Unitary products group Pt8 User manual

035-19670-003 Rev. A (1004)

EFFICIENCY

RATING

CERTIFIED

This product was manufactured

in a plant whose quality system

is certified/registered as being

in conformity with ISO 9001.

HIGH EFFICIENCY

TUBULAR HEAT EXCHANGER SERIES

MODELS: PT8/ FC8T / FL8T / LC8T / LL8T

(Two Stage Upflow / Horizontal / LoNOx)

57 - 120 MBH INPUT

(16.70 - 35.17 KW) INPUT

INSTALLATION MANUAL

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. It is also used to

alert against unsafe practices and hazards involving only property dam-

age.

Improper installation may create a condition where the operation of

the product could cause personal injury or property damage.

Improper installation, adjustment, alteration, service or mainte-

nance can cause injury or property damage. Refer to this manual

for assistance or for additional information, consult a qualified con-

tractor, installer or service agency.

This product must be installed in strict compliance with the installa-

tion instructions and any applicable local, state, and national codes

including, but not limited to building, electrical, and mechanical

codes.

TABLE OF CONTENTS

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

DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

VENT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . .16

WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

LIST OF FIGURES

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Furnace Base Rectangular Blockoff Panel . . . . . . . . . . . . . . . . . . . . .5

Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . . 6

Side Return Cutout Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Upflow Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Horizontal Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Line Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Field Wiring for Single Stage Thermostat . . . . . . . . . . . . . . . . . . . . .10

Field Wiring for Two Stage Thermostat . . . . . . . . . . . . . . . . . . . . . . .10

Accessory Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Vent Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Typical Chimney Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Alternate Air Intake, Air Outlet and Chimney Connections . . . . . . . . .12

Typical Sidewall Vent Application . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Typical Sidewall Vent and Termination Configuration . . . . . . . . . . . .12

Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Combustion Airflow Path Through The Furnace Casing

to the Burner Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Air Inlet, Outlet and Chimney Connections . . . . . . . . . . . . . . . . . . . . .14

Alternate Air Intake, Air Outlet and Chimney Connections . . . . . . . . .14

Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . .15

Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Furnace Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

LIST OF TABLES

Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Minimum Duct Sizing For Proper Airflow . . . . . . . . . . . . . . . . . . . . . . .4

Round Duct Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Filter Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

High Altitude Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Ratings & Physical / Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Roof Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Horizontal Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

Unconfined Space Minimum Area in Square Inch . . . . . . . . . . . . . . .15

Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Filter Performance - Pressure Drop Inches W.C. and (kPa) . . . . . . . .21

Blower Performance CFM - Upflow (without filter) - Bottom Return . .22

Blower Performance CFM - Upflow (without filter) - Left Side Return 23

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

035-19670-003 Rev. A (1004)

2Unitary Products Group

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 SEC-

TION VII of these instructions.

6. Test for gas leaks as specified in SECTION VIII of these instruc-

tions.

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 fur-

nace casing and terminating outside the space containing the fur-

nace.

9. The furnace is not to be used for temporary heating of buildings or

structures under construction.

10. When installed in a Approved Modular Home or building con-

structed on-site, combustion air shall not be supplied from occu-

pied 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 ple-

num dimensions in Figure 1. 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 CSA listed or approved for installation

into a Manufactured (Mobile) Home.

• This furnace is not approved for installation in trailers or recre-

ational 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 elec-

trical characteristics match. All models use nominal 115 VAC, 1

Phase, 60-Hertz power supply. DO NOT CONNECT THIS APPLI-

ANCE TO A 50 HZ POWER SUPPLY OR A VOLTAGE ABOVE

130 VOLTS.

• Furnace shall be installed so the electrical components are pro-

tected 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 precau-

tions 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 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 fur-

nace 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 fur-

nace is located in an area where the furnace is being exposed to the fol-

lowing 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.

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 prop-

erty damage, personal injury or loss of life.

035-19670-003 Rev. A (1004)

Unitary Products Group 3

INSPECTION

As soon as a unit is received, it should be inspected for possible dam-

age during transit. If damage is evident, the extent of the damage

should be noted on the carrier’s freight bill. A separate request for

inspection by the carrier’s agent should be made in writing. Also, before

installation the unit should be checked for screws or bolts, which may

have loosened in transit. There are no shipping or spacer brackets

which need to be removed.

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 oper-

ating 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 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, leading to premature heat exchanger failure.

3. If this furnace is installed in an unconditioned space and an

extended power failure occurs, there will be potential damage to

the internal components. Following a power failure situation, do

not operate the unit until inspection and repairs are performed.

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 clear-

ances for combustible materials where accessibility clearances are

greater.

Installation in a residential garage:

1. 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.

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.

3. Create a closed duct system. For residential and Modular Home

installations, when a furnace is installed so that the supply ducts

carry air circulated by the furnace to areas outside the space con-

taining 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 condi-

tioned space.

The furnace area must not be used as a broom closet or for any

other storage purposes, as a fire hazard may be created. Never

store items such as the following on, near or in contact with the fur-

nace.

1. Spray or aerosol cans, rags, brooms, dust mops, vacuum

cleaners or other cleaning tools.

2. Soap powders, bleaches, waxes or other cleaning com-

pounds; plastic items or containers; gasoline, kerosene, ciga-

rette lighter fluid, dry cleaning fluids or other volatile fluid.

3. Paint thinners and other painting compounds.

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. Improper installation in an ambient below 32ºF (0.0° C) could create

a hazard, resulting in damage, injury or death.

TABLE 1:

Unit Clearances to Combustibles

APPLICATION TOP FRONT REAR LEFT SIDE RIGHT SIDE FLUE FLOOR/

BOTTOM CLOSET ALCOVE ATTIC LINE

CONTACT

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

UPFLOW 1 (25.4) 6 (15.24) 0 (0.0) 0 (0.0) 3 (7.62)16 (15.24) COMBUSTIBLE YES YES YES NO

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

HORIZONTAL 326 (15.24) 0 (0.0) 1 (25.4) 0 (0.0) 6 (15.24) COMBUSTIBLE NO YES YES YES3

HORIZONTAL B-VENT 0 (0.0) 3 (7.62) 0 (0.0) 1 (25.4) 0 (0.0) 1 (25.4) COMBUSTIBLE NO YES YES YES3

1. 14-1/2” cabinet models only. All other units “0” clearance.

2. 14-1/2” cabinet left airflow applications only. All other units and right hand airflow applications “0” clearance.

3. 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.

035-19670-003 Rev. A (1004)

4Unitary Products Group

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 pre-

vent the furnace or the air conditioner from operating unless the damper

is in full heat or cool position.

DUCTWORK INSTALLATION AND SUPPLY PLENUM

CONNECTION

Attach the supply plenum to the furnace outlet duct connec-

tion 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 crosshatched 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 con-

trols 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 fur-

nace operation.

Use the Example below to help you in calculating the duct area to deter-

mine whether the ducts have sufficient area so that the furnace oper-

ates at the specified external static pressure and within the air

temperature rise specified on the nameplate.

Example: The furnace input is 80,000 BTUH and 1,200 CFM. The rec-

ommended 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 3.

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 pres-

sure and within the air temperature rise specified on the nameplate.

1. The Air Temperature Rise is determined by subtracting the Return

Air Temperature Reading from the Supply Air Temperature Read-

ing.

2. The External Static Pressure is determined by adding the Supply

Duct Static Pressure reading to the Return Duct Static Pressure

reading and adding the pressure drop across any applied a-coil.

Tables 2 & 3 is 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 & 3 IS 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 cm). The fur-

nace will not operate properly on a shorter plenum height. The minimum

recommended rectangular duct height is 4 inch (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 fil-

ter box or an electronic air cleaner is installed, take the return air read-

ings before the filter box or air cleaner.

The cooling coil must be installed in the supply air duct, down-

stream of the furnace. Cooled air may not be passed over the heat

exchanger.

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 pres-

sures and/or high temperature rises which can result in a heat

exchanger OVERHEATING CONDITION. This condition can result

in premature heat exchanger failure, which can result in personal

injury, property damage, or death.

TABLE 2:

Minimum Duct Sizing For Proper Airflow

BTU/H(kW) BTU/H(kW) Airflow Return1

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

Rectangular2

2. Example return main trunk duct minimum dimensions.

Round2Supply3

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

High/Low

Fire Input High/Low

Fire Output CFM

(m³) In²

(cm²) in. x in.

(cm x cm) in.

(cm)dia. In

²(cm²)

60/42

(17.58/12.31) 46/34

(13.46/9.96) 1,200

(33.98) 280

(711) 14 x 20

(35.6 x 50.8) 18

(45.7) 216

(549)

80/59

(23.44/17.29) 64/48

(18.76/14.07) 1,200

(33.98) 280

(711) 14 x 20

(35.6 x 50.8) 18

(45.7) 216

(549)

80/59

(23.44/17.29) 64/48

(18.76/14.07) 1,600

(45.31) 360

(914) 18 x 20

(45.7 x 50.8) 22

(55.8) 280

(711)

100/65

(29.31/19.05) 80/53

(23.45/15.53) 1,200

(33.98) 320

(813) 16 x 20

(40.6 x 50.8) 20

(50.8) 336

(853)

100/65

(29.31/19.05) 8 /53

(23.45/15.53) 2,000

(56.63) 440

(1,118) 20 x 22

(50.8 x 55.8) 24

(60.9) 390

(991)

120/78

(35.17/22.86) 96/64

(28.13/18.76) 1,600

(45.31) 360

(914) 18 x 20

(45.7 x 50.8) 22

(55.8) 280

(711)

120/78

(35.17/22.86) 96/64

(28.13/18.76) 2,000

(56.63) 440

(1,118) 20 x 22

(50.8 x 55.8) 24

(60.9) 390

(991)

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 pres-

sures.

TABLE 3:

Round Duct Size

Round Duct Size Calculated Area For Each Round Duct Size

inches (cm) Sq.in (cm2)

5 (13) 19.6 (126)

6 (15) 28.2 (182)

7 (18) 38.4 (248)

8 (20) 50.2 (324)

9 (23) 63.6 (410)

10 (25) 78.5 (506)

11 (28) 95 (613)

12 (30) 113.1 (730)

13 (33) 132.7 (856)

14 (36) 153.9 (993)

035-19670-003 Rev. A (1004)

Unitary Products Group 5

If a matching cooling coil is used, it may be placed directly on the fur-

nace 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 indi-

cate the presence of leaks in the heat exchanger. This access cover

shall be attached in such a manner as to prevent leaks.

RESIDENTIAL AND MODULAR HOME UPFLOW

RETURN PLENUM CONNECTION

Return air may enter the furnace through the side(s) or bottom depend-

ing on the type of application. Return air may not be connected into the

rear panel of the unit. In order to achieve the airflow indicated, it is rec-

ommended 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.

BOTTOM RETURN AND ATTIC INSTALLATIONS

Bottom return applications normally pull return air through a base plat-

form or return air plenum. Be sure the return platform structure or return

air plenum is suitable to support the weight of the furnace.

The furnace base is equipped with a rectangular blockoff panel that can

be removed by performing the following steps:

1. Lay the furnace on its back.

2. Remove the toe plate. See Figure 2.

3. Slide the blockoff panel out and then replace the toe plate.

4. Bend the 3/4” flanges that will be used to attach the return air ple-

num using the scribe marks in the furnace base. Refer to Figure 2

“Bottom Image Return End”.

5. Be sure to seal the furnace to plenum connections to prevent air

leakage. Refer to Figure 1 for unit and plenum dimensions.

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.

HORIZONTAL MODELS

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 VIII for additional informa-

tion on correcting the problem.

FIGURE 1: Dimensions

3/4”

FLANGE

BOTTOM IMAGE

(FRONT)

TOP IMAGE

(FRONT)

VENT

CONNECTION

(Vent Size)

28-1/2

(WITH K.O.

REMOVED)

FRONT LEFT SIDE RIGHT SIDE

B20

A28-1/2

3/4

14-3/4

5-3/8

(VENT CONNECTIONS)

POWER WIRING

7/8” HOLE

2-1/2

ACCESS

WIRING

7/8” K.O.

8-3/4

T’STAT WIRING

7/8” K.O.

1-1/8

2-1/4

23-1/2

32-1/2

13-3/4

GAS INLET

1-1/4 x 2-1/2

TABLE 4:

Cabinet and Duct Dimensions

BTUH Input BTUH Output CFM (m3/min) Cabinet

Size Cabinet Dimension

MBH kW MBH kW A A (cm) B B (cm) C C (cm) D D (cm) F F (cm) E E (cm)

60/42 17.6/12.3 46/34 13.5/10.0 1200 (33.98) A 14 1/2 36.8 13 1/4 33.6 10 1/8 25.7 4.0 10.2 10 1/8 25.7 3 3/4 9.5

80/59 23.4/17.3 64/48 18.8/14.1 1200 (33.98) A 14 1/2 36.8 13 1/4 33.6 10 1/8 25.7 4.0 10.2 10 1/8 25.7 3 3/4 9.5

80/59 23.4/17.3 64/48 18.8/14.1 1600 (45.31) B 17 1/2 44.4 16 1/4 41.3 13 1/8 33.3 4.0 10.2 11 5/8 29.5 3 3/4 9.5

100/65 29.3/19.1 80/53 23.4/15.5 1200 (33.98) B 17 1/2 44.4 16 1/4 41.3 13 1/8 33.3 4.0 10.2 11 5/8 29.5 3 3/4 9.5

100/65 29.3/19.1 80/53 23.4/15.5 2000 (56.63) C 21 53.3 19 3/4 50.2 16 5/8 42.2 4.0 10.2 13 3/8 34 3 3/4 9.5

120/78 35.2/22.9 96/64 28.1/18.8 1600 (45.31) C 21 53.3 19 3/4 50.2 16 5/8 42.2 4.0 10.2 13 3/8 34 3 3/4 9.5

120/78 35.2/22.9 96/64 28.1/18.8 2000 (56.63) C 21 53.3 19 3/4 50.2 16 5/8 42.2 4.0 10.2 13 3/8 34 3 3/4 9.5

FIGURE 2: Furnace Base Rectangular Blockoff Panel

Toe Plate

Removable Rectangular

Base Panel.

035-19670-003 Rev. A (1004)

6Unitary Products Group

Horizontal Installations With a Cooling Coil Cabinet

The furnace should be installed with coil cabinet part number specifi-

cally intended for Horizontal application. If a matching cooling coil is

used, it may be placed directly on the furnace outlet and sealed to pre-

vent leakage. Follow the coil instructions for installing the supply ple-

num. 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 under the air conditioning coil can overheat

and melt Refer to the installation instructions supplied with the air condi-

tioning 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 con-

nected 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 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 fur-

nace. 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 typi-

cally 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 fur-

nace 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

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 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.

SUSPENDED FURNACE / CRAWL SPACE

INSTALLATION

The furnace can be hung from floor hoists or installed on suitable blocks

or pad. Blocks or pad installations shall provide adequate height to

ensure the unit will not be subject to water damage. Units may also be

suspended from rafters or floor joists using rods, pipe angle supports or

straps. Angle supports should be placed at the supply air end and near

the blower deck. Do not support at return air end of unit. All four sus-

pension points must be level to ensure quite furnace operation. When

suspending the furnace use a secure a platform constructed of plywood

or other building material secured to the floor joists. Refer top Figure 4

for typical crawl space installation.

SECTION III: FILTERS

FILTER INSTALLATION

All applications require the use of an internal or external filter. Filter(s)

and the filter retainer are not provided on all models Some models are

shipped with a high velocity filter that must be field installed. A field-sup-

plied internal or external filter and filter retainer hardware must be pro-

vided if the filter and the filter retainer are not shipped with the furnace.

Refer to Table 5 for the recommended filter size.

FIGURE 3: Typical Attic Installation

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.

FIGURE 4: Typical Suspended Furnace / Crawl Space Installation

In any application where temperatures below freezing are possible,

see “BELOW FREEZING LOCATIONS”.

LINE CONTACT ONLY PERMISSIBLE

BETWEEN LINES FORMED BY THE

INTERSECTION OF FURNACE TOP

AND TWO SIDES AND BUILDING

JOISTS, STUDS OR FRAMING

SUPPLY AIR

VENT (MAINTAIN

REQUIRED CLEARANCES

TO COMBUSTIBLES

SHEET METAL IN

FRONT OF FURNACE

COMBUSTIBLE AIR

OPENINGS IS

RECOMMENDED

SEDIMENT

TRAP

RETURN AIR

FILTER RACK

MUST BE A

MINIMUM

DISTANCE

OF 18” (45.7 CM)

FROM THE

FURNACE

30” MIN.

WORK AREA

12”

GAS PIPING

ANGLE IRON

BRACKET

1” MAX. BETWEEN

ROD & FURNACE 6” MIN. BETWEEN

ROD & FURNACE

1” MAX. BETWEEN

ROD & FURNACE

SUPPORT

ROD

035-19670-003 Rev. A (1004)

Unitary Products Group 7

SIDE RETURN - EXTERNAL INSTALLATION

Locate and knock out the square corner locators. These indicate the

size of the cutout to be made in the furnace side panel. Refer to Figure

Install the side filter rack following the instructions provided with that

accessory. If a filter(s) is provided at another location in the return air

system, the ductwork may be directly attached to the furnace side

panel. An accessory filter rack is available for mounting the filter exter-

nal to the cabinet.

IMPORTANT: Some accessories such as electronic air cleaners and

pleated media may require a larger side opening. Follow the instruc-

tions supplied with that accessory for side opening requirements. Do

not cut the opening larger than the dimensions shown in Figure 1.

HORIZONTAL APPLICATION

Horizontal Filters

All filters and mounting provision must be field supplied. Filters(s) may

be located in the duct system external to the furnace or in a return filter

grille(s). Filters(s) may be located in the duct system using an external

duct filter box attached to the furnace plenum. Filters must be a mini-

mum distance of 18” (45.7 cm) from the furnace. Any branch duct (rect-

angular or round duct) attached to the plenum must attach to the

vertical plenum above the filter height. The use of straps and / or sup-

ports is required to support the weight of the external filter box.

SECTION IV: GAS PIPING

GAS SAFETY

IMPORTANT: Plan your gas supply before determining the correct gas

pipe entry. Use 90-degree service elbow(s), or short nipples and con-

ventional 90-degree elbow(s) to enter through the cabinet access holes.

GAS PIPING INSTALLATION

Properly sized wrought iron, approved flexible or steel pipe must be

used when making gas connections to the unit. If local codes allow the

use of a flexible gas appliance connection, always use a new listed con-

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

appliance.

Some utility companies or local codes require pipe sizes larger than the

minimum sizes listed in these instructions and in the codes. The furnace

rating plate and the instructions in this section specify the type of gas

approved for this furnace - only use those approved gases. The instal-

lation of a drip leg and ground union is required. Refer to Figures 9 or

10.

TABLE 5:

Filter Sizes

Cabinet Size Side (in) Side (cm) Bottom (in) Bottom (cm)

A 16 x 26 40.6 x 66.0 14 x 26 35.6 x 66.0

B 16 x 26 40.6 x 66.0 16 x 26 40.6 x 66.0

C (2) 16 x 26 (2) 40.6 x 66.0 20 x 26 50.8 x 66.0

D (2) 16 x 26 (2) 40.6 x 66.0 20 x 26 50.8 x 66.0

FIGURE 5: Side Return Cutout Markings

All installations must have a filter installed.

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.

FRONT OF

FURNACE

CORNER

MARKINGS

FIGURE 6: Gas Valve

INLET OUTLET

ON / OFF SWITCH

WRENCH

BOSS

CHECKING THE GAS PRESSURES

1. The pressure ports on the gas valve are marked OUT P and IN

2. The manifold pressure must be taken at the port marked OUT P.

3. The inlet gas supply pressure must be taken at the port marked

IN P.

4. Using a 3/32” (0.2 cm) Allen wrench, loosen the set screw by

turning it 1 turn counter clockwise. DO NOT REMOVE THE

SET SCREW FROM THE PRESSURE PORT.

5. Push one end the 3/8” (0.9 cm) ID flexible tubing over the pres-

sure port so that the body of the port is inside the tubing.

6. Use a reducer connector to connect the 3/8” (0.9 cm) ID flexible

tube to a 1/4” (0.6 cm) ID flexible tube that is connected to a "U”

tube manometer or digital pressure measuring equipment.

IMPORTANT: The inlet gas pressure operating range table specifies

what the minimum and maximum gas line pressures must be for the

furnace to operate safely. The gas line pressure MUST BE a mini-

mum of:

• 7” W.C. (1.74 kPA) for Natural Gas

• 11” W.C. (2.74 kPA) for Propane (LP) Gas

in order to obtain the BTU input specified on the rating plate and/or

the nominal manifold pressure specified in these instructions and on

the rating plate.

TABLE 6:

Inlet Gas Pressure Range

INLET GAS PRESSURE RANGE

Natural Gas Propane (LP)

Minimum 4.5” W.C. (1.12 kPa) 8.0” W.C. (1.99 kPa)

Maximum 10.5” W.C. (2.61 kPa) 13.0” (3.24 kPa) W.C.

035-19670-003 Rev. A (1004)

8Unitary Products Group

IMPORTANT: An accessible manual shutoff valve must be installed

upstream of the furnace gas controls and within 6 feet (1.8 m) of the fur-

nace.

The furnace must be isolated from the gas supply piping system by

closing its individual external manual shutoff valve during any pressure

testing of the gas supply piping system at pressures equal to or less

than 1/2 psig (3.5 kPa).

Gas piping may be connected from either side of the furnace using any

of the gas pipe entry knockouts on both sides of the furnace. Refer to

Figure 1 dimensions.

GAS ORIFICE CONVERSION FOR PROPANE (LP)

This furnace is constructed at the factory for natural gas-fired operation,

but may be converted to operate on propane (LP) gas by using a fac-

tory-supplied LP conversion kit. Follow the instructions supplied with

the LP kit. Refer to Table 7 or the instructions in the propane (LP) con-

version kit for the proper gas orifice size.

HIGH ALTITUDE GAS ORIFICE CONVERSION

This furnace is constructed at the factory for natural gas-fired operation

at 0 – 2,000 ft. (0 m – 610 m) above sea level.

The gas orifices on this furnace must be changed in order to maintain

proper and safe operation, when the furnace is installed in a location

where the altitude is greater than 2,000 ft. (610 m) above sea level on

natural gas or the altitude is greater than 4,000 ft. (1219 m) above sea

level on propane (LP) gas. Refer to Table 7 or the instructions in the

high altitude conversion kit for the proper gas orifice size.

The unit may also be converted for altitudes up to 10,000 ft. (3048 m)

on natural and propane (LP) gas with additional derate as shown in

Table 7 or refer to ANSI Z223.1 NFPA 54 National Fuel Gas Code or in

Canada CAN/CGA-B149.1-00 Natural Gas and Propane Installation

Code.

HIGH ALTITUDE PRESSURE SWITCH CONVERSION

For installation in locations where the altitude is less than 4,500 feet

(1372 m), it is not required that the pressure switch be changed. For

altitudes above 4,500 feet (137 m), refer to Instructions in the Acces-

sory High Altitude Kit.

FIGURE 7: Upflow Gas Piping

FIGURE 8: Horizontal Gas Piping

The gas valve body is a very thin casting that cannot take any

external pressure. Never apply a pipe wrench to the body of the gas

valve when installing piping. A wrench must be placed on the octa-

gon hub located on the gas inlet side of the valve. Placing a wrench

to the body of the gas valve will damage the valve causing improper

operation and/or the valve to leak.

EXTERNAL MANUAL

SHUTOFF VALVE

TO GAS

SUPPLY

TO GAS

SUPPLY

GROUNDED JOINT UNION

MAY BE INSTALLED

INSIDE OR OUTSIDE UNIT.

DRIP

LEG

MANUAL

SHUT-OFF

VALVE

DRIP

LEG

GAS

PIPE GAS BURNERS

GAS VALVE

GAS

PIPE

DRIP

LEG MANUAL

SHUT-OFF VALVE

LoNOx furnaces requiring propane (LP) gas must have the LoNOx

screens removed prior to installation and operation. See propane

instructions 035-14445-000 or the start up procedure at the back of

these instructions on proper removal of the NOx screens.

TABLE 7:

High Altitude Conversion

Type

Of Gas Orifice at

Sea Level 2,000 ft.

(610 m) 3,000 ft.

(914 m) 4,000 ft.

(1219 m) 5,000 ft.

(1524 m) 6,000 ft.

(1829 m) 7,000 ft.

(2134 m) 8,000 ft.

(2438 m) 9,000 ft.

(2743 m) 10,000 ft.

(3048 m)

Natural #45 #46 #47 #47 #47 #48 #48 #49 #49 #50

Propane #55 #55 #55 #55 #56 #56 #56 #56 #56 #57

PROPANE AND HIGH ALTITUDE CONVERSION KITS

It is very important to choose the correct kit and/or gas orifices for the altitude and the type of gas for which the furnace is being installed.

Only use natural gas in furnaces designed for natural gas. Only use propane (LP) gas for furnaces that have been properly converted to use pro-

pane (LP) gas. Do not use this furnace with butane gas.

Incorrect gas orifices or a furnace that has been improperly converted will create an extremely dangerous condition resulting in premature heat

exchanger failure, excessive sooting, high levels of carbon monoxide, personal injury, property damage, a fire hazard and/or death.

High altitude and propane (LP) conversions are required in order for the appliance to satisfactory meet the application.

An authorized distributor or dealer must make all gas conversions.

In Canada, a certified conversion station or other qualified agency, using factory specified and/or approved parts, must perform the conversion.

The installer must take every precaution to insure that the furnace has been converted to the proper gas orifice size when the furnace is installed.

Do not attempt to drill out any orifices to obtain the proper orifice size. Drilling out a gas orifice will cause misalignment of the burner flames,

causing premature heat exchanger burnout, high levels of carbon monoxide, excessive sooting, a fire hazard, personal injury, property damage

and/or death.

035-19670-003 Rev. A (1004)

Unitary Products Group 9

SECTION V: ELECTRICAL POWER

Electrical Power Connections

Field wiring to the unit must be grounded. Electric wires that are field

installed shall conform to the temperature limitation for 63°F (35°C) rise

wire when installed in accordance with instructions. Refer to Table 8 in

these instructions for specific furnace electrical data.

Annual Fuel Utilization Efficiency (AFUE) numbers are determined in accordance with DOE Test procedures.

Wire size and over current protection must comply with the National Electrical Code (NFPA-70-latest edition) and all local codes.

The furnace shall be installed so that the electrical components are protected from water.

SUPPLY VOLTAGE CONNECTIONS

1. Provide a power supply separate from all other circuits. Install

overcurrent protection and disconnect switch per local/national

electrical codes. The switch should be close to the unit for conve-

nience in servicing. With the disconnect or fused switch in the OFF

position, check all wiring against the unit wiring label. Refer to the

wiring diagram in this instruction.

2. Remove the screws retaining the wiring box cover. Route the

power wiring through the opening in the unit into the junction box

with a conduit connector or other proper connection. In the junc-

tion box there will be three wires, a Black Wire, a White Wire and a

Green Wire. Connect the power supply as shown on the unit-wir-

ing label on the inside of the blower compartment door or the wir-

ing schematic in this section. The black furnace lead must be

connected to the L1 (hot) wire from the power supply. The white

furnace lead must be connected to neutral. Connect the green fur-

nace lead (equipment ground) to the power supply ground. An

alternate wiring method is to use a field provided 2” (5.1 cm) x 4”

(10.2 cm) box and cover on the outside of the furnace. Route the

furnace leads into the box using a protective bushing where the

wires pass through the furnace panel. After making the wiring con-

nections replace the wiring box cover and screws. Refer to Figure

11.

3. The furnace's control system requires correct polarity of the power

supply and a proper ground connection. Refer to Figure 11 or

"FURNACE CONTROL DIAGONSICS" for symptoms of reversed

power supply polarity.

IMPORTANT: The power connection leads and wiring box may be relo-

cated to the left side of the furnace. Remove the screws and cut wire tie

holding excess wiring. Reposition on the left side of the furnace and fas-

ten using holes provided.

POWER SUPPLY POLARITY - Ignition Control: If the power supply

polarity is reversed, the control board will flash 9 times. The furnace will

not operate until the polarity is corrected.

LOW VOLTAGE CONTROL WIRING CONNECTIONS

Install the field-supplied thermostat by following the instructions that

come with the thermostat. With the thermostat set in the OFF position

and the main electrical source disconnected, connect the thermostat

wiring from the wiring connections on the thermostat to the terminal

strip on the integrated control board, as shown in Figure 13 for single

stage or Figure 14 for two stage. Electronic thermostats may require the

common wire to be connected to the "C" terminal as shown in Figures

13 & 14. Apply strain relief to thermostat wires passing through cabinet.

If air conditioning equipment is installed, use thermostat wiring to con-

nect the Y and C terminals on the integrated control board to the yellow

and brown wires on the condensing unit (unit out side) as shown in Fig-

ure 13 or 14.

Use copper conductors only.

TABLE 8: Ratings & Physical / Electrical Data

Input Output Nominal Cabinet Width

AFUE Air Temp. Rise Max. Outlet Air Temp.

MBH kW MBH kW CFM cmm In. cm °F °C °F °C

60/42 17.6/12.3 46/34 13.5/10.0 1200 34.0 14-1/2 36.8 80.0 25-55 13-31 165 73.9

80/59 23.4/17.3 64/48 18.8/14.1 1200 34.0 14-1/2 36.8 80.0 30-60 19-36 175 79.4

80/59 23.4/17.3 64/48 18.8/14.1 1600 45.3 17 1/2 44.5 80.0 25-55 14-31 160 71.1

100/65 29.3/19.1 80/53 23.4/15.5 1200 34.0 17 1/2 44.5 80.0 25-55 14-31 170 76.7

100/65 29.3/19.1 80/53 23.4/15.5 2000 56.6 21 53.3 80.0 25-55 14-31 160 71.1

120/78 35.2/22.9 96/64 28.1/18.8 1600 45.3 21 53.3 80.0 25-55 14-31 180 82.2

120/78 35.2/22.9 96/64 28.1/18.8 2000 56.6 21 53.3 80.0 25-55 14-31 170 76.7

Input Output Blower Blower

Size Total

Unit Max Over-current

Size (awg) @

75 ft.protect

Min.

Wire

one way

Operation

WGT. Operation

WGT.

MBH kW MBH kW Hp Amps In. cm Amps LBS Kg

60/42 17.6/12.3 46/34 13.5/10.0 1/3 6.2 10 x 7 25.4 x 17.8 9.0 20 14 107 48.5

80/59 23.4/17.3 64/48 18.8/14.1 1/3 6.2 10 x 7 25.4 x 17.8 9.0 20 14 119 54.0

80/59 23.4/17.3 64/48 18.8/14.1 3/4 11.5 11 x 8 27.9 x 20.3 12.0 20 14 129 58.5

100/65 29.3/19.1 80/53 23.4/15.5 1/2 7.0 10 x 8 25.4 x 20.3 12.0 20 14 131 59.4

100/65 29.3/19.1 80/53 23.4/15.5 1.0 12.2 11 x 10 27.9 x 25.4 14.0 20 12 149 67.6

120/78 35.2/22.9 96/64 28.1/18.8 1/2 10.4 10 x 10 25.4 x 25.4 12.0 20 14 149 67.6

120/78 35.2/22.9 96/64 28.1/18.8 1.0 12.2 11 x 10 27.9 x 25.4 14.0 20 12 151 68.5

FIGURE 9: Electrical Wiring

BLK/BLK

WHT/WHT

GRN/GRN

HUM

EAC

(HOT)

NGND

HUM (HOT)

EAC (HOT)

GRN

WHT

BLK

JUNCTION

BOX

DOOR SWITCH

CLASS 2 SYSTEM

CONTROL WIRING

TO THERMOSTAT

WIRING INSIDE

JUNCTION BOX

BURNER

COMPARTMENT

BLOWER

COMPARTMENT

IGNITION

MODULE

035-19670-003 Rev. A (1004)

10 Unitary Products Group

IMPORTANT: Set the heat anticipator in the room thermostat to 0.10

amps. Setting it lower will cause short cycles. Setting it higher will cause

the room temperature to exceed the set points.

Apply strain relief to thermostat wires passing through the cabinet.

IMPORTANT: Some electronic thermostats do not have adjustable heat

anticipators. They may have other type cycle rate adjustments. Follow

the thermostat manufacturer's instructions.

The 24-volt, 40 VA transformer is sized for the furnace components

only, and should not be connected to power auxiliary devices such as

humidifiers, air cleaners, etc. The transformer may provide power for an

air conditioning unit contactor.

ACCESSORY CONNECTIONS

The furnace control will allow power-switching control of various acces-

sories. Refer to Figure 15, for connection details.

ELECTRONIC AIR CLEANER CONNECTION

Two 1/4” (0.64 cm) spade terminals (EAC and NEUTRAL) for electronic

air cleaner connections are located on the control board. The terminals

provide 115 VAC (1.0 amp maximum) during circulating blower opera-

tion.

HUMIDIFIER CONNECTION

Two 1/4” (0.64 cm) spade terminals (EAC and NEUTRAL) for humidifier

connections are located on the control board. The terminals provide 115

VAC (1.0 amp maximum) during heating system operation.

TWINNING

These furnaces are not to be twinned. If more than one furnace is

needed in an application, each furnace must have its own completed

duct system and its own wall thermostat.

FIGURE 10: Line Wiring Connections

FIGURE 11: Field Wiring for Single Stage Thermostat

FIGURE 12: Field Wiring for Two Stage Thermostat

BLK

WHT

GRN

BLK (HOT)

WHT (NEUTRAL)

GRN

NOMINAL

120 VOLT

Y1 Y2

W2 RGC

SINGLE STAGE

THERMOSTAT

T’STAT

COMMON

CONNECTION

INTEGRATED

CONTROL

T’STAT

COMMON

CONNECTION

TWO-STAGE

THERMOSTAT

OUTDOOR

UNIT

Set the heat anticipator in the room thermostat as shown below. Set-

ting it lower will cause short cycles. Setting it higher will cause the

room temperature to exceed the setpoint.

Two-Stage Thermostat First Stage .4 Amps

Second Stage .1 Amps

Single Stage Thermostat .4 Amps

FIGURE 13: Accessory Connections

BLK

115 VOLT

HUMIDIFIER

HUM. HOT

WHT

EAC HOT

115 VOLT

ELECTRONIC

AIR CLEANER

BLK

WHT EAC

HUM NEUTRALS

EAC

HUM SWITCHED

CIRCUITS

035-19670-003 Rev. A (1004)

Unitary Products Group 11

SECTION VI: VENT SYSTEM

VENT SAFETY

This Category I, furnace is designed for residential application. It may

be installed without modification in a basement, garage, equipment

room, alcove, attic or any other indoor location where all required clear-

ance to combustibles and other restrictions are met.

CATEGORY 1 - 450 F. MAX. VENT TEMP.

The venting system must be installed in accordance with Section 5.3,

Air for Combustion and Ventilation, of the National Fuel Gas Code

Z223.1/NFPA 54 (latest edition), or Sections 7.2, 7.3 or 7.4 of CSA

B149.1, National Gas and Propane Codes (latest edition) or applicable

provisions of the local building code and these instructions.

The furnace shall be connected to any type of B, BW or L vent connec-

tor, and shall be connected to a factory-built or masonry chimney. The

furnace shall not be connected to a chimney flue serving a sepa-

rate appliance designed to burn solid fuel.

The furnace rating plate lists the maximum vent gas temperature. This

temperature must be used to select the appropriate venting materials

and clearances.

It is recommended that the appliance is installed in a location where the

space temperature is 32 °F (0°C) or higher. If the appliance is installed

in a location where the ambient temperature is below 32 °F (0°C), the

combustion by-products could condense causing damage to the appli-

ance heat exchanger.

IMPORTANT: The “VENT SYSTEM” must be installed as specified in

these instructions for Residential and Modular Homes.

This appliance may be common vented with another gas appliance for

residential installations as allowed by the codes and standards listed in

these instructions.

Approved Modular Homes must be vented with an approved roof jack

and may not be common vented with other appliances.

VENTING

Category I venting consists of vertically venting one or more appliances

in B-vent or masonry chimney (as allowed), using single wall metal pipe

or B-vent connectors. Type B-vent system extends in a general vertical

direction and does not contain offsets exceeding 45 degrees. A vent

system having not more than one 60 degree offset is permitted.

If installing furnace at altitudes between 2000 - 4500 ft. (610 – 1372 m),

vent pipe length must be reduced by 10 ft. (3.05 m). If the installation

requires the maximum allowable vent pipe length, the furnace must be

converted for high altitude operation. Refer to SECTION IV “GAS PIP-

ING” of these instructions and the proper high altitude application

instruction for details.

FIGURE 14: Vent Termination

FIGURE 15: Vent Termination

TABLE 9:

Roof Pitch

ROOF PITCH H(min) ft m

Flat to 6/12 1.0 0.30

6/12 to 7/12 1.25 0.38

Over 7/12 to 8/12 1.5 0.46

Over 8/12 to 9/12 2.0 0.61

Over 9/12 to 10/12 2.5 0.76

Over 10/12 to 11/12 3.25 0.99

Over 11/12 to 12/12 4.0 1.22

Over 12/12 to 14/12 5.0 1.52

Over 14/12 to 16/12 6.0 1.83

Over 16/12 to 18/12 7.0 2.13

Over 18/12 to 20/12 7.5 2.27

Over 20/12 to 21/12 8.0 2.44

WALL OR

PARAPET

CHIMNEY

NOTE: NO

HEIGHT ABOVE

PARAPET REQUIRED

WHEN DISTANCE

FROM WALLS OR

PARAPET IS MORE

THAN 10 FT (3.0 m).

3 FT (0.9 m)

MIN.

MORE THAN

10 FT (3.0 M)

2 FT(0.6 m)

MIN

RIDGE

CHIMNEY

HEIGHT ABOVE ANY

ROOF SURFACE WITHIN

10 FT (3.0 m) HORIZONTALLY

3 FT (0.9 m)

MIN

MORE THAN

10 FT (3.0 M)

LOWEST DISCHARGE OPENING

LISTED CAP

LISTED GAS

VENT

H (min) - MINIMUM HEIGHT FROM ROOF

TO LOWEST DISCHARGE OPENING

12 X

ROOF PITCH

IS X/12

FIGURE 16: Typical Chimney Connections

FURNACE

WATER

HEATER

CHIMNEY OR

GAS VENT

OPENING

035-19670-003 Rev. A (1004)

12 Unitary Products Group

VENTING INTO AN EXISTING CHIMNEY

For Category I installations, the furnace shall be connected to a factory

built chimney or vent complying with a recognized standard, or a

masonry or concrete chimney lined with a material acceptable to the

authority having jurisdiction. Venting into an unlined masonry chimney

or concrete chimney is prohibited.

Whenever possible, B-1 metal pipe should be used for venting. Where

use of an existing chimney is unavoidable, the following rules must be

followed:

1. The masonry chimney must be built and installed in accordance

with nationally recognized building codes or standards and must

be lined with approved fire clay tile flue liners or other approved

liner material that will resist corrosion, softening, or cracking from

flue gases. THIS FURNACE IS NOT TO BE VENTED INTO AN

UNLINED MASONRY CHIMNEY.

2. This furnace must be vented into a fire clay tile lined masonry

chimney only if a source of dilution air is provided, such as by com-

mon venting with a draft hood equipped water heater. If no source

of dilution air is available, Type B vent must be used, or masonry

chimney vent kit 1CK0603 or 1CK0604 must be used. Refer to the

instructions with the kit to properly apply these masonry chimney

kits.

3. The chimney must extend at least 3 ft (0.91 cm) above the highest

point where it passes through a roof of a building and at least two

feet higher than any portion of the building with a horizontal dis-

tance of ten feet.

4. The chimney must extend at least 5 ft (1.5 cm) above the highest

equipment draft hood or flue collar.

HORIZONTAL SIDEWALL VENTING

For applications where vertical venting is not possible, the only

approved method of horizontal venting is the use of an auxiliary power

vent. Approved power venters are Fields Controls Model SWG-4Y or

Tjernlund Model GPAK-JT. Follow all application and installation details

provided by the manufacturer of the power vent.

VENT PIPING ASSEMBLY

The final assembly procedure for the vent piping is as follows:

1. Cut piping to the proper length beginning at the furnace.

2. Deburr the piping inside and outside.

3. Dry-fit the vent piping assembly from the furnace to the termination

checking for proper fit support and slope. Piping should be sup-

ported with pipe hangers to prevent sagging. The maximum spac-

ing between hangers is 4 feet (1.22 m).

4. Assemble the vent piping from the furnace to the termination

securing the pipe connections with screws.

VENT CLEARANCES

IMPORTANT: The vent must be installed with the following minimum

clearances as shown in Figure 22, and must comply with local codes

and requirements.

FIGURE 17: Alternate Air Intake, Air Outlet and Chimney Connections

FURNACE

WATER

HEATER

OUTLET

AIR

VENTILATION LOUVERS

(each end of attic)

CHIMNEY OR

GAS VENT

INLET

AIR

ALTERNATE

AIR INLET

VENTILATION LOUVERS FOR UNHEATED CRAWL SPACE FIGURE 18: Typical Sidewall Vent Application

FIGURE 19: Typical Sidewall Vent and Termination Configuration

FAN ASSISTED FURNACE

& WATER HEATER

FAN ASSISTED

FURNACES

VENT

PIPE

HOT

WATER

TANK

FURNACE

OPTIONAL

SIDEWALL

VENT SYSTEM

(field supplied)

EXTERIOR

VENT HOOD

VENT PIPE

FLUE

PIPE

BURNER

ACCESS

PANEL

CELLAR

WALL

OPTIONAL

SIDEWALL

VENT SYSTEM

(field supplied)

TOP

COVER

BAROMETRIC

DAMPER

TABLE 10:

Horizontal Venting

High / Low

Fire Inputs High / Low

Fire Outputs Heating

Output Furnace

Airflow Furnace

Airflow Pipe Size Min. Vent Length Max. Vent Length

Inches cm

BTU/H (kW) BTU/H (kW) kW CFM cm/m Feet meters Feet meters

60/42 (17.6/12.3) 46/34 (13.5/9.96) A 1200 33.98 4 10.16 4.5 1.37 34.5 10.82

80/59 (23.4/17.3) 64/48 (18.8/14.1) A 1200 33.98 4 10.16 4.5 1.37 34.5 10.82

80/59 (23.4/17.3) 64/48 (18.8/14.1) B 1600 45.31 4 10.16 4.5 1.37 34.5 10.82

100/65 (29.3/19.1) 80/53 (23.4/15.5) B 1200 33.98 4 10.16 4.5 1.37 34.5 10.82

100/65 (29.3/19.1) 80/53 (23.4/15.5) C 2000 56.63 4 10.16 4.5 1.37 34.5 10.82

120/78 (35.1/22.9) 96/64 (28.1/18.8) C 1600 45.31 4 10.16 4.5 1.37 34.5 10.82

120/78 (35.1/22.9) 96/64 (28.1/18.8) C 2000 56.63 4 10.16 4.5 1.37 34.5 10.82

035-19670-003 Rev. A (1004)

Unitary Products Group 13

† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor. For clearance not specified in ANSI Z223.1 / NFPA 54 or CSA B149.1-00.

Clearance in accordance with local installation codes and the requirements of the gas supplier and the manufacturer’s Installation Manual.

Any fresh air or make up inlet for dryer or furnace area is considered to be forced air inlet.

Avoid areas where condensate drippage may cause problems such as above planters, patios, or adjacent to windows where steam may cause fogging.

A terminus of a vent shall be either:

Fitted with a cap in accordance with the vent manufacturer’s installation instructions, or In accordance with the installation instructions for a special venting system.

* Does not apply to multiple installations of this furnace model. Refer to "VENTING MULTIPLE UNITS" in this section of these instructions.

IMPORTANT: Consideration must be given for degradation of building materials by flue gases. Sidewall termination may require sealing or shielding of building surfaces with a corrosion resistant

material to protect against combustion product corrosion. Consideration must be given to wind direction in order to prevent flue products and/or condensate from being blown against

the building surfaces. If a metal shield is used it must be a stainless steel material at a minimum dimension of 20 inches. It is recommended that a retaining type collar be used that is

attached to the building surface to prevent movement of the vent pipe.

Responsibility for the provision of proper adequate venting and air supply for application shall rest with the installer.

Vent shall extend high enough above building, or a neighboring obstruction, so that wind from any direction will not create a positive pressure in the vicinity of the vent.

HORIZONTAL VENT APPLICATIONS AND

TERMINATION

When selecting the location for a horizontal combustion air / vent termi-

nation, the following should be considered:

1. Observe all clearances listed in vent clearances in these instruc-

tions.

2. Termination should be positioned where vent vapors will not dam-

age plants or shrubs or air conditioning equipment.

3. Termination should be located where it will not be affected by wind

gusts, light snow, airborne leaves or allow recirculation of flue

gases.

4. Termination should be located where it will not be damaged or

exposed to flying stones, balls, etc.

5. Termination should be positioned where vent vapors are not objec-

tionable.

6. Horizontal portions of the vent system must slope upwards and be

supported to prevent sagging. The vent system may be supported

by the use of clamps or hangers secured to a permanent part of

the structure every 4 ft. (1.22 m).

FAN-ASSISTED COMBUSTION SYSTEM

An appliance equipped with an integral mechanical means to either

draw or force products of combustion through the combustion chamber

and/or heat exchanger.

FIGURE 20: Home Layout

OPERABLE

FIXED

CLOSED

VENT TERMINAL

AIR SUPPLY

AREA WHERE TERMINAL IS NOT PERMITTED

FIXED

CLOSED

Canadian Installations1US Installation2

A. Clearance above grade, veranda, porch, deck, or balcony 12 inches (30 cm) 12 inches (30 cm)

B. Clearance to window or door that may be opened

6 inches (15 cm) for applications ≤10,000 Btuh (3kW),

12 inches (30 cm) for appliances > 10,000 Btuh (3kW)

and ≤100,000 Btuh (30kW), 36 inches (91 cm)

for appliances > 100,000 Btuh (30kW)

6 inches (15 cm) for applications ≤10,000 Btuh (3kW),

9 inches (23 cm) for appliances > 10,000 Btuh (3kW)

and ≤50,000 Btuh (15kW), 12 inches (30 cm)

for appliances > 50,000 Btuh (30kW)

C.Clearance to permanently closed window “ “

D.Vertical clearance to ventilated soffit located

above the terminal within a horizontal distance

of 2 feet (61 cm) from the center line of the terminal ““

E. Clearance to unventilated soffit ““

F. Clearance to outside corner ““

G. Clearance to inside corner ““

H.Clearance to each side of center line extended

above meter/regulator assembly 3 feet (91 cm) within a height 15 feet (4.5 m) above the

meter/regulator assembly “

I. Clearance to service regulator vent outlet 3 feet (91 cm) “

J. Clearance to nonmechanical air supply inlet to building

or the combustion air inlet to any other appliance

6 inches (15 cm) for applications ≤10,000 Btuh (3kW),

12 inches (30 cm) for appliances > 10,000 Btuh (3kW)

and ≤100,000 Btuh (30kW), 36 inches (91 cm)

for appliances > 100,000 Btuh (30kW)

6 inches (15 cm) for applications ≤10,000 Btuh (3kW),

9 inches (23 cm) for appliances > 10,000 Btuh (3kW)

and ≤50,000 Btuh (15kW), 12 inches (30 cm)

for appliances > 50,000 Btuh (30kW)

K. Clearance to a mechanical supply inlet 6 feet (1.83 m) 3 feet (91 cm) above if within 10 feet (3 cm) horizontally

L. Clearance above paved sidewalk or paved driveway located on public property 7 feet (2.13 m) †“

M.Clearance under veranda, porch, deck, or balcony 12 inches (30 cm) ‡“

Dryer Vent 3 ft (91.44 cm) 3 ft (91.44 cm)

Plumbing Vent Stack 3 ft (91.44 cm) 3 ft (91.44 cm)

Gas Appliance Vent Terminal 3 ft (91.44 cm) * 3 ft (91.44 cm) *

Vent Termination from any Building Surface 12" (30.4 cm) 12" (30.4 cm)

Above Any Grade Level 12" (30.4 cm) 12" (30.4 cm)

Above anticipated snow depth 12" (30.4 cm) 12" (30.4 cm)

Any forced air inlet to the building. 10 ft (304.8 cm) 10 ft (304.8 cm)

The vent shall extend above the highest point where it passes through the roof,

not less than 18" (46 cm) 18" (46 cm)

Any obstruction within a horizontal distance Not less than 18" (46 cm) Not less than 18" (46 cm)

1. In accordance with the current CSA B149.1-00, Natural Gas and Propane Installation Code.

2. In accordance with the current ANSI Z223.1 / NFPA 54, National Gas Code.

035-19670-003 Rev. A (1004)

14 Unitary Products Group

Ambient Combustion Air Supply

This type installation will draw the air required for combustion from

within the space surrounding the appliance and from areas or rooms

adjacent to the space surrounding the appliance. This may be from

within the space in a non-confined location or it may be brought into the

furnace area from outdoors through permanent openings or ducts. A

properly sized duct from the outside to the furnace location must be pro-

vided.

An unconfined space is not less than 50 cu.ft (1.42 m3) per 1,000 Btu/

hr (0.2928 kW) input rating for all of the appliances installed in that

area.

Rooms communicating directly with the space containing the appli-

ances are considered part of the unconfined space, if openings are fur-

nished with doors.

A confined space is an area with less than 50 cu.ft (1.42 m3) per 1,000

Btu/hr (0.2928 kW) input rating for all of the appliances installed in that

area. The following must be considered to obtain proper air for combus-

tion and ventilation in confined spaces.

Combustion Air Source From Outdoors

The blocking effects of louvers, grilles and screens must be given con-

sideration in calculating free area. If the free area of a specific louver or

grille is not known, refer to Table 11, to estimate free area.

* Do not use less than 1/4” mesh

+ Free area or louvers and grille varies widely; the installer should follow louver or grille

manufacturer’s instructions.

Dampers, Louvers and Grilles (Canada Only)

1. The free area of a supply air opening shall be calculated by sub-

tracting the blockage area of all fixed louvers grilles or screens

from the gross area of the opening.

2. Apertures in a fixed louver, a grille, or screen shall have no dimen-

sion smaller than 0.25” (6.4 mm).

3. A manually operated damper or manually adjustable louvers are

not permitted for use.

4. A automatically operated damper or automatically adjustable lou-

vers shall be interlocked so that the main burner cannot operate

unless either the damper or the louver is in the fully open position.

FIGURE 21: Combustion Airflow Path Through The Furnace Casing to

the Burner Box

This type of installation requires that the supply air to the appli-

ance(s) be of a sufficient amount to support all of the appliance(s)

in the area. Operation of a mechanical exhaust, such as an exhaust

fan, kitchen ventilation system, clothes dryer or fireplace may cre-

ate conditions requiring special attention to avoid unsatisfactory

operation of gas appliances. A venting problem or a lack of supply

air will result in a hazardous condition, which can cause the appli-

ance to soot and generate dangerous levels of CARBON MONOX-

IDE, which can lead to serious injury, property damage and / or

death.

FIGURE 22: Air Inlet, Outlet and Chimney Connections

COMBUSTION AIR VENT PIPE CEMENTS

INTO SOCKET JUST

ABOVE TOP PANEL

FURNACE

WATER

HEATER

OUTLET

AIR

VENTILATION LOUVERS

(each end of attic)

CHIMNEY OR

GAS VENT

INLET AIR DUCT

[ends 1 ft (30 cm)

above floor]

TABLE 11:

Estimated Free Area

Wood or Metal

Louvers or Grilles Wood 20-25%*

Metal 60-70% *

Screens+ 1/4” (0.635 cm)

mesh or larger 100%

FIGURE 23: Air Inlet, Outlet and Chimney Connections

FIGURE 24: Alternate Air Intake, Air Outlet and Chimney Connections

FURNACE

WATER

HEATER

OUTLET

AIR

VENTILATION LOUVERS

(each end of attic)

CHIMNEY OR

GAS VENT

INLET AIR DUCT

[ends 1 ft (30 cm)

above floor]

FURNACE

WATER

HEATER

OUTLET

AIR

VENTILATION LOUVERS

(each end of attic)

CHIMNEY OR

GAS VENT

INLET

AIR

ALTERNATE

AIR INLET

VENTILATION LOUVERS FOR UNHEATED CRAWL SPACE

035-19670-003 Rev. A (1004)

Unitary Products Group 15

Vent and Supply (Outside) Air Safety Check Procedure

For Category I furnaces, vent installations shall be in accordance with

Parts 7 and 11 of the National Fuel Gas Code, ANSI Z223.1/NFPA 54,

and or Section 7 and Appendix B of the CSA B149.1, Natural Gas and

Propane Installation Codes, the local building codes, furnace and vent

manufacture's instructions.

Multi-story or common venting systems are permitted and must be

installed in accordance with the National Fuel Gas Code, ANSI Z223.1/

NFPA 54 and / or the CSA B149.1, Natural Gas and Propane Installa-

tion Codes, local codes, and the manufacture's instructions.

Vent connectors serving Category I furnaces shall not be connected

into any portion of mechanical draft systems operating under positive

pressure.

Horizontal portions of the venting system shall be supported to prevent

sagging using hangers or perforated straps and must slope upwards

not less than 1/4" per foot (0.635 cm/m) from the furnace to the vent ter-

minal.

It is recommended that you follow the venting safety procedure below.

This procedure is designed to detect an inadequate ventilation system

that can cause the appliances in the area to operate improperly causing

unsafe levels of Carbon Monoxide or an unsafe condition to occur.

TABLE 12:

Free Area

BTUH Input

Rating

Minimum Free Area Required for Each Opening

Horizontal Duct

(2,000 BTUH)

Vertical Duct or

Opening to Outside

(4,000 BTUH)

Round Duct

(4,000 BTUH)

60,000 30 in2(193 cm2) 15 in2(97 cm2)5” (13 cm)

80,000 40 in2(258 cm2) 20 in2(129 cm2)5” (13 cm)

100,000 50 in2(322 cm2) 25 in2(161 cm2)6” (15 cm)

120,000 60 in2(387 cm2) 30 in2(193 cm2)7” (18 cm)

EXAMPLE: Determining Free Area.

Appliance 1Appliance 2Total Input

100,000 + 30,000 = (130,000 ÷4,000) = 32.5 Sq. In. Vertical

Appliance 1Appliance 2Total Input

100,000 + 30,000 = (130,000 ÷2,000) = 65 Sq. In. Horizontal

TABLE 13:

Unconfined Space Minimum Area in Square Inch

BTUH Input Rating Minimum Free Area in Square Feet

Required for Each Opening

60,000 375 (34.84 m2)

80,000 500 (46.45 m2)

100,000 625 (58.06 m2)

120,000 750 (69.68 m2)

EXAMPLE: Square feet is based on 8 foot ceilings.

28,000 BTUH X 50 Cubic Ft. = 1,400 = 175 Sq. Ft.

1,000 8’ Ceiling Height

FIGURE 25: Outside and Ambient Combustion Air

GABLE

VENT

GAS

VENT

SOFFIT

VENT

VENTILATED

ATTIC

TOP ABOVE

INSULATION

OPTIONAL

INLET (a)

OUTLET

AIR (a)

VENTILATED

CRAWL SPACE

GAS

WATER

HEATER

VENTILATED

ATTIC

TOP ABOVE

INSULATION

GAS

VENT

GABLE

VENT

SOFFIT

VENT

GAS

WATER

HEATER INLET

AIR (a)

INLET

AIR (b)

GAS

VENT

OUTLET

AIR (a)

OUTLET

AIR (b)

INLET

AIR (a)

INLET

AIR (b)

GAS

WATER

HEATER

FURNACE

1. An opening may be used in lieu of a duct to provide to provide the outside air

supply to an appliance unless otherwise permitted by the authority having

jurisdiction. The opening shall be located within 12” (30.5 cm) horizontally from,

the burner level of the appliance. Refer to “AIR SOURCE FROM OUTDOORS

AND VENT AND SUPPLY AIR SAFETY CHECK” in these instructions for

additional information and safety check procedure.

2. The duct shall be either metal, or a material meeting the class 1

requirements of CAN4-S110 Standard for Air Ducts.

3. The duct shall be least the same cross-sectional area as the free

area of the air supply inlet opening to which it connects.

4. The duct shall terminate within 12 in (30.5 cm) above, and

within 24 in (61 cm) horizontally from, the burner level of

the appliance having the largest input.

5. A square or rectangular shaped duct shall only be used

when the required free area of the supply opening is

9 in (58.06 cm ) or larger. When a square or rectangular

duct is used, its small dimensionshall not be less than

3 in (7.6 cm).

6. An air inlet supply from outdoors shall be equipped with

a means to prevent the direct entry of rain and wind.

Such means shall not reduce the required free area of

the air supply opening.

7. An air supply inlet opening from the outdoors shall

be located not less than 12” (30.5 cm) above the

outside grade level.

AIR SUPPLY OPENINGS AND DUCTS

COMBUSTION AIR SOURCE FROM OUTDOORS

1. Two permanent openings, one within 12 in (30.5 mm) of the top and

one within 12 in (30.5 mm) of bottom of the confined space,

shall communicate directly or by means of ducts

with the outdoors, crawl spaces or attic spaces.

Two

permanent openings,

2. One permanent openings, commencing within 12 in (30.5 mm)of the

top of the enclosure shall be permitted where the equipment has

clearances of at least 1 in (2.54 cm) from the sides and back and

6 in (15.24 cm) from the front of the appliance. The opening shall

communicate directly with the outdoors and shall have a minimum

free area of:

3. The duct shall be least the same cross-sectional area as the free

area of the air supply inlet opening to which it connects.

1 square in per 3000 Btu per hour (6.45 cm 0.879 kW) of the total

input rating of all equipment located in the enclosure.

Not less than the sum of all vent connectors in the confined space.

4. The blocking effects of louvers, grilles and screens must be given

consideration in calculating free area. If the free area of a specific

louver aor grille is not known.

When a Category I furnace is removed or replaced, the original

venting system may no longer be correctly sized to properly vent

the attached appliances.

An improperly sized vent system can cause CARBON MONOXIDE

to spill into the living space causing personal injury, and or death.

035-19670-003 Rev. A (1004)

16 Unitary Products Group

SECTION VII: SAFETY CONTROLS

CONTROL CIRCUIT FUSE

A 3-amp fuse is provided on the control circuit board to protect the 24-

volt transformer from overload caused by control circuit wiring errors.

This is an ATO 3, automotive type fuse and is located on the control

board.

BLOWER DOOR SAFETY SWITCH

This unit is equipped with an electrical interlock switch mounted in the

blower compartment. This switch interrupts all power at the unit when

the panel covering the blower compartment is removed.

Electrical supply to this unit is dependent upon the panel that covers the

blower compartment being in place and properly positioned.

ROLLOUT SWITCH CONTROLS

These controls are mounted on the burner box assembly. If the temper-

ature in the burner box exceeds its set point, the ignition control and the

gas valve are de-energized. The operation of this control indicates a

malfunction in the combustion air blower, heat exchanger or a blocked

vent pipe connection. Corrective action is required. These are manual

reset controls that must be reset before operation can continue.

PRESSURE SWITCHES

This furnace is supplied with two pressure switches, which monitor the

flow through the combustion air/vent piping system. This switches de-

energize the ignition control module and the gas valve if any of the fol-

lowing conditions are present. Refer to Figure 28 for tubing connec-

tions.

1. Blockage of vent piping or terminal.

2. Failure of combustion air blower motor.

LIMIT CONTROLS

There is high temperature limit control located on the furnace vestibule

panel near the gas valve. This is an automatic reset control that pro-

vides over temperature protection due to reduced airflow, that may be

caused by a dirty filter, or if the indoor fan motor should fail. The control

module will lockout if the limit trips 5 consecutive times. Control will

reset and try again after 1 hour.

SECTION VIII: START-UP AND

ADJUSTMENTS

The initial start-up of the furnace requires the following additional

procedures:

IMPORTANT: All electrical connections made in the field and in the fac-

tory should be checked for proper tightness.

When the gas supply is initially connected to the furnace, the gas piping

may be full of air. In order to purge this air, it is recommended that the

ground union be loosened until the odor of gas is detected. When gas is

detected, immediately retighten the union and check for leaks. Allow

five minutes for any gas to dissipate before continuing with the start-up

procedure. Be sure proper ventilation is available to dilute and carry

away any vented gas.

CARBON MONOXIDE POISONING HAZARD

Failure to follow the steps outlined below for each appliance connected to the venting system being placed into operation could result in carbon-

monxide poisoning or death.

The following steps shall be followed for each appliance connected to the venting system being placed into operation, while all other appliances

connected to the venting system are not in operation:

1. Inspect the venting system for proper size and horizontal pitch. Determine that there is no blockage, restriction, leakage, corrosion or other

deficiencies, which could cause an unsafe condition

2. Close all building doors and windows and all doors.

3. Turn on clothes dryers and TURN ON any exhaust fans, such as range hoods and bathroom exhausts, so they shall operate at maximum

speed. Open the fireplace dampers. Do not operate a summer exhaust fan.

4. Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so the appliance shall operate contin-

uously.

5. Test each appliance (such as a water heater) equipped with a draft hood for spillage (down-draft or no draft) at the draft hood relief opening

after 5 minutes of main burner operation. Appliances that do not have draft hoods need to be checked at the vent pipe as close to the

appliance as possible. Use a combustion analyzer to check the CO2 and CO levels of each appliance. Use a draft gauge to check for a

downdraft or inadequate draft condition.

6. After it has been determined that each appliance properly vents when tested as outlined above, return doors, windows, exhaust fans, fire-

place dampers and any other gas burning appliance to their normal condition.

7. If improper venting is observed during any of the above tests, a problem exists with either the venting system or the appliance does not

have enough combustion air (Supply Air from outside) to complete combustion. This condition must be corrected before the appliance can

function safely.

NOTE: An unsafe condition exists when the CO reading exceeds 40 ppm and the draft reading is not in excess of - 0.1 in. W.C. (-25 kPa) with

all of the appliance(s) operating at the same time.

8. Any corrections to the venting system and / or to the supply (outside) air system must be in accordance with the National Fuel Gas Code

Z223.1 or CAN/CGA B149.1-00 Natural Gas and Propane Installation Code (latest editions). If the vent system must be resized, follow the

appropriate tables in Appendix G of the above codes or for this appliance.

Main power to the unit must still be interrupted at the main power

disconnect switch before any service or repair work is to be done to

the unit. Do not rely upon the interlock switch as a main power dis-

connect.

Blower and burner must never be operated without the blower

panel in place.

FIGURE 26: Pressure Switch Tubing Routing

035-19670-003 Rev. A (1004)

Unitary Products Group 17

NOx SCREEN REMOVAL (Lo-NOx Models Only)

If the furnace is equipped with NOx screens and is to be used with LP

(propane) gas, the screens must be removed prior to startup.

1. Make sure that the electrical power to the unit is turned off and that

the gas supply is turned off at the shutoff valve.

2. Remove the blower compartment and burner compartment access

doors.

3. Disconnect the gas supply piping at the union to permit removal of

the entire burner and gas control assembly from the vestibule

panel. Use the wrench boss on the gas valve when removing or

installing the piping.

4. Unplug the ignitor from the wire harness. Disconnect the flame

sensor wires located on top of the air shield. Unplug the gas valve

from the wiring harness.

5. Remove the ignitor and ignitor bracket. Handle the ignitor very

carefully since it is fragile and easily broken.

6. Remove the screws holding the burner assembly to the vestibule

panel. It may be necessary to remove the rollout switch bracket(s)

to gain access to one or more of these screws.

7. Remove the burner assembly. It should be possible to swing the

burner assambly out of the way without disconnecting the remain-

ing wires.

8. With the burner assembly out of the way, simply slide the NOx

screens out of the heat exchanger tubes and discard the screens.

9. Replace all components in reverse order. Reconnect all wiring.

TOOLS AND INFORMATION THAT WILL BE

REQUIRED IN ORDER TO PROPERLY PERFORM THE

FURNACE STARTUP PROCEDURE.

1. Call the local gas supplier to obtain heating value of the natural

gas. If you cannot obtain the heating valve of the gas from the gas

supplier, you may use a default value of 1030 BTU/SCF (38.8 MJ /

m³).

2. You will need a thermometer or portable digital thermometer to

read the supply and return air temperatures.

3. You will need a U-tube manometer or digital equipment that has

the ability to read pressures between 0 – 15” in.w.c (0 - 3.73 kPa)

in order to measure the gas line and the manifold pressures.

4. You will need a 3/32” Allen wrench for the pressure port plugs in

the gas valve.

5. You will need 2 pieces of 1/8” (0.3 cm) ID flexible tubing that is 12”

(30 cm) in length, 2 – pieces of 1/8” (0.3 cm) tubing that are 4”

(10.0 cm) in length, a 1/8” (0.3 cm) tee and a 1/8” (0.3 cm) adapter

to connect the U-tube manometer or the digital pressure measur-

ing equipment to the gas valve pressure ports.

There is an accessory kit (1PK0601) available from Source 1, which

has the following items:

• 1 - 12” (30 cm) length x 1/8” (0.3 cm) diameter tubing

• 2 – pieces of 4” (10 cm) length x 1/8” (0.3 cm) diameter tubing

• 1 - 5/16” (0.8 cm) tee

• 1 – 5/16” (0.8 cm) x 1/8” (3.175 mm) reducing coupling

• 1 – 1/8” (0.3 cm) adapter

There is a accessory kit (1PK0602) available from Source 1, which has

the following items:

• 12” (30 cm) length x 1/8” (0.3 cm) diameter tubing

• 2 – pieces of 4” (10 cm) length x 1/8” (0.3 cm) diameter tubing

• 1 - 5/16” (0.8 cm) tee

• 1 – 5/16” (0.8 cm) x 1/8” (0.3 cm) reducing coupling

• 1 – 1/8” (0.3 cm) adapter

• 1 - Dwyer – Manometer

These items are required in order to properly perform the required star-

tup procedure.

IGNITION SYSTEM SEQUENCE

1. Turn the gas supply ON at external valve and main gas valve.

2. Set the thermostat above room temperature to call for heat.

3. System start-up will occur as follows:

a. The induced draft blower motor will start and come up to

speed. Shortly after inducer start-up, the hot surface igniter

will glow for about 17 seconds.

b. After this warm up, the ignition module will energize (open)

the main gas valve.

c. After flame is established, the supply air blower will start in

about 30 seconds.

IMPORTANT: Burner ignition may not be satisfactory on first startup

due to residual air in the gas line or until gas manifold pressure is

adjusted. The ignition control will make 3 attempts to light before lock-

ing out.

With furnace in operation, check all of the pipe joints, gas valve connec-

tions and manual valve connections for leakage using an approved gas

detector, a non-corrosive leak detection fluid, or other leak detection

methods. Take appropriate steps to stop any leak. If a leak persists,

replace the component.

The furnace and its equipment shutoff valve must be disconnected from

the gas supply piping system during any pressure testing of that system

at test pressures in excess of 1/2 PSI (3.45 kPa).

The furnace must be isolated from the gas supply piping system by

closing the equipment shutoff valve during any pressure testing of the

gas supply piping system.

CALCULATING THE FURNACE INPUT

(NATURAL GAS)

NOTE: Burner orifices are sized to provide proper input rate using natu-

ral gas with a heating value of 1050 BTU/Ft3(39.12 MJ/m3). If

the heating value of your gas is significantly different, it may be

necessary to replace the orifices.

NOTE: Front door of burner box must be secured when checking gas

input.

1. Turn off all other gas appliances connected to the gas meter.

2. At the gas meter, measure the time (with a stop watch) it takes to

use 2 cubic ft. (0.0566 m3.) of gas.

3. Calculate the furnace input by using one of the following equa-

tions.

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 the detection of leaks

to check all connections. A fire or explosion may result causing

property damage, personal injury or loss of life.

035-19670-003 Rev. A (1004)

18 Unitary Products Group

In the USA use the following formula to calculate the furnace input.

For natural gas multiply the heat content of the gas BTU/SCF (or Default 1030 BTU/SCF (38.4 MJ/m3), times 2 cubic ft. (0.056 m) of gas measured

at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time (In seconds) it took to

measure 2 cubic ft. (0.056 m) of gas from the gas meter.

For propane (LP) gas multiply the heat content of the gas BTU/SCF (or Default 2500 BTU/SCF (93.15 MJm3), times 1 cubic ft. (0.028 m) of gas mea-

sured at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time (In seconds) it

took to measure 1 cubic ft. (0.028 m) of gas from the gas meter.

The formula for US input calculation using a cubic foot gas meter:

In Canada you will use the following formula to calculate the furnace input if you are using a cubic foot gas meter.

For Natural Gas multiply the Heat content of the gas MJ/m3(or Default 39.2), times 2 cubic ft. of gas x 0.02831 to convert from cubic feet to cubic

meters measured at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time it

took to measure 2 cubic ft. (0.056 m) of gas from the gas meter.

For Propane (LP) Gas multiply the Heat content of the gas MJ/m3(or Default 93.14), times 1 cu. ft. of gas x 0.02831 to convert from cubic feet to

cubic meters measured at the gas meter, times a barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the

time it took to measure 1 cubic ft. (0.028 m) of gas from the gas meter.

The formula for metric input calculation using a cubic foot gas meter:

In Canada use the following formula to calculate the furnace input if you are using a gas meter that measures cubic meters.

For Natural Gas multiply the Heat content of the gas MJ/m3(or Default 39.2), times 0.0566 m3of gas measured at the gas meter, times a barometric

pressure and temperature correction factor of 0.960; times 3600, then divided by the time it took to measure 2 cubic ft. (0.0566 m3) of gas from the

gas meter.

For Propane (LP) Gas multiply the Heat content of the gas MJ/m3(or Default 93.14), times 0.00283 m3of gas measured at the gas meter, times a

barometric pressure and temperature correction factor of 0.960; times 3600, then divided by the time it took to measure 1 cubic ft. (0.0283 cm) of gas

from the gas meter.

The formula for metric input calculation using a cubic foot gas meter:

DO NOT ADJUST the manifold pressure regulator if the actual input is equal to or within 8% less than the furnace input specified on the rating plate

or if the furnace rise is above the specified rise range on the rating plate.

If the actual input is significantly higher than the furnace input specified on the rating plate then replace the gas orifice spuds with the gas ori-

fice spuds of the proper size for the type of gas you are using.

For altitudes above 2,000 ft. (610 m) the furnace input MUST BE DERATED. Refer to the GAS CONVERSION FOR PROPANE (LP) AND HIGH

ALTITUDES IN SECTION IV for information on high altitude conversions.

BTU/f3x 2 cu.ft. x 0.960 x 3600 =BTU/H BTU/f3x 2 cu.ft. x 0.960 x 3600 =BTU/H

Seconds it took to measure the 2 cu.ft. of gas Seconds it took to measure the 2 cu.ft. of gas

NATURAL GAS INPUT CALCULATION PROPANE (LP) GAS INPUT CALCULATION

EXAMPLE: EXAMPLE:

1030 x 2 x 0.960 x 3600 = 79,997.38 2500 x 1 x 0.960 x 3600 = 80,000.00

90.5 108

Natural Gas Propane Gas

BTU/SCF 1030 BTU/SCF 2500

MJ/m3x (2 cu.ft. x 0.028) x 0.960 x 3600 = MJ/H x 0.2777 = kW x 3412.14 = BTU/H

Seconds it took to measure the 2 cu.ft. of gas

NATURAL GAS INPUT CALCULATION

EXAMPLE:

39.2 x (2 x 0.028) x 0.960 x 3600 = 84.83 x 0.2777 = 23.28 x 3412.14 = 79,433

90.5

Natural Gas

BTU/SCF 1030 = 39.2 MJ/m3

PROPANE (LP) GAS INPUT CALCULATION

EXAMPLE:

93.15 x (1 x 0.028) x 0.960 x 3600 = 84.41 x 0.2777 = 23.45 x 3412.14 = 80,000.00

108

Propane Gas

BTU/SCF 2500 = 93.15 MJ/m3

MJ/m3x m3 x 0.960 x 3600 = MJ/H x 0.2777 = kW x 3412.14 = BTU/H

Seconds it took to measure the 2 cu.ft. of gas

NATURAL GAS INPUT CALCULATION

EXAMPLE:

39.2 x 0.1 x 0.960 x 3600 = 84.67 x 0.2777 = 23.51 x 3412.14 = 80,231

160

Natural Gas

BTU/SCF 1030 = 39.2 MJ/m3

PROPANE (LP) GAS INPUT CALCULATION

EXAMPLE:

93.15 x 0.028 x 0.960 x 3600 = 84.48 x 0.2777 = 23.18 x 3412.14 = 79,107

107.97

Propane Gas

BTU/SCF 2500 = 93.15 MJ/m3

035-19670-003 Rev. A (1004)

Unitary Products Group 19

IMPORTANT: The inlet gas pressure operating range table specifies

what the minimum and maximum gas line pressures must be for the fur-

nace to operate safely. The gas line pressure MUST BE

• 7” W.C. (1.74 kPA) for Natural Gas

• 11” W.C. (2.74 kPA) for Propane (LP) Gas

in order to obtain the BTU input specified on the rating plate and/or the

nominal manifold pressure specified in these instructions and on the

rating plate.

ADJUSTMENT OF MANIFOLD GAS PRESSURE

Manifold gas pressure may be measured by connecting the “U” tube

manometer to the gas valve with a piece of tubing and on an adapter.

Follow the appropriate section in the instructions below. Refer to Figure

29 for a drawing of the locations of the pressure ports on the gas valve.

Turn gas off at the ball valve or gas cock on gas supply line

before the gas valve. Find the pressure ports on the gas

valve marked Out Pressure Tap and Inlet Pressure Tap.

1. The manifold pressure must be taken at the port marked OUT

Pressure Tap.

2. The gas line pressure must be taken at the port marked Inlet Pres-

sure Tap.

Using a screw driver, remove the cap that covers the manifold pressure

set screw.

Read the inlet gas pressure

Connect the positive side of the manometer to the adapter previously

installed in the Out pressure Tap on the gas valve. Do not connect any

tubing to the negative side of the manometer, as it will reference atmo-

spheric pressure. Refer to Figure 30 for connection details.

IMPORTANT: The cap for the pressure regulator must be removed

entirely to gain access to the adjustment screw. Loosening or tightening

the cap does not adjust the flow of gas.

NOTE: The regulated outlet pressures, both low and high, have been

calibrated at the factory. Additional pressure adjustment should

not be necessary. If adjustment is necessary, set to the following

specifications. After adjustment, check for gas leakage.

High Outlet Pressure Adjustment

1. Turn off all electrical power to the system at main fuse or circuit

breaker.

2. Attach a manometer to the outlet pressure tap of the valve.

3. Turn on power and energize main and redundant (P.M.) solenoids

as well as the HI terminal.

4. Remove high adjustment seal screw to expose the 3/32”. See Fig-

ure 29.

5. To increase outlet pressure, turn the 3/32” set screw clockwise. To

decrease outlet pressure, turn the set screw counterclockwise.

Adjust regulator until pressure shown on manometer matches the

pressure specified on the appliance rating plate.

6. Replace low adjustment seal screw and tighten securely. Cycle the

valve several times to verify regulator setting.

7. Remove manometer and replace the outlet pressure tap plug.

Low Outlet Pressure Adjustment

1. Turn off all electrical power to the system at main fuse or circuit

breaker.

2. Attach a manometer to the outlet pressure tap of the valve.

3. Turn on power and energize main and redundant (P.M.) solenoids.

Do not energize HI terminal.

4. Remove low adjustment seal screw. See Figure 29.

5. To increase outlet pressure, turn the 3/32” (0.24 cm) set screw

below the low adjustment seal screw clockwise. To decrease outlet

pressure, turn the set screw counterclockwise. Adjust regulator

until pressure shown on manometer matches the pressure speci-

fied on the appliance rating plate.

6. Replace high adjustment seal screw and tighten securely. Cycle

the valve two and three times to verify regulator setting.

7. Remove manometer and replace the outlet pressure tap.

IMPORTANT: If gas valve regulator is turned in (clockwise), manifold

pressure is increased. If screw is turned out (counterclockwise), mani-

fold pressure will decrease.

8. After the manifold pressure has been adjusted, re-calculate the

furnace input to make sure you have not exceeded the specified

input on the rating plate. Refer to “CALCULATING THE FURNACE

INPUT (NATURAL GAS)”.

9. Once the correct BTU (kW) input has been established, turn the

gas valve to OFF and turn the electrical supply switch to OFF; then

remove the flexible tubing and fittings from the gas valve pressure

tap and re-install the plug in the Out Pressure Port using a com-

pound (on the threads) resistant to the action of LP gases.

Replace the burner box front cover (if it was removed) and replace

the pressure reference hose.

10. Turn the electrical and gas supplies back on, and with the burners

in operation, check for gas leakage around the gas valve pressure

port for leakage using an approved non-corrosive gas leak detec-

tion fluid, or other non-flammable leak detection methods.

Be sure to relight any gas appliances that were turned off at the

start of this input check.

TABLE 14:

Inlet Gas Pressure Range

INLET GAS PRESSURE RANGE

Natural Gas Propane (LP)

Minimum 4.5” W.C. (1.12 kPa) 8.0” W.C. (1.99 kPa)

Maximum 10.5” W.C. (2.61 kPa) 13.0” (3.24 kPa) W.C.

TABLE 15:

Nominal Manifold Pressure

NOMINAL MANIFOLD PRESSURE

Natural Gas (High Fire) 3.5" w.c. (0.87 kPa)

Natural Gas (Low Fire) 1.6" w.c. (0.40 kPa)

Propane (LP) Gas (High Fire) 10.0" w.c. (2.488 kPa)

Propane (LP) Gas (Low Fire) 4.0" w.c. (0.99 kPa)

FIGURE 27: Gas Valve

INLET OUTLET

ON / OFF SWITCH

WRENCH

BOSS

LOW FIRE

REGULATOR

ADJUSTMENT

SEAL SCREW

HIGH FIRE

REGULATOR

ADJUSTMENT

SEAL SCREW

HI ADJUST

LO ADJUST

035-19670-003 Rev. A (1004)

20 Unitary Products Group

DIRECT DRIVE MOTORS

Adjustment of Fan-Off Control Settings

This furnace is equipped with a time-on/time-off heating fan control. The

fan-on is fixed at 30 seconds. The fan-off delay is factory set to 60 sec-

onds; however, it is field-adjustable to 90, 120 or 180 seconds. The fan-

off setting must be long enough to adequately cool the furnace, but not

so long that cold air is blown into the heated space.

Adjustment of Fan Control Settings

This furnace is equipped with a time-on/time-off heating fan control. The

fan on delay is fixed at 30 seconds. The fan off delay has 4 settings (60,

90, 120 and 180 seconds). The fan off delay is factory set to 120 sec-

onds. The fan-off setting must be long enough to adequately cool the

furnace, but not so long that cold air is blown into the heated space. The

fan-off timing may be adjusted by positioning the jumper on two of the

four pins as shown in Figure 26.

Heating Indoor Fan Off Delay

The jumper pins are located on the main control board. Refer to Figure

30 for the jumper settings to obtain the desired fan OFF delay. The

blower off delay must be long enough to adequately cool the furnace,

but not so long that cold air is blown into the living space.

The blower on delay is fixed at 30 seconds and can not be adjusted.

Continuous Blower Operation

The blower will run continuously whenever the wall thermostat fan

switch is in the "ON" position. The furnace blower will run at the speed

selected on the "FAN SPEED" jumpers on the main control board (HI

COOL, LO COOL, HI HEAT or LO HEAT).

Intermittent Blower Cooling

On cooling/ heating thermostats with a fan switch, when the fan switch

is set in the auto position and the thermostat calls for cooling, a circuit is

completed between the R, Y and G terminals. The motor is energized

through the Y1 cool terminal and runs on the speed selected on the

board. The fan off setting is fixed at 60 seconds for maximum cooling

efficiency furnace control.

Intermittent Blower Heating

On cooling/ heating thermostats with a fan switch, when the fan switch

is set in the auto position and the thermostat calls for heating, a circuit is

completed between the R and W terminals. The indoor fan motor is

energized through the W1 heat terminal and runs on the speed selected

on the furnace control board.

ADJUSTMENT OF TEMPERATURE RISE

The temperature rise, or temperature difference between the return air

and the heated supply air from the furnace, must be within the range

shown on the furnace rating plate and within the application limitations

The manifold pressure must be checked with the screw-off cap for

the gas valve pressure regulator in place. If not, the manifold pres-

sure setting could result in an over-fire condition. A high manifold

pressure will cause an over-fire condition, which could cause pre-

mature heat exchanger failure. If the manifold pressure is too low,

sooting and eventual clogging of the heat exchanger could occur.

Be sure that gas valve regulator cap is in place and burner box to

gas valve pressure reference hose is connected.

MAINFOLD PRESSURE “U” TUBE CONNECTION

FIGURE 28: Reading Gas Pressure

Do not energize more than one motor speed at a time or damage to

the motor will result.

U-TUBE

MANOMETER

3.5 IN

WATER

COLUMN

GAS

PRESSURE

SHOWN

GAS

BURNERS

OUTLET

PRESSURE TAP

GAS VALVE

FLAME

SENSOR

1/4” TUBING

MAINIFOLD

PIPE

FIGURE 29: Furnace Control Board

The temperature rise, or temperature difference between the return

air and the supply (heated) air from the furnace, must be within the

range shown on the furnace rating plate and within the application

limitations shown in Table 8 “ELECTRICAL AND PERFORMANCE

DATA”.

The supply air temperature cannot exceed the “Maximum Supply

Air Temperature” specified in these instructions and on the fur-

nace rating plate. Under NO circumstances can the furnace be

allowed to operate above the Maximum Supply Air Temperature.

Operating the furnace above the Maximum Supply Air Temperature

will cause premature heat exchanger failure, high levels of Carbon

Monoxide, a fire hazard, personal injury, property damage, and/or

death.

Y1 Y2

W2 RGC

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