ignition  
25 INVAL ID MODEL SELECTION OR SETUP ERROR - Indicates either the model  
plug is missing or incorrect or, setup switch "SW1-1" or "SW1-6" is positioned  
improperly. If code flashes 4 times on power-up control is defaulting to model  
selection stored in memory.Check for: -Thermostat call with SW1-1, SW1-6 or  
both SW1-1 & SW1-6 ON. - Board date code 2103 or later required to recognize model  
plug 007. - Proper model plug number and resistance values per wiring diagram  
31 HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR  
REOPENED - Control relay may be defective. Refer to status code #32.  
32 LOW-HEAT PRESSURE SWITCH DID NOT CLOSE OR REOPENED - If open  
longer than five minutes, inducer shuts off for 15 minutes before retry. If opens  
during blower on-delay period, blower will come on for the selected blower  
25  
41  
- Green/Yellow wire MUST be connected to furnace sheet metal  
41 BLOWER MOTOR FAULT - Indicates the blower failed to reach 250 RPM  
or the blower failed to communicate within the prescribed times limits. Thirty  
seconds after being turned ON or ten seconds during steady-state operation.  
43 LOW-HEAT PRESSURE SWITCH OPEN WHILE HIGH-HEAT PRESSURE  
SWITCH IS CLOSED - Check for: - Mis-wired pressure switches  
- Low-heat pressure switch stuck open - Low inlet gas pressure (if LGPS used)  
- Disconnected or obstructed pressure tubing  
BLOWER MOTOR FAULT - Indicates  
blower motor failed test. Check  
blower, wiring, and furnace control.  
To repeat component test turn setup switch  
"SW1-6" OFF and then back ON. After component  
test is completed put setup switch "SW1-6" in the  
OFF position and reconnect the "R" thermostat  
lead.  
45 CONTROL CIRCUITRY LOCKOUT Auto-reset after one hour lockout due to;  
- Gas valve relay stuck open - Flame sense circuit failure - Software check error  
Reset power to clear lockout. Replace control if status code repeats.  
off-delay. Check for: - Excessive wind  
- Restricted vent - Proper vent sizing  
328787-101 REV. A  
A04015  
Fig. 52 -- Service Label  
Adjustments  
Furnace gas input rate on rating plate is for installations at  
altitudes up to 2000 Ft. (610 M). Furnace input rate must be  
within +/--2 percent of furnace rating plate input. For altitudes  
above 5500 Ft. (1676 M), a field--supplied high altitude pressure  
switch is required.  
!
WARNING  
FIRE HAZARD  
1. Determine the correct gas input rate.  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
The input rating for altitudes above 2,000 ft. (610 M) must  
be reduced by 4 percent for each 1,000 ft. (305 M) above  
sea level.  
For installations below 2000 Ft. (610 M), refer to the unit  
rating plate. For installations above 2000 Ft. (610 M),  
multiply the input on the rating plate by the de--rate multi-  
plier in Table 10 for the correct input rate.  
DO NOT bottom out gas valve regulator adjusting screw.  
This can result in unregulated manifold pressure and result  
in excess overfire and heat exchanger failures.  
!
CAUTION  
2. Determine the correct orifice and manifold pressure adjust-  
ment. All models in all positions except Low NOx models  
in downflow and horizontal positions use Table 14  
(22,000 Btuh per burner.) Low NOx models in downflow  
or horizontal positions must use Table 15 (21,000 Btuh  
per burner.) See input listed on rating plate.  
FURNACE DAMAGE HAZARD  
Failure to follow this caution may result in reduced furnace  
life.  
DO NOT redrill orifices. Improper drilling (burrs,  
out--of--round holes, etc.) can cause excessive burner noise  
and misdirection of burner flames. This can result in flame  
impingement of heat exchangers, causing failures. (See Fig.  
50.)  
a. Obtain average yearly gas heat value (at installed alti-  
tude) from local gas supplier.  
b. Obtain average yearly gas specific gravity from local  
gas supplier.  
36  
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c. Find installation altitude in Table 14 or 15.  
d. Turn gas valve ON/OFF switch to ON.  
d. Find closest natural gas heat value and specific gravity  
in Table 14 or 15.  
e. Move setup SW1—2 on furnace control to ON posi-  
tion to lock furnace in low--heat operation. (See Table  
10 and Fig. 24.)  
e. Follow heat value and specific gravity lines to point of  
intersection to find orifice size and low--and high--heat  
manifold pressure settings for proper operation.  
f. Manually close blower door switch.  
g. Jumper R and W/W1 thermostat connections on con-  
trol to start furnace. (See Fig. 24.)  
h. Remove regulator adjustment cap from low heat gas  
valve pressure regulator (See Fig. 49.) and turn low--  
heat adjusting screw (3/16 or smaller flat--tipped  
screwdriver) counterclockwise (out) to decrease input  
rate or clockwise (in) to increase input rate.  
f. Check and verify burner orifice size in furnace.  
NEVER ASSUME ORIFICE SIZE. ALWAYS  
CHECK AND VERIFY.  
NOTE: If orifice hole appears damaged or it is suspected to have  
been redrilled, check orifice hole with a numbered drill bit of  
correct size. Never redrill an orifice. A burr--free and squarely  
aligned orifice hole is essential for proper flame characteristics.  
NOTE: DO NOT set low--heat manifold pressure less than  
1.4--In. W.C. or more than 1.7--In. W.C. for natural gas. If  
manifold pressure is outside this range, change main burner  
orifices.  
g. Replace orifice with correct size, if required by Table  
14 or 15. Use only factory--supplied orifices. See  
EXAMPLE 1.  
i. Install low--heat regulator adjustment cap.  
Table 11 – Altitude Derate Multiplier for U.S.A.  
j. Move setup switch SW1--2 to off position after com-  
pleting low--heat adjustment.  
ALTITUDE  
FT. (M)  
0–2000  
(0---610)  
2001–3000  
(610---914)  
3001–4000  
(914---1219)  
4001–5000  
(1219---1524)  
5001–6000  
1524---1829)  
6001–7000  
(1829---2134)  
7001–8000  
(2134---2438)  
8001–9000  
(2438---2743)  
PERCENT  
DERATE MULTIPLIER  
FACTOR*  
k. Leave manometer or similar device connected and  
proceed to Step 4.  
OF DERATE  
0
1.00  
0.90  
0.86  
0.82  
0.78  
0.74  
0.70  
0.66  
0.62  
4. Adjust manifold pressure to obtain high fire input rate.  
(See Fig. 49.)  
8–12  
a. Jumper R to W/W1 and W2 thermostat connections on  
furnace control. This keeps furnace locked in high--  
heat operation.  
12–16  
16–20  
20–24  
24–28  
28–32  
32–36  
36–40  
b. Remove regulator adjustment cap from high--heat gas  
valve pressure regulator (See Fig. 49) and turn high  
heat adjusting screw (3/16--in. or smaller flat--tipped  
screwdriver) counterclockwise (out) to decrease input  
rate or clockwise (in) to increase input rate.  
NOTE: DO NOT set high--heat manifold pressure less than  
3.2--In. W.C. or more than 3.8 In. W.C. for natural gas. If  
manifold pressure is outside this range, change main burner  
orifices to obtain manifold pressure in this range.  
c. When correct input is obtained, replace caps that con-  
ceal gas valve regulator adjustment screws. Main  
burner flame should be clear blue, almost transparent  
(See Fig. 55.)  
9001–10,000  
(2743---3048)  
Table 12 – Blower Off Delay Setup Switch  
d. Remove jumpers R to W/W1 and R to W2.  
SETUP SWITCH  
( S W --- 7 A N D --- 8 )  
POSITION  
5. Verify natural gas input rate by clocking meter.  
DESIRED HEATING MODE  
BLOWER OFF DELAY (SEC.)  
NOTE: Gas valve regulator adjustment caps must be in place for  
proper input to be clocked.  
S W 1 --- 7  
OFF  
ON  
OFF  
ON  
SW1---8  
OFF  
OFF  
ON  
90  
a. Turn off all other gas appliances and pilots served by  
the meter.  
b. Move setup switch SW1--2 to ON position. This  
keeps furnace locked in low--heat operation.  
120  
150  
180  
ON  
c. Jumper R to W/W1.  
d. Run furnace for 3 minutes in low--heat operation.  
EXAMPLE 1: 0–2000 ft. (0--610 M) altitude  
For 22,000 Btuh per burner application use Table 14.  
Heating value = 1000 Btuh/cu ft.  
Specific gravity = 0.62  
Therefore: Orifice No. 43*  
e. Measure time (in sec) for gas meter to complete 1  
revolution and note reading. The 2 or 5 cubic feet dial  
provides a more accurate measurement of gas flow.  
Manifold pressure: 3.7--In. W.C. for high--heat  
1.6--In. W.C. for low--heat  
* Furnace is shipped with No. 43 orifices. In this example all  
main burner orifices are the correct size and do  
not need to be changed to obtain proper input rate.  
f. Refer to Table 13 for cubic ft. of gas per hr.  
g. Multiply gas rate cu ft./hr by heating value (Btuh/cu  
ft.) to obtain input. If clocked rate does not match re-  
quired input from Step 1, increase manifold pressure to  
increase input or decrease manifold pressure to de-  
crease input. Repeat steps b through e until correct  
low--heat input is achieved. Re--install low heat regu-  
lator seal cap on gas valve.  
h. Move setup switch SW1--2 to OFF position and jump-  
er R to W/W1, and W2. This keeps furnace locked in  
high--heat operation. Repeat items d through g for  
high--heat operation.  
3. Adjust manifold pressure to obtain low fire input rate. (See  
Fig. 49.)  
a. Turn gas valve ON/OFF switch to OFF.  
b. Remove manifold pressure tap plug from gas valve.  
c. Connect a water column manometer or similar device  
to manifold pressure tap.  
37  
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6. Set Temperature Rise  
e. Repeat Steps a through c as required to adjust for high  
heat temperature rise.  
f. When correct high heat input rate and temperature rise  
is achieved, turn gas valve ON/OFF switch to OFF.  
NOTE: Blower access door must be installed when taking  
temperature rise reading. Leaving blower access door off will  
result in incorrect temperature measurements.  
g. Release blower access door switch.  
h. Remove manometer or similar device from gas valve.  
!
CAUTION  
i. Re--install manifold pressure tap plug in gas valve.  
(See Fig. 49.)  
FURNACE DAMAGE HAZARD  
Failure to follow this caution may result in shorten furnace  
life.  
!
WARNING  
Set air temperature rise within limits specified on the rating  
plate to prevent reduced life of furnace components.  
Operation is within a few degrees of the mid--point of rise  
range when setup switch SW1--4 is OFF.  
FIRE HAZARD  
Failure to follow this warning could result in personal  
injury, death, and/or property damage.  
Reinstall manifold pressure tap plug in gas valve to prevent  
gas leak.  
!
CAUTION  
j. Remove thermostat jumper wire from furnace control  
board.  
UNIT DAMAGE HAZARD  
Failure to follow this caution may result in overheating the  
heat exchangers or condensing flue gases in heat exchanger  
areas not designed for condensate.  
k. Turn gas valve ON/OFF switch to ON.  
!
CAUTION  
Temperature rise must be within limits specified on unit  
rating plate. Operation is within a few degrees of midpoint  
of rise range when setup switch SW1--4 is OFF.  
FURNACE OVERHEATING HAZARD  
Failure to follow this caution may result in reduced furnace  
life.  
When setup switch SW1--4 is ON, operation will be near the high  
end of the rise range for improved comfort.  
Furnace must operate within ranges of temperature rise specified  
on the furnace rating plate. Determine air temperature rise as  
follows:  
Recheck temperature rise. It must be within limits specified  
on the rating plate. Recommended operation is at the  
mid--point of rise range or slightly above.  
l. Proceed to Step 6, “Set Blower Off Delay” before in-  
stalling blower access door.  
a. Place thermometers in return and supply ducts as near  
furnace as possible. Be sure thermometers do not see  
heat exchanger so that radiant heat does not affect  
readings. This practice is particularly important with  
straight--run ducts.  
b. When thermometer readings stabilize, subtract return--  
air temperature from supply--air temperature to determ-  
ine air temperature rise.  
7. Set Blower Off Delay  
a. Remove blower access door if installed.  
b. Turn Dip switch SW--7 or SW--8 ON or OFF for de-  
sired blower off delay. (See Table 10 and Fig. 26 and  
53.)  
8. Set thermostat heat anticipator.  
NOTE: Temperature rise can be determined for low--heat  
operation by placing setup switch SW1--2 on furnace control in  
ON position. For high--heat operation, place setup switch SW1--2  
in OFF position and jumper R--W2 on furnace control. DO NOT  
forget to return setup switch to OFF position and remove R--W2  
jumper upon completion of testing.  
a. Mechanical thermostat. Set thermostat heat anticipator  
to match the amp. draw of the electrical components in  
the R--W/W1 circuit. Accurate amp. draw readings can  
be obtained at the wires normally connected to ther-  
mostat subbase terminals, R and W. The thermostat  
anticipator should NOT be in the circuit while measur-  
ing current.  
c. This furnace is capable of automatically providing  
proper airflow to maintain the temperature rise within  
the range specified on furnace rating plate. If temperat-  
ure rise is outside this range, proceed as follows:  
(1.) Set SW1--2 switch on furnace control board to  
ON.  
(2.) Remove thermostat from subbase or from wall.  
(1.) Check gas input for low-- and high--heat opera-  
tion.  
(3.) Connect an amp. meter as shown in Fig. 51.  
across the R and W subbase terminals or R and  
W wires at wall.  
(2.) Check derate for altitude if applicable.  
(3.) Check all return and supply ducts for excessive  
restrictions causing static pressure greater than  
0.5--In. W.C..  
(4.) Record amp. draw across terminals when furnace  
is in low heat and after blower starts.  
(5.) Set heat anticipator on thermostat per thermostat  
instructions and install on subbase or wall.  
(4.) Ensure Low Heat Rise Adjust switch SW1--3 on  
furnace control is in ON position when a bypass  
humidifier is used. (See Fig. 26 for switch loca-  
tion.)  
(6.) Turn SW1--2 switch OFF.  
(7.) Install blower access door.  
b. Electronic thermostat: Set cycle rate for 3 cycles per  
hr.  
(5.) Make sure proper model plug is installed.  
d. Remove thermostat jumpers and release blower access  
door switch.  
9. Set Airflow for Air Conditioning --Single Stage and High  
Stage Cooling  
The ECM blower can be adjusted for a range of airflow  
38  
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for Low Speed or High Speed cooling. See Table 5--Air  
Delivery -- CFM (With Filter ). Depending on the model  
size, the cooling airflow can be adjusted from 1. tons nom-  
inal cooling to 3 ., to 4 or to 6 tons of nominal cooling  
based on 350 cfm ton.  
The cooling airflow is adjusted by turning Setup switches  
SW2--1, SW2--2 and SW2--3 either ON or OFF. Select the  
required airflow from Fig. 57. Fig. 57 is based on 350  
CFM per ton. For airflow at 400 CFM per ton, turn Setup  
SW1--5 ON (See Table 10 and Fig. 26 and 53.)  
ous fan speeds different than heating or cooling fan speed.  
See Table 5 -- Air Delivery -- CFM (With Filter). Select the  
required continuous fan airflow from Fig. 57.  
The continuous fan speed is also the fan speed for low  
speed cooling when furnace is used with a 2--speed cool-  
ing unit. Adjust the Continuous Fan CFM to match the  
airflow required for low speed cooling. Select the required  
airflow from Fig. 55. For airflow at 400 CFM per ton, turn  
Setup SW1--5 ON (See Fig. 57.) The airflow selected for  
low speed cooling will also be the airflow used for con-  
tinuous fan.  
The continuous fan speed can be further adjusted at the  
thermostat using the “Comfort Fan” select function.  
Changing the continuous fan speed at the thermostat  
DOES NOT change the low speed cooling airflow selec-  
ted at the control board.  
NOTE: 6 ton airflow will truncate at 2200 cfm on applicable  
models. For a complete explanation of cooling airflow, refer to  
the section titled “Sequence of Operation.”  
10. Set Airflow For Continuous Fan/Low Speed Cooling Air-  
flow The ECM blower motor can be adjusted for continu-  
39  
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A08464  
Fig. 53 -- Wiring Diagram  
40  
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Table 13 – Gas Rate (CU ft./hr)  
SIZE OF TEST DIAL  
2 Cu Ft.  
720  
SIZE OF TEST DIAL  
SECONDS G  
SECONDS  
FOR 1 REVOLUTION  
FOR 1 REVOLUTION  
1 Cu Ft.  
360  
327  
300  
277  
257  
240  
225  
212  
200  
189  
180  
171  
164  
157  
150  
144  
138  
133  
129  
124  
120  
116  
113  
109  
106  
103  
100  
97  
95  
92  
90  
88  
86  
84  
82  
80  
78  
76  
75  
73  
5 Cu Ft.  
1800  
1636  
1500  
1385  
1286  
1200  
1125  
1059  
1000  
947  
900  
857  
818  
783  
750  
720  
692  
667  
643  
621  
600  
581  
563  
545  
529  
514  
500  
486  
474  
462  
450  
439  
429  
419  
1 Cu Ft.  
72  
71  
69  
68  
67  
65  
64  
63  
62  
61  
60  
58  
56  
54  
53  
51  
50  
48  
47  
46  
45  
44  
43  
42  
41  
40  
39  
38  
38  
37  
36  
35  
35  
34  
33  
33  
32  
31  
30  
2 Cu Ft.  
144  
141  
138  
136  
133  
131  
129  
126  
124  
122  
120  
116  
112  
109  
106  
103  
100  
97  
95  
92  
90  
88  
86  
84  
82  
80  
78  
76  
75  
74  
72  
71  
69  
68  
67  
65  
64  
62  
5 Cu Ft.  
360  
355  
346  
340  
333  
327  
321  
316  
310  
305  
300  
290  
281  
273  
265  
257  
250  
243  
237  
231  
225  
220  
214  
209  
205  
200  
196  
192  
188  
184  
180  
178  
173  
170  
167  
164  
161  
155  
150  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
28  
29  
30  
31  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
45  
46  
47  
48  
49  
50  
51  
52  
53  
54  
55  
56  
57  
58  
59  
60  
62  
64  
66  
68  
70  
72  
74  
76  
78  
80  
82  
84  
86  
88  
90  
92  
94  
96  
655  
600  
555  
514  
480  
450  
424  
400  
379  
360  
343  
327  
313  
300  
288  
277  
267  
257  
248  
240  
232  
225  
218  
212  
206  
200  
195  
189  
185  
180  
176  
172  
98  
100  
102  
104  
106  
108  
110  
112  
116  
120  
167  
164  
160  
157  
153  
150  
147  
409  
400  
391  
383  
375  
367  
60  
41  
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Table 14 – Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate  
(Tabulated Data Based on 22,000 Btuh High--Heat/14,500 Btuh for Low--Heat per Burner, Derated 4 Percent for Each 1000 Ft.  
(305 M) Above Sea Level)  
SPECIFIC GRAVITY OF NATURAL GAS  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
0.58  
Manifold  
0.60  
Manifold  
0.62  
Manifold  
0.64  
Manifold  
ALTITUDE RANGE  
FT. (M)  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.5/1.5  
3.3/1.4  
3.8/1.7  
3.6/1.6  
3.5/1.5  
3.3/1.4  
3.6/1.6  
3.4/1.5  
3.3/1.4  
Pressure  
High/Low  
3.6/1.6  
3.4/1.5  
3.3/1.4  
3.8/1.6  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.5/1.5  
3.4/1.5  
Pressure  
High/Low  
3.7/1.6  
3.5/1.5  
3.4/1.5  
3.2/1.4  
3.7/1.6  
3.5/1.5  
3.4/1.5  
3.2/1.4  
3.5/1.5  
Pressure  
High/Low  
3.5/1.5  
3.7/1.6  
3.5/1.5  
3.3/1.4  
3.8/1.7  
3.6/1.6  
3.5/1.5  
3.3/1.4  
3.2/1.4  
900  
925  
42  
42  
43  
43  
43  
43  
44  
44  
44  
42  
42  
42  
43  
43  
43  
43  
44  
44  
42  
42  
42  
42  
43  
43  
43  
43  
44  
41  
42  
42  
42  
43  
43  
43  
43  
43  
950  
975  
0 to  
USA  
1000  
1025  
1050  
1075  
1100  
2000  
(0 to 610)  
SPECIFIC GRAVITY OF NATURAL GAS  
0.58  
0.60 0.62  
0.64  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
ALTITUDE RANGE  
FT. (M)  
Manifold  
Manifold  
Pressure  
High/Low  
Manifold  
Manifold  
Pressure  
High/Low  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
Pressure  
High/Low  
800  
825  
850  
875  
900  
925  
950  
975  
1000  
42  
42  
43  
43  
43  
44  
44  
44  
45  
3.4/1.5  
3.2/1.4  
3.7/1.6  
3.5/1.5  
3.3/1.4  
3.5/1.5  
3.4/1.5  
3.2/1.4  
3.7/1.6  
42  
42  
43  
43  
43  
43  
44  
44  
45  
3.5/1.5  
3.3/1.4  
3.8/1.6  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.5/1.5  
3.3/1.4  
3.8/1.7  
42  
42  
42  
43  
43  
43  
44  
44  
44  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.7/1.6  
3.5/1.5  
3.3/1.4  
3.6/1.6  
3.4/1.5  
3.2/1.4  
42  
42  
42  
43  
43  
43  
43  
44  
44  
3.7/1.6  
3.5/1.5  
3.3/1.4  
3.8/1.7  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.5/1.5  
3.4/1.5  
2001 to  
3000 (610  
to 914)  
USA  
SPECIFIC GRAVITY OF NATURAL GAS  
0.58  
0.60 0.62  
0.64  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
ALTITUDE RANGE  
FT. (M)  
Manifold  
Manifold  
Pressure  
High/Low  
Manifold  
Manifold  
Pressure  
High/Low  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
Pressure  
High/Low  
775  
800  
825  
850  
875  
900  
925  
950  
42  
43  
43  
43  
44  
44  
45  
46  
3.2/1.4  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.5/1.5  
3.3/1.4  
3.8/1.6  
3.8/1.6  
42  
43  
43  
43  
44  
44  
44  
45  
3.3/1.4  
3.8/1.6  
3.5/1.5  
3.3/1.4  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.7/1.6  
42  
42  
43  
43  
43  
44  
44  
45  
3.4/1.5  
3.2/1.4  
3.7/1.6  
3.4/1.5  
3.3/1.4  
3.5/1.5  
3.3/1.5  
3.8/1.7  
42  
42  
43  
43  
43  
43  
44  
44  
3.5/1.5  
3.3/1.4  
3.8/1.6  
3.6/1.5  
3.4/1.5  
3.2/1.4  
3.4/1.5  
3.3/1.4  
3001 to  
4000  
USA  
(914 to  
1219)  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
0.58  
0.64  
ALTITUDE RANGE  
FT. (M)  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
Manifold  
Manifold  
Pressure  
High/Low  
Manifold  
Manifold  
Pressure  
High/Low  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
Pressure  
High/Low  
750  
775  
800  
825  
850  
875  
900  
925  
43  
43  
43  
44  
44  
45  
46  
46  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.4/1.5  
3.2/1.4  
3.7/1.6  
3.7/1.6  
3.5/1.5  
43  
43  
43  
44  
44  
45  
46  
46  
3.8/1.6  
3.5/1.5  
3.3/1.4  
3.6/1.5  
3.4/1.5  
3.8/1.7  
3.8/1.7  
3.6/1.6  
42  
43  
43  
43  
44  
44  
45  
46  
3.2/1.4  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.5/1.5  
3.3/1.4  
3.7/1.6  
3.7/1.6  
42  
43  
43  
43  
44  
44  
44  
46  
3.3/1.4  
3.8/1.6  
3.5/1.5  
3.3/1.4  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.8/1.7  
4001 to  
5000  
USA  
(1219 to  
1524)  
* Orifice numbers 43 are factory installed  
42  
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Table 14 -- Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Con’t.)  
(Tabulated Data Based on 22,000 Btuh High--Heat/14,500 Btuh for Low--Heat per Burner, Derated 4 Percent for Each 1000 Ft.  
Above Sea Level)  
SPECIFIC GRAVITY OF NATURAL GAS  
AVG. GAS  
ALTITUDE  
RANGE  
0.58  
0.60  
0.62  
Manifold  
0.64  
Manifold  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
Manifold  
Manifold  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.4/1.5  
3.2/1.4  
3.4/1.5  
3.2/1.4  
3.8/1.7  
3.6/1.6  
3.8/1.7  
3.6/1.6  
Pressure  
High/Low  
3.5/1.5  
3.3/1.4  
3.5/1.5  
3.3/1.4  
3.8/1.6  
3.7/1.6  
3.5/1.5  
3.8/1.6  
Pressure  
High/Low  
3.6/1.6  
3.4/1.5  
3.2/1.4  
3.4/1.5  
3.2/1.4  
3.8/1.7  
3.6/1.6  
3.4/1.5  
Pressure  
High/Low  
3.7/1.6  
3.5/1.5  
3.3/1.4  
3.5/1.5  
3.3/1.4  
3.8/1.6  
3.7/1.6  
3.5/1.5  
FT. (M)  
725  
750  
775  
800  
825  
850  
875  
900  
43  
43  
44  
44  
46  
46  
47  
47  
43  
43  
44  
44  
45  
46  
46  
47  
43  
43  
43  
44  
44  
46  
46  
46  
43  
43  
43  
44  
44  
45  
46  
46  
5001 to  
6000  
(1524  
to  
USA  
1829)  
AVG. GAS  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
ALTITUDE  
RANGE  
FT. (M)  
0.58  
0.64  
Manifold  
Pressure  
High/Low  
3.4/1.5  
3.6/1.6  
3.4/1.5  
3.8/1.7  
3.7/1.6  
3.5/1.5  
3.7/1.6  
3.5/1.5  
Manifold  
Pressure  
High/Low  
3.7/1.6  
3.5/1.5  
3.2/1.4  
3.5/1.5  
3.2/1.4  
3.7/1.6  
3.6/1.6  
3.4/1.5  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
675  
700  
725  
750  
775  
800  
825  
850  
43  
44  
44  
45  
46  
46  
47  
47  
43  
43  
43  
44  
44  
45  
46  
46  
6001 to  
7000  
(1829  
to  
USA  
2134)  
AVG. GAS  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
ALTITUDE  
RANGE  
FT. (M)  
0.58  
0.64  
Manifold  
Pressure  
High/Low  
3.6/1.6  
3.3/1.5  
3.8/1.6  
3.7/1.6  
3.4/1.5  
3.6/1.6  
3.4/1.5  
3.7/1.6  
Manifold  
Pressure  
High/Low  
3.5/1.5  
3.2/1.4  
3.4/1.5  
3.2/1.4  
3.8/1.6  
3.6/1.5  
3.8/1.6  
3.6/1.5  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
650  
675  
700  
725  
750  
775  
800  
825  
44  
44  
45  
46  
46  
47  
47  
48  
43  
43  
44  
44  
46  
46  
47  
47  
7001 to  
8000  
(2134  
to  
USA  
2438)  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
Manifold Manifold  
AVG. GAS  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
ALTITUDE  
RANGE  
FT. (M)  
0.58  
0.64  
Manifold  
Pressure  
High/Low  
3.3/1.5  
3.7/1.6  
3.6/1.6  
3.8/1.7  
3.6/1.6  
3.8/1.7  
3.6/1.5  
3.7/1.6  
3.6/1.6  
3.8/1.6  
3.5/1.5  
3.7/1.6  
3.5/1.5  
Manifold  
Pressure  
High/Low  
3.2/1.4  
3.4/1.5  
3.8/1.7  
3.7/1.6  
3.5/1.5  
3.7/1.6  
3.5/1.5  
3.4/1.5  
3.8/1.6  
3.7/1.6  
3.4/1.5  
3.6/1.6  
3.8/1.7  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.5/1.5  
3.2/1.4  
3.8/1.6  
3.5/1.5  
3.7/1.6  
3.5/1.5  
3.7/1.6  
3.8/1.7  
3.7/1.6  
3.4/1.5  
3.6/1.6  
3.8/1.7  
3.6/1.6  
Pressure  
High/Low  
3.6/1.6  
3.3/1.4  
3.7/1.6  
3.6/1.6  
3.8/1.7  
3.6/1.6  
3.8/1.7  
3.3/1.4  
3.8/1.7  
3.6/1.5  
3.7/1.6  
3.5/1.5  
3.7/1.6  
625  
650  
675  
700  
725  
750  
775  
600  
625  
650  
675  
700  
725  
44  
45  
46  
47  
47  
48  
48  
45  
46  
47  
47  
48  
48  
44  
44  
46  
46  
47  
47  
48  
45  
46  
46  
47  
48  
48  
44  
44  
45  
46  
47  
47  
48  
44  
46  
46  
47  
47  
48  
43  
44  
45  
46  
46  
47  
47  
44  
45  
46  
46  
47  
48  
8001 to  
9000  
(2438  
to  
USA  
2743)  
9001 to  
10,000  
2743 to  
3048)  
USA  
* Orifice numbers 43 are factory installed  
43  
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Table 15 – Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate  
(Tabulated Data Based on 21,000 Btuh High--Heat/14,500 Btuh for Low--Heat Per Burner, Derated 4 Percent for Each 1000 Ft.  
(305 M) Above Sea level)  
SPECIFIC GRAVITY OF NATURAL GAS  
AVG. GAS  
HEAT VALUE  
(BTUH/CU  
FT.)  
ALTITUDE RANGE  
FT. (M)  
0.58  
0.60  
0.62  
0.64  
Manifold  
Manifold  
Manifold  
Manifold  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.2/1.5  
3.7/1.8  
3.5/1.7  
3.3/1.6  
3.6/1.7  
3.4/1.6  
3.3/1.6  
3.8/1.8  
3.8/1.8  
Pressure  
High/Low  
3.3/1.6  
3.8/1.8  
3.6/1.7  
3.4/1.6  
3.3/1.6  
3.6/1.7  
3.4/1.6  
3.2/1.5  
3.7/1.8  
Pressure  
High/Low  
3.4/1.6  
3.2/1.5  
3.7/1.8  
3.5/1.7  
3.4/1.6  
3.2/1.5  
3.5/1.7  
3.3/1.6  
3.2/1.5  
Pressure  
High/Low  
3.5/1.7  
3.3/1.6  
3.8/1.8  
3.7/1.7  
3.5/1.7  
3.3/1.6  
3.2/1.5  
3.4/1.6  
3.3/1.6  
900  
925  
42  
43  
43  
43  
44  
44  
44  
45  
46  
42  
43  
43  
43  
43  
44  
44  
44  
45  
42  
42  
43  
43  
43  
43  
44  
44  
44  
42  
42  
43  
43  
43  
43  
43  
44  
44  
950  
0 to  
975  
2000  
USA  
1000  
1025  
1050  
1075  
1100  
(0 to 610)  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
Manifold Manifold  
0.58  
0.64  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
Manifold  
Pressure  
High/Low  
3.8/1.8  
3.5/1.7  
3.3/1.6  
3.2/1.5  
3.4/1.6  
3.2/1.5  
3.7/1.8  
3.7/1.8  
3.5/1.7  
Manifold  
Pressure  
High/Low  
3.4/1.6  
3.2/1.5  
3.7/1.8  
3.5/1.7  
3.3/1.6  
3.6/1.7  
3.4/1.6  
3.2/1.5  
3.7/1.8  
ALTITUDE RANGE  
FT. (M)  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.2/1.5  
3.7/1.7  
3.5/1.6  
3.3/1.6  
3.5/1.7  
3.3/1.6  
3.8/1.8  
3.8/1.8  
3.6/1.7  
Pressure  
High/Low  
3.3/1.6  
3.8/1.8  
3.6/1.7  
3.4/1.6  
3.2/1.5  
3.5/1.6  
3.3/1.6  
3.8/1.8  
3.8/1.8  
800  
825  
850  
875  
900  
925  
950  
975  
1000  
43  
43  
43  
43  
44  
44  
45  
46  
46  
42  
43  
43  
43  
44  
44  
45  
46  
46  
42  
43  
43  
43  
43  
44  
44  
45  
46  
42  
42  
43  
43  
43  
44  
44  
44  
45  
2001 to  
USA  
3000 (610  
to 914)  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
Manifold Manifold  
0.58  
0.64  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
Manifold  
Pressure  
High/Low  
3.5/1.7  
3.3/1.6  
3.6/1.7  
3.4/1.6  
3.8/1.8  
3.8/1.8  
3.6/1.7  
3.4/1.6  
Manifold  
Pressure  
High/Low  
3.2/1.5  
3.7/1.7  
3.4/1.6  
3.2/1.5  
3.5/1.7  
3.3/1.6  
3.8/1.8  
3.8/1.8  
ALTITUDE RANGE  
FT. (M)  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.7/1.7  
3.4/1.6  
3.2/1.5  
3.5/1.7  
3.3/1.6  
3.8/1.8  
3.7/1.8  
3.5/1.7  
Pressure  
High/Low  
3.8/1.8  
3.5/1.7  
3.3/1.6  
3.6/1.7  
3.4/1.6  
3.2/1.5  
3.7/1.8  
3.7/1.7  
775  
800  
825  
850  
875  
900  
925  
950  
43  
43  
44  
44  
45  
46  
46  
46  
43  
43  
43  
44  
44  
45  
46  
46  
43  
43  
43  
44  
44  
44  
45  
46  
42  
43  
43  
43  
44  
44  
45  
46  
3001 to  
4000 (914  
to 1219)  
USA  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
Manifold Manifold  
0.58  
0.64  
AVG. GAS  
HEAT VALUE  
(BTUH/CU FT.)  
Manifold  
Pressure  
High/Low  
3.3/1.6  
3.6/1.7  
3.3/1.6  
3.8/1.8  
3.8/1.8  
3.5/1.7  
3.8/1.8  
3.6/1.7  
Manifold  
Pressure  
High/Low  
3.6/1.7  
3.4/1.6  
3.2/1.5  
3.5/1.6  
3.3/1.6  
3.7/1.8  
3.7/1.8  
3.5/1.7  
ALTITUDE RANGE  
FT. (M)  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.4/1.6  
3.2/1.5  
3.4/1.6  
3.2/1.5  
3.7/1.8  
3.7/1.7  
3.5/1.7  
3.7/1.8  
Pressure  
High/Low  
3.5/1.7  
3.3/1.6  
3.6/1.7  
3.4/1.6  
3.8/1.8  
3.8/1.8  
3.6/1.7  
3.8/1.8  
750  
775  
800  
825  
850  
875  
900  
925  
43  
44  
44  
45  
46  
46  
47  
47  
43  
43  
44  
44  
45  
46  
46  
47  
43  
43  
44  
44  
45  
46  
46  
47  
43  
43  
43  
44  
44  
45  
46  
46  
4001 to  
5000  
USA  
(1219 to  
1524)  
* Orifice numbers 43 are factory installed  
44  
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Table 15 -- Orifice Size and Manifold Pressure (In. W.C.) for Gas Input Rate (Con’t.)  
(Tabulated Data Based on 21,000 Btuh High--Heat/14,500 Btuh for Low--Heat Per Burner, Derated 4 Percent for Each 1000 Ft.  
(305 M) Above Sea level)  
AVG. GAS  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
Manifold Manifold  
HEAT VALUE  
0.58  
Manifold  
0.64  
Manifold  
ALTITUDE RANGE  
FT. (M)  
AT ALTITUDE  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.5/1.7  
3.3/1.6  
3.7/1.8  
3.7/1.8  
3.5/1.7  
3.7/1.8  
3.5/1.7  
3.8/1.8  
Pressure  
High/Low  
3.2/1.5  
3.4/1.6  
3.2/1.5  
3.8/1.8  
3.6/1.7  
3.8/1.8  
3.6/1.7  
3.4/1.6  
Pressure  
High/Low  
3.3/1.6  
3.5/1.7  
3.3/1.6  
3.8/1.8  
3.7/1.8  
3.5/1.7  
3.7/1.8  
3.5/1.7  
Pressure  
High/Low  
3.4/1.6  
3.2/1.5  
3.4/1.6  
3.2/1.5  
3.8/1.8  
3.6/1.7  
3.4/1.6  
3.7/1.7  
(BTUH/CU  
FT.)  
725  
44  
44  
45  
46  
46  
47  
47  
48  
43  
44  
44  
46  
46  
47  
47  
47  
43  
44  
44  
45  
46  
46  
47  
47  
43  
43  
44  
44  
46  
46  
46  
47  
750  
5001 to  
775  
6000  
800  
USA  
825  
(1524 to  
850  
1829)  
875  
900  
AVG. GAS  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
0.58  
0.64  
ALTITUDE RANGE  
FT. (M)  
Manifold  
Pressure  
High/Low  
3.5/1.7  
3.3/1.6  
3.7/1.8  
3.6/1.7  
3.4/1.6  
3.6/1.7  
3.4/1.6  
3.7/1.7  
Manifold  
Pressure  
High/Low  
3.4/1.6  
3.2/1.5  
3.4/1.6  
3.8/1.8  
3.8/1.8  
3.5/1.7  
3.8/1.8  
3.5/1.7  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
675  
700  
725  
750  
775  
800  
825  
850  
44  
44  
45  
46  
46  
47  
47  
48  
43  
43  
44  
45  
46  
46  
47  
47  
6001 to  
7000  
USA  
(1829 to  
2134)  
SPECIFIC GRAVITY OF NATURAL GAS  
0.60 0.62  
Manifold Manifold  
AVG. GAS  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
0.58  
0.64  
ALTITUDE RANGE  
FT. (M)  
Manifold  
Pressure  
High/Low  
3.3/1.6  
3.7/1.8  
3.6/1.7  
3.8/1.8  
3.5/1.7  
3.8/1.8  
3.6/1.7  
3.3/1.6  
Manifold  
Pressure  
High/Low  
3.2/1.5  
3.4/1.6  
3.8/1.8  
3.7/1.8  
3.5/1.6  
3.7/1.7  
3.4/1.6  
3.7/1.8  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Pressure  
High/Low  
3.4/1.6  
3.8/1.8  
3.7/1.8  
3.5/1.7  
3.7/1.8  
3.4/1.6  
3.7/1.8  
3.5/1.6  
Pressure  
High/Low  
3.5/1.7  
3.3/1.6  
3.8/1.8  
3.6/1.7  
3.8/1.8  
3.6/1.7  
3.8/1.8  
3.6/1.7  
650  
675  
700  
725  
750  
775  
800  
825  
44  
45  
46  
47  
47  
48  
48  
48  
44  
45  
46  
46  
47  
47  
48  
48  
44  
44  
46  
46  
47  
47  
48  
48  
43  
44  
45  
46  
46  
47  
47  
48  
7001 to  
8000  
USA  
(2134 to  
2438)  
AVG. GAS  
HEAT VALUE  
AT ALTITUDE  
(BTUH/CU FT.)  
0.58  
0.64  
ALTITUDE RANGE  
FT. (M)  
Manifold  
Pressure  
High/Low  
3.7/1.8  
3.6/1.7  
3.8/1.8  
3.5/1.7  
3.7/1.8  
3.5/1.7  
3.8/1.8  
3.6/1.7  
3.7/1.8  
3.4/1.6  
3.6/1.7  
3.4/1.6  
3.7/1.8  
Manifold  
Pressure  
High/Low  
3.4/1.6  
3.8/1.8  
3.7/1.7  
3.4/1.6  
3.6/1.7  
3.8/1.8  
3.6/1.7  
3.7/1.8  
3.6/1.7  
3.8/1.8  
3.5/1.7  
3.7/1.8  
3.5/1.7  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
Orifice  
No.  
625  
650  
675  
700  
725  
750  
775  
600  
625  
650  
675  
700  
725  
45  
46  
47  
47  
48  
48  
49  
46  
47  
47  
48  
48  
49  
44  
45  
46  
46  
47  
48  
48  
45  
46  
47  
47  
48  
48  
8001 to  
9000  
USA  
(2438 to  
2743)  
9001 to  
10,000  
USA  
(2743 to  
3048)  
* Orifice numbers 43 are factory installed  
45  
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Check Safety Controls  
SW1--7 and SW1--8 for the blower OFF DELAY are set as  
desired per Table 10.  
3. Verify that blower and burner access doors are properly in-  
stalled.  
The flame sensor, gas valve, and pressure switch were all checked  
in the Start--up procedure section as part of normal operation.  
1. Check Main Limit Switch  
4. Cycle test furnace with room thermostat.  
5. Check operation of accessories per manufacturer’s instruc-  
tions.  
6. Review User’s Guide with owner.  
7. Attach literature packet to furnace.  
This control shuts off combustion system and energizes  
air--circulating blower motor, if furnace overheats. By us-  
ing this method to check limit control, it can be established  
that limit is functioning properly and will operate if there  
is a restricted return--air supply or motor failure. If limit  
control does not function during this test, cause must be  
determined and corrected.  
SERVICE AND MAINTENANCE  
PROCEDURES  
a. Run furnace for at least 5 minutes.  
b. Gradually block off return air with a piece of card-  
board or sheet metal until the limit trips.  
c. Unblock return air to permit normal circulation.  
d. Burners will re--light when furnace cools down.  
!
WARNING  
FIRE, INJURY OR DEATH HAZARD  
2. Check draft safeguard switch. The purpose of this control  
is to cause the safe shutdown of the furnace during certain  
blocked vent conditions.  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
The ability to properly perform maintenance on this  
equipment requires certain knowledge, mechanical skills,  
tools, and equipment. If you do not possess these, do not  
attempt to perform any maintenance on this equipment  
other than those procedures recommended in the User’s  
Manual.  
a. Verify vent pipe is cool to the touch.  
b. Disconnect power to furnace and remove vent con-  
nector from furnace vent elbow.  
c. Restore power to furnace and set room thermostat  
above room temperature.  
d. After normal start--up, allow furnace to operate for 2  
minutes, then block vent elbow in furnace 80 percent  
of vent area with a piece of flat sheet metal.  
!
CAUTION  
e. Furnace should cycle off within 2 minutes. If gas does  
not shut off within 2 minutes, determine reason draft  
safeguard switch did not function properly and correct  
condition.  
f. Remove blockage from furnace vent elbow.  
g. Switch will auto--reset when it cools.  
h. Re--install vent connector.  
ENVIRONMENTAL HAZARD  
Failure to follow this caution may result in environmental  
pollution.  
Remove and recycle all components or materials (i.e. oil,  
refrigerant, control board, etc.) before unit final disposal.  
NOTE: Should switch remain open longer than 3 minutes,  
furnace control board will lockout the furnace for 3 hours. To  
reset furnace control board, turn thermostat below room  
temperature or from HEAT to OFF and turn 115--v power OFF,  
then back ON.  
!
WARNING  
ELECTRICAL SHOCK, FIRE OR EXPLOSION  
HAZARD  
3. Check Pressure Switch(es)  
This control proves operation of the draft inducer blower.  
a. Turn off 115--v power to furnace.  
Failure to follow this warning could result in personal  
injury or death, or property damage.  
b. Disconnect inducer motor lead wires from wire har-  
ness.  
c. Turn on 115--v power to furnace.  
Before installing, modifying, or servicing system, main  
electrical disconnect switch must be in the OFF position and  
install a lockout tag. There may be more than one  
disconnect switch. Lock out and tag switch with a suitable  
warning label. Verify proper operation after servicing.  
d. Set thermostat to “call for heat” and wait 1 minute.  
When pressure switch is functioning properly, hot sur-  
face igniter should NOT glow and control diagnostic  
light flashes a status code 32. If hot surface igniter  
glows when inducer motor is disconnected, shut down  
furnace immediately.  
!
CAUTION  
e. Determine reason pressure switch did not function  
properly and correct condition.  
ELECTRICAL OPERATION HAZARD  
f. Turn off 115--v power to furnace.  
g. Reconnect inducer motor wires, replace outer door,  
and turn on 115--v power.  
h. Blower will run for 90 seconds before beginning the  
call for heat again.  
Failure to follow this caution may result in improper  
furnace operation or failure of furnace.  
Label all wires prior to disconnection when servicing  
controls. Wiring errors can cause improper and dangerous  
operation.  
i. Furnace should ignite normally.  
Checklist  
General  
1. Put away tools and instruments. Clean up debris.  
These instructions are written as if the furnace is installed in an  
upflow application. An upflow furnace application is where the  
blower is located below the combustion and controls section of  
2. Verify that switches SW1--1 and SW1--6 are OFF and oth-  
er setup switches are set as desired. Verify that switches  
46  
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the furnace, and conditioned air is discharged upward. Since this  
furnace can be installed in any of the 4 positions shown in Fig. 4,  
you must revise your orientation to component location  
accordingly.  
NOTE: The Status Codes cannot be retrieved by disconnecting  
the limit switch or draft safeguard switch. To retrieve Status  
Codes, follow the procedure below.  
2. Turn Setup Switch, SW1--1 “ON.”  
3. Manually close blower access door switch.  
4. Control will flash up to 7 Status Codes.  
5. The last Status Code, or 8th Code, will be Code 11.  
6. Turn SW1--1 “OFF.”  
7. A continuously--lit Amber LED will appear and indicates  
proper operation.  
8. Release blower access door switch, install blower access  
door and replace outer door or refer to the SERVICE label  
on the front of the blower access door for more informa-  
tion.  
Electrical Controls and Wiring  
!
WARNING  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal injury  
or death.  
There may be more than one electrical supply to the furnace.  
Check accessories and cooling unit for additional electrical  
supplies that must be shut off during furnace servicing. Lock  
out and tag switch with a suitable warning label.  
Component Self--Test  
Component Test can ONLY be initiated by performing the  
following:  
The electrical ground and polarity for 115--v wiring must be  
properly maintained. Refer to Fig. 25 for field wiring information  
and to Fig. 53 for furnace wiring information.  
NOTE: If the polarity is not correct, the STATUS LED on the  
control will flash rapidly and prevent the furnace from heating.  
The control system also requires an earth ground for proper  
operation of the control and flame--sensing electrode.  
1. Remove outer access door.  
2. Remove blower access door.  
3. Remove the wire from the “R” terminal of the control  
board.  
4. Turn Setup Switch, SW--1--6 “ON.”  
5. Manually close blower access door switch.  
The 24--v circuit contains an automotive--type, 3--amp. fuse  
located on the control. (See Fig. 26.) Any shorts of the 24--v  
wiring during installation, service, or maintenance will cause this  
fuse to blow. If fuse replacement is required, use ONLY a 3--amp.  
fuse. The control LED will display status code 24 when fuse  
needs to be replaced.  
Blower access door switch opens 115--v power to control. No  
component operation can occur unless switch is closed. Caution  
must be taken when manually closing this switch for service  
purposes.  
!
Proper instrumentation is required to service electrical controls.  
The control in this furnace is equipped with a Status Code LED  
(Light--Emitting Diode) to aid in installation, servicing, and  
troubleshooting. Status codes can be viewed at the sight glass in  
blower access door. The amber furnace control LED is either ON  
continuously, rapid flashing, or a code composed of 2 digits. The  
first digit is the number of short flashes, the second digit is the  
number of long flashes.  
WARNING  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal injury,  
or death.  
Blower access door switch opens 115--v power to furnace  
control. No component operation can occur unless switch is  
closed. Exercise caution to avoid electrical shock from  
exposed electrical components when manually closing this  
switch for service purposes.  
For an explanation of status codes, refer to service label located  
on blower access door or Fig. 52, and the troubleshooting guide  
which can be obtained from your distributor.  
See Fig. 58, a brief Troubleshooting Guide.  
6. Component Test sequence will function as follows:  
For 2--Stage Variable Speed ECM Controls the stored status  
codes will NOT be erased from the control memory, when 115--  
or 24--v power is interrupted. The control will store up to the last  
7 Status Codes in order of occurrence.  
a. Inducer motor starts on high--speed and continues to  
run until Step (d.) of component test sequence.  
b. Hot surface igniter is energized for 15 sec, then deen-  
ergized.  
1. To retrieve status codes, proceed with the following:  
c. Blower operates for 10 sec, then turns off.  
NOTE: NO thermostat signal may be present at control, and all  
d. Inducer motor goes to low--speed for 10 seconds, then  
turns off.  
e. After component test is completed, one or more status  
codes (11, 25, or 41) will flash. See component test  
section of service label for explanation of status codes.  
blower--OFF delays must be completed.  
a. Leave 115--v power to furnace turned on.  
b. Remove outer access door.  
c. Look into blower access door sight glass for current  
LED status.  
d. Remove blower access door.  
NOTE: To repeat component test, turn setup switch SW1--6 OFF  
then back ON.  
f. Turn setup switch SW1--6 OFF.  
47  
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7. RELEASE BLOWER ACCESS DOOR SWITCH, reat-  
tach wire to “R” terminal on furnace control board, replace  
blower access door, and replace outer access door.  
3. Check electrical connections for tightness and controls for  
proper operation each heating season. Service as neces-  
sary.  
CARE AND MAINTENANCE  
4. Inspect burner compartment before each heating season  
for rust, corrosion, soot or excessive dust. If necessary,  
have furnace and burner serviced by a qualified service  
agency.  
5. Inspect the vent pipe/vent system before each heating sea-  
son for rust, corrosion, water leakage, sagging pipes or  
broken fittings. Have vent pipes/vent system serviced by a  
qualified service agency.  
!
WARNING  
FIRE OR EXPLOSION HAZARD  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
Never store anything on, near, or in contact with the  
furnace, such as:  
6. Inspect any accessories attached to the furnace such as a  
humidifier or electronic air cleaner. Perform any service or  
maintenance to the accessories as recommended in the ac-  
cessory instructions.  
1. Spray or aerosol cans, rags, brooms, dust mops,  
vacuum cleaners, or other cleaning tools.  
2. Soap powders, bleaches, waxes or other cleaning  
compounds, plastic or plastic containers, gasoline,  
kerosene, cigarette lighter fluid, dry cleaning fluids,  
or other volatile fluids.  
3. Paint thinners and other painting compounds, paper  
bags, or other paper products. Exposure to these  
materials could lead to corrosion of the heat  
exchangers.  
Cleaning and/or Replacing Air Filter  
The air filter arrangement will vary depending on the application.  
NOTE: If the filter has an airflow direction arrow, the arrow  
must point towards the blower.  
!
CAUTION  
CUT HAZARD  
Failure to follow this caution may result in personal injury.  
For continuing high performance and to minimize possible  
furnace failure, periodic maintenance must be performed on this  
furnace. Consult your local dealer about proper frequency of  
maintenance and the availability of a maintenance contract.  
Sheet metal parts may have sharp edges or burrs. Use care  
and wear appropriate protective clothing, safety glasses and  
gloves when handling parts, and servicing furnaces.  
Media cabinet filter procedures:  
!
WARNING  
1. Turn off electrical supply to furnace before removing filter  
access door.  
2. Remove filter cabinet door.  
3. Slide filter out of cabinet.  
4. If equipped with permanent, washable 3/4--in. (19 mm)  
filter, clean filter by spraying cold tap water through filter  
in opposite direction of airflow. Rinse filter and let dry.  
Oiling or coating of the filter is not recommended. See  
Table 15 for size information.  
ELECTRICAL SHOCK AND FIRE HAZARD  
Failure to follow this warning could result in personal injury,  
death, and/or property damage.  
Turn off the gas and electrical supplies to the furnace and  
install lockout tag before performing any maintenance or  
service. Follow the operating instructions on the label  
attached to the furnace.  
5. If equipped with factory--specified disposable media filter,  
replace only with media filter having the same part num-  
ber and size. For expandable replacement media, refer to  
the instructions included with the replacement media.  
!
WARNING  
CARBON MONOXIDE POISONING AND FIRE  
HAZARD  
6. Slide filter into cabinet.  
7. Replace filter cabinet door.  
8. Turn on electrical supply to furnace.  
Blower Motor and Wheel  
Failure to follow this warning could result in personal  
injury, death and/or property damage.  
Never operate furnace without a filter or with filter access  
door removed.  
!
WARNING  
!
CAUTION  
ELECTRICAL SHOCK HAZARD  
Failure to follow this warning could result in personal  
injury or death.  
CUT HAZARD  
Failure to follow this caution may result in personal injury.  
Blower access door switch opens 115--v power to control.  
No component operation can occur unless switch is closed.  
Caution must be taken when manually closing this switch  
for service purposes.  
Sheet metal parts may have sharp edges or burrs. Use care  
and wear appropriate protective clothing, safety glasses and  
gloves when handling parts, and servicing furnaces.  
The minimum maintenance on this furnace is as follows:  
NOTE: The blower wheel should not be dropped or bent as  
balance will be affected.  
1. Check and clean air filter each month or more frequently if  
required. Replace if torn.  
2. Check blower motor and wheel for cleanliness each heat-  
ing and cooling season. Clean as necessary.  
The following steps should be performed by a qualified  
service agency.  
To ensure long life and high efficiency, clean accumulated dirt  
and grease from blower wheel and motor annually.  
48  
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Table 16 – Filter Size Information -- In. (mm)  
FILTER SIZE  
FURNACE CASING WIDTH  
SIDE  
RETURN  
BOTTOM  
RETURN  
FILTER TYPE  
16 X 25 X 3/4  
14 X 25 X 3/4  
14---1/2 (368)  
17---1/2 (445)  
21 (533)  
Washable*  
Washable*  
Washable*  
Washable*  
(406 X 635 X 19)  
(356 X 635 X 19)  
16 X 25 X 3/4  
(406 X 635 X 19)  
16 X 25 X 3/4  
(406 X 635 X 19)  
16 X 25 X 3/4  
(406 X 635 X 19)  
16 X 25 X 3/4  
(406 X 635 X 19)  
20 X 25 X 3/4  
(508 X 635 X 19)  
24 X 25 X 3/4  
(610 X 635 X 19)  
24 (610)  
* Recommended  
The inducer and blower motors are pre--lubricated and require no  
additional lubrication. These motors can be identified by the  
absence of oil ports on each end of the motor.  
15. Reconnect blower leads to furnace control. Refer to fur-  
nace wiring diagram, and connect thermostat leads if pre-  
viously disconnected.  
Clean blower motor and wheel as follows:  
1. Turn off electrical supply to furnace.  
2. Remove outer door.  
16. To check blower for proper rotation:  
a. Turn on electrical supply.  
!
3. For downflow or horizontal furnaces having vent pipes  
within the furnace that pass in front of the blower access  
door:  
WARNING  
ELECTRICAL SHOCK HAZARD  
a. Disconnect vent connector from furnace vent elbow.  
b. Disconnect and remove short piece of vent pipe from  
within furnace.  
Failure to follow this warning could result in personal  
injury, or death.  
Blower access door switch opens 115--v power to furnace  
control. No component operation can occur unless switch is  
closed. Exercise caution to avoid electrical shock from  
exposed electrical components when manually closing this  
switch for service purposes.  
4. Remove 2 screws from blower access door and remove  
blower access door.  
5. All factory wires can be left connected, but field thermo-  
stat connections may need to be disconnected depending  
on their length and routing.  
b. Manually close blower access door switch.  
6. Remove 2 screws holding blower assembly to blower  
deck and slide blower assembly out of furnace.  
NOTE: If R--W/W1 thermostat terminals are jumpered at the  
time blower access door switch is closed, blower will run for 90  
sec before beginning a heating cycle.  
7. Clean blower wheel and motor using a vacuum with soft  
brush attachment. Blower wheel blades may be cleaned  
with a small paint or flux brush. Do not remove or disturb  
balance weights (clips) on blower wheel blades.  
8. Vacuum any loose dust from blower housing, wheel and  
motor.  
c. Perform component self--test as shown at the bottom  
of the SERVICE label, located on the front of blower  
access door.  
d. Verify blower is rotating in the correct direction  
17. If furnace is operating properly, RELEASE BLOWER  
ACCESS DOOR SWITCH. Remove any jumpers or re-  
connect any disconnected thermostat leads. Replace  
blower access door.  
18. Downflow or horizontal furnaces with vent pipe through  
furnace only:  
9. If a greasy residue is present on blower wheel, remove  
wheel from the blower housing and wash it with an appro-  
priate degreaser. To remove wheel:  
NOTE: Before disassembly, mark blower mounting arms, motor,  
and blower housing so motor and each arm is positioned at the  
same location during reassembly.  
a. Install and connect short piece of vent pipe inside fur-  
nace to existing vent.  
a. Disconnect ground wire attached to blower housing.  
b. Remove screws securing cutoff plate and remove  
cutoff plate from housing.  
b. Connect vent connector to vent elbow.  
19. Reinstall outer door.  
c. Loosen set screw holding blower wheel on motor shaft  
(160+/--20 in.--lb. when assembling).  
20. Turn on gas supply and cycle furnace through one com-  
plete heating and cooling cycle. Verify the furnace temper-  
ature rise as shown in Adjustments Section. Adjust tem-  
perature rise as shown in Adjustments Section. If outdoor  
temperature is below 70_F, turn off circuit breaker to out-  
door unit before running furnace in the cooling cycle.  
Turn outdoor circuit breaker on after completing cooling  
cycle.  
d. Remove bolts holding motor to blower housing and  
slide motor out of wheel (40+/--10 in.--lb. when reas-  
sembling).  
e. Remove blower wheel from housing.  
f. Clean wheel and housing.  
10. Reassemble motor and blower by reversing steps 9a,  
through 9e. Be sure to reattach ground wire to the blower  
housing.  
Cleaning Heat Exchanger  
The following steps should be performed by a qualified  
service agency:  
11. Verify that blower wheel is centered in blower housing  
and set screw contacts the flat portion of the motor shaft.  
Loosen set screw on blower wheel and reposition if neces-  
sary.  
NOTE: If the heat exchangers get a heavy accumulation of soot  
and carbon, they should be replaced rather than trying to clean  
them thoroughly. A build--up of soot and carbon indicates that a  
problem exists which needs to be corrected, such as improper  
adjustment of manifold pressure, insufficient or poor quality  
combustion air, incorrect size or damaged manifold orifice(s),  
improper gas, or a restricted heat exchanger. Action must be taken  
to correct the problem.  
12. Spin the blower wheel by hand to verify that the wheel  
does not rub on the housing.  
13. Reinstall blower assembly in furnace.  
14. Reinstall 2 screws securing blower assembly to blower  
deck.  
49  
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9. Using field--provided 25--caliber rifle cleaning brush,  
36--in. (914 mm) long, 1/4--in. (6 mm) diameter steel  
spring cable, a variable speed, follows:  
a. Remove metal screw fitting from wire brush to allow  
insertion into cable.  
b. Insert the twisted wire end of brush into end of spring  
cable, and crimp tight with crimping tool or crimp by  
striking with ball--peen hammer. TIGHTNESS IS  
VERY IMPORTANT.  
NOTE: The materials needed in item 9 can usually be purchased  
at local hardware stores.  
(1.) Attach variable--speed, reversible drill to the end  
of spring cable (end opposite brush).  
(2.) Insert brush end of cable into the outlet opening  
of cell and slowly rotate with drill. DO NOT  
force cable. Gradually insert cable into upper pass  
of cell. (See Fig. 57.)  
(3.) Work cable in and out of cell 3 or 4 times to ob-  
tain sufficient cleaning. DO NOT pull cable with  
great force. Reverse drill and gradually work  
cable out.  
A05025  
Fig. 54 -- Igniter Position -- Side View  
(4.) Insert brush end of cable in burner inlet opening  
of cell, and proceed to clean 2 lower passes of  
cell in same manner as upper pass.  
1-7/8  
(47.6 mm)  
(5.) Repeat foregoing procedures until each cell in  
furnace has been cleaned.  
(6.) Using vacuum cleaner, remove residue from each  
cell.  
(7.) Using vacuum cleaner with soft brush attachment,  
clean burner assembly.  
(8.) Clean flame sensor with fine steel wool.  
(9.) Install NOx baffles (if removed).  
A05026  
Fig. 55 -- Igniter Position -- Top View  
If it becomes necessary to clean the heat exchangers because of  
dust or corrosion, proceed as follows:  
1. Turn OFF gas and electrical power to furnace.  
2. Remove outer access door.  
3. Disconnect vent connector from furnace vent elbow.  
4. For downflow or horizontal furnace having an internal  
vent pipe, remove internal vent pipe within the casing.  
5. Disconnect wires to the following components. Mark  
wires to aid in reconnection (be careful when disconnect-  
ing wires from switches because damage may occur):  
a. Draft safeguard switch.  
b. Inducer motor.  
A91252  
Fig. 56 -- Cleaning Heat Exchanger Cell  
c. Pressure switches.  
d. Limit overtemperature switch.  
e. Gas valve.  
(10.) Reinstall burner assembly. Center burners in cell  
openings.  
10. Remove old sealant from cell panel and collector box  
flange.  
11. Spray releasing agent on the heat exchanger cell panel  
where collector box assembly contacts cell panel.  
f. Hot surface igniter.  
g. Flame--sensing electrode.  
h. Flame rollout switches.  
6. Remove screws that fasten the collector box assembly to  
the cell panel. Be careful not to damage the collector box.  
Inducer assembly and elbow need not be removed from  
collector box.  
NOTE: A releasing agent such as cooking spray or equivalent  
(must not contain corn or canola oil, aromatic or halogenated  
hydrocarbons or inadequate seal may occur) and RTV sealant  
(G.E. 162, 6702, or Dow--Corning 738) are needed before  
starting installation. DO NOT substitute any other type of RTV  
sealant. G.E. 162 (P771--9003) is available through RCD in 3--oz  
tubes.  
7. Disconnect gas line from gas manifold.  
8. Remove the four screws that attach the burner assembly to  
the cell panel. The gas valve and individual burners need  
not be removed from support assembly. Remove NOx  
baffles, if installed.  
12. Apply new sealant to flange of collector box and attach to  
cell panel using existing screws, making sure all screws  
are secure.  
NOTE: Be very careful when removing burner assembly to  
avoid breaking igniter. See Fig. 54--55 for correct igniter location.  
50  
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13. Reconnect wires to the following components (Use con-  
nection diagram on wiring label, if wires were not marked  
for reconnection locations.):  
Sequence of Operation  
NOTE: Furnace control must be grounded for proper operation  
or else control will lock out. Control is grounded through  
green/yellow wire routed to gas valve and burner box screw.  
Using the schematic diagram in Fig. 53, follow the sequence of  
operation through the different modes. Read and follow the  
wiring diagram very carefully.  
a. Draft safeguard switch.  
b. Inducer motor.  
c. Pressure switches.  
d. Limit overtemperature switch.  
e. Gas valve.  
NOTE: If a power interruption occurs during a call for heat  
(W/W1 or W/W1--and--W2), the control will start a 90--second  
blower--only ON period two seconds after power is restored, if  
the thermostat is still calling for gas heating. The amber LED  
light will flash code 12 during the 90--second period, after which  
the LED will be ON continuous, as long as no faults are detected.  
After the 90--second period, the furnace will respond to the  
thermostat normally.  
f. Hot surface igniter.  
g. Flame--sensing electrode.  
h. Flame rollout switches.  
14. Reinstall internal vent pipe, if applicable.  
15. Reinstall vent connector on furnace vent elbow. Securely  
fasten vent connector to vent elbow with 2 field--supplied,  
corrosion--resistant, sheet metal screws located 180_ apart.  
The blower door must be installed for power to be conducted  
through the blower door interlock switch ILK to the furnace  
control CPU, transformer TRAN, inducer motor IDM, blower  
motor BLWM, hot--surface igniter HSI, and gas valve GV.  
16. Replace blower access door only if it was removed.  
17. Set thermostat above room temperature and check furnace  
for proper operation.  
1. Two--Stage Heating (Adaptive Mode) with Single--Stage  
Thermostat  
18. Verify blower airflow and speed changes between heating  
and cooling.  
See Fig. 27 -- 34 for thermostat connections  
NOTE: The low--heat only switch SW1--2 selects either the  
low--heat only operation mode when ON, (see item 2. below) or  
the adaptive heating mode when OFF in response to a call for  
heat. (See Table 10.) When the W2 thermostat terminal is  
energized it will always cause high--heat operation when the  
R--to--W circuit is closed, regardless of the setting of the low--heat  
only switch. This furnace can operate as a two--stage furnace with  
a single--stage thermostat because the furnace control CPU  
!
WARNING  
FIRE OR EXPLOSION HAZARD  
Failure to follow this warning could result in personal  
injury, death, and/or property damage.  
Never purge a gas line into a combustion chamber. Never  
test for gas leaks with an open flame. Use a commercially  
available soap solution made specifically for the detection  
of leaks to check all connections.  
includes  
a
programmed adaptive sequence of controlled  
operation, which selects low--heat or high--heat operation. This  
selection is based upon the stored history of the length of  
previous gas--heating periods of the single--stage thermostat.  
19. Check for gas leaks.  
51  
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COOLING TONNAGE VS. AIRFLOW (CFM)  
AIR CONDITIONING  
AIRFLOW  
070 MODEL  
090 MODEL  
110, 135,  
TONS (12,000 BTU/HR)  
(CFM)  
525  
& 155 MODELS  
1-1/2  
X2  
X
X
2
2-1/2  
3
700  
X2  
X
X
875  
X
X2  
X
1050  
1225  
1400  
1750  
2100  
X1  
X
X
3-1/2  
4
X1  
X
X
X
5
X1  
X
6
X-INDICATES AN ALLOWABLE SELECTION.  
AIR CONDITIONING (A/C) OR CONTINUOUS-FAN (CF) AIRFLOW SELECTION CHART  
BASED ON 350 CFM/TON  
SW1-5 OFF  
SWITCH SW3 POSITIONS  
MODEL  
SIZE  
070  
090  
DEF  
DEF  
5252  
525  
700  
700  
7002  
8752  
875  
875  
10501  
1050  
1225  
1225  
1225  
1400  
1225  
14001  
17501  
1225  
1400  
2100  
110,135,155 DEF  
1050  
BASED ON 400 CFM/TON  
SW1-5 ON  
SWITCH SW3 POSITIONS  
MODEL  
SIZE  
070  
090  
DEF  
DEF  
6002  
600  
800  
8002  
1000  
1000  
1200  
12001  
1200  
1400  
1400  
1400  
1600  
1400  
1400  
1600  
2200  
16001  
110,135,155 DEF  
800  
10002  
2000  
1
1.DEFAULT A/C AIRFLOW WHEN A/C SWITCHES ARE IN OFF POSITION (FACTORY SETTING)  
2.DEFAULT CONT. FAN AIRFLOW WHEN CF SWITCHES ARE IN OFF POSITION (FACTORY SETTING)  
3. SWITCH POSITIONS ARE ALSO SHOWN ON FURNACE WIRING DIAGRAM  
A08470  
Fig. 57 -- Cooling (A/C) or Continuous--Fan (CF) Airflow Selection Chart  
The furnace will start up in either low-- or high--heat. If the  
tinue to run the inducer motor IDM at high--  
speed.  
furnace starts up in low--heat, the control CPU determines the  
low--heat on--time (from 0 to 16 minutes) which is permitted  
before switching to high--heat.  
If the power is interrupted, the stored history is erased and the  
control CPU will select low--heat for up to 16 minutes and then  
switch to high--heat, as long as the thermostat continues to call for  
heat. Subsequent selection is based on stored history of the  
thermostat cycle times.  
The wall thermostat “calls for heat”, closing the R--to--W circuit.  
The furnace control performs a self--check, verifies the low--heat  
and high--heat pressure switch contacts LPS and HPS are open,  
and starts the inducer motor IDM in high--speed.  
(2.) If the furnace control CPU selects high--heat op-  
eration, the inducer motor IDM remains running  
at high--speed, and the high--heat pressure switch  
relay HPSR is de--energized to close the NC con-  
tact. When sufficient pressure is available the  
high--heat pressure switch HPS closes, and the  
high--heat gas valve solenoid GV--HI is ener-  
gized. The furnace control CPU begins a  
15--second prepurge period after the low--heat  
pressure switch LPS closes. If the high--heat pres-  
sure switch HPS fails to close and the low--heat  
pressure switch LPS closes, the furnace will oper-  
ate at low--heat gas flow rate until the high--heat  
pressure switch closes for a maximum of 2 min-  
utes after ignition.  
a. Inducer Prepurge Period  
(1.) If the furnace control CPU selects low--heat oper-  
ation the inducer motor IDM comes up to speed,  
the low--heat pressure switch LPS closes, and the  
furnace control CPU begins a 15--second prepur-  
ge period. If the low--heat pressure switch LPS  
fails to remain closed the inducer motor IDM will  
remain running at high--speed. After the low--heat  
pressure switch re--closes the furnace control CPU  
will begin a 15--second prepurge period, and con-  
b. Igniter Warm--Up --At the end of the prepurge period,  
the Hot--Surface Igniter HSI is energized for a  
17--second igniter warm--up period.  
c. Trial--For--Ignition Sequence --When the igniter  
warm--up period is completed the main gas valve relay  
contact GVR closes to energize the gas valve solenoid  
GV--M. The gas valve solenoid GV--M permits gas  
flow to the burners where it is ignited by the HSI. Five  
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seconds after the GVR closes, a 2--second flame prov-  
ing period begins. The HSI igniter will remain ener-  
gized until the flame is sensed or until the 2--second  
flame proving period begins. If the furnace control  
CPU selects high--heat operation, the high--heat gas  
valve solenoid GV--HI is also energized.  
R--to-- W1--and--W2 circuits always causes high--heat operation,  
regardless of the setting of the low--heat only switch.  
The wall thermostat “calls for heat”, closing the R--to--W1 circuit  
for low--heat or closing the R--to--W1--and--W2 circuits for  
high--heat. The furnace control performs a self--check, verifies the  
low--heat and high--heat pressure switch contacts LPS and HPS  
are open, and starts the inducer motor IDM in high--speed.  
d. Flame--Proving -- When the burner flame is proved at  
the flame--proving sensor electrode FSE, the inducer  
motor IDM switches to low--speed unless the furnace  
is operating in high--heat, and the furnace control CPU  
begins the blower--ON delay period and continues to  
hold the gas valve GV--M open. If the burner flame is  
not proved within two seconds, the control CPU will  
close the gas valve GV--M, and the control CPU will  
repeat the ignition sequence for up to three more Tri-  
als--For--Ignition before going to Ignition--Lockout.  
Lockout will be reset automatically after three hours,  
or by momentarily interrupting 115 vac power to the  
furnace, or by interrupting 24 vac power at SEC1 or  
SEC2 to the furnace control CPU (not at W/W1, G, R,  
etc.). If flame is proved when flame should not be  
present, the furnace control CPU will lock out of Gas--  
Heating mode and operate the inducer motor IDM on  
high speed until flame is no longer proved.  
e. Blower--On delay -- If the burner flame is proven the  
blower--ON delays for low--heat and high--heat are as  
follows:  
Low--heat -- 45 seconds after the gas valve GV--M is  
opened the blower motor BLWM is turned ON at  
low--heat airflow.  
High--heat -- 25 seconds after the gas valve GV--M is  
opened the BLWM is turned ON at high--heat airflow.  
Simultaneously, the humidifier terminal HUM and  
electronic air cleaner terminal EAC--1 are energized  
and remain energized throughout the heating cycle.  
The start up and shut down functions and delays described in  
item 1. above apply to the 2--stage heating mode as well, except  
for switching from low-- to high--Heat and vice versa.  
a. Switching from Low-- to High--Heat -- If the thermo-  
stat R--to--W1 circuit is closed and the R--to--W2 cir-  
cuit closes, the furnace control CPU will switch the  
inducer motor IDM speed from low to high. The  
high--heat pressure switch relay HPSR is de--energized  
to close the NC contact. When sufficient pressure is  
available the high--heat pressure switch HPS closes,  
and the high--heat gas valve solenoid GV--HI is ener-  
gized. The blower motor BLWM will transition to  
high--heat airflow five seconds after the R--to--W2 cir-  
cuit closes.  
b. Switching from High-- to Low--Heat --If the thermo-  
stat R--to-- W2 circuit opens, and the R--to--W1 circuit  
remains closed, the furnace control CPU will switch  
the inducer motor IDM speed from high to low. The  
high--heat pressure switch relay HPSR is energized to  
open the NC contact and de--energize the high--heat  
gas valve solenoid GV--HI. When the inducer motor  
IDM reduces pressure sufficiently, the high--heat pres-  
sure switch HPS will open. The gas valve solenoid  
GV--M will remain energized as long as the low--heat  
pressure switch LPS remains closed. The blower motor  
BLWM will transition to low--heat airflow five  
seconds after the R--to--W2 circuit opens.  
3. Cooling mode  
f. Switching from Low-- to High--Heat -- If the furnace  
control CPU switches from low--heat to high--heat, the  
furnace control CPU will switch the inducer motor  
IDM speed from low to high. The high--heat pressure  
switch relay HPSR is de--energized to close the NC  
contact. When sufficient pressure is available the high--  
heat pressure switch HPS closes, and the high--heat gas  
valve solenoid GV--HI is energized. The blower motor  
BLWM will transition to high--heat airflow five  
seconds after the furnace control CPU switches from  
low--heat to high--heat.  
The thermostat “calls for cooling”.  
a. Single--Speed Cooling--  
See Fig. 27 for thermostat connections  
The thermostat closes the R--to--G--and--Y circuits. The  
R--to-- Y circuit starts the outdoor unit, and the R--to--  
G--and--Y/Y2 circuits start the furnace blower motor  
BLWM on cooling airflow. Cooling airflow is based  
on the A/C selection shown in Fig. 57. The electronic  
air cleaner terminal EAC--1 is energized with 115 vac  
when the blower motor BLWM is operating.  
When the thermostat is satisfied, the R--to--G--and--Y  
circuits are opened. The outdoor unit will stop, and the  
furnace blower motor BLWM will continue operating  
at cooling airflow for an additional 90 seconds. Jump-  
er Y/Y2 to DHUM to reduce the cooling off--delay to  
5 seconds. (See Fig. 26.)  
g. Switching from High-- to Low--Heat --The furnace  
control CPU will not switch from high--heat to low--  
heat while the thermostat R--to--W circuit is closed  
when using a single--stage thermostat.  
h. Blower--Off Delay --When the thermostat is satisfied,  
the R to W circuit is opened, de--energizing the gas  
valve GV--M, stopping gas flow to the burners, and  
de--energizing the humidifier terminal HUM. The in-  
ducer motor IDM will remain energized for a  
5--second post--purge period. The blower motor  
BLWM and air cleaner terminal EAC--1 will remain  
energized at low--heat airflow or transition to low--heat  
airflow for 90, 120, 150, or 180 seconds (depending  
on selection at blower--OFF delay switches). The fur-  
nace control CPU is factory--set for a 120--second  
blower--OFF delay.  
b. Single--Stage Thermostat and Two--Speed Cooling  
(Adaptive Mode) --  
See Fig. 34 for thermostat connections.  
This furnace can operate a two--speed cooling unit  
with a single--stage thermostat because the furnace  
control CPU includes a programmed adaptive se-  
quence of controlled operation, which selects low--  
cooling or high--cooling operation. This selection is  
based upon the stored history of the length of previous  
cooling period of the single--stage thermostat.  
NOTE: The air conditioning relay disable jumper ACRDJ must  
be connected to enable the adaptive cooling mode in response to  
a call for cooling. (See Fig. 26.) When ACRDJ is in place the  
furnace control CPU can turn on the air conditioning relay ACR  
to energize the Y/Y2 terminal and switch the outdoor unit to  
high--cooling.  
2. Two--Stage Thermostat and Two--Stage Heating  
See Fig. 27--34 for thermostat connections.  
NOTE: In this mode the low--heat only switch SW1--2 must be  
ON to select the low--heat only operation mode in response to  
closing the thermostat R--to--W1 circuit. Closing the thermostat  
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The furnace control CPU can start up the cooling unit in either  
low-- or high--cooling. If starting up in low--cooling, the furnace  
control CPU determines the low--cooling on--time (from 0 to 20  
minutes) which is permitted before switching to high--cooling. If  
the power is interrupted, the stored history is erased and the  
furnace control CPU will select low--cooling for up to 20 minutes  
and then energize the air conditioning relay ACR to energize the  
Y/Y2 terminal and switch the outdoor unit to high--cooling, as  
long as the thermostat continues to call for cooling. Subsequent  
selection is based on stored history of the thermostat cycle times.  
The wall thermostat “calls for cooling”, closing the  
R--to--G--and--Y circuits. The R--to--Y1 circuit starts the outdoor  
unit on low--cooling speed, and the R--to--G--and--Y1 circuits  
starts the furnace blower motor BLWM at low--cooling airflow  
which is the true on--board CF selection as shown in Fig. 57.  
If the furnace control CPU switches from low--cooling to  
high--cooling, the furnace control CPU will energize the air  
conditioning relay ACR. When the air conditioning relay ACR is  
energized the R--to--Y1--and--Y2 circuits switch the outdoor unit  
to high--cooling speed, and the R--to--G--and--Y1--and--Y/Y2  
circuits transition the furnace blower motor BLWM to  
high--cooling airflow. High--cooling airflow is based on the A/C  
selection shown in Fig. 57.  
vac is detected by the furnace control on the DHUM input,  
the furnace control operates in Thermidistat mode. If the  
DHUM input is low for more than 48 hours, the furnace  
control reverts back to non--Thermidistat mode.  
The cooling operation described in item 3. above also ap-  
plies to operation with a Thermidistat. The exceptions are  
listed below:  
a. Low cooling-- W h e n t h e R -- t o -- G -- a n d -- Y 1 c i r c u i t i s  
closed and there is a demand for dehumidification, the  
furnace blower motor BLWM will drop the blower  
airflow to 86 percent of low--cooling airflow which is  
the true on--board CF (continuous fan) selection as  
shown in Fig. 55.  
b. High cooling-- W h e n t h e R -- t o -- G -- a n d Y / Y 2 c i r c u i t i s  
closed and there is a demand for dehumidification, the  
furnace blower motor BLWM will drop the blower  
airflow to 86 percent of high--cooling airflow. High--  
cooling airflow is based on the A/C (air conditioning)  
selection shown in Fig. 55.  
c. Cooling off--delay--When the “call for cooling” is  
satisfied and there is a demand for dehumidification,  
the cooling blower--off delay is decreased from 90  
seconds to 5 seconds.  
5. Super--Dehumidify Mode  
NOTE: When transitioning from low--cooling to high--cooling  
the outdoor unit compressor will shut down for 1 minute while  
the furnace blower motor BLWM transitions to run at  
high--cooling airflow.  
The electronic air cleaner terminal EAC--1 is energized with 115  
vac whenever the blower motor BLWM is operating.  
When the thermostat is satisfied, the R--to--G--and--Y circuit are  
opened. The outdoor unit stops, and the furnace blower BLWM  
and electronic air cleaner terminal EAC--1 will remain energized  
for an additional 90 seconds. Jumper Y1 to DHUM to reduce the  
cooling off--delay to 5 seconds. (See Fig. 26.)  
Super--Dehumidify mode can only be entered if the fur-  
nace control is in the Thermidistat mode and there is a de-  
mand for dehumidification. The cooling operation de-  
scribed in item 3. above also applies to operation with a  
Thermidistat. The exceptions are listed below:  
a. When the R--to--Y1 circuit is closed, R--to--G circuit is  
open, and there is a demand for dehumidification, the  
furnace blower motor BLWM will drop the blower  
airflow to 65 percent of low--cooling airflow for a  
maximum of 10 minutes each cooling cycle or until  
the R--to--G circuit closes or the demand for dehumidi-  
fication is satisfied. Low--cooling airflow is the true  
on--board CF (continuous fan) selection as shown in  
Fig. 57.  
c. Two--Stage Thermostat and Two--Speed Cooling  
See Fig. 33 for thermostat connections  
NOTE: The air conditioning relay disable jumper ACRDJ must  
be disconnected to allow thermostat control of the outdoor unit  
staging. (See Fig. 26.)  
b. When the R--to--Y/Y2 circuit is closed, R--to--G circuit  
is open, and there is a demand for dehumidification,  
the furnace blower motor BLWM will drop the blower  
airflow to 65 percent of high--cooling airflow for a  
maximum of 10 minutes each cooling cycle or until  
the R--to--G circuit closes or the demand for dehumidi-  
fication is satisfied. High--cooling airflow is based on  
the A/C (air conditioning) selection shown in Fig. 57.  
The thermostat closes the R--to--G--and--Y1 circuits for  
low--cooling or closes the R--to--G--and--Y1--and--Y2 circuits for  
high--cooling. The R--to--Y1 circuit starts the outdoor unit on  
low--cooling speed, and the R--to--G--and--Y1 circuit starts the  
furnace blower motor BLWM at low--cooling airflow which is the  
true on--board CF (continuous fan) selection as shown in Fig. 55.  
The R--to--Y1--and--Y2 circuits start the outdoor unit on  
high--cooling speed, and the R--to-- G--and--Y/Y2 circuits start the  
furnace blower motor BLWM at high--cooling airflow.  
High--cooling airflow is based on the A/C (air conditioning)  
selection shown in Fig. 57.  
c. When the “call for cooling” is satisfied and there is a  
demand for dehumidification, the cooling blower--off  
delay is decreased from 90 seconds to 5 seconds.  
6. Continuous Blower Mode  
When the R--to--G circuit is closed by the thermostat, the  
blower motor BLWM will operate at continuous blower  
airflow. Continuous blower airflow selection is initially  
based on the CF (continuous fan) selection shown in Fig.  
57. Factory default is shown in Fig. 57. Terminal EAC--1  
is energized as long as the blower motor BLWM is ener-  
gized.  
During a call for heat, the furnace control CPU will trans-  
ition the blower motor BLWM to continuous blower air-  
flow, low--heat airflow, or the mid--range airflow,  
whichever is lowest. The blower motor BLWM will re-  
main ON until the main burners ignite then shut OFF and  
remain OFF for the blower--ON delay (45 seconds in low--  
heat, and 25 seconds in high--heat), allowing the furnace  
heat exchangers to heat up more quickly, then restarts at  
the end of the blower--ON delay period at low--heat or  
high--heat airflow, respectively.  
The electronic air cleaner terminal EAC--1 is energized with 115  
vac whenever the blower motor BLWM is operating.  
When the thermostat is satisfied, the R--to--G--and--Y1 or R--to--  
G--and--Y1--and--Y2 circuits are opened. The outdoor unit stops,  
and the furnace blower BLWM and electronic air cleaner terminal  
EAC--1 will remain energized for an additional 90 seconds.  
Jumper Y1 to DHUM to reduce the cooling off--delay to 5  
seconds. (See Fig. 26.)  
4. Thermidistat Mode  
See Fig. 27--29 for thermostat connections.  
The dehumidification output, DHUM on the Thermidistat  
should be connected to the furnace control thermostat ter-  
minal DHUM. When there is a dehumidify demand, the  
DHUM input is activated, which means 24 vac signal is  
removed from the DHUM input terminal. In other words,  
the DHUM input logic is reversed. The DHUM input is  
turned ON when no dehumidify demand exists. Once 24  
The blower motor BLWM will revert to continuous--  
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blower airflow after the heating cycle is completed. In  
high--heat, the furnace control CPU will drop the blower  
motor BLWM to low--heat airflow during the selected  
blower--OFF delay period before transitioning to continu-  
ous--blower airflow.  
When the thermostat “calls for low--cooling”, the blower  
motor BLWM will switch to operate at low--cooling air-  
flow. When the thermostat is satisfied, the blower motor  
BLWM will operate an additional 90 seconds at low--cool-  
ing airflow before transitioning back to continuous--  
blower airflow.  
When the thermostat “calls for high--cooling”, the blower  
motor BLWM will operate at high cooling airflow. When  
the thermostat is satisfied, the blower motor BLWM will  
operate an additional 90 seconds at high--cooling airflow  
before transitioning back to continuous--blower airflow.  
When the R--to--G circuit is opened, the blower motor  
BLWM will continue operating for an additional 5  
seconds, if no other function requires blower motor  
BLWM operation.  
still energized the furnace control CPU will transition the  
blower motor BLWM to low--cooling airflow. If both the  
Y1 and Y/Y2 signals disappear at the same time, the  
blower motor BLWM will remain on at low--heat airflow  
for the selected blower--OFF delay period. At the end of  
the blower-- OFF delay, the blower motor BLWM will  
shut OFF unless G is still energized, in which case the  
blower motor BLWM will operate at continuous blower  
airflow.  
8. Component test  
The furnace features a component test system to help dia-  
gnose a system problem in the case of a component fail-  
ure. To initiate the component test procedure, ensure that  
there are no thermostat inputs to the control and all time  
delays have expired. Turn on setup switch SW1--6. (See  
Fig. 26.)  
NOTE: The component test feature will not operate if the control  
is receiving any thermostat signals or until all time delays have  
expired.  
The component test sequence is as follows:  
Continuous Blower Speed Selection from Thermostat  
To select different continuous--blower airflow from the  
room thermostat, momentarily turn off the FAN switch or  
push button on the room thermostat for 1--3 seconds after  
the blower motor BLWM is operating. The furnace control  
CPU will shift the continuous--blower airflow from the  
factory setting to the next highest CF selection airflow as  
shown in Fig. 57. Momentarily turning off the FAN switch  
again at the thermostat will shift the continuous--blower  
airflow up one more increment. If you repeat this proced-  
ure enough you will eventually shift the continuous--  
blower airflow to the lowest CF selection as shown in Fig.  
57. The selection can be changed as many times as desired  
and is stored in the memory to be automatically used fol-  
lowing a power interruption.  
a. The furnace control CPU turns the inducer motor ON  
at high--heat speed and keeps it ON through step c.  
b. After waiting 10 seconds the furnace control CPU  
turns the hot surface igniter ON for 15 seconds, then  
OFF.  
c. The furnace control CPU then turns the blower motor  
BLWM on at mid--range airflow for 15 seconds, then  
OFF.  
d. After shutting the blower motor OFF the furnace con-  
trol CPU switches the inducer to low--heat speed for  
10 seconds, then OFF.  
NOTE: The EAC terminals are energized when the blower is  
operating.  
After the component test is completed, 1 or more status codes (11,  
25, or 41) will flash. See component test section or Service Label  
(Fig. 52) for explanation of status codes.  
NOTE: If the blower--off delay is set to the maximum, the  
adjustable continuous--fan feature is locked (i.e., fan speed cannot  
be changed from its current setting).  
NOTE: To repeat component test, turn setup switch SW1--6 to  
OFF and then back ON.  
7. Heat pump  
See Fig. 29 -- 32 for thermostat connections.  
Wiring Diagram  
When installed with a heat pump, the furnace control auto-  
matically changes the timing sequence to avoid long  
blower off times during demand defrost cycles. Whenever  
W/W1 is energized along with Y1 or Y/Y2, the furnace  
control CPU will transition to or bring on the blower mo-  
tor BLWM at cooling airflow, low--heat airflow, or the  
mid--range airflow, whichever is lowest. The blower motor  
BLWM will remain on until the main burners ignite then  
shut OFF and remain OFF for 25 seconds before coming  
back on at heating airflow. When the W/W1 input signal  
disappears, the furnace control begins a normal inducer  
post--purge period while changing the blower airflow. If  
Y/Y2 input is still energized the furnace control CPU will  
transition the blower motor BLWM airflow to cooling air-  
flow. If Y/Y2 input signal disappears and the Y1 input is  
Refer to wiring diagram Fig. 53.  
Troubleshooting  
Refer to the service label. (See Fig. 52—Service Label.)  
The Troubleshooting Guide (See Fig. 58.) can be a useful tool in  
isolating furnace operation problems. Beginning with the word  
“Start,” answer each question and follow the appropriate arrow to  
the next item.  
The Guide will help to identify the problem or failed component.  
After replacing any component, verify correct operation  
sequence.  
A more detailed Troubleshooting Guide is available from your  
distributor.  
55  
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A02108A  
Fig. 58 -- Troubleshooting Guide  
56  
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A02108B  
57  
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A02108C  
58  
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Table 17 – Accessory List  
PART NUMBER  
DESCRIPTION  
NOTES  
FILCABXX0016  
FILCABXX0020  
FILCABXX0024  
FILXXCAR0016  
FILXXCAR0020  
FILXXCAR0024  
EXPXXUNV0016  
EXPXXUNV0020  
EXPXXUNV0024  
EXPXXFIL0016  
EXPXXFIL0020  
EXPXXFIL0024  
KGAFR0401B14  
KGAFR0501B17  
KGAFR0601B21  
KGAFR0701B24  
KGAFR0801SRE  
KGAWF1301UFR†  
KGAWF1401UFR  
KGAWF1501UFR  
KGAWF1306UFR†  
KGAWF1406UFR  
KGAWF1506UFR  
KGAFE0112UPH  
KGATW0601HSI  
KGASB0201ALL  
KGBVG0101DFG  
KGAVE0101DNH  
KGACA02014FC  
KGACA02015FC  
KGANP4601ALL  
KGAPN3901ALL  
KGALB0101KIT  
KGASD0301FMS  
KGAFP0301APM  
Filter cabinet 16” (406 mm) for 4” (102 mm) wide filter  
Filter cabinet 20” (508 mm) for 4” (102 mm) wide filter  
Filter cabinet 24” (610 mm) for 4” (102 mm) wide filter  
Filter Cartridge replacements for FILCAB media cabinet  
Filter Cartridge replacements for FILCAB media cabinet  
Filter Cartridge replacements for FILCAB media cabinet  
16” (406 mm) Replacement Expandable Filter assembly  
20” (508 mm) Replacement Expandable Filter assembly  
24” (610 mm) Replacement Expandable Filter assembly  
16” (406 mm) Replacement filter for EXPUNV assembly  
20” (508 mm) Replacement filter for EXPUNV assembly  
24” (610 mm) Replacement filter for EXPUNV assembly  
Bottom return filter rack 14” (356 mm) casing  
Bottom return filter rack 17” (432 mm) casing  
Bottom return filter rack 21” (533 mm) casing  
Bottom return filter rack 24” (610 mm) casing  
E x t . S id e f ilt e r r a ck --- a ll ca sin g s --- in clu d e s f ilt e r  
(1) unframed filter 16x25x3/4 (406x635x19 mm)  
(1) unframed filter 20x25x3/4 (508x635x19 mm)  
(1) unframed filter 24x25x3/4 (610x635x19 mm)  
(6) unframed filter 16x25x3/4 (406x635x19 mm)  
(6) unframed filter 20x25x3/4 (508x635x19 mm)  
(6) unframed filter 24x25x3/4 (610x635x19 mm)  
(12) vent extension 4” (102 mm) dia. x 3---1/2” (89 mm)  
Single or two stage PSC equipped units only  
Adjustable floor base --- fits all casing sizes  
Media Filter Cabinet  
Cartridge Media Filter  
EZ Flex Media Filter with End Caps  
Replacement EZ Flex Filter Media  
External Bottom Return Filter Rack  
External Side Return Filter Rack  
Unframed Filter 3/4---in. (19 mm)  
Flue Extension  
*Twinning Kit  
Combustible Floor Base  
Downflow Vent Guard  
Vent Extension Kit  
Vent flue shield --- downflow venting outside casing  
Downflow, through casing vent extension  
Masonry chimney adapter 4” (102 mm)  
Chimney Adapter Kit  
Masonry chimney adapter 5” (127 mm)  
N a t u r a l --- t o --- P r o p a n e C o n v e r si o n K i t  
P r o p a n e --- t o --- N a t u r a l C o n v e r si o n K i t  
Label Kit  
Gas conversion natural to propane all  
Gas conversion propane to natural all  
Downflow orientation label replacement  
**ECM Motor Simulator  
ECM blower and inducer simulator --- variable speed units  
PC software and hardware for Troubleshooting variable speed units  
**Advanced Product Monitor  
* Not for ECM or variable---speed ECM models  
** Variable---speed ECM models only  
59  
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PARTS REPLACEMENT INFORMATION GUIDE  
CASING GROUP  
Outer door  
GAS CONTROL GROUP  
Manifold  
Blower door  
Burner assembly  
Orifice  
Flame sensor  
Top filler plate  
Bottom filler plate  
Bottom enclosure  
Hot surface igniter  
Gas valve  
ELECTRICAL GROUP  
Control bracket  
Junction box  
Manual reset limit switches  
Burner support assembly  
HEAT EXCHANGER GROUP  
Heat exchanger cell  
Limit switch(es)  
Circuit board  
Door switch  
Cell panel  
Transformer  
Lox NOx baffle (California models only)  
Wiring harness 115v  
Wiring harness 24v  
INDUCER GROUP  
Housing assembly  
Pressure switch  
BLOWER GROUP  
Blower housing  
Inducer motor  
Blower cutoff  
Inducer wheel  
Blower motor  
Vent elbow assembly  
Draft safeguard switch  
Blower wheel  
Capacitor (where used)  
Capacitor strap (where used)  
Grommet  
Power choke (where used)  
TO OBTAIN INFORMATION ON PARTS: Consult your installing dealer or classified section of your local telephone directory under  
“Heating Equipment” or “Air Conditioning Contractors and Systems” headings for dealer listing by brand name or contact:  
BRYANT HEATING & COOLING SYSTEMS  
Consumer Relations Department  
P.O. Box 4952  
Syracuse, New York 13221--4952  
1--800--428--4326  
Have available the model number, series number, and serial number located on the unit rating plate to ensure correct replacement part.  
Example of Model Number  
COOLING  
SIZE  
(AIRFLOW)  
IGNITION  
TYPE  
HEATING  
SIZE  
MODEL  
VOLTAGE  
VARIATION  
SERIES  
VARIATION  
315A  
A
V
066  
155  
A
F
JA  
WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause personal injury, property damage, or death.  
Consult a qualified installer, service agency, or your local gas supplier for information or assistance. The qualified installer or service agency  
must use only factory--authorized replacement parts, kits, or accessories when modifying this product.  
EBryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231  
Printed in U.S.A.  
Edition Date: 06/10  
Catalog No. II315A--- 7 0 --- 1 1  
Replaces: II315A---70---10  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
60  
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