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.
4
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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"
6
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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".
8
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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.
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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
|