For Installation In:
1. Manufactured (Mobile) Homes
2. Recreational Vehicles & Park Models
3. Modular Homes & Buildings
HIGH EFFICIENCY
INSTALLATION MANUAL
SEALED COMBUSTION GAS FURNACE
MODELS: DGAA and DGAH
(Single Stage Downflow Only)
56 - 90 MBH INPUT
(16.41 - 26.38 KW) INPUT
LIST OF SECTIONS
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
RETURN AIR REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
GAS LINE INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
LIST OF FIGURES
Furnace Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Air Distribution Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Closet To Door Clearance - 5” or Greater . . . . . . . . . . . . . . . . . . . . . .5
Furnace To Closet Door Clearance - 1” To 5” . . . . . . . . . . . . . . . . . . . 6
Furnace To Closet Door Clearance - Less Than 1” . . . . . . . . . . . . . . .6
Duct Connector Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Recommended Floor Cut-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Duct Connector Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Duct Connector Screw Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Duct Connector Tab Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Anti-Backflow Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Floor Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Furnace Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Burner Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Line Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Wiring for Heat Only Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
ROOF JACK VENT/COMBUSTION AIR SYSTEM . . . . . . . . . . . . . 13
SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 20
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Wiring for Electronic Heat-Cool Thermostat . . . . . . . . . . . . . . . . . . . 13
Wiring for Standard Heat-Cool Thermostat . . . . . . . . . . . . . . . . . . . 13
Wiring for Blend Air Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Standard Roof Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Roof Jack With Removable Crowns . . . . . . . . . . . . . . . . . . . . . . . . . 16
Roof Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Connecting Roof Jack to Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Roof Jack Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Ceiling Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Furnace Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Wiring Diagram - DGAA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Wiring Diagram - DGAH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
LIST OF TABLES
Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
External Static Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Filter Sizes - All Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
High Altitude Duration Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Ratings & Physical / Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . .13
Roof Jack Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Blower Performance CFM - Downflow Without Filters . . . . . . . . . . . 25
AC Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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 minor or moderate injury.
alert against unsafe practices and hazards involving only property damage.
Johnson Controls Unitary Products 129098-UIM-G-0411
.
.
It is also used to
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. Refer to this manual
for assistance or for additional information, consult a qualified contractor, installer or service agency.
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.
129098-UIM-G-0411
SPECIFIC SAFETY RULES AND PRECAUTIONS
1. Only Natural gas or Propane (LP) gas are approved for use with
this furnace. Refer to the furnace rating plate or Section IV of
these instructions.
2. Install this furnace only in a location and position as specified in
SECTION I of these instructions.
3. A gas-fired furnace for installation in a residential garage must be
installed as specified in SECTION I of 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.
4. Test for gas leaks as specified in SECTION IX of these instructions.
5. 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.
6. 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 Sealed Combustion Direct Vent System and provided a return air duct system and return air plenum
are not required by state, local, or regional codes.
Improper installation may damage equipment, can create a shock
hazard, and will void the warranty.
The furnace shall be installed so the electrical components are protected from water.
The furnace is not to be used for temporary heating of buildings or
structures under construction.
Do not test the fuel system at more than 14 inches water column
after furnace has been connected to the fuel line. Such testing may
void the warranty. Any test run above 14 inches water column may
damage the furnace control valve which could cause an explosion,
fire, or asphyxiation.
The following requirements to be met:
a. Clean, outside combustion air is provided to the furnace to
minimize the impact of corrosive adhesives, sealants, and
other construction materials. Drywall dust is a major concern
during construction, which can be pulled into the combustion
air path, leading to plugged heat exchangers, burners, and
inducer assemblies.
b. Filter must be installed in the furnace as specified in the
installation instructions, and must be replaced or thoroughly
cleaned prior to occupancy of the home. Again, drywall dust
is the key issue, as that dust can be pulled into the circulating
blower motor, plugging the motor vents, coating the rotors
and stators, etc. which can lead to a potential fire hazard.
c. The temperature of the retur n air to the furnace must not be
less than 55° F (13° C), with no evening setback or furnace
shutdown, to prevent condensation in the primary heat
exchangers.
d. The air temperature rise must be within the stated rise range
as indicated on the furnace rating plate, and the firing input
rate must be set to the unit nameplate value.
e. The external static pressure of the air distribution system
ductwork must be set for heating operation to be at least 0.10
to 0.20 inches water column, based on the input rate of the
furnace, with the lower value for input rates less than 55,000
btu/hr and the upper value for units with input rates above
100,000 btu/hr.
f. The furnace and ductwork should be thoroughly and com-
pletely cleaned prior to occupancy of the dwelling to insure
the proper operation of the furnace and to avoid potential
health concerns.
7. In Canada refer to the Natural Gas and Propane Installation code,
section on Central Furnaces. When installed in a Manufactured
(Mobile) Home, combustion air shall not be supplied from occupied spaces.
8. 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.
9. Manufactured (Mobile) Home and Modular Home Installation:
This appliance must be installed in a (sealed combustion) configuration using a roof jack vent system. A roof jack is only approved
vent system that can be used to vent this appliance.
10. 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.
11. Manufactured (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 house is built, transported and installed on a nonremovable chassis.
SAFETY REQUIREMENTS
• Provide clearances from combustible materials as listed under
Furnace Locations and Clearances.
• Provide clearances for servicing ensuring that service access is
allowed for both the burners and blower.
• These models are CSA listed and approved for installation into a
Modular Home, Manufactured (Mobile) Home, or Recreational
Vehicles.
• Failure to carefully read and follow all instructions in this
manual can result in furnace malfunction, death, personal
injury and/or property damage.
• 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 Modular
Home and Manufactured (Mobile) Home home construction practices. These instructions are required as a minimum for a safe
installation.
2 Johnson Controls Unitary Products
129098-UIM-G-0411
Manufactured homes in the U.S.A.:
• Federal Manufactured Home Construction & Safety Standard
(H.U.D. Title 24, Part 3280).
• National Fuel Gas Code (ANSI-Z223.1, NFPA-54).
• National Electrical Code (NFPA 70).
Manufactured homes in Canada:
• Natural Gas and Propane Installation Code (CAN/CSA B149.1).
• Canadian Electrical Code, Part 1 (CSA C22.1)
Recreational Vehicles in U.S.A.:
• Standard on Recreational Vehicles (NFPA 1192, formerly NFPA
501C).
• National Electrical Code (NFPA 70).
Recreational Vehicles in Canada:
• Unit installation shall comply with current CSA standard CAN/
CGA-Z240.4.2 - Installation Requirements for Propane Appliances and Equipment in Recreational Vehicles.
• Unit electrical wiring and grounding shall comply with current
CSA standard C22.2 No.148/CAN/CSA-Z240.6.2 - Electrical
Requirements for recreational vehicles.
COMBUSTION AIR QUALITY
(LIST OF CONTAMINANTS)
The furnace will require OUTDOOR AIR for combustion AT ALL TIMES,
INCLUDING any of the following environments.
• Restricted Environments
• Commercial buildings
• Buildings with indoor pools
• Laundry rooms
• Hobby or craft rooms
• Near chemical storage areas
• Chemical exposure
This furnace requires OUTDOOR AIR for combustion AT ALL TIMES,
AS WELL AS 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.
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
3. Containers; gasoline, kerosene, cigarette lighter fluid, dry
cleaning fluids or other volatile fluid.
4. Paint thinners and other painting compounds.
5. 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.
INSPECTION
As soon as the furnace and/or accessories are received, it should be
inspected for 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 furnace and/or accessories should be
checked for screws or bolts which have loosened in transit or shipping
and spacer brackets the need to be removed.
FURNACE LOCATION AND CLEARANCES
The furnace shall be located using the following guidelines:
1. The furnace should be located where the roof jack can be installed
with out major modifications to the roof of the structure.
2. As centralized with the air distribution as possible.
3. Where there is access to fresh air particularly when the blend air
accessory will be installed.
4. Where it will not interfere with proper air circulation in the confined
space.
5. Where the outdoor roof jack terminal will not be blocked or
restricted. Refer to “VENT CLEARANCES” located in SECTION
VII of these instructions. These minimum clearances must be
maintained through out the installation.
6. Where the unit will be installed in a level position with no more
than 1/4” (0.64 cm) slope side-to-side and front-to-back to provide
a proper roof jack connection and seal.
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 may fall below 32° F (0° C)
providing the flue temperature does not fall below 260° F (127° C)
at any point in the flue pipe. If the flue temperature falls below 260°
F (127° C) the flue products will condense in the vent pipe causing
the vent pipe to deteriorate rapidly.
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.
Installation in an ambient below 32ºF (0.0° C) could create a hazard, resulting in damage, injury or death.
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.
Clearances for access:
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. See Table 1.
Check the rating plate and power supply to be sure that the electrical characteristics match. All models use nominal 115 VAC, 1
Phase 60Hz power supply.
Furnace shall be installed so the electrical components are protected from water.
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.
Johnson Controls Unitary Products 3
129098-UIM-G-0411
DGAH Series
DGAA Series
A
B
C
D
E
F
G
B
C
D
E
F
G
C
D
E
F
G
Inches
59-1/2”
76”
24.3/4”
23”
19-1/2”
9-3/4”
12”
c.m.
151.0
193.0
62.9
58.4
49.5
24.8
30.5
A
TABLE 1:
Application
Unit Clearances to Combustibles
Top Front Rear Sides Roof Jack Flue
Floor
1
Duct
Closet Alcove Closet Alcove Closet Alcove Closet Alcove Closet Alcove Closet Alcove Closet Alcove
1
In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm) In. (cm)
Downflow2(50.8)2(50.8)6(15.24)24(60.96)0000000000
1. Approved duct connector required for use on combustible floor.
FIGURE 1: Furnace Dimensions
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 with standards of NFPA (National Fire
Protection Association) as outlined in NFPA pamphlets 90A and
90B (latest editions), in Canada CAN/CGA-B149.1-00 Natural Gas
and Propane Installation Code. or applicable national, provincial,
or state, and local fire and safety codes.
3. For Manufacture (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 a return air duct and plenum
are not required by state, local, or regional codes. The only vent
system that is approved for use on this furnace is a Roof Jack
which is a Sealed Combustion Direct Vent System.
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, and must comply with (H.U.D.) TITLE 24, PART
3280.709
When the furnace is used in conjunction 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.
The duct system must be properly sized to obtain the correct airflow
for the furnace size that is being installed.
Refer to the furnace rating plate for the correct rise range and Table
4 for 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.
HAZARD OF ASPHYXIATION, DO NOT COVER OR RESTRICT
FLOOR OPENING.
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.
Fabricate and install an inspection door in the plenum base below
the unit to allow an annual inspection of the heat exchangers. The
inspection door can be fabricated by the following method.
1. Cut a rectangular opening in the plenum base.
2. A sheet metal plate can be made that completely covers the opening in the base.
3. The plate must be secured with screws.
4. This plate must be sealed to prevent leaks.
4 Johnson Controls Unitary Products
The supply air temperature MUST NEVER exceed the Maximum
A
Single trunk duct
Dual trunk duct
Transition duct
1
B*
Dual trunk duct with crossover connector
Crossover
C
Transition Duct with Branches
Branches
3
1. Crossover Duct must be centered directly under furnace.
2. Use 12” (30.5 cm) Diameter Round or insulated Flex-duct only.
3. Terminate Flex-duct (opposite furnace) in the center of the trunk duct.
4. Flex-duct material must be pulled tight — No Loops or unnecessary dips — Air Flow may be impeded.
4
2
5 in (12.7 cm) or greater * Closet
to Door Clearance
Furnace to Closet Door Clearance —
5 Inches (12.7 cm) or more
1.
2.
Return Air Grille Part No.
7900-287P/A * White
The closet door have a minimum of
of free area in the upper half of the door.
MUST 250 Inches (1613 cm )
22
250 IN. (161 cm )
MINIMUM
FREE AREA
22
50 IN. (322 cm )
MINIMUM
FREE AREA
22
250 IN. (161 cm )
MINIMUM
FREE AREA
22
B
CLOSET
DOOR
FURNACE
A
If opening for return air is located in the floor or sidewalls and
below the top of the furnace casing:
Return Air Closet Door Part No.
7900-7771/C* White
6 inches (15.2 cm) minimum clearance must be maintained from
the front of furnace.
6 inches (15.2 cm) minimum clearance must be provided on side
where return is located, and
Supply Air Temperature, specified on the nameplate.
Operating the furnace above the maximum supply air temperature
will cause the heat exchanger to overheat, causing premature heat
exchanger failure. Improper duct sizing, dirty air filters, incorrect
manifold pressure, incorrect gas orifice and/or a faulty limit switch
can cause the furnace to operate above the maximum supply air
temperature. Refer to sections II, III and XI for additional information on correcting the problem.
DUCTWORK INSTALLATION
Air Distribution Systems
For proper air distribution, the supply duct system shall be designed so
that the static pressure does not exceed the listed static pressure rating
on the furnace rating plate.
Three typical distribution systems are illustrated in Figure 2.
Location, size and number of registers should be selected on the basis
of best air distribution and floor plan of the home.
The Air Temperature Rise is to be adjusted to obtain a temperature rise
within the range(s) specified on the furnace rating plate.
129098-UIM-G-0411
DUCT DESIGN - CANADA
Supply duct design shall be in accordance with the latest HRA Digest,
the ASHRAE Handbook Fundamentals, or other good engineering principles.
NOTE: Refer to HRA Digest Residential Air System Design Manual,
Sections 5 and 6, the requirements of which are summarized as follows:
1. The kilowatt output of each duct register shall not exceed 2.35 kW.
2. The furnace output should not be more than 20% greater than the
calculated heat loss of the home. If a larger furnace is used, the
duct system shall be capable of the increased air volumes neces-
sary to maintain a maximum air temperature rise of 50
o
C as the
air passes over the furnace heat exchanger.
3. At least one warm air supply outlet shall be provided in each room.
4. When rooms are located adjacent to the exterior walls, warm air
outlets shall be located so as to bathe at least one exterior wall
and, where practical, a window area with warm air, except for bathrooms or kitchens where this might not be practical.
5. Where practical, outlets shall be provided near the exterior doors
of the home.
CLEARANCE REQUIREMENTS - CANADA
Supply air ducts from warm air furnaces having a specified minimum
plenum clearance shall maintain this clearance from combustible material for at least the distance specified in CSA Standards C22.2 No. 23 or
B140.10 or CGA Standard CAN/CGA-2.3.
FIGURE 2: Air Distribution Systems
FIGURE 3: Closet To Door Clearance - 5” or Greater
Johnson Controls Unitary Products 5
129098-UIM-G-0411
Furnace to Closet Door Clearance —
Greater than 1 Inch (2.54 cm) and Up to 5 (12.7 cm) Inches
1.
2.
A fully louvered closet door have a minimum of
of free area in the upper half of the door.
MUST
250 Inches
22
(1613 cm )
The closet door have a minimum of (1613 cm f free
area in the upper half of the door and a minimum of (322 cm ) of
free area in the lower area of the door.
MUST 250 Inches
50 Inches
The lower closet door grille may be
omitted if an undercut of 2-1/2 inches (16.1 cm) is provided in the door.
22
22
)o
250 IN. (161 cm )
MINIMUM
FREE AREA
22
50 IN. (322 cm )
MINIMUM
FREE AREA
22
250 IN. (161cm )
MINIMUM
FREE AREA
22
B
As an option to the lower grill,
an undercut of 2-1/2" will provide
50 inches (322 cm ) of free area.
22
Furnace to Closet Door Clearance —
Less than 1 Inch (2.54 cm)
The closet door MUST have three return air grilles. The total free area of the
two upper grilles must be minimum of (1613 cm ) . The total
free area of the lower grille MUST be a minimum of .
250 Inches
50 Inches (322 cm )
22
22
The grilles MUST BE ALIGNED directly opposite the return air grille of
the furnace door.
250 IN. (161 cm )
MINIMUM
FREE AREA
22
50 IN. (322 cm )
MINIMUM
FREE AREA
22
2-3/8
(6.0 cm)
12
(30.5 cm)
13
(33.0 cm)
11
(27.9 cm
18-3/4 (47.6 cm)
14 (35.6 cm)
SEE
CHART
DUCT CONNECTOR
PART NUMBER
DUCT CONNECTOR
DEPTH
7990-6011
7990-6021
7990-6041
7990-6061
7990-6071
7990-6081
7990-6101
7990-6121
1” (2.5 cm)
2” (5.7 cm)
4-1/2” (11.4 cm
6-1-2” (16.5 cm)
7-1/2” (19.0 cm)
8-1/2” (21.6 cm)
10-1/4” (26.0 cm)
12-1/4” (21.1 cm)
DUCT CONNECTOR DIMENSIONS
2-3/8
(6.0 cm)
18-3/4
(47.6 cm)
4-3/8
(11.1 cm)
2-3/8
(6.0 cm)
12
(30.5 cm)
13
(33.0 cm)
11
(27.9 cm
18-3/4 (47.6 cm)
14 (35.6 cm)
SEE
CHART
DUCT CONNECTOR
PART NUMBER
DUCT CONNECTOR
DEPTH
1” (2.5 cm)
2” (5.7 cm)
4-1/2” (11.4 cm
6-1-2” (16.5 cm)
7-1/2” (19.0 cm)
8-1/2” (21.6 cm)
10-1/4” (26.0 cm)
12-1/4” (21.1 cm)
DUCT CONNECTOR DIMENSIONS
2-3/8
(6.0 cm)
18-3/4
(47.6 cm)
4-3/8
(11.1 cm)
7990-6211
7990-6221
7990-6241
7990-6261
7990-6271
7990-6281
7990-6301
7990-6321
FIGURE 4: Furnace To Closet Door Clearance - 1” To 5”
FIGURE 5: Furnace To Closet Door Clearance - Less Than 1”
DUCT CONNECTORS
FIGURE 6: Duct Connector Dimensions
6 Johnson Controls Unitary Products
FIGURE 7: Recommended Floor Cut-out
2-3/4 (7.0 cm)
MIN.
23-1/4 (59.1 cm)
20-1/2 (52.1 cm)
9-7/8
(25.1 cm
1-3/8
(3.5 cm)
6-3/8
(16.2 cm)
9-3/4
24.8 cm)
20
(50.8 cm)
1-1/8
(2.9 cm)
15
(38.1 cm)
15
(38.1 cm)
1
REAR WALL
OF ENCLOSURE
CEILING CUT-OUT
FOR ROOF JACK
FLOOR CUT-OUT
FOR DUCT
CONNECTOR
FLOOR
FUTURE
REFRIGERANT
LINE ENTRANCE
FRONT PANEL
OF FURNACE
3-1/4
(8.3 cm)
FURNACE
OUTLINE
OPTIONAL GAS
OR ELECTRIC
ENTRANCE
2-1/8 (5.4 cm)
DUCT CONNECTOR
DEPTH
FLOOR
FLOOR
JOIST
SUPPLY DUCT
LOCATOR BRACKET
NAILS, FLAT HEAD SCREWS
OR STAPLES
SCREWS
FLOOR
SUPPLY DUCT
LOCATOR BRACKET
NAILS, FLAT HEAD SCREWS
OR STAPLES
BEND TABS UNDER
DUCT OPENING TO
SECURE TO THE
SUPPLY DUCT.
FLOOR
SUPPLY DUCT
FIGURE 8: Duct Connector Depth
FIGURE 9: Duct Connector Screw Attachment
INSTALLATION OF SCREW ATTACHMENT DUCT
CONNECTOR
1. Make floor cut out as shown in Figure 7.
2. Determine the depth of the floor cavity from the surface of the floor
to the top of the supply air duct and select the appropriate duct
connector from the chart. See Figures 6 and 8.
3. Place locating bracket (supplied with the duct connector) to the
back edge of the floor opening. See Figure 9.
4. Apply a water based duct sealant to the 1/2" supply duct attach-
5. Determine which of the four positions the duct connector best cen-
6. When properly aligned with the supply duct, secure the duct con-
ment flange of the duct connector.
ters over the supply duct and insert it through the floor cut-out.
nector to the floor with nails, flat head screws or staples.
7. Use screws as required to secure the duct connector to the supply
duct.
8. Cut out the opening to the supply duct. If sealant was not used, the
Johnson Controls Unitary Products 7
installer should tape the mating flanges to provide a good air seal.
129098-UIM-G-0411
NOTE: Duct sealant and tape must be classified as meeting HUD Standard 3280.715, U.L. Standard 181A.
If tape is used to provide a better air seal, it should be a type approved
by the applicable national or local codes.
FIGURE 10: Duct Connector Tab Attachment
INSTALLATION OF TAB ATTACHMENT DUCT
CONNECTORS
1. Make floor cut out as shown in Figure 7.
2. Determine the depth of the floor cavity from the surface of the floor
to the top of the supply air duct and select the appropriate duct
connector from the chart. See Figures 6 and 8.
3. Place locating bracket (supplied with the duct connector) to the
rear of the floor area for the furnace. See Figure 10.
4. Determine which of the four positions the duct connector best centers over the supply duct and insert it through the floor cut-out.
5. Mark cut-out location on the supply duct and remove the duct connector.
6. Cut out the opening to the supply duct.
7. Bend tabs down through and back up under the supply duct.
8. Secure the duct connector to the floor with nails, flat head screws
or staples.
The duct connector is designed for use on ducts down to 12" in width.
When using the connector on smaller width ducts, there will not be sufficient clearance to bend the tabs on two sides of the duct connector.
In such cases the tabs may be attached to the sides of the duct by
using sheet metal screws or other suitable fasteners. Holes for sheet
metal screws are provided in three (3) tabs on each side of the duct
connector. If more than 3 tabs need to be used to provide a more
secure and air tight connection, the remaining tabs can also be fastened to the duct with screws after drilling the required screw hole.
Furnace and Air Conditioner In stallations
If an air conditioner is installed which does not use the blower for air distribution and operates completely independent of the furnace, the thermostat system must have an interlock to prevent the furnace and air
conditioner from operating at the same time. This interlock system usually contains a heat-cool switch which must be turned to either HEAT or
COOL to activate either heating or cooling operation, or a positive OFF
switch on the cooling thermostat.
When used in connection with a cooling unit the furnace shall be
installed parallel with or on the upstream side of the cooling unit to avoid
condensation in the heat exchanger.
For installations with a parallel flow arrangement, the furnace must be
equipped with a damper to prevent cold air from being discharged up
around the heat exchanger. Cold air causes condensation inside the
exchanger and can cause it to rust out which can allow products of
combustion to be circulated into the living area by the furnace blower
resulting in possible asphyxiation. An air flow activated automatic
damper, P/N 7900-6771, is available from furnace manufacturer. See
Figure 11.
129098-UIM-G-0411
AUTOMATIC
DAMPER
SUPPLY DUCT
OPENING
FURNACE
BASE
DUCT
CONNECTOR
NOTE: FOR BEST AIR DELIVERY INSTALL DAMPER
WITH BLADES PARALLEL TO SUPPLY DUCT.
WARM AIR DUCT
DUCT CONNECTOR
FLOOR
BLEND AIR
FLEX DUCT
BLEND AIR
DAMPER
NOTE: See label on coil panel for conversion and lighting instructions.
Obtain a temperature rise within the ranges specified on the name
plate.
FIGURE 11: Anti-Backflow Damper
INSTALLATION RECOMMENDATIONS
1. Remove the front panels and set the furnace onto the duct connector. Slide it back until the rear of the unit engages the locator
bracket.
2. Secure the front of the furnace with two screws at the mounting
holes provided.
3. Secure the top of the furnace to a structural member using screw
through the strap at the back of the furnace. Strap may be moved
to any of the holes located along the top back of the furnace.
Installer may provide an equivalent method, such as screws
through the casing side.
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.
Consideration should be given to the heating capacity required and also
to the air quantity (CFM) required. These factors can be determined by
calculating the heat loss and heat gain of the home or structure. If these
calculations are not performed and the furnace is over-sized, the following may result:
1. Short cycling of the furnace.
2. Wide temperature fluctuations from the thermostat setting.
3. Reduced overall operating efficiency of the furnace.
The supply and return duct system must be of adequate size and
designed such that the furnace will operate within the designed air temperature rise range and not exceed the maximum designed static pressure. These values are listed in Table 2.
SECTION III: RETURN AIR
REQUIREMENTS
CLOSET INSTALLATIONS
Additional Requirements
Additional requirements for floor and ceiling return system for closet
installed sealed combustion heating appliance are given in the next
paragraph.
HAZARD OF ASPHYXIATION, DO NOT COVER OR RESTRICT
FLOOR OPENING.
TABLE 2:
MBH kW MBH kW CFM cmm In.W.C kPa In.W.C kPa
56 16.4 45 12.9 1305 36.9 0.10 0.0249 0.30 0.0747
70 20.5 56 16.4 1305 36.9 0.10 0.0249 0.30 0.0747
77 22.5 62 18.0 1305 36.9 0.10 0.0249 0.30 0.0747
90 26.3 72 21.1 1305 36.9 0.10 0.0249 0.30 0.0747
The air temperature rise should be taken only after the furnace has
been operating for at least 15 minutes. Temperatures should be
taken 6" (15.2 cm) past the first bend from the furnace in the supply
duct. The return air temperature must be taken at the return air louvered door. Return static pressures can be taken by pushing probe
through the air filter on the louvered door.
BLEND AIR INSTALLATIONS
If a blend air ventilation system is installed, the 5” (12.7 cm) diameter
knockout in the top cover must be removed. The blend air damper is to
be placed on the top cover and secured with screws as shown in Figure
12. The power wires for the Blend Air Damper are inserted through the
7/8” (2.22 cm) hole in the top cover. The wires to the Blend Air Damper
will be connected as shown in Figure 20. Refer to the Blend Air Installation Manual to complete the installation.
External Static Pressure Range
Input Output
1. Std. Blower-High Speed-No Coil.
Nominal
Air Flow
Ext. Static Pressure
1
Minimum Maximum
8 Johnson Controls Unitary Products
FIGURE 12: Floor Installation
129098-UIM-G-0411
Air Filters Can Be
Found On The Inside
Of This Panel
SECTION IV: FILTERS
FILTER INSTALLATION
All applications require the use of a filter. A standard air filter is located
in the return filter rack on the louvered door. The air filter(s) must be
replaced with air filter(s) that are the same size and same type.
Replacement filter size is shown in Table 3.
All installations must have a filter installed.
Downflow Filters:
There are two types of downflow filter racks.
1. FURNACE FILTER RACK: A return filter rack with two standard
throwaway type filters are supplied on all models. The return filter
rack is located on the inside of the louvered door. This type of filter
rack is designed for two standard air filters only. Pleated Media or
Washable Filters cannot be used in this filter rack because they
cause too much pressure drop causing a reduction in airflow.
Refer to Figure 13.
2. EXTERNAL RETURN FILTER GRILLE: The second type is an
external return air filter grille that can only be used in applica-
tions where the furnace is installed in a closet. This type of filter grille is typically installed in a closet door or wall with the filters
located within 12" (30.5 cm) of the return air opening of the furnace. There must be a minimum clearance of 6" (15.2 cm)
between the front of the furnace and the closet door and/or the furnace and the filter grille to prevent the return air flow from being
obstructed. Refer to Table 1 Unit Clearances to Combustibles.
NOTE: Remove air filters inside louvered door when using an external
filter grille.
a. If the standard throwaway filter are used the external filter
grille must have a minimum area of 540 in² (3483 cm²) which
would equal a 15" X 36" filter grille.
b. If the Pleated Media or Washable Filters are used the exter-
nal filter grille must have a minimum area of 684 in² (4413
cm²) which would equal a 18" X 38" filter grille. The increased
area is to reduce the pressure drop across the air filter.
c. Consideration should be given when locatin g the return filter
grille for maintenance.
d. Any filter that has a large pressure drop should be checked to
be sure the pressure drop caused by the air filter will not prevent the furnace from operating within the rise range, specified on the rating plate and in Table 7. If the furnace does not
operate within the specified rise range then a larger air filter
or an air filter that has a lower pressure drop must be
installed.
FIGURE 13: Furnace Air Filters
TABLE 3:
1. All Models shipped with disposable filters mounted inside upper furnace door.
2. Pleated filters have high pressure drop and require cleaning every 60 days.
3. Dirty filters can cause excess heating bills, lower air flow, and reduce heat exchanger life.
SECTION V: GAS LINE INSTALLATION
GAS SAFETY
This furnace is designed to operate on NATURAL GAS or PROPANE GAS ONLY. Do Not Burn any other Fuel in this furnace.
Burning any fuel except NATURAL GAS or PROPANE GAS can
cause premature heat exchanger burnout, high levels of carbon
monoxide, excessive sooting, a fire hazard, personal injury, property damage and /or death.
.
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.
Filter Sizes - All Models
Input Output Air Flow Cabinet Width
MBH kW MBH kW CFM cmm In In cm
56 16.4 44.8 13.1 1305 34.0 19 3/4 2 - 16 x 20 x 1 2 x 41 x 51
70 20.5 56 16.4 1305 34.0 19 3/4 2 - 16 x 20 x 1 2 x 41 x 51
77 22.5 62 18.1 1305 34.0 19 3/4 2 - 16 x 20 x 1 2 x 41 x 51
90 26.3 72 21.1 1305 34.0 19 3/4 2 - 16 x 20 x 1 2 x 41 x 51
Door Filter
GAS PIPING
Installation and Checking of Gas Line
Gas Supply piping must be sized in accordance with the recommendations contained in National Fuel Gas Code (ANSI-Z223.1, NFPA-54)
unless local codes or regulations state otherwise.
Materials used and pipe sizing for U.S. manufactured homes must comply with requirements contained in Manufactured Homes A119.1, Recreational Vehicles A119.2 and H.U.D. Title 24, Section 3280.705 and
any local or state codes.
NOTE: The gas line inlet on the gas valve is 1/2-14 N.P.T. The gas line
may be installed through the furnace floor or furnace side to the gas
valve.
If the gas input to the furnace is too great because of excessive gas
pressure, wrong size orifice, high altitude, etc., the burner flame will
be sooty and may produce carbon monoxide, which could result in
unsafe operation, explosion, and/or fire or asphyxiation.
1
Johnson Controls Unitary Products 9
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