Johnson Controls YM8M-YMLM-MP, TM8M-TMLM-MP, CM8M-CMLM-MP, LM8M-LMLM-MP User Manual

INSTALLATION MANUAL

RESIDENTIAL GAS FURNACE
WITH PSC MOTOR

MODELS:
TM8M/TMLM*MP, YM8M/YMLM*MP,
CM8M/CMLM*MP, LM8M/LMLM*MP

(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

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

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

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

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

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

EFFICIENCY
RATING
CERTIFIED

ISO 9001

Certified Quality

Management System

These high efficiency, compact units employ induced combustion, reli­able 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 applica­tions.
These furnaces are designed for residential installation in a basement,
closet, alcove, attic, recreation room or garage and are also ideal fo r
commercial applications. All units are factory assembled, wired and
tested to assure safe dependable and economical installation and oper­ation.
These units are Category I listed and may be common vented with
another gas appliance as allowed by the National Fuel Gas Code.

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.

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 m inor or moderate injury.
alert against unsafe practices and hazards involving only property dam­age.

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 mainte­nance can cause injury or property damage. Failure to carefully

read and follow all instructions in this manual can result in fur­nace malfunction, death, personal injury and/or property dam­age. Only a qualifie d contractor, installer or service agency should

install this product.

.

.

It is also used to

368261-UIM-A-0508

368261-UIM-A-0508

SPECIFIC SAFETY RULES AND PRECAUTIONS

1. Only Natural gas or Propane (LP) gas are approved for use with
this furnace.

2. Install this furnace only in a location and position as specified in
these instructions.

3. A gas-fired furnace for installation in a residential garage must be
installed as specified in these instructions.

4. Provide adequate combustion and ventilation air to the furnace
space as specified in these instructions.

5. Combustion products must be discharged outdoors. Connect this
furnace to an approved vent system only, as specified in SEC­TION VII of these instructions.

6. Test for gas leaks as specified in these instructions.

FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result in serious

injury, death or property damage.
Never test for gas leaks with an open flame. Use a commercially

available soap solution made specifically for detection of leaks to
check all connections. A fire or explosion may result causing prop­erty damage, personal injury or loss of life.

7. Always install the furnace to operate within the furnace’s intended
temperature rise range. Only connect the furnace to a duct system
which has an external static pressure within the allowable range,
as specified on the furnace rating plate.

8. When a furnace is installed so that supply ducts carry air circulated
by the furnace to areas outside the space containing the furnace,
the return air shall also be handled by duct(s) sealed to the fur­nace casing and terminating outside the space containing the fur­nace.

9. It is permitted to use the furnace for heating of buildings or struc­tures under construction where the application and use must com­ply with all manufacturer’s installation instructions including:

• Proper vent installation;

• Furnace operating under thermostatic control;

• Return air duct sealed to the furnace;

• Air filters in place;

• Set furnace input rate and temperature rise per rating plate

marking;

• Means for providing outdoor air required for combustion;

• Return air temperature maintained between 55ºF (13ºC) and

80ºF (27ºC);

• The air filter must be replaced upon substantial completion of

the construction process;

• Clean furnace, duct work and components upon substantial

completion of the construction process, and verify furnace­operating conditions including ignition, input rate, temperature
rise and venting, according to the manufacturer’s instructions.

10. When installed in a Non-HUD-Approved Modular Home or building
constructed on-site, combustion air shall not be supplied from
occupied spaces.

11. The size of the unit should be based on an acceptable heat loss
calculation for the structure. ACCA, Manual J or other approved
methods may be used.

SAFETY REQUIREMENTS

This product must be installed in strict compliance with the installa­tion instructions and any applicable local, state, and national codes
including, but not limited to building, electrical, and mechanical
codes.

• Refer to the unit rating plate for the furnace model number, and
then see the dimensions page of this instruction for return air ple­num dimensions in Figure 14, "Dimensions". The plenum must be
installed according to the instructions.

• Provide clearances from combustible materials as listed under
Clearances to Combustibles.

• Provide clearances for servicing ensuring that service access is
allowed for both the burners and blower.

• These models ARE NOT
into a HUD Approved Modular Home
(Mobile) Home.

• This furnace is not approved for installation in trailers or recre­ational vehicles.

• Furnaces for installation on combustible flooring shall not be
installed directly on carpeting, tile or other combustible material
other than wood flooring.

• Check the rating plate and power supply to be sure that the elec­trical characteristics match. All models use nominal 115 VAC, 1
Phase, 60-Hertz power supply. DO NOT CONNECT THIS APPLI­ANCE TO A 50 HZ POWER SUPPLY OR A VOLTAGE ABOVE
130 VOLTS.

• Furnace shall be installed so the electrical components are pro­tected from water.

• Installing and servicing heating equipment can be hazardous due
to the electrical components and the gas fired components. Only
trained and qualified personnel should install, repair, or service
gas heating equipment. Untrained service personnel can perform
basic maintenance functions such as cleaning and replacing the
air filters. When working on heating equipment, observe precau­tions in the manuals and on the labels attached to the unit and
other safety precautions that may apply.

CSA listed or approved for installation

or a Manufactured

COMBUSTION AIR QUALITY
(LIST OF CONTAMINANTS)

The furnace requires OUTDOOR AIR for combustion when the furnace
is located in any of the following environments.

• Restricted Environments

• Commercial buildings

• Buildings with indoor pools

• Furnaces installed in laundry rooms

• Furnaces installed in hobby or craft rooms

• Furnaces installed near chemical storage areas

• Chemical exposure

The furnace requires OUTDOOR AIR for combustion when the furnace
is located in an area where the furnace is being exposed to the follow­ing substances and / or chemicals.

• Permanent wave solutions

• Chlorinated waxes and cleaners

• Chlorine based swimming pool chemicals

• Water softening chemicals

• De-icing salts or chemicals

• Carbon tetrachloride

• Halogen type refrigerants

• Cleaning solvents (such as perchloroethylene)

• Printing inks, paint removers, varnishes, etc.

• Hydrochloric acid

• Cements and glues

• Antistatic fabric softeners for clothes dryers

• Masonry acid washing materials

When outdoor air is used for combustion, the combustion air intake duct
system termination must be located external to the building and in an
area where there will be no exposure to the substances listed above.

2 Johnson Controls Unitary Products

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 fur­nace.

1. Spray or aerosol cans, rags, brooms, dust mops, vacuum
cleaners or other cleaning tools.

2. Soap powders, bleaches, waxes or other cleaning com­pounds; plastic items or containers; gasoline, kerosene, ciga­rette lighter fluid, dry cleaning fluids or other volatile fluid.

3. Paint thinners and other painting compounds.

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.

CODES AND STANDARDS

Follow all national, local codes and standards in addition to this installa­tion manual. The installation must comply with regulations of the serv­ing gas supplier, local building, heating, plumbing, and other codes. In
absence of local codes, the installation must comply with the national
codes listed below and all authorities having jurisdiction.

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. Natu­ral Gas and Propane Installation Codes (NSCNGPIC)

STEP 2 -General Installation

• US: Current edition of the NFGC and NFPA 90B. For copies, con­tact the

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.
Washington DC 20001

or www.NFPA.org

• 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

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 Soci­ety of Heating, Refrigeration, and Air Conditioning Engineers
(ASHRAE) 1997 Fundamentals Handbook Chapter 32.

STEP 5 -Acoustical Lining and Fibrous Glass Duct

• 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

368261-UIM-A-0508

These instructions cover minimum requirements and conform to exist­ing 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.

FOR FURNACES INSTALLED IN THE COMMON­WEALTH OF MASSACHUSETTS ONLY

For all side wall horizontally vented gas fueled equipment installed in
every dwelling, building or structure used in whole or in part for resi­dential purposes, including those owned or operated by the Com­monwealth 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 require­ments shall be satisfied:

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

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.

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 mon­oxide detector with an alarm shall be installed.

2. APPROVED CARBON MONOXIDE DETECTORS. Each car­bon monoxide detector as required in accordance with the
above provisions shall comply with NFPA 720 and be ANSI/UL
2034 listed and IAS certified.

3. SIGNAGE. A metal or plastic identification plate shall be perma­nently 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 OBSTRUC­TIONS".

4. INSPECTION. The state or lo cal gas inspector of the side wall
horizontally vented gas fueled equipment shall not approve the
installation unless, upon inspection, the inspector observes car­bon monoxide detectors and signage installed in accordance
with the provisions of 248 CMR 5.08(2)(a)1 through 4.

INSPECTION

As soon as a unit is received, it should be inspected for possib le dam­age 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.

Johnson Controls Unitary Products 3

368261-UIM-A-0508

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.

2. As centralized with the air distribution as possible.

3. Where adequate combustion air will be available.

4. Where it will not interfere with proper air circulation in the confined
space.

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.

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.

Installation in freezing temperatures:

1. Furnace shall be installed in an area where ventilation facilities
provide for safe limits of ambient temperature under normal oper­ating conditions.

Table 1: Unit Clearances to Combustibles (All Dimensions in Inches, and All Surfaces Identified with the Unit in an Upflow Configuration)

Application

Upflow B-Vent 1 (2.5) 3 (7.6) 0 (0.0) 0 (0.0) 0 (0.0) 1 (2.5) Combustible Yes Yes Yes No
Downflow B-Vent 1 (2.5) 3 (7.6) 0 (0.0) 0 (0.0) 0 (0.0) 1 (2.5)
Horizontal B-Vent 1 (2.5) 3 (7.6) 0 (0.0) 0 (0.0) 0 (0.0) 1 (2.5) Combustible No Yes Yes

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.

Top Front Rear Left Side Right Side Flue

In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm)

SECTION II: DUCTWORK

DUCTWORK GENERAL INFORMATION

The duct system’s design and installation must:

1. Handle an air volume appropriate for the served space and within
the operating parameters of the furnace specifications.

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 Modu­lar Home installations, when a furnace is installed so that the sup­ply ducts carry air circulated by the furnace to areas outside the
space containing the furnace, the return air shall also be handled
by a duct(s) sealed to the furnace casing and terminating outside
the space containing the furnace.

4. Complete a path for heated or cooled air to circulate through the
air conditioning and heating equipment and to and from the condi­tioned space.

The cooling coil must be installed in the supply air duct, down­stream 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 condensa­tion in the primary heat exchanger. When a parallel flow arrangement is
used, dampers or other means used to control airflow must be ade­quate to prevent chilled air from entering the furnace. If manually oper­ated, 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.

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.

Clearances for access/service:

Ample clearances should be provided to permit easy access to the unit.
The following minimum clearances are recommended:

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.

2. Eighteen (18) inches (46 cm) at the side where access is required
for passage to the front when servicing or for inspection or replace­ment of flue/vent connections.

In all cases, accessibility clearances shall take precedence over clear­ances for combustible materials where accessibility clearances are
greater.

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.

Floor/

Bottom

1 (25.4)

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
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 con­trols may not operate at all.

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.

The minimum plenum height is 12” (30.5 cm). The furnace will not
operate properly on a shorter plenum height. The minimum recom­mended rectangular duct height is 4 inches (10 cm) attached to the
plenum.

If a matching cooling coil is used, it may be placed directly on the fur­nace outlet and sealed to prevent leakage. If thermoplastic evaporator
‘A’ coil drain pans are to be installed in the upflow/horizontal configura­tion, then extra 2” minimum spacing may be needed to ensure against
drain pan distortion.

The duct system must be properly sized to obtain the correct airflow
for the furnace size that is being installed.

Refer to Table6, "Ratings & Physical / Electrical Data" or the fur­nace rating plate for the correct rise range and static pressures.

If the ducts are undersized, the result will be high duct static pres­sures 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.

Closet Alcove Attic

1

Yes Yes Yes No

Line

Contact

Yes

2

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368261-UIM-A-0508

DUCT FLANGES

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 posi­tion as shipped.

For duct attachment,
if needed.

Factory
installed

FIGURE 1: Duct Attachment

DUCTWORK INSTALLATION AND SUPPLY PLENUM
CONNECTION - UPFLOW/HORIZONTAL

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.

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 instruc­tions supplied with the combustible floor base accessory.
This combustible floor base can be replaced with a match­ing cooling coil, properly sealed to prevent leaks. Follow the
instructions supplied with the cooling coil cabinet for install­ing 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

The furnace should be installed with coil cabinet part number specifi­cally intended for downflow application. If a matching cooling coil is
used, it may be placed directly on the furnace outlet and sealed to pre­vent leakage. For details of the coil cabinet dimensions and installation
requirements, refer to the installation instructions supplied with the coil
cabinet.

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 fur­nace, air conditioning coil cabinet, duct connector, and supply air duct
must be sealed to prevent air leakage.

COIL INSTALLATION

COIL/FURNACE ASSEMBLY - MC/FC/PC SERIES
COILS

Furnace

Furnace

UPFLOW

DOWNFLOW

FIGURE 2: Vertical Applications

FURNACE ASSEMBLY - MC & FC SERIES COILS

These coils are factory shipped for installation in either upflow or down­flow applications with no conversion.

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.

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".

FACTORY

FLANGE

LOCATION

(Used for upflow

or horizontal

ALTERNATE
FLANGE LOCATION
(Used for downflow or
horizontal left installations)

right installations)

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 hor­izontal applications with the horizontal drain pan side down.

On all installations without a coil, a removable access panel is rec-

Mounting Plate

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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368261-UIM-A-0508

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 desig­nated as top side. See Figures 4 & 5.

Mounting Plate

Furnace

FIGURE 5: Horizontal Left Application

FURNACE ASSEMBLY - PC SERIES COILS

These upflow coils are designed for installation on top of upflow fur­naces 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 Fig­ure 6, "PC Series Upflow Coil Installation".

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.

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

CRITICAL COIL PROJECTION

The coil assembly must be located in the duct such that a minimum dis­tance 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

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.

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.

Use tie plate
supplied with coil

Gas Furnace

Air flow

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 connec­tors are designed to be connected to the rectangular duct under the
floor and sealed. Refer to the instructions supplied with the duct con­nector for proper installation. Refer to the separate accessory parts list
at the end of these instructions for the approved accessory duct con­nectors.

Flexible
Duct Collar

Field
Fabricated
Ductwork

Upflow
Coil

Upflow
Furnace

Primary

Drain

Secondary

Drain

Do not drill
or Screw
this flange

Alternate

Drain Location

FIGURE 6: PC Series Upflow Coil Installation

Table 2: Coil Projection Dimensions - PC Series Coils

COIL SIZE DIMENSION “C” INCH

PC18 3-1/2
PC24 4-1/2

PC30, PC32, PC35 4-1/2

PC42, PC43, PC36, PC37 5-1/2

PC48 6-1/2
PC60 9

NOTE: Dimension “C” should be at least 2/3 of dimension “D”. See Fig­ure 6, "PC Series Upflow Coil Installation"

FURNACE

WARM AIR PLENUM
WITH 1” FLANGES

FIBERGLASS
INSULATION

FIBERGLASS TAPE
UNDER FLANGE

COMBUSTIBLE FLOOR
BASE ACCESSORY

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 depend­ing on the type of application. Return air may not be connected into the
rear panel of the unit.

6 Johnson Controls Unitary Products

BOTTOM RETURN AND ATTIC INSTALLATIONS

Bottom return applications normally pull return air through a base plat­form or return air plenum. Be sure the return platform structure or return
air plenum is suitable to support the weight of the furnace.

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.

HORIZONTAL APPLICATION

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.

368261-UIM-A-0508

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.

SUSPENDED FURNACE / CRAWL SPACE
INSTALLATION

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 sus­pension 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.

ATTIC INSTALLATION

Line contact only permissible
between lines formed by the
intersection of furnace top
and two sides and building
joists, studs or framing

Filter rack
must be a minimum
distance
of 18” (45.7 cm)
from the
furnace

Return
Air

Gas Piping

Sediment

Trap

30” MIN.
Work Area

FIGURE 10: Typical Attic Installation

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, "Typi­cal Attic Installation".

12”

12”

Supply
Air

Vent (Maintain
required
clearances to
combustibles)

Sheet metal in
front of furnace
combustion air
Openings is
Recommended

Angle Iron
Bracket

6” Min. Between
Rod & Front of Furnace

1” Max. Between
Rod & Back of Furnace

Support
Bracket

FIGURE 11: Typical Suspended Furnace / Crawl Space Installation

DOWNFLOW APPLICATION

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".

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 fur­nace 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".

For downflow
installation,rotate

Rotate vent
blower 90°

gas valve upwards,
as shown

either way

LEFT SIDE VENT

RIGHT SIDE VENT

FIGURE 12: Downflow Venting FIGURE 13: Downflow Installation - Gas Valve Rotation

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368261-UIM-A-0508

LEFT SIDE

(For Cladded door add

appoximately an additional .75”)

.5”

B

.5”

24.38”

SUPPLY END

20”

28.5”

29.5”

Vent
Outlet

Electrical
Entry

Gas Pipe
Entry

Thermostat
Wiring

Vent
Outlet

C

FRONT

A

33”

Electrical
Entry

Vent Outlet

Gas Pipe
Entry

Thermostat
Wiring

B

RIGHT SIDE

23”

24.25”

RETURN END

FIGURE 14: Dimensions
Table 3: Cabinet and Duct Dimensions

BTUH (kW)

Input

Nominal

CFM (m

3

/min)

Cabinet

Size

AA (cm)BB (cm)CC (cm) Lbs

Cabinet Dimensions (Inches)

60 (17.6) 1200 (34.0) A 14 1/2 36.8 13 1/2 34.3 10.3 26.2 94
80 (23.4) 1200 (34.0) B 17 1/2 44.4 16 1/2 41.9 11.8 29.9 103

80 (23.4) 1600 (45.3) C 21 53.3 20 50.8 13.6 34.5 114
100 (29.3) 1600 (45.3) C 21 53.3 20 50.8 13.6 34.5 118
100 (29.3) 2000 (56.6) C 21 53.3 20 50.8 13.6 34.5 122
120 (35.1) 2000 (56.6) C 21 53.3 20 50.8 15.8 40.1 129

14”

1.5”

.5”

1”

.5”

Approximate

Operating Weights

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.
Table 4: Recommended Filter Sizes (High Velocity 600 FPM)

CFM

(m³/min)

1200 (34.0) A 16 x 25 14 x 25
1200 (34.0) B 16 x 25 16 x 25
1600 (45.3) C 16 x 25 20 x 25
2000 (56.6) C (2) 16 x 25 20 x 25

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.

Cabinet

Size

Side

(in)

Bottom

(in)

SIDE RETURN

Locate the “L” shaped corner locators. These indicate the size of the cut­out to be made in the furnace side panel. Refer to Figure 15, "Side
Return Cutout Markings".

Front of
Furnace

Side of
Furnace

Corner
Markings

FIGURE 15: Side Return Cutout Markings
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.

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 Johnson Controls Unitary Products

368261-UIM-A-0508

HORIZONTAL APPLICATION

Horizontal Filters

All filters and mounting provision must be field supplied. All installa­tions 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 filte r
box.

Downflow Filters

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.

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.

SECTION IV: GAS PIPING

GAS SAFETY

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.

External Manual
Shutoff Valve

To Gas
Supply

Drip Leg

FIGURE 17: Upflow/Downflow Gas Piping

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.

Grounded Joint Union

may be Installed

Inside or Outside Unit.

Manual
Shut-off
Valve

Gas
Pipe

Gas
Pipe

Drip
Leg

To Gas
Supply

Drip
Leg

Gas Burners

Gas Valve

Manual
Shut-off Valve

On/Off
Knob

Inlet
Pressure
Tap

FIGURE 16: Gas Valve

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.

Main
Regulator
Adjustment

Outlet
Pressure
Tap

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 con­nector. Do not use a connector that has previously serviced another gas
appliance.

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 instal­lation of a drip leg and ground union is required. Refer to Figure 17,
"Upflow/Downflow Gas Piping".

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).

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 octa­gon 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.

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".

GAS CONVERSION FOR PROPANE (LP)

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 fac­tory-supplied LP conversion kit which includes a LP gas valve. Follow
the instructions supplied with the LP kit.

LoNOx furnaces requiring propane (LP) gas must have the LoNOx
screens removed prior to installation and operation. See propane
instructions.

Johnson Controls Unitary Products 9