Johnson Controls Furnace CM8M CMLMMP User Manual

INSTALLATION MANUAL  
RESIDENTIAL GAS FURNACE  
WITH PSC MOTOR  
EFFICIENCY  
RATING  
CERTIFIED  
MODELS:  
TM8M/TMLM*MP, YM8M/YMLM*MP,  
CM8M/CMLM*MP, LM8M/LMLM*MP  
ISO 9001  
Certified Quality  
Management System  
(80% Modulating Multi-position / Low NOx)  
LIST OF SECTIONS  
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  
DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
TWINNING AND STAGING . . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
VENT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . 20  
SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24  
NORMAL OPERATION AND DIAGNOSTICS . . . . . . . . . . . . . 25  
REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . 27  
REPLACEMENT PART CONTACT INFORMATION . . . . . . . . 27  
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28  
LIST OF FIGURES  
Duct Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Vertical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Coil Flange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6  
Horizontal Right Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Horizontal Left Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
PC Series Upflow Coil Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
Horizontal Left or Right application (Right Shown) . . . . . . . . . . . . . . 8  
Combustible Floor Base Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
Horizontal Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . 9  
Downflow Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
Downflow Installation - Gas Valve Rotation . . . . . . . . . . . . . . . . . . . . 9  
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Side Return Cutout Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Upflow/Downflow Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Horizontal Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Thermostat Chart - Single Stage Air Conditioner –  
Variable Speed or PSC Modulating Furnace . . . . . . . . . . . . . . . . . .14  
Thermostat Chart - Two Stage Air Conditioner –  
Variable Speed or PSC Modulating Furnace . . . . . . . . . . . . . . . . . .15  
Thermostat Chart - Two Stage Air Conditioner with Single Stage  
Thermostat – Variable Speed or PSC Modulating Furnace . . . . . . .16  
Thermostat Chart - Single Stage Heat Pump –  
Variable Speed or PSC Modulating Furnace . . . . . . . . . . . . . . . . . .17  
Thermostat Chart - Single Stage Heat Pump –  
Variable Speed or PSC Modulating Furnace . . . . . . . . . . . . . . . . . .18  
Thermostat Chart - Two Stage Heat Pump –  
Variable Speed or PSC Modulating Furnace . . . . . . . . . . . . . . . . . .19  
Combustion Air Inducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20  
Combustion Airflow Path Through The Furnace  
Casing to the Burner Compartment . . . . . . . . . . . . . . . . . . . . . . . . .20  
Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . .21  
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25  
Furnace Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26  
Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30  
LIST OF TABLES  
Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Coil Projection Dimensions - PC Series Coils . . . . . . . . . . . . . . . . . . 6  
Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
Recommended Filter Sizes (High Velocity 600 FPM) . . . . . . . . . . . . 8  
High Altitude Orifices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Ratings & Physical / Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . 10  
Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
Unconfined Space Minimum Area in Square Inch . . . . . . . . . . . . . .19  
Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19  
Gas Rate (CU FT/HR) at Full Input . . . . . . . . . . . . . . . . . . . . . . . . . .22  
Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23  
Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23  
Cooling Airflow - A/C Capacity in Tons . . . . . . . . . . . . . . . . . . . . . . .24  
These high efficiency, compact units employ induced combustion, reli-  
able hot surface ignition and high heat transfer aluminized tubular heat  
exchangers. The units are factory shipped for installation in upflow or  
horizontal applications and may be converted for downflow applica-  
tions.  
DANGER indicates an imminently hazardous situation, which, if not  
avoided, will result in death or serious injury.  
WARNING indicates a potentially hazardous situation, which, if not  
avoided, could result in death or serious injury.  
CAUTION indicates a potentially hazardous situation, which, if not  
avoided may result in minor or moderate injury. It is also used to  
alert against unsafe practices and hazards involving only property dam-  
age.  
These furnaces are designed for residential installation in a basement,  
closet, alcove, attic, recreation room or garage and are also ideal for  
commercial applications. All units are factory assembled, wired and  
tested to assure safe dependable and economical installation and oper-  
ation.  
These units are Category I listed and may be common vented with  
another gas appliance as allowed by the National Fuel Gas Code.  
Improper installation may create a condition where the operation of  
the product could cause personal injury or property damage.  
Improper installation, adjustment, alteration, service or mainte-  
nance can cause injury or property damage. Failure to carefully  
read and follow all instructions in this manual can result in fur-  
nace malfunction, death, personal injury and/or property dam-  
age. Only a qualified contractor, installer or service agency should  
install this product.  
SECTION I: SAFETY  
This is a safety alert symbol. When you see this symbol on  
labels or in manuals, be alert to the potential for personal  
injury.  
Understand and pay particular attention to the signal words DANGER,  
WARNING, or CAUTION.  
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These instructions cover minimum requirements and conform to exist-  
ing national standards and safety codes. In some instances these  
instructions exceed certain local codes and ordinances, especially  
those who have not kept up with changing residential and non-HUD  
modular home construction practices. These instructions are required  
as a minimum for a safe installation.  
The furnace area must not be used as a broom closet or for any  
other storage purposes, as a fire hazard may be created. Never  
store items such as the following on, near or in contact with the fur-  
nace.  
1. Spray or aerosol cans, rags, brooms, dust mops, vacuum  
cleaners or other cleaning tools.  
FOR FURNACES INSTALLED IN THE COMMON-  
WEALTH OF MASSACHUSETTS ONLY  
2. Soap powders, bleaches, waxes or other cleaning com-  
pounds; plastic items or containers; gasoline, kerosene, ciga-  
rette lighter fluid, dry cleaning fluids or other volatile fluid.  
3. Paint thinners and other painting compounds.  
For all side wall horizontally vented gas fueled equipment installed in  
every dwelling, building or structure used in whole or in part for resi-  
dential purposes, including those owned or operated by the Com-  
monwealth and where the side wall exhaust vent termination is less  
than seven (7) feet above finished grade in the area of the venting,  
including but not limited to decks and porches, the following require-  
ments shall be satisfied:  
4. Paper bags, boxes or other paper products  
Never operate the furnace with the blower door removed. To  
do so could result in serious personal injury and/or equipment  
damage.  
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At  
the time of installation of the side wall horizontal vented gas  
fueled equipment, the installing plumber or gasfitter shall  
observe that a hard wired carbon monoxide detector with an  
alarm and battery back-up is installed on the floor level where  
the gas equipment is to be installed. In addition, the installing  
plumber or gasfitter shall observe that a battery operated or  
hard wired carbon monoxide detector with an alarm is installed  
on each additional level of the dwelling, building or structure  
served by the side wall horizontal vented gas fueled equipment.  
It shall be the responsibility of the property owner to secure the  
services of qualified licensed professionals for the installation of  
hard wired carbon monoxide detectors  
CODES AND STANDARDS  
Follow all national, local codes and standards in addition to this installa-  
tion manual. The installation must comply with regulations of the serv-  
ing 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.  
In the United States and Canada, follow all codes and standards for the  
following, using the latest edition available:  
STEP 1 -Safety  
US: National Fuel Gas Code (NFGC) NFPA 54/ANSI Z223.1 and  
the Installation Standards, Warm Air Heating and Air Conditioning  
Systems ANSI/NFPA 90B  
CANADA: CAN/CGA-B149.1 National Standard of Canada. Natu-  
ral Gas and Propane Installation Codes (NSCNGPIC)  
a. In the event that the side wall horizontally vented gas  
fueled equipment is installed in a crawl space or an attic,  
the hard wired carbon monoxide detector with alarm and  
battery back-up may be installed on the next adjacent floor  
level.  
STEP 2 -General Installation  
US: Current edition of the NFGC and NFPA 90B. For copies, con-  
tact the  
b. In the event that the requirements of this subdivision can  
not be met at the time of completion of installation, the  
owner shall have a period of thirty (30) days to comply with  
the above requirements; provided, however, that during  
said thirty (30) day period, a battery operated carbon mon-  
oxide detector with an alarm shall be installed.  
National Fire Protection Association Inc.  
Batterymarch Park  
Quincy, MA 02269  
or for only the NFGC, contact the  
American Gas Association,  
400 N. Capital, N.W.  
2. APPROVED CARBON MONOXIDE DETECTORS. Each car-  
bon monoxide detector as required in accordance with the  
above provisions shall comply with NFPA 720 and be ANSI/UL  
2034 listed and IAS certified.  
Washington DC 20001  
3. SIGNAGE. A metal or plastic identification plate shall be perma-  
nently mounted to the exterior of the building at a minimum  
height of eight (8) feet above grade directly in line with the  
exhaust vent terminal for the horizontally vented gas fueled  
heating appliance or equipment. The sign shall read, in print  
size no less than one-half (1/2) inch in size, "GAS VENT  
DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUC-  
TIONS".  
CANADA: NSCNGPIC. For a copy contact:  
Standard Sales, CSA International  
178 Rexdale Boulevard  
Etobicoke, (Toronto) Ontario Canada M9W 1RS  
STEP 3 -Combustion and Ventilation Air  
US: Section 5.3 of the NFGC, air for Combustion and Ventilation  
CANADA: Part 7 of NSCNGPIC, Venting Systems and Air Supply  
for Appliances  
4. INSPECTION. The state or local gas inspector of the side wall  
horizontally vented gas fueled equipment shall not approve the  
installation unless, upon inspection, the inspector observes car-  
bon monoxide detectors and signage installed in accordance  
with the provisions of 248 CMR 5.08(2)(a)1 through 4.  
STEP 4 -Duct Systems  
US and CANADA: Air Conditioning Contractors Association  
(ACCA) Manual D, Sheet Metal and Air Conditioning Contractors  
Association National Association (SMACNA), or American Soci-  
ety of Heating, Refrigeration, and Air Conditioning Engineers  
(ASHRAE) 1997 Fundamentals Handbook Chapter 32.  
INSPECTION  
STEP 5 -Acoustical Lining and Fibrous Glass Duct  
As soon as a unit is received, it should be inspected for possible dam-  
age during transit. If damage is evident, the extent of the damage  
should be noted on the carrier’s freight bill. A separate request for  
inspection by the carrier’s agent should be made in writing. Also, before  
installation, the unit should be checked for screws or bolts which may  
have loosened in transit. There are no shipping or spacer brackets  
which need to be removed from the interior of this unit.  
US and CANADA: Current edition of SMACNA and NFPA 90B as  
tested by UL Standard 181 for Class I Rigid Air Ducts  
STEP 6 -Gas Piping and Gas Pipe Pressure Testing  
US: NFGC; chapters 2, 3, 4, & 9 and National Plumbing Codes  
CANADA: NSCNGPIC Part 5  
STEP 7 -Electrical Connections  
US: National Electrical Code (NEC) ANSI/NFPA 70  
CANADA: Canadian Electrical Code CSA C22.1  
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2. Do not allow return air temperature to be below 55º F (13° C) for  
extended periods. To do so may cause condensation to occur in  
the main heat exchanger, leading to premature heat exchanger  
failure.  
FURNACE LOCATION AND CLEARANCES  
The furnace shall be located using the following guidelines:  
1. Where a minimum amount of air intake/vent piping and elbows will  
be required.  
Clearances for access/service:  
2. As centralized with the air distribution as possible.  
3. Where adequate combustion air will be available.  
Ample clearances should be provided to permit easy access to the unit.  
The following minimum clearances are recommended:  
4. Where it will not interfere with proper air circulation in the confined  
space.  
1. Twenty-four (24) inches (61 cm) between the front of the furnace  
and an adjacent wall or another appliance, when access is  
required for servicing and cleaning.  
5. Where the outdoor vent terminal will not be blocked or restricted.  
Refer to “VENT CLEARANCES” located in SECTION VII of these  
instructions. These minimum clearances must be maintained in  
the installation.  
2. Eighteen (18) inches (46 cm) at the side where access is required  
for passage to the front when servicing or for inspection or replace-  
ment of flue/vent connections.  
6. Where the unit will be installed in a level position with no more than  
1/4” (6.4 mm) slope side-to-side and front-to-back.  
In all cases, accessibility clearances shall take precedence over clear-  
ances for combustible materials where accessibility clearances are  
greater.  
Installation in freezing temperatures:  
1. Furnace shall be installed in an area where ventilation facilities  
provide for safe limits of ambient temperature under normal oper-  
ating conditions.  
Installation in a residential garage:  
A gas-fired furnace for installation in a residential garage must be  
installed so the burner(s) and the ignition source are located not less  
than 18 inches (46 cm) above the floor, and the furnace must be located  
or protected to avoid physical damage by vehicles.  
Table 1: Unit Clearances to Combustibles (All Dimensions in Inches, and All Surfaces Identified with the Unit in an Upflow Configuration)  
Top  
Front  
Rear  
Left Side  
In. (cm)  
0 (0.0)  
Right Side  
In. (cm)  
0 (0.0)  
Flue  
Floor/  
Bottom  
Line  
Contact  
Application  
Closet  
Alcove  
Attic  
In. (cm) In. (cm) In. (cm)  
In. (cm)  
Upflow B-Vent  
1 (2.5)  
1 (2.5)  
1 (2.5)  
3 (7.6)  
3 (7.6)  
3 (7.6)  
0 (0.0)  
0 (0.0)  
0 (0.0)  
1 (2.5) Combustible  
1 (25.4)1  
1 (2.5)  
Yes  
Yes  
No  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
No  
No  
Downflow B-Vent  
Horizontal B-Vent  
0 (0.0)  
0 (0.0)  
Yes2  
0 (0.0)  
0 (0.0)  
1 (2.5) Combustible  
1. Special floor base or air conditioning coil required for use on combustible floor.  
2. Line contact only permitted between lines formed by the intersection of the rear panel and side panel (top in horizontal position) of the furnace jacket and building  
joists, studs or framing.  
When replacing an existing furnace, if the existing plenum is not the  
same size as the new furnace then the existing plenum must be  
removed and a new plenum installed that is the proper size for the new  
SECTION II: DUCTWORK  
DUCTWORK GENERAL INFORMATION  
The duct system’s design and installation must:  
furnace. If the plenum is shorter than 12” (30.5 cm) the turbulent air flow  
may cause the limit controls not to operate as designed, or the limit con-  
trols may not operate at all.  
1. Handle an air volume appropriate for the served space and within  
the operating parameters of the furnace specifications.  
The duct system is a very important part of the installation. If the duct  
system is improperly sized the furnace will not operate properly.  
The ducts attached to the furnace plenum, should be of sufficient size  
so that the furnace operates at the specified external static pressure  
and within the air temperature rise specified on the nameplate.  
2. Be installed in accordance of National Fire Protection Association  
as outlined in NFPA standard 90B (latest editions) or applicable  
national, provincial, state, and local fire and safety codes.  
3. Create a closed duct system. For residential and Non-HUD Modu-  
lar Home installations, when a furnace is installed so that the sup-  
ply ducts carry air circulated by the furnace to areas outside the  
space containing the furnace, the return air shall also be handled  
by a duct(s) sealed to the furnace casing and terminating outside  
the space containing the furnace.  
The minimum plenum height is 12” (30.5 cm). The furnace will not  
operate properly on a shorter plenum height. The minimum recom-  
mended rectangular duct height is 4 inches (10 cm) attached to the  
plenum.  
4. Complete a path for heated or cooled air to circulate through the  
air conditioning and heating equipment and to and from the condi-  
tioned space.  
If a matching cooling coil is used, it may be placed directly on the fur-  
nace outlet and sealed to prevent leakage. If thermoplastic evaporator  
‘A’ coil drain pans are to be installed in the upflow/horizontal configura-  
tion, then extra 2” minimum spacing may be needed to ensure against  
drain pan distortion.  
The cooling coil must be installed in the supply air duct, down-  
stream of the furnace. Cooled air may not be passed over the heat  
exchanger.  
When the furnace is used with a cooling coil, the coil must be installed  
parallel with, or in the supply air side of the furnace to avoid condensa-  
tion in the primary heat exchanger. When a parallel flow arrangement is  
used, dampers or other means used to control airflow must be ade-  
quate to prevent chilled air from entering the furnace. If manually oper-  
ated, the damper must be equipped with means to prevent the furnace  
or the air conditioner from operating unless the damper is in full heat or  
cool position.  
The duct system must be properly sized to obtain the correct airflow  
for the furnace size that is being installed.  
Refer to Table 6, "Ratings & Physical / Electrical Data" or the fur-  
nace rating plate for the correct rise range and static pressures.  
If the ducts are undersized, the result will be high duct static pres-  
sures and/or high temperature rises which can result in a heat  
exchanger OVERHEATING CONDITION. This condition can result  
in premature heat exchanger failure, which can result in personal  
injury, property damage, or death.  
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DUCT FLANGES  
COIL/FURNACE ASSEMBLY - MC/FC/PC SERIES  
COILS  
Four flanges are provided to attach ductwork to the furnace. These  
flanges are rotated down for shipment. In order to use the flanges,  
remove the screw holding an individual flange, rotate the flange so it is  
in the upward position and reinstall the screw then repeat this for all 4  
flanges.  
If the flanges are not used, they should remain in the rotated down posi-  
tion as shipped.  
Factory  
installed  
For duct attachment,  
if needed.  
UPFLOW  
FIGURE 2: Vertical Applications  
DOWNFLOW  
FIGURE 1: Duct Attachment  
FURNACE ASSEMBLY - MC & FC SERIES COILS  
These coils are factory shipped for installation in either upflow or down-  
flow applications with no conversion.  
DUCTWORK INSTALLATION AND SUPPLY PLENUM  
CONNECTION - UPFLOW/HORIZONTAL  
Position the coil casing over or under the furnace opening as shown in  
Figure 2, "Vertical Applications" after configuring coil flanges as  
required see “Coil Flange” section below.  
Attach the supply plenum to the furnace outlet. The use of  
an approved flexible duct connector is recommended on all  
installations. This connection should be sealed to prevent  
air leakage. The sheet metal should be crosshatched to  
eliminate any popping of the sheet metal when the indoor  
fan is energized.  
COIL FLANGE INSTALLATION  
The coils include removable flanges to allow proper fit up with furnaces  
having various inlet and outlet flange configurations. The two flanges  
are attached to the top of the coil in the factory during production. For  
proper configuration of flanges refer to Figure 3, "Coil Flange".  
FLOOR BASE AND DUCTWORK INSTALLATION -  
DOWNFLOW  
Installations on combustible material or directly on any  
floors must use a combustible floor base shown in Figure 8,  
"Combustible Floor Base Accessory". Follow the instruc-  
tions supplied with the combustible floor base accessory.  
This combustible floor base can be replaced with a match-  
ing cooling coil, properly sealed to prevent leaks. Follow the  
instructions supplied with the cooling coil cabinet for install-  
ing the cabinet to the duct connector. Plug intake and vent  
pipe holes in bottom panel and move grommet to desired  
vent side exit.  
Downflow Air Conditioning Coil Cabinet  
FACTORY  
FLANGE  
LOCATION  
(Used for upflow  
or horizontal  
The furnace should be installed with coil cabinet part number specifi-  
cally intended for downflow application. If a matching cooling coil is  
used, it may be placed directly on the furnace outlet and sealed to pre-  
vent leakage. For details of the coil cabinet dimensions and installation  
requirements, refer to the installation instructions supplied with the coil  
cabinet.  
right installations)  
ALTERNATE  
FLANGE LOCATION  
(Used for downflow or  
horizontal left installations)  
Attach the air conditioning coil cabinet to the duct connector, and then  
position the furnace on top of the coil cabinet. The connection to the fur-  
nace, air conditioning coil cabinet, duct connector, and supply air duct  
must be sealed to prevent air leakage.  
FIGURE 3: Coil Flange  
FURNACE ASSEMBLY - MC SERIES COILS ONLY  
MC coils are supplied ready to be installed in a horizontal position. A  
horizontal pan is factory installed. MC coils should be installed in all hor-  
izontal applications with the horizontal drain pan side down.  
COIL INSTALLATION  
Mounting Plate  
On all installations without a coil, a removable access panel is rec-  
ommended in the outlet duct such that smoke or reflected light  
would be observable inside the casing to indicate the presence of  
leaks in the heat exchanger. This access cover shall be attached in  
such a manner as to prevent leaks.  
Furnace  
FIGURE 4: Horizontal Right Application  
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For horizontal left hand applications no conversion is required to an MC  
coil when used with a downflow/horizontal furnace. A mounting plate,  
supplied with every coil should always be installed on the side desig-  
nated as top side. See Figures 4 & 5.  
CRITICAL COIL PROJECTION  
The coil assembly must be located in the duct such that a minimum dis-  
tance is maintained between the top of the coil and the top of the duct.  
Refer to Table 2, "Coil Projection Dimensions - PC Series Coils".  
COIL / FURNACE ASSEMBLY - HC SERIES COILS  
Mounting Plate  
These coils are supplied ready to be installed in a right hand position or  
a left hand position. When used in conjunction with a horizontal furnace  
(blow through) application, the coil should be oriented with the opening  
of the “A” coil closest to the furnace. See Figures 7.  
Furnace  
NOTE: Each coil is shipped with an external tie plate that should be  
used to secure the coil to the furnace. It should be installed on the back  
side of the coil using the dimpled pilot holes. See Figures 7.  
FIGURE 5: Horizontal Left Application  
Use tie plate  
supplied with coil  
FURNACE ASSEMBLY - PC SERIES COILS  
These upflow coils are designed for installation on top of upflow fur-  
naces only.  
If the coil is used with a furnace of a different size, use a 45° transition  
to allow proper air distribution through the coil.  
1. Position the coil casing over the furnace opening as shown in Fig-  
ure 6, "PC Series Upflow Coil Installation".  
Gas Furnace  
2. Place the ductwork over the coil casing flange and secure.  
3. Check for air leakage between the furnace and coil casing and  
seal appropriately.  
FIGURE 7: Horizontal Left or Right application (Right Shown)  
DOWNFLOW DUCT CONNECTORS  
All downflow installations must use a suitable duct connector approved  
by the furnace manufacturer for use with this furnace. The duct connec-  
tors are designed to be connected to the rectangular duct under the  
floor and sealed. Refer to the instructions supplied with the duct con-  
nector for proper installation. Refer to the separate accessory parts list  
at the end of these instructions for the approved accessory duct con-  
nectors.  
Do not drill any holes or drive any screws into the front duct  
flange on the coil in order to prevent damaging coil tubing. See  
Figure 6, "PC Series Upflow Coil Installation"  
C
(Min)  
D
Flexible  
Duct Collar  
FURNACE  
Field  
Fabricated  
Ductwork  
WARM AIR PLENUM  
WITH 1” FLANGES  
Do not drill  
or Screw  
this flange  
FIBERGLASS  
INSULATION  
Upflow  
Coil  
Upflow  
Furnace  
FIBERGLASS TAPE  
UNDER FLANGE  
Alternate  
Drain Location  
Primary  
Drain  
Secondary  
Drain  
FIGURE 6: PC Series Upflow Coil Installation  
Table 2: Coil Projection Dimensions - PC Series Coils  
COMBUSTIBLE FLOOR  
BASE ACCESSORY  
COIL SIZE  
DIMENSION “C” INCH  
PC18  
PC24  
3-1/2  
4-1/2  
4-1/2  
5-1/2  
6-1/2  
9
FIGURE 8: Combustible Floor Base Accessory  
RESIDENTIAL AND MODULAR HOME UPFLOW  
RETURN PLENUM CONNECTION  
Return air may enter the furnace through the side(s) or bottom depend-  
ing on the type of application. Return air may not be connected into the  
rear panel of the unit.  
PC30, PC32, PC35  
PC42, PC43, PC36, PC37  
PC48  
PC60  
NOTE: Dimension “C” should be at least 2/3 of dimension “D”. See Fig-  
ure 6, "PC Series Upflow Coil Installation"  
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BOTTOM RETURN AND ATTIC INSTALLATIONS  
Bottom return applications normally pull return air through a base plat-  
form or return air plenum. Be sure the return platform structure or return  
air plenum is suitable to support the weight of the furnace.  
When a furnace is installed in an attic or other insulated space,  
keep all insulating materials at least 12 inches (30.5 cm) away from  
furnace and burner combustion air openings.  
The internal bottom panel must be removed for this application.  
Attic installations must meet all minimum clearances to combustibles  
and have floor support with required service accessibility.  
SUSPENDED FURNACE / CRAWL SPACE  
INSTALLATION  
HORIZONTAL APPLICATION  
The furnace can be hung from floor joists or installed on suitable blocks  
or pad. Blocks or pad installations shall provide adequate height to  
ensure the unit will not be subject to water damage. Units may also be  
suspended from rafters or floor joists using rods, pipe angle supports or  
straps. Angle supports should be placed at the supply air end and near  
the blower deck. Do not support at return air end of unit. All four sus-  
pension points must be level to ensure quite furnace operation. When  
suspending the furnace use a secure platform constructed of plywood  
or other building material secured to the floor joists. Refer to for typical  
crawl space installation.  
FIGURE 9: Horizontal Application  
This furnace may be installed in a horizontal position on either side  
as shown above. It must not be installed on its back.  
ATTIC INSTALLATION  
Support  
Angle Iron  
Bracket  
Bracket  
Line contact only permissible  
between lines formed by the  
intersection of furnace top  
and two sides and building  
joists, studs or framing  
Supply  
Air  
Vent (Maintain  
required  
clearances to  
combustibles)  
Filter rack  
must be a minimum  
distance  
of 18” (45.7 cm)  
from the  
furnace  
6” Min. Between  
Rod & Front of Furnace  
Rod & Back of Furnace  
Sheet metal in  
front of furnace  
combustion air  
Openings is  
1” Max. Between  
Gas Piping  
12”  
FIGURE 11: Typical Suspended Furnace / Crawl Space Installation  
Recommended  
12”  
DOWNFLOW APPLICATION  
30” MIN.  
Work Area  
To apply the furnace in a downflow position, it will be necessary to  
rotate the vent blower 90° left or right so that the vent pipe passes  
through the side of the furnace casing rather than the end. See Figure  
12, "Downflow Venting".  
Return  
Air  
Sediment  
Trap  
FIGURE 10: Typical Attic Installation  
For modulating furnaces to be used in the downflow position, it is  
necessary to rotate the gas valve so that it is upright when the fur-  
nace is installed. Loosen the pipe union between the gas valve and  
manifold, rotate the valve as far upward as it will go, and tighten the  
union. See Figure 13, "Downflow Installation - Gas Valve Rotation".  
This appliance is certified for line contact when the furnace is installed  
in the horizontal left or right position. The line contact is only permissible  
between lines that are formed by the intersection of the top and two  
sides of the furnace and the building joists, studs or framing. This line  
may be in contact with combustible material. Refer to Figure 10, "Typi-  
cal Attic Installation".  
For downflow  
installation,rotate  
gas valve upwards,  
as shown  
Rotate vent  
blower 90°  
either way  
LEFT SIDE VENT  
RIGHT SIDE VENT  
FIGURE 12: Downflow Venting  
FIGURE 13: Downflow Installation - Gas Valve Rotation  
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Vent  
Outlet  
RIGHT SIDE  
FRONT  
LEFT SIDE  
Electrical  
Entry  
Vent Outlet  
Electrical  
Entry  
Gas Pipe  
Entry  
Gas Pipe  
Entry  
33”  
23”  
Thermostat  
Wiring  
Thermostat  
Wiring  
14”  
A
28.5”  
29.5”  
1”  
1.5”  
(For Cladded door add  
appoximately an additional .75”)  
Vent  
Outlet  
.5”  
24.38”  
.5”  
.5”  
B
B
C
.5”  
20”  
24.25”  
SUPPLY END  
RETURN END  
FIGURE 14: Dimensions  
Table 3: Cabinet and Duct Dimensions  
Approximate  
Operating Weights  
Cabinet Dimensions (Inches)  
Nominal  
CFM (m3/min)  
BTUH (kW)  
Input  
Cabinet  
Size  
A
14 1/2  
17 1/2  
21  
A (cm)  
36.8  
44.4  
53.3  
53.3  
53.3  
53.3  
B
13 1/2  
16 1/2  
20  
B (cm)  
34.3  
41.9  
50.8  
50.8  
50.8  
50.8  
C
C (cm)  
26.2  
29.9  
34.5  
34.5  
34.5  
40.1  
Lbs  
94  
60 (17.6)  
80 (23.4)  
80 (23.4)  
100 (29.3)  
100 (29.3)  
120 (35.1)  
1200 (34.0)  
1200 (34.0)  
1600 (45.3)  
1600 (45.3)  
2000 (56.6)  
2000 (56.6)  
A
B
C
C
C
C
10.3  
11.8  
13.6  
13.6  
13.6  
15.8  
103  
114  
118  
122  
129  
21  
20  
21  
20  
21  
20  
SIDE RETURN  
Locate the “L” shaped corner locators. These indicate the size of the cut-  
out to be made in the furnace side panel. Refer to Figure 15, "Side  
Return Cutout Markings".  
SECTION III: FILTERS  
FILTER INSTALLATION  
All applications require the use of a field installed filter. All filters and  
mounting provision must be field supplied.  
Filters must be installed external to the furnace cabinet. DO NOT  
attempt to install filters inside the furnace.  
Front of  
Furnace  
Table 4: Recommended Filter Sizes (High Velocity 600 FPM)  
Side of  
Furnace  
CFM  
(m³/min)  
Cabinet  
Size  
Side  
(in)  
Bottom  
(in)  
1200 (34.0)  
1200 (34.0)  
1600 (45.3)  
2000 (56.6)  
A
B
C
C
16 x 25  
16 x 25  
14 x 25  
16 x 25  
20 x 25  
20 x 25  
Corner  
Markings  
16 x 25  
FIGURE 15: Side Return Cutout Markings  
(2) 16 x 25  
Install the side filter rack following the instructions provided with that  
accessory. If a filter(s) is provided at another location in the return air  
system, the ductwork may be directly attached to the furnace side  
panel.  
NOTES:  
1. Air velocity through throwaway type filters may not exceed 300 feet per  
minute (91.4 m/min). All velocities over this require the use of high velocity  
filters.  
2. Do not exceed 1800 CFM using a single side return and a 16x25 filter. For  
CFM greater than 1800, you may use two side returns or one side and the  
bottom or one side return with a transition to allow use of a 20x25 filter.  
Some accessories such as electronic air cleaners and pleated  
media may require a larger side opening. Follow the instructions  
supplied with that accessory for side opening requirements. Do not  
cut the opening larger than the dimensions shown in Figure 14,  
"Dimensions".  
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HORIZONTAL APPLICATION  
Horizontal Filters  
External Manual  
Shutoff Valve  
To Gas  
Supply  
To Gas  
Supply  
All filters and mounting provision must be field supplied. All installa-  
tions must have a filter installed.  
Any branch duct (rectangular or round duct) attached to the plenum  
must attach to the vertical plenum before the filter. The use of straps  
and / or supports is required to support the weight of the external filter  
box.  
Grounded Joint Union  
may be Installed  
Inside or Outside Unit.  
Drip Leg  
Downflow Filters  
FIGURE 17: Upflow/Downflow Gas Piping  
Downflow furnaces typically are installed with the filters located above  
the furnace, extending into the return air plenum or duct. Any branch  
duct (rectangular or round duct) attached to the plenum must attach to  
the vertical plenum above the filter height.  
Manual  
Shut-off  
Valve  
Filter(s) may be located in the duct system external to the furnace using  
an external duct filter box attached to the furnace plenum or at the end  
of the duct in a return filter grille(s). The use of straps and/or supports is  
required to support the weight of the external filter box.  
Drip  
Leg  
Gas  
Pipe  
Gas Burners  
Gas Valve  
SECTION IV: GAS PIPING  
Gas  
Pipe  
GAS SAFETY  
Drip  
Leg  
Manual  
Shut-off Valve  
An overpressure protection device, such as a pressure regulator,  
must be installed in the gas piping system upstream of the furnace  
and must act to limit the downstream pressure to the gas valve so it  
does not exceed 0.5 PSI (14" w.c. (3.48 kPa). Pressures exceeding  
0.5 PSI (14” w.c. (3.48 kPa) at the gas valve will cause damage to  
the gas valve, resulting in a fire or explosion or cause damage to  
the furnace or some of its components that will result in property  
damage and loss of life.  
FIGURE 18: Horizontal Gas Piping  
An accessible manual shutoff valve must be installed upstream of  
the furnace gas controls and within 6 feet (1.8 m) of the furnace.  
The furnace must be isolated from the gas supply piping system by  
closing its individual external manual shutoff valve during any pressure  
testing of the gas supply piping system at pressures equal to or less  
than 1/2 psig (3.5 kPa).  
Main  
Regulator  
Adjustment  
The gas valve body is a very thin casting that cannot take any  
external pressure. Never apply a pipe wrench to the body of the gas  
valve when installing piping. A wrench must be placed on the octa-  
gon hub located on the gas inlet side of the valve. Placing a wrench  
to the body of the gas valve will damage the valve causing improper  
operation and/or the valve to leak.  
On/Off  
Knob  
Outlet  
Pressure  
Tap  
Inlet  
Pressure  
Tap  
Gas piping may be connected from either side of the furnace using any  
of the gas pipe entry on both sides of the furnace. Refer to Figure 14,  
"Dimensions".  
FIGURE 16: Gas Valve  
GAS CONVERSION FOR PROPANE (LP)  
Plan your gas supply before determining the correct gas pipe entry.  
Use 90-degree service elbow(s), or short nipples and conventional  
90-degree elbow(s) to enter through the cabinet access holes.  
This furnace is constructed at the factory for natural gas-fired operation,  
but may be converted to operate on propane (LP) gas by using a fac-  
tory-supplied LP conversion kit which includes a LP gas valve. Follow  
the instructions supplied with the LP kit.  
GAS PIPING INSTALLATION  
Properly sized wrought iron, approved flexible or steel pipe must be  
used when making gas connections to the unit. If local codes allow the  
use of a flexible gas appliance connection, always use a new listed con-  
nector. Do not use a connector that has previously serviced another gas  
appliance.  
LoNOx furnaces requiring propane (LP) gas must have the LoNOx  
screens removed prior to installation and operation. See propane  
instructions.  
Some utility companies or local codes require pipe sizes larger than the  
minimum sizes listed in these instructions and in the codes. The furnace  
rating plate and the instructions in this section specify the type of gas  
approved for this furnace - only use those approved gases. The instal-  
lation of a drip leg and ground union is required. Refer to Figure 17,  
"Upflow/Downflow Gas Piping".  
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Example – You have a 100,000 BTU/H furnace installed at an elevation  
of 6,000 feet. You clock the gas meter and find that the furnace is actu-  
ally fired at 64,000 BTU/H. Divide 64,000 by 100,000, which gives 0.64  
(64%). The closest number to 64% in the left-hand “Actual Rate” col-  
umn is 65. Read across that row to the column for 6,000 feet elevation,  
which shows “#43”. You should change from the factory #45 orifices to  
larger #43 orifices, which will bring the input rate back up to approxi-  
mately 76,000 BTU/H, which is what it should be for that furnace at  
6,000 feet.  
HIGH ALTITUDE NATURAL GAS ORIFICE  
CONVERSION  
The National Fuel Gas Code requires that gas appliances installed  
above 2,000 feet elevation have their inputs de-rated by 4% per 1,000  
feet above sea level. The modulating furnaces automatically de-rate for  
altitude by measuring the inducer blower pressure and using that to  
determine if there is adequate air to support good combustion. If there  
is not enough combustion air to properly support 100% of the furnace  
nameplate input rate, the control will reduce the input to the point that  
there will be good combustion.  
Table 5: High Altitude Orifices  
The factory gas orifice sizes are based on a gas heating value of  
1030 BTU/Cu.ft., so if your gas value is significantly higher or  
lower than that, it may be necessary to change to smaller or larger  
gas orifices.  
Elevation in Feet Above Sea Level  
Actual Rate  
(percent of  
nameplate)  
4,000 5,000 6,000 7,000 8,000 9,000 10,000  
84% 80% 76% 72% 68% 64%  
Orifice Drill Size  
60%  
The chart below shows recommended gas orifice sizes to use at vari-  
ous altitudes and at various de-ration levels. To use the chart, follow  
these instructions:  
100  
95  
90  
85  
80  
75  
70  
65  
60  
55  
50  
48  
47  
46  
45  
45  
44  
43  
42  
41  
40  
39  
49  
48  
47  
46  
45  
45  
44  
43  
42  
41  
40  
49  
49  
48  
47  
46  
45  
44  
43  
42  
41  
40  
50  
50  
49  
48  
47  
45  
45  
44  
43  
32  
40  
51  
50  
49  
49  
48  
47  
45  
45  
44  
43  
43  
51  
50  
49  
49  
48  
47  
45  
45  
45  
43  
42  
52  
51  
50  
50  
49  
49  
48  
47  
46  
44  
42  
1. Clock the gas meter and calculate the actual input rate using your  
local gas heating value. See "CALCULATING THE FURNACE  
INPUT (NATURAL GAS)" in this manual.  
2. Divide that input rate by the input rate shown on the furnace rating  
plate to get the actual de-ration percent.  
3. Read down the left-hand “Actual Rate” column to find the closest  
number to your actual de-ration percent.  
4. Read across that row to the column for the elevation at your loca-  
tion. The number listed there is the orifice size that is proper for  
your unit.  
PROPANE KITS  
It is very important to choose the correct kit and/or gas orifices for the altitude and the type of gas for which the furnace is being installed.  
Only use natural gas in furnaces designed for natural gas. Only use propane (LP) gas for furnaces that have been properly converted to use pro-  
pane (LP) gas. Do not use this furnace with butane gas.  
Incorrect gas orifices or a furnace that has been improperly converted will create an extremely dangerous condition resulting in premature heat  
exchanger failure, excessive sooting, high levels of carbon monoxide, personal injury, property damage, a fire hazard and/or death.  
Propane (LP) conversions are required in order for the appliance to satisfactory meet the application.  
An authorized distributor or dealer must make all gas conversions.  
In Canada, a certified conversion station or other qualified agency, using factory specified and/or approved parts, must perform the conversion.  
The installer must take every precaution to insure that the furnace has been converted to the proper gas orifice size when the furnace is installed.  
Do not attempt to drill out any orifices to obtain the proper orifice size. Drilling out a gas orifice will cause misalignment of the burner flames,  
causing premature heat exchanger burnout, high levels of carbon monoxide, excessive sooting, a fire hazard, personal injury, property damage  
and/or death.  
SECTION V: ELECTRICAL POWER  
ELECTRICAL POWER CONNECTIONS  
Use copper conductors only.  
Field wiring to the unit must be grounded. Electric wires that are field  
installed shall conform to the temperature limitation for 63°F (35°C) rise  
wire when installed in accordance with instructions. Refer to Table 6,  
"Ratings & Physical / Electrical Data" in these instructions for specific  
furnace electrical data.  
Table 6: Ratings & Physical / Electrical Data  
Input  
Max/Min  
Output  
Max/Min  
Nominal  
Airflow  
Air Temp. Rise Air Temp. Rise  
Max Input Min Input  
Max. Outlet  
Air Temp  
Max  
Min. wire Size  
Total Unit  
Amps  
AFUE  
Over-Current (awg) @ 75 ft  
m3/min  
Protect  
one way  
MBH  
kW  
MBH  
kW  
CFM  
°F °C °F °C  
°F  
°C  
60/30 17.6/8.8 48/24 14.1/7.0 1200 34.0  
80/40 23.5/11.8 64/32 18.8/9.4 1200 34.0  
80/40 23.5/11.8 64/32 18.8/9.4 1600 45.3  
100/50 29.3/14.7 80/40 23.4/11.7 1600 45.3  
100/50 29.3/14.7 80/40 23.4/11.7 2000 56.6  
120/60 33.7/16.9 96/48 28.1/14.1 2000 56.6  
7.0  
7.5  
80.0 35-65 19-36 20-50 11-28  
80.0 40-70 22-39 20-50 11-28  
80.0 40-70 22-39 20-50 11-28  
80.0 40-70 22-39 20-50 11-28  
80.0 35-65 19-36 20-50 11-28  
80.0 45-75 25-42 25-55 13-31  
15  
15  
15  
15  
20  
20  
14  
14  
14  
14  
12  
12  
165 73.9  
170 76.7  
170 76.7  
170 76.7  
165 73.9  
175 79.4  
10.0  
10.0  
17.0  
17.0  
Annual Fuel Utilization Efficiency (AFUE) numbers are determined in accordance with DOE Test procedures.  
Wire size and over current protection must comply with the National Electrical Code (NFPA-70-latest edition) and all local codes.  
10  
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SUPPLY VOLTAGE CONNECTIONS  
LOW VOLTAGE CONTROL WIRING CONNECTIONS  
Install the field-supplied thermostat by following the instructions that  
come with the thermostat. With the thermostat set in the OFF position  
and the main electrical source disconnected, connect the thermostat  
wiring from the wiring connections on the thermostat to the terminal  
board on the ignition module, as shown in Figures 20-25, Thermostat  
Charts. Electronic thermostats may require the common wire to be con-  
nected as shown in Figure 16, "Gas Valve". Apply strain relief to ther-  
mostat wires passing through cabinet.  
Junction  
Box  
Connect ground  
lead to screw  
Electrical Entry  
BLK  
L1-Hot  
WHT  
Neutral  
Set the heat anticipator in the room thermostat to 0.4 amps. Setting  
it lower will cause short cycles. Setting it higher will cause the room  
temperature to exceed the set points.  
FIGURE 19: Electrical Wiring  
1. Provide a power supply separate from all other circuits. Install  
overcurrent protection and disconnect switch per local/national  
electrical codes. The switch should be close to the unit for conve-  
nience in servicing. With the disconnect or fused switch in the OFF  
position, check all wiring against the unit wiring label. Refer to the  
wiring diagram in this instruction.  
Some electronic thermostats do not have adjustable heat anticipa-  
tors. They should be set to six cycles per hour. Follow the thermo-  
stat manufacturer's instructions.  
The 24-volt, 40 VA transformer is sized for the furnace components  
only, and should not be connected to power auxiliary devices such as  
humidifiers, air cleaners, etc. The transformer may provide power for an  
air conditioning unit contactor.  
2. Remove the screws retaining the wiring box cover. Route the  
power wiring through the opening in the unit into the junction box  
with a conduit connector or other proper connection. In the junc-  
tion box there will be 3 wires, a Black Wire, a White Wire. Connect  
the power supply as shown on the unit-wiring label on the inside of  
the blower compartment door or the wiring schematic in this sec-  
tion. The black furnace lead must be connected to the L1 (hot)  
wire from the power supply. The white furnace screw must be con-  
nected to neutral. Connect the power supply ground to the green  
screw (equipment ground) An alternate wiring method is to use a  
field provided 2” (5.1 cm) x 4” (10.2 cm) box and cover on the out-  
side of the furnace. Route the furnace leads into the box using a  
protective bushing where the wires pass through the furnace  
panel. After making the wiring connections replace the wiring box  
cover and screws. Refer to Figure 19, "Electrical Wiring".  
AIR CONDITIONER CONNECTIONS  
This furnace may be used with single-stage or two-stage air condition-  
ing units.  
For Single-Stage A/C - Connect the low voltage wiring as shown in  
Figures 20, Thermostat Chart.  
For Two-Stage A/C - Use a two-stage thermostat, connect the low volt-  
age wiring as shown in Figures 21, Thermostat Chart.  
For Two-Stage A/C using a Single-Stage Thermostat - connect the  
low voltage wiring as shown in Figures 21, Thermostat Chart.  
This furnace control board can control a two-stage A/C using only a sin-  
gle-stage thermostat. In this case, the furnace control switches between  
high cool and low cool based on the calculated cooling load.  
3. The furnace's control system requires correct polarity of the power  
supply and a proper ground connection. Refer to Figure 19, "Elec-  
trical Wiring"  
ZONING OPERATION  
This furnace may be used in zoning systems, using a separate after-  
market zoning control. For use in zoned systems, put the ZONE CON-  
TROL jumper on the furnace control board in the “YES” position.  
The power connection leads and wiring box may be relocated to the  
left side of the furnace. Remove the screws and cut wire tie holding  
excess wiring. Reposition on the left side of the furnace and fasten  
using holes provided.  
HEAT PUMP OPERATION  
This furnace may be used in conjunction with a heat pump in dual fuel  
applications. For heat pump applications, put the HEAT PUMP jumper  
on the furnace control board in the “YES” position. Connect the low volt-  
age wiring as shown in Figures 20-25, Thermostat Charts. If a two-  
stage heat pump is to be used, a two-stage thermostat is required.  
Johnson Controls Unitary Products  
11  
Download from Www.Somanuals.com. All Manuals Search And Download.  
368261-UIM-A-0508  
Product Catalog Section.  
ID MODELS  
TM(8,L)M  
YM(8,L)M  
CM(8,L)M  
THERMOSTAT  
LM(8,L)M  
SINGLE STAGE  
MODULATING  
FURNACE  
AIR  
*PP11C70224