Unitary products group G8C, GF8 Installation Manual

INSTALLATION MANUAL

HIGH EFFICIENCY CLAM TUBE HEAT EXCHANGER SERIES

MODELS: G8C/GF8 (Single Stage Multi-Position)

50 - 150 MBH INPUT (14.65 - 44.00 KW) INPUT

TABLE OF CONTENTS

SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

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

GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

LIST OF FIGURES

Upflow/Horizontal Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Downflow/Horizontal Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Vent Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Top Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

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

Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . .9

Side Return Cutout Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Horizontal Mount and Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Downflow Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Return Filter Grill and Return Duct Installation . . . . . . . . . . . . . . . . . . 11

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Upflow Configuration (50-125 MBH Model Only) . . . . . . . . . . . . . . . . 12

Downflow Configuration (50-125 MBH Model Only) . . . . . . . . . . . . . 12

Upflow/Horizontal Configuration (150 MBH Model Only) . . . . . . . . . . 12

Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Electrical Wiring - Upflow Position . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Line Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Two-Stage Heating and Cooling Thermostat Connections . . . . . . . .14

LIST OF TABLES

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

Minimum Duct Sizing For Proper Airflow . . . . . . . . . . . . . . . . . . . . . . . 6

External Static Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Filter Sizes - Upflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

High Altitude Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Ratings & Physical / Electrical Data - Upflow Models . . . . . . . . . . . .13

Roof Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

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

EFFICIENCY RATING CERTIFIED

ISO 9001

Certified Quality

Management System

ACCESSORY CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

TWINNING AND STAGING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

VENT/COMBUSTION AIR SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . .16

SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Accessory Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Typical Twinned Furnace Application . . . . . . . . . . . . . . . . . . . . . . . . .15

Single Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . .15

Two-Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . .16

Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Alternate Air Intake, Air Outlet and Chimney Connections . . . . . . . . .17

Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . . . . . . . . . . .17

Typical Sidewall Vent Application . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Typical Sidewall Vent and Termination Configuration . . . . . . . . . . . .18

Typical Chimney Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Horizontal Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . .18

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

Combustion Airflow Path Through The Furnace

Casing to the Burner Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . .21

Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Typical Heat/Cool Speed Tap Connections . . . . . . . . . . . . . . . . . . . .26

Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Horizontal Sidewall Venting Clearances . . . . . . . . . . . . . . . . . . . . . . .18

Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Unconfined Space Minimum Area in Square Feet . . . . . . . . . . . . . . .20

Field Installed Accessories - Non Electrical . . . . . . . . . . . . . . . . . . . .23

Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Filter Performance - Pressure Drop Inches W.C. and (kPa) . . . . . . . .26

Blower Performance - CFM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

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.

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 mo derate injury. alert against unsafe practices and hazards involving only property damage.

It is also used to

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.

66832-UIM-D-1205

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.

4. Provide adequate combustion and ventilation air to the furnace space as specified in SECTION VII of 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.

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.

6. Test for gas leaks as specified in SECTION XI of these instructions.

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 be use the furnace for heating of buildings or structures under construction. Installation 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.

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 gas valves, 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 return air to the furnace must not be

less than 55 degrees F (13 deg 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 at 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. A return air duct must be used, sealed to the furnace cabinet,

and terminated outside the space where the furnace is installed. This prevents any recirculation of supply air, which can generate a negative pressure condition at the furnace for non-direct vent furnaces, leading to possible flame rollout or combustion problems.

g. 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.

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 furnace should be installed in accordance with all national and local building/safety codes and requirements, local plumbing or wastewater codes, and other applicable codes. In the absence of local codes, install in accordance with the National Fuel Gas Code ANSI Z223.1/NFPA 54, National Fuel Gas Code, and/or CAN/CGA B149.1 Natural Gas and Propane Installation Code (latest editions). 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 5. 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.

• 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.

CSA listed or approved for installation

or a Manufactured

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66832-UIM-D-1205

• 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.

COMBUSTION AIR QUALITY (LIST OF CONTAMINANTS)

The furnace will require 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 will require 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

If 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 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.

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, and any shipping or spacer brackets which need to be removed.

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” (0.64 cm) 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 falling below 32° F (0° C) may result in the flue temperature falling below 260° F (127° C) at any point in the flue pipe between the furnace and the chimney or a B-Vent. The flue products will condense in the vent pipe if the flue temperature falls below 260° F (127° C) 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.

Improper 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.

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66832-UIM-D-1205

Downflow furnaces for installation on combustible flooring only when installed on the accessory combustible floor base on wood flooring only and shall not be installed directly on carpeting, tile or other combustible material. 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.

TABLE 1:

Unit Clearances to Combustibles

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.

APPLICATION

UPFLOW 1 (25.4) 2 (5.08) 0 (0.0) 0 (0.0) 6 (15.24) COMBUSTIBLE YES YES YES NO

UPFLOW B-VENT 1 (25.4) 3 (7.62) 0 (0.0) 0 (0.0) 6 (15.24) COMBUSTIBLE YES YES YES NO

HORIZONTAL 1 (25.4) 2 (5.08) 0 (0.0) 1 (5.08) 6 (15.24) COMBUSTIBLE NO YES YES

HORIZONTAL B-VENT 1 (25.4) 3 (7.62) 0 (0.0) 0 (0.0) 6 (15.24) COMBUSTIBLE NO YES YES

DOWNFLOW 1 (25.4) 2 (5.08) 0 (0.0) 0 (0.0) 6 (15.24) NON-COMBUSTIBLE YES YES YES NO

DOWNFLOW B-VENT 1 (25.4) 3 (7.62) 0 (0.0) 0 (0.0) 6 (15.24) NON-COMBUSTIBLE YES YES YES NO

1. 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 SIDES SINGLE WALL VENT

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

FLOOR/

BOTTOM

CLOSET ALCOVE ATTIC

LINE

CONTACT

YES YES

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) or applicable national, provincial, or state, and local fire and safety codes or in Canada, refer to the Natural Gas and Propane Installation Code B149.1-00.

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 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 Table 8 and 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.

INSTALLATION POSITION (50-125 MBH Models)

This furnace may be installed in an upflow, downflow or horizontal position. Depending on the configuration shipped from the factory, it may be necessary to convert the furnace from downflow to upflow or from upflow to downflow configuration. Use conversion instructions in this document.

INSTALLATION POSITION (150 MBH Models)

This furnace may be installed in an upflow or horizontal position. No conversion is necessary. This furnace is not approved for downflow application.

CONVERSION INFORMATION (50-125 MBH Models)

This furnace may be shipped in either the upflow or the downflow configuration. To convert from upflow to downflow or vice-versa it is necessary only to exchange the top and bottom casing caps and to rotate the vent blower 180 degrees. Use the step by step instructions to perform the conversion.

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66832-UIM-D-1205

TO CONVERT FROM DOWNFLOW TO UPFLOW CONFIGURATION (50-125 MBH Models)

1. Lay the furnace on its back.

2. Remove the front door.

3. Remove the seven sheet metal screws that are used to fasten the

top cap to the casing. Remove the top cap and save the screws.

4. Remove the four sheet metal screws that are used to fasten the

bottom cap to the casing. Remove the bottom cap and save the screws.

5. Unplug the vent blower wires.

6. Disconnect the pressure hose from the vent blower.

7. Remove the four machine screws that fasten the vent blower to

the vent pan and save the screws. Leave the gasket in place on the pan.

8. Remove the two extra machine screws in the vent pan front and

save the screws.

9. Rotate the vent blower and transition 180° so that its outlet points

to the outlet air end of the furnaces as shown in Figure 1.

10. Line up the vent blower mounting holes with the holes in the vent

pan and screw it into place. Use the same machine screws that held the vent blower in place previously.

11. Install the two extra machine screws in the two open holes in the

front of the vent pan See Figure 1.

12. Plug in the vent motor wires.

13. Plug the pressure hose into the vent blower.

14. Remove the rectangular knockout in the center of the top cap. See

Figure 4.

15. Install the top cap at the same end of the furnace as the vent

blower, using the sheet metal screws saved earlier. See Figure 1.

16. Install the bottom cap on the bottom of the furnace using the sheet

metal screws saved earlier. See Figure 1.

17. The conversion is now complete. The furnace may now be

installed in the upflow position or in the horizontal position on either side.

TRANSITION

EXTRA

SCREWS

GASKET

TOP

CAP

VENT PAN

PRESSURE

HOSE

PRESSURE

SWITCH

VENT

BLOWER

TOP

CAP

TRANSITION

BOTTOM

CAP

PRESSURE

HOSE

VENT PAN

EXTRA

SCREWS

BLOWER

GASKET

VENT

FIGURE 2: Downflow/Horizontal Configuration

TO CONVERT FROM UPFLOW TO DOWNFLOW CONFIGURATION (50-125 MBH Models)

1. Lay the furnace on its back.

2. Remove the front door.

3. Remove the seven sheet metal screws that are used to fasten the top cap to the casing.

4. Remove the four sheet metal screws that are used to fasten the bottom cap to the casing. Remove the bottom cap and save the screws.

5. Unplug the vent blower wires.

6. Disconnect the pressure hose from the vent blower.

7. Remove the four machine screws that fasten the vent blower to the vent pan and save the screws. Leave the gasket in place on the vent pan.

8. Remove the two extra machine screws in the vent pan front and save the screws.

9. Install the cast aluminum transition on the vent blower, using the three screws supplied on the vent blower. See Figure 3.

FIGURE 1: Upflow/Horizontal Configuration

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BOTTOM

CAP

TRANSITION

FIGURE 3: Vent Blower

66832-UIM-D-1205

10. Rotate the vent blower 180º so that its outlet points toward the inlet air end of the furnace. See Figure 2.

11. Line up the vent blower mounting holes with the holes in the vent pan and screw it into place. Use the same machine screws that held the vent blower in place previously.

12. Install the two extra machine screws in the two open holes in the front of the vent pan. See Figure 2.

13. Plug in the vent motor wires.

14. Plug the pressure hose into the vent blower.

15. Remove the round knockout at the right side of the top cap. See Figure 4.

UPFLOW VENT OPENING

DOWNFLOW VENT OPENING

FIGURE 4: Top Cap

16. Install the top cap at the opposite end of furnace from the vent blower, using the seven sheet metal screws saved earlier. See Figure 2.

17. Install the bottom cap on the bottom of the furnace using the sheet metal screws saved earlier. See Figure 2.

18. The conversion is now complete. The furnace may now be installed in the downflow position or in the horizontal position on either side.

INSTALLATION POSITION (150 MBH Models)

This furnace may be installed in an upflow or horizontal position. No conversion is necessary. This furnace is not approved for downflow application.

FLOOR BASE AND DUCTWORK INSTALLATION

Upflow Instructions

Attach the supply plenum to the furnace outlet duct connection flanges. This is typically through the use of S cleat material when a metal plenum is used. 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 cross-hatched to eliminate any popping of the sheet metal when the indoor fan is energized.

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.

Table 2 is a guide for determining whether the rectangular duct system that the furnace is being connected to be of sufficient size for proper furnace operation.

Use the Example below to help you in calculating the duct area to determine whether the ducts have sufficient area so that the furnace operates at the specified external static pressure and within the air temperature rise specified on the nameplate.

Example: The furnace input is 80,000 BTUH, 1,200 CFM. The recommended duct area is 280 sq.in, there are two 8 x 14 rectangular ducts attached to the plenum and there are two 7 inch round ducts attached to the furnace.

1. Take 8 x 14, which equals 112 sq.in. X 2, which equals 224 square inch then go to round duct size located in Table 2.

2. The square inch area for 7 inch round pipe is 38.4, multiply by 2 for two round ducts which equals 76.8 square inch.

3. Then take the 224 square inch from the rectangular duct and add it to the 76.8 sq.in. of round duct. The total square inch of duct attached to the furnace plenum is 300.8 square inch. This exceeds the recommended 280 square inch of duct.

In this example, the duct system attached to the plenum has a sufficient area 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 Tables 2 and 3.

TABLE 2:

NOTE: This chart does not replace proper duct sizing calculations or take into account static pressure drop for run length and fittings. Watch out for the temperature rise and static pressures.

TABLE 3:

Minimum Duct Sizing For Proper Airflow

Input Airflow

BTU/H

(kW)

50000

(14.65)

75000

(21.98)

75000

(21.98)

100000

(29.31)

100000

(29.31)

125000

(36.63)

150000

(43.96)

1. Maximum return air velocity in rigid duct @ 700 feet per minute (19.82 m3 / minute).

2. Example return main trunk duct minimum dimensions.

3. Maximum supply a i r velocity in rigid duct @ 900 feet per minute (25.49 m3 / minute).

CFM

(m³)

1,200

(33.98)

1,200

(33.98)

1,600

(45.31)

1,600

(45.31)

2,000

(56.63)

2,000

(56.63)

2,000

(56.63)

Return

In²

(cm²)

280

(711)

280

(711)

360

(914)

360

(914)

440

(1,118)

440

(1,118)

440

(1,118)

Rectangular

(cm x cm)

(35.6 x 50.8)

(45.7 x 50.8))

(45.7 x 50.8)

(50.8 x 55.8)

in. x in.

14 x 20

18 x 20

20 x 22

Round

in.

(cm) dia.

(45.7)

(55.8)

(60.9)

Supply

In²

(cm²)

216

(549)

216

(549)

280

(711)

280

(711)

390

(991)

390

(991)

390

(991)

External Static Pressure Range

Input Output

Nominal Air Flow

Ext. Static Pressure

Minimum Maximum

MBH kW MBH kW CFM cmm In.W.C kPa In.W.C kPa

50 14.7 40 11.7 1200 34.0 0.10 0.0249 0.50 0.1245 75 22.0 60 17.6 1200 34.0 0.12 0.0299 0.50 0.1245

75 22.0 60 17.6 1600 45.3 0.12 0.0299 0.50 0.1245 100 29.3 80 23.4 1600 45.3 0.15 0.0374 0.50 0.1245 100 29.3 80 23.4 2000 56.6 0.15 0.0374 0.50 0.1245 125 36.6 100 29.3 2000 56.6 0.20 0.0498 0.50 0.1245 150 44.0 120 35.2 2000 56.6 0.20 0.0498 0.50 0.1245

6 Unitary Products Group

66832-UIM-D-1205

TABLES 2 and 3 are to be used as a guide only to help the installer determine if the duct sizes are large enough to obtain the proper air flow (CFM) through the furnace. TABLES 2 and 3 ARE NOT to be used to design ductwork for the building where the furnace is being installed. There are several variables associated with proper duct sizing that are not included in the tables. To properly design the ductwork for the building, Refer to the ASHRAE Fundamentals Handbook, Chapter on “DUCT DESIGN” or a company that specializes in Residential and Modular Home duct designs.

IMPORTANT: The minimum plenum height is 12" (30.5). 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.

IMPORTANT: The air temperature rise should be taken only after the furnace has been operating for at least 15 minutes. Temperatures and external static pressures should be taken 6" (15 cm) past the first bend from the furnace in the supply duct and the return duct. If an external filter box or an electronic air cleaner is installed, take the return air readings before the filter box or air cleaner.

DOWNFLOW

31-1/2

The supply air temperature MUST NEVER exceed the Maximum 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 IX for additional information on correcting the problem.

If a matching cooling coil is used, it may be place directly on the furnace outlet and sealed to prevent leakage. Follow the coil instructions for installing the supply plenum. 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.

UPFLOW

31-1/2

16-1/4

29-3/4

BOTTOM VIEW

29-3/4

BOTTOM VIEW

FIGURE 5: Dimensions TABLE 4:

125/100 (36.6/29.3) 150/120 (44.0/35.2)

1. 4-position models may be factory configured as upflow (MU) or downflow (MD).

2. All models are supplied with 3” (7.62 cm) vent connections. An installer supplied transition to 4” (10.16 cm) or 5” (12.7 cm) must be used where necessary.

3. 3-position 150 MBH model available only in upflow/horizontal (UH) configuration.

4. Dimensions “B”, “C”, “D”, and “E” are with duct flanges turned up. “F”, “G”, “H”, & “J” are with flanges flat.

Cabinet and Duct Dimensions

BTUH (kW)

Input/Output

50/40 (14.7/11.7) 75/60 (22.0/17.6)

75/60 (22.0/17.6) 100/80 (29.3/23.4) 100/80 (29.3/23.4)

1 1 1

1 1

BTUH (kW)

Input/Output

50/40 (14.7/11.7)

75/60 (22.0/17.6)

75/60 (22.0/17.6) 100/80 (29.3/23.4) 100/80 (29.3/23.4)

1 1 1

1 1

Nominal

CFM (m

1200 (33.98) B 17 1/2 44.4 16 1/2 41.9 20 3/8 51.8 20.0 50.8 16 40.6

/min)

Cabinet

Size

A(in.) A(cm) B(in.) B(cm) C(in.) C(cm) D(in.) D(cm) E(in.) E(cm)

Cabinet Dimension

1200 (33.98) B 17 1/2 44.5 16 1/2 41.9 20 3/8 51.8 20.0 50.8 16 40.6 1600 (45.31) C 21 53.3 20 50.8 20 3/8 51.8 20.0 50.8 19 1/2 49.5 1600 (45.31) C 21 53.3 20 50.8 20 3/8 51.8 20.0 50.8 19 1/2 49.5 2000 (58.63) D 24.5 62.2 23 1/2 59.7 20 3/8 51.8 20.0 50.8 23 58.4

2000 (58.63) D 24.5 62.2 23 1/2 59.7 20 3/8 51.8 20.0 50.8 23 58.4

2000 (58.63) D 24 1/2 62.2 23 1/2 59.7 20 3/8 51.8 20.0 50.8 23 58.4

Nominal

CFM (m

/min)

Cabinet

Size

F(in.) F(cm) G(in.) G(cm) H(in.) H(cm) J(in.) J(cm)

K Vent

(in.)

1200 (33.98) B 14 3/4 37.46 18 3/4 47.62 15 1/8 38.4 19.0 48.2 3 7.62 1200 (33.98) B 14 3/4 37.46 18 3/4 47.62 15 1/8 38.4 19.0 48.2 1600 (45.31) C 18 1/4 46.35 18 3/4 47.62 18 5/8 47.3 19.0 48.2 1600 (45.31) C 18 1/4 46.35 18 3/4 47.62 18 5/8 47.3 19.0 48.2 2000 (58.63) D 21 3/4 55.24 18 3/4 47.62 22 1/8 56.2 19.0 48.2

2000 (58.63) D 21 3/4 55.24 18 3/4 47.62 22 1/8 56.2 19.0 48.2

4 4 4 4 5 5

3 2 2 2 2 2

K Vent

(cm)

10.16

12.7

2 2 2 2

Unitary Products Group 7

66832-UIM-D-1205

RESIDENTIAL AND NON HUD 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. In order to achieve the airflow indicated, it is recommended those applications over 1800 CFM (57 m³/min) use return air from two sides, one side and the bottom or bottom only. For single return application, see data and notes on blower performance data tables in this manual.

NOTE: The only return duct configurations that is approved for models

that have two separate fans are:

• Return duct attached to both sides of the furnace.

• Bottom and side return duct.

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 return air ducts to the furnace must have a total cross sectional area of not less than two square inches per 1000 BTUH of furnace input rating for heating operation. If air conditioning is to be installed with the furnace, larger return air ducts may be required, depending on the capacity of the air conditioner and the airflow required. The return air opening in the top of the furnace is large enough for the largest capacity air conditioner for which the furnace blower is rated. The return air duct or plenum can be connected to the furnace by performing the following steps:

1. Bend the 3/4" flanges that will be used to attach the return air plenum using the scribe marks in the furnace base. Refer to Figure 5 for flange locations.

2. Be sure to seal the furnace to plenum connections to prevent air leakage. Refer to Figure 5 for unit and plenum dimensions. Attic installations must meet all minimum clearances to combustibles and have floor support with required service accessibility.

Attic installations must meet all minimum clearances to combustibles and have floor support with required service accessibility.

FLOOR BASE AND DUCTWORK INSTALLATION

Downflow Combustible Floor Base

Installations on combustible material or floors must use a combustible floor base shown in Figure 6. The perforations in the wrapper flanges must be bent in towards the heat exchanger to allow for the coil duct flange to recess into the furnace 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. Refer to the installation instructions for additional information.

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.

IMPORTANT: If an external mounted filter rack is being used see the instructions provided with that accessory for proper hole cut size.

DOWNFLOW FURNACE

WARM AIR PLENUM WITH 1” FLANGES

FIBERGLASS INSULATION

FIBERGLASS TAPE UNDER FLANGE

COMBUSTIBLE FLOOR BASE ACCESSORY

FIGURE 6: Combustible Floor Base Accessory

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.

The perforations in the wrapper flanges must be bent away from the heat exchanger to create duct flanges so the air conditioning coil can be properly seated on the furnace. 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.

IMPORTANT: 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.

RESIDENTIAL AND NON HUD MODULAR HOME DOWNFLOW RETURN PLENUM CONNECTION

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. The use of an approved flexible duct connector is recommended on all installations. 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.

IMPORTANT: If an external mounted filter rack is being used see the instructions provided with that accessory for proper hole cut size.

HORIZONTAL MODELS

8 Unitary Products Group

66832-UIM-D-1205

Horizontal Installations With a Cooling Coil Cabinet

The furnace should be installed with coil cabinet part number specifically intended for Horizontal application. If a matching cooling coil is used, it may be placed directly on the furnace outlet and sealed to prevent leakage. Follow the coil instructions for installing the supply plenum. For details of the coil cabinet dimensions and installation requirements, refer to the installation instructions supplied with the coil cabinet The perforations in the wrapper flanges must be bent away from the heat exchanger to create duct flanges so the air conditioning coil can be properly seated on the furnace. Attach the supply plenum to the air conditioning coil cabinet outlet duct flanges through the use of S cleat material when a metal plenum is used. The use of an approved flexible duct connector is recommended on all installations. The connection to the furnace, air conditioning coil cabinet and the supply plenum 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. The minimum plenum height is 12” (30.5 cm). 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. Also the plastic drain pan in the air conditioning coil can overheat and melt. Refer to the installation instructions supplied with the air conditioning coil for additional information.

Horizontal Installations Without a Cooling Coil Cabinet

When installing this appliance, the furnace must be installed so as to create a closed duct system, the supply duct system must be connected to the furnace outlet and the supply duct system must terminate outside the space containing the furnace. 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. Attach the supply plenum to the furnace outlet duct flanges through the use of S cleat material when a metal plenum is used. 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. 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.

Residential and Non Hud Modular Home Horizontal Return Plenum Connections

The return duct system must be connected to the furnace inlet and the return duct system must terminate outside the space containing the furnace. 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. 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. The use of an approved flexible duct connector is recommended on all installations. 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. Attic installations must meet all minimum clearances to combustibles and have floor support with required service accessibility.

IMPORTANT: if an external mounted filter rack is being used see the instructions provided with that accessory for proper hole cut size.

ATTIC INSTALLATION

LINE CONNECT 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

SEDIMENT TRAP

SHEET METAL IN FRONT OF FURNACE COMBUSTION AIR OPENINGS IS RECOMMENDED

30” MIN. WORK AREA

SUPPLY AIR

PLYWOOD FLOOR

FIGURE 7: Typical Attic Installation

This appliance is design 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.

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 quiet furnace operation. When suspending the furnace use a secure platform constructed of plywood or other building material secured to the floor joists. Refer to Figure 8 for typical crawl space installation.

ANGLE IRON BRACKET

1” MAX. BETWEEN ROD & FURNACE

6” MIN. BETWEEN ROD & FURNACE

SUPPORT ROD

1” MAX. BETWEEN ROD & FURNACE

FIGURE 8: Typical Suspended Furnace / Crawl Space Installation

SECTION III: FILTERS

FILTER INSTALLATION

All applications require the use of a filter. A high velocity filter and retainer are provided for field installation on G8C models. Models must have a field-supplied filter and mounting hardware. Replacement filter size is shown in Table 5.

Unitary Products Group 9

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Unitary products group G8C, GF8 Installation Manual

Specifications and Main Features

Frequently Asked Questions

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