Johnson Controls MG9S*MP Installation Manual

EFFICIENCY
RATING
CERTIFIED

ISO 9001

Certified Quality

Management System

MANUFACTURED HOUSING OR MODULAR

INSTALLATION MANUAL

HOME GAS FURNACE

MODELS:
MG9S*MP - 33” Models –

(95.5% AFUE Single Stage Multi-position)

SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

CONDENSATE PIPING AND FURNACE

VENTING CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Duct Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Attachment to Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Combustible Floor Base Accessory . . . . . . . . . . . . . . . . . . . . . . . 6

Mobile Home Filter Frame Accessories . . . . . . . . . . . . . . . . . . . . 6

Blend Air Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Blend Air Installation (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Vertical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Coil Flange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

PC Series Upflow Coil Installation . . . . . . . . . . . . . . . . . . . . . . . . 8

Combustible Floor Base Accessory . . . . . . . . . . . . . . . . . . . . . . . 8

Downflow Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Dimensions (Upflow configuration shown) . . . . . . . . . . . . . . . . . 9

Side Return Cutout Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Upflow/Downflow Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Line Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Single Stage Heat Thermostat Connections . . . . . . . . . . . . . . . 12

Accessory Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Shipped in Downflow Configuration

LIST OF SECTIONS

LIST OF FIGURES

COMBUSTION AIR and VENT SYSTEM . . . . . . . . . . . . . . . . . 17

START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . 23

SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

NORMAL OPERATION AND DIAGNOSTICS . . . . . . . . . . . . . 29

REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . 31

REPLACEMENT PART CONTACT INFORMATION . . . . . . . . 31

WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Typical. Condensate drain, vertical in stallation . . . . . . . . . . . . . 13

Typical. Combustion Pipe Drain Tee . . . . . . . . . . . . . . . . . . . . . 14

Upflow Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Downflow Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Termination Configuration - 2 Pipe . . . . . . . . . . . . . . . . . . . . . . 20

Termination Configuration - 2 Pipe Basement . . . . . . . . . . . . . 20

Double Horizontal Combustion Air Intake

and Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Double Vertical Combustion Air Intake

and Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Direct Vent Air Intake Connection and Vent Connection . . . . . . 21

Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . 22

Attic and Crawl Space Combustion Air Termination . . . . . . . . . 23

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Furnace Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Furnace Control Event Schedule . . . . . . . . . . . . . . . . . . . . . . . 31

Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

LIST OF TABLES

Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . 4

Coil Projection Dimensions - PC Series Coils . . . . . . . . . . . . . . . 8

Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Recommended Filter Sizes (High Velocity 600 FPM) . . . . . . . . .9

Nominal Manifold Pressure - High Fire . . . . . . . . . . . . . . . . . . . 11

Ratings & Physical / Electrical Data . . . . . . . . . . . . . . . . . . . . . 12

Maximum Equivalent Pipe Length . . . . . . . . . . . . . . . . . . . . . . . 17

Elbow Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Equivalent Length of Fittings . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

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 downflow
applications and may be converted for upflow applications.

Combustion Air Intake and Vent Connection

Size at Furnace (All Models) . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Unconfined Space Minimum Area in Square Inch . . . . . . . . . . . 21

Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Gas Rate (CU FT/HR) at Full Input . . . . . . . . . . . . . . . . . . . . . . 25

Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Blower Performance CFM - Any Position (Without Filter) . . . . . 28

These furnaces are designed for residential installation in a basement,
closet, alcove, attic, recreation room or garage applications. All units
are factory assembled, wired and tested to assure safe dependable and
economical installation and operation.

These units are Category IV listed and may not be common vented with
another gas appliance as allowed by the National Fuel Gas Code.

420705-UIM-C-0310

420705-UIM-C-0310

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 resul t in minor 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 qualified cont ractor, installer or service agency should

install this product.

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, "COMBUSTION AIR and VENT SYSTEM" 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 may also be handled by duct(s) sealed to the furnace
casing and terminating outside the space containing the furnace.
The return air duct system is not required by the furnace manufac­turer provided the combustion air and vent system have been
installed and maintained as a Two Pipe Sealed Combustion Air
System and provided a return air duct system and return air ple­num are not required by state, local, or regional codes.

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;

.

It is also used to

• 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 Manufactured (Mobile) Home, 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.

12. When moving or handling this furnace prior to installation, always
leave the doors on the furnace to provide support and to prevent
damage or warping of the cabinet. When lifting the furnace by the
cabinet, support the ends of the furnace rather than lifting by the
cabinet flanges at the return air openings (bottom or sides) or sup­ply air opening.

13. When lifting the furnace, it is acceptable to use the primary heat
exchanger tubes as a lifting point provided that the tubes are lifted
at the front of the heat exchangers where attached to the vestibule
panel. Do not use the top return bend of the heat exchangers as
lifting points as the tubes may shift out of position or their location
brackets/baffles.

14. Manufactured (Mobile) Home Installation: This appliance must
be installed in a two-pipe (direct vent) configuration. The combus­tion air pipe must terminate in the same atmospheric zone, exter­nal to the building.

15. Modular Home Installations: A (two pipe) direct vent configura­tion. This configuration has a combustion air pipe and the vent
pipe that terminate in the same atmospheric zone, external to the
building, Refer to Figures 26 or 27 for combustion air and vent ter­minations.

16. Modular Home Definition: Factory-built home constructed to the
state, local, or regional code where the house will be located. The
home is transported in one or more modules and joined at the
home site.

17. Mobile Home Definition: Factory-built home constructed, trans­ported and installed under the federal building code administered
by the U.S. Department of Housing and Urban Development (HUD
Code), rather than to building codes at their destination. The home
is built, transported, installed on a non-removable chassis.

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.

• A manufactured (mobile) home installation must conform with
Manufactured Home Construction and Safety Standard, Title 24
CFR, Part 3280, or when such standard is not applicable, the
standard for Manufactured Home Installations (Manufactured
Home Sites, Communities, and Set-ups) ANSI/NCS A225.1, and
/or the Canadian Standard for CAN/CSA Z240 MH, Series M92
Mobile Homes. Furnaces have been certified to the latest edition
of standard ANSI Z21-47 • CSA 2.3.

• 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 12. The plenum must be installed
according to the instructions.

• Provide clearances from combustible materials as listed under
Clearances to Combustibles in Table 1.

2 Johnson Controls Unitary Products

420705-UIM-C-0310

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

• These models ARE

HUD Approved Modular Home
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.

• 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.

CSA listed or approved for installation into a

or a Manufactured (Mobile)

COMBUSTION AIR QUALITY
(LIST OF CONTAMINANTS)

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.

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.

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

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.

Johnson Controls Unitary Products 3

420705-UIM-C-0310

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 local 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 possible 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.

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 (particularly
when the appliance is not using outdoor combustion air).

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 to provide
proper condensate drainage.

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. Ambient temperatures must not fall below 32°F
(0°C) unless the condensate system is protected from freezing.

Improper installation in an ambient below 32ºF (0.0° C) could create
a hazard, resulting in damage, injury or death.

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.

3. If this furnace is installed in an unconditioned space and an
extended power failure occurs, there will be potential damage to
the internal components. Following a power failure situation, do
not operate the unit until inspection and repairs are performed.

Liquid anti-freeze will cause damage to internal plastic parts of this
furnace. D O NOT attempt to winterize the furnace using liquid

anti-freeze.

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.

Table 1:

Unit Clearances to Combustibles

Application Upflow Downflow

Top 1" 0"
Vent 0" 0"
Rear 0" 0"
Side 0" 0"

Front* 0" 0"

Floor Combustible

Closet Yes Yes

Line Contact No No

1. For combustible floors only when used with special sub-base.
* - 24" clearance in front and 18" on side recommended for service access.
All furnaces approved for alcove installation.

Combustible

1

4 Johnson Controls Unitary Products

420705-UIM-C-0310

Factory
installed

For duct attachment,
if needed.

Tie down
perforated
strap

Attach to
wall stud with a
nail or screw

Attach to Furnace
with screw

Vent
Pipe

Vent
Pipe

Vent
Drain

WALL

WALL

SUPPLY AIR DUCT

Combustion
Air Pipe

Combustion Air Pipe

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. For Manufactured (Mobile) Home and Modular Home Return
Duct System Installations: The return air duct and the return air
plenum are not required by the furnace manufacturer provided the
combustion air and vent system have been installed and main­tained as a Two Pipe Sealed Combustion Air System and provided
a return air duct and plenum are not required by state, local or
regional codes.

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.

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.

On all installations without a coil, a removable access panel is recom­mended 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.

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 must remain in the rotated down posi­tion as shipped.

FIGURE 1: Duct Attachment

DUCTWORK INSTALLATION AND SUPPLY PLENUM
CONNECTION - UPFLOW

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.

Attachment to Structure

A furnace for installation in a manufactured (mobile) home must be
securely attached to the building structure. The perforated strap sup­plied with the furnace may be used for that purpose. Refer to Figure 2.

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

Refer to T able 6 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.

Johnson Controls Unitary Products 5

FIGURE 2: Attachment to Structure

420705-UIM-C-0310

FURNACE

WARM AIR PLENUM
WITH 1” FLANGES

FIBERGLASS
INSULATION

FIBERGLASS TAPE
UNDER FLANGE

COMBUSTIBLE FLOOR
BASE ACCESSORY

FLOOR BASE AND DUCTWORK INSTALLATION ­DOWNFLOW

Installations on combustible material or directly on any
floors must use a combustible floor base shown in Figure 3.
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.

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.

DOWNFLOW RETURN PLEN UM CONN ECTION

The return air duct and the return air plenum are not required by the fur­nace manufacturer provided the combustion air and vent system have
been installed and maintained as a Two Pipe Sealed Combustion Air
System and provided a return air duct and plenum are not required by
state, local or regional codes.

• If a return air duct system and return plenum are required by
state, local or regional codes then the return plenum may be con­nected to the furnace inlet and must terminate outside the space
containing the furnace. The external air filter accessory shown in
Figure 4 is designed and recommended for use inside the return
plenum. Attach the return plenum to the furnace inlet duct
flanges. This is typically through the use of S cleat material when
a metal plenum is used. Installations where a return air duct sys­tem is utilized, the use of a listed flexible duct connector is recom­mended. The connection of the plenum to the furnace and all the
ducts connecting to the plenum must 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.
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 must 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 and in Table 3.

• If the return air duct and plenum are not required by state, local or
regional codes then the filter can be attached to the top of the fur­nace as shown in Figure 6.

When replacing an existing the furnace, if a return air plenum is
used and 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 a return duct
mounted filter rack or filter grille is being used, see the instructions
provided with that accessory for proper hole cut size.

FIGURE 3: 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.

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.

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.

FIGURE 4: Mobile Home Filter Frame Accessories

6 Johnson Controls Unitary Products

420705-UIM-C-0310

Screw x2

Blend Air
Bracket

18”
Max.

9155 Series
Filter Kit

Gas
Furnace

Blend Air Bracket (3500-5241)
mounted to wall next to furnace

Blend Air
Damper

Coil

Cabinet

Run flexible duct tubing
as close to the wall
as possible

UPFLOW

DOWNFLOW

Furnace

Furnace

Alternate Flange Location
(Used for downflow installations)

Factory Flange

Location(Used for

upflow installations)

BLEND AIR INSTALLATIONS

Upflow

This bracket is to be used only for Alcove application on the 90% Gas
Furnaces. It helps in installation of Blend Air Damper Tube close to the
furnace. It is recommended that the Blend Air be installed with the help
of this bracket as close to the furnace as possible. The Blend Air
Bracket Assembly should be installed no higher than 18 inches above
the furnace. See Figure 6.

FIGURE 5: Blend Air Bracket

Downflow

This bracket is to be used only for Alcove application on the 95% Gas
Furnaces. It helps in installation of Blend Air Damper Tube close to the
furnace. It is recommended that the Blend Air be installed with the help
of this bracket as close to the furnace as possible. The Blend Air
Bracket Assembly should be installed as close to the return air grille as
possible. See Figure 5.

COIL INSTALLATION

On all installations without a coil, a removable access panel is rec­ommended 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.

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

FIGURE 7: 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 7 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 8.

FIGURE 6: Blend Air Installation (Optional)

Johnson Controls Unitary Products 7

FIGURE 8: Coil Flange

420705-UIM-C-0310

Flexible
Duct Collar

Do not drill
or Screw
this flange

Field
Fabricated
Ductwork

Upflow
Coil

Upflow
Furnace

Secondary

Drain

Primary

Drain

D

C

(Min)

Alternate

Drain Location

FURNACE

WARM AIR PLENUM
WITH 1” FLANGES

FIBERGLASS
INSULATION

FIBERGLASS TAPE
UNDER FLANGE

COMBUSTIBLE FLOOR
BASE ACCESSORY

LEFT SIDE VENT RIGHT SIDE VENT

Rotate vent
blower 90°
either way

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 9.

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 9.

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.

FIGURE 9: 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

Dimension “C” should be at least 2/3 of dimension “D”. See Figure 9.

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 6.

FIGURE 10: Combustible Floor Base Accessory

DOWNFLOW APPLICATION

Furnace is shipped in downflow configuration. It may be necessary to
rotate the vent blower 180° left so that the vent pipe passes through the
side of the furnace casing. See Figure 11.

FIGURE 11: Downflow Venting

8 Johnson Controls Unitary Products

FIGURE 12: Dimensions (Upflow configuration shown)

FRONT

33

A

LEFT SIDE

Combustion Air Inlet

Condensate Drain
(Downflow)

Vent Outlet

Thermostat
Wiring

28.5”

Gas Pipe
Entry

Electrical
Entry

Condensate
Drain

Thermostat
Wiring

RIGHT SIDE

Vent Outlet

Condensate Drain
(Downflow)

14”

1”

1.5”

23”

Combustion Air Inlet

Gas Pipe
Entry

Electrical
Entry

Condensate
Drain

Optional Return Air
Cutout (Either side)

29.5”

(For Cladded door add appoximately an additional .75”)

C

SUPPLY END

.56”

.56”

20”

B

3”

23.8”

.56”

Combustion
Air Inlet

Vent
Outlet

RETURN END

B

24.25”

NOTICE

Front of
Furnace

Corner
Markings

Side of
Furnace

Table 3: Cabinet and Duct Dimensions

420705-UIM-C-0310

BTUH (kW)

Input

Nominal

CFM (m

3

/min)

Cabinet

60 (17.6) 1200 (34.0) B 17 1/2 44.4 16 3/8 41.6 13 1/4 33.7 122
80 (23.4) 1200 (34.0) B 17 1/2 44.4 16 3/8 41.6 14 3/4 37.5 126

80 (23.4) 1600 (45.3) C 21 53.3 19 7/8 50.5 16 1/2 41.9 136
100 (29.3) 1600 (45.3) C 21 53.3 19 7/8 50.5 18 1/4 46.4 142
100 (29.3) 2000 (56.6) C 21 53.3 19 7/8 50.5 18 1/4 46.4 145
120 (35.1) 2000 (56.6) D 24 1/2 62.2 23 3/8 59.4 21 3/4 55.2 156

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.

Single side return above 1800 CFM is approved as long as the filter
velocity does not exceed filter manufacturer’s recommendation and
a transition is used to allow use on a 20x25 filter.

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

CFM

Cabinet

(m³/min)

1200 (34.0) B 16 x 25 16 x 25
1600 (45.3) 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
2200 (62.3) C (2) 16 x 25 20 x 25

2000 (56.6) D (2) 16 x 25 22 x 25

1.Air velocity through throwaway type filters may not exceed 300 feet per min-

2.Do not exceed 1800 CFM using a single side return and a 16x25 filter. For

Johnson Controls Unitary Products 9

ute (91.4 m/min). All velocities over this require the use of high velocity fil­ters.

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.

Size

Side

Size

(in)

Cabinet Dimensions (Inches)

Approximate

Operating Weights

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

SIDE RETURN - UPFLOW ONLY

Locate the “L” shaped corner locators. These indicate the size of the cut­out to be made in the furnace side panel. Refer to Figure 13.

Bottom

(in)

FIGURE 13: 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 12.

420705-UIM-C-0310

INLET

WRENCH
BOSS

INLET
PRESSURE
PORT

ON

OFF

ON/OFF SWITCH
(Shown in ON position)

MAIN REGULATOR
ADJUSTMENT

OUTLET

OUTLET
PRESSURE
PORT

VENT PORT

Upflow

Configuration

Downflow

Configuration

External
Manual
Shut-off
Valve

External
Manual
Shut-off
Valve

To Gas
Supply

To Gas
Supply

To Gas
Supply

To Gas
Supply

Drip
Leg

Drip
Leg

Drip
Leg

Drip
Leg

Gas
Pipe

Gas
Valve

Gas
Pipe

Gas
Valve

Ground
Union

Ground
Union

Ground
Union

Ground
Union

NOTE: Ground Union maybe installed inside or outside unit.

SECTION IV: GAS PIPING

GAS SAFETY

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.

FIGURE 14: Gas 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.

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 15.

FIGURE 15: Upflow/Downflow 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).

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 knockouts on both sides of the furnace. Refer to
Figure 12.

10 Johnson Controls Unitary Products

GAS ORIFICE 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.

The gas supply must be shut off prior to disconnecting the elec­trical power, before proceeding with the conversion.

SHOCK HAZARD - Turn off electrical supply to furnace.

1. Shut off gas supply at valve upstream from furnace or at meter as
required.

2. Disconnect gas supply piping from gas valve on furnace.

3. Disconnect electrical wires from gas valve, noting which wires are
connected to which terminals

4. Remove the screws that attach the gas manifold to the burner sup­port box.

5. Remove and discard natural gas orifices.