HP 422690 I User Manual

HIGH-EFFICIENCY UPFLOW FURNACE

INSTALLER'S INFORMATION MANUAL

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ATTENTION, INSTALLER! After installing the

furnace, show the user how to turn off gas and electricity to
the furnace. Point out control and switch locations for
turning off gas and electricity. Go over the User’s
Information Manual and Section 23, “Maintaining Fu rnace
In Good Working Order" in this manual with the user. Make
sure the user understands the importance of following all
safety precautions , including what could happen if they do
not.

Attach the following documents to or adjacent to the
furnace. Tell the user where these documents are located.

• User's Information Manual

• Installer's Information Manual

• Parts List

• Warranty Informat ion
While these instructions have been written as accurately

and thoroughly as possible, they can not cover every
system variation or contingency. Questions of
interpretation may arise. For more information, solutions to
particular problems or clarification, contact your local
distributor or the manufacturer.

ATTENTION, USER! Your furnace installer should

give you the documents listed on opposite side. You
should immediately read the User’s Information Manual for
important safety information to keep you and your family
safe. Keep these as long as you keep your furnace. Pass
them on to future furnace purchasers or users. If any of the
documents are missing or illegible, contact your installer or
furnace manufacturer for replacement. Throughout this
manual, when we use the word "you" we refer to the
qualified service technician who is responsible for
application, installation and service of your furnace.

?? Do not store or use gasoline or other flammable vapors

and liquids in the vicinity of this or any other appliance.

?? WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electrical switch.

• Do not use any phone in your building.

• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's inst ructions.

• If you cannot reach gas supplier, call the fire
department.

WARNING: Individuals who install this fu rnace, must have the training and experience necessary to install gas
furnaces. They must also have training and experience necessary to install related comfort air conditioning appliances.
Improper installation could create a hazard, resulting in the possibility of damage, injury or death.

422690 I

TABLE OF CONTENTS

SECTION 1. IMPORTANT SAFETY RULES ............................................................................................................. 2

SECTION 2. MEETING CODES .............................................................................................................................. 3

SECTION 3. DETERMINING BEST FURNACE LOCATION...................................................................................... 3

SECTION 4. PROVIDING VENTIN G AND COMBUSTION AIR.................................................................................. 5

SECTION 5. CONDENSATE DRAIN.......................................................................................................................14

SECTION 6. INSTALLIN G GAS PIPING ..................................................................................................................14

SECTION 7. INSTALLING ELECTRICAL WIRING...................................................................................................15

SECTION 8. SEQUENCE OF OPERATION ............................................................................................................17

SECTION 9. INSTALLIN G DUCT SYSTEM.............................................................................................................18

SECTION 10. SELECTIN G AND INSTALLING FILTER CABINETS ..........................................................................18

SECTION 11. CHECKS BEFORE STARTING FURNACE ........................................................................................20

SECTION 12. GAS SUPPLY PRESSURE AND PILOT ADJUSTMENT .....................................................................20

SECTION 13. MANIFOLD PRESSURE ADJUSTMENT...........................................................................................21

SECTION 14. CHECKING GAS INPUT RATE .........................................................................................................21

SECTION 15. DERATING FOR HIGH ALTITUDE ....................................................................................................22

SECTION 16. DETERMINING CORRECT ORIFICE SIZE ........................................................................................22

SECTION 17. CHANGING MAIN BURNER ORIFICES ............................................................................................23

SECTION 18. ADJUSTIN G BLOWER SPEED.........................................................................................................24

SECTION 19. MEASURING DUCT SYSTEM STATIC PRESSURE ..........................................................................24

SECTION 20. MEASURING AIR TEMPERATURE RISE ..........................................................................................25

SECTION 21. CHECKING CONTROLS ..................................................................................................................25

SECTION 22. SETTING BLOWER TIMINGS ...........................................................................................................26

SECTION 23. MAINTAINING FURNACE IN GOOD WORKING ORDER...................................................................26

SECTION 24. ACCESSORIES .............................................................................................................................27

SECTION 25. OTHER INFORMATION AND PUBLICATIONS ..................................................................................27

SECTION 1. IMPORTANT SAFETY
RULES

To alert you to potential hazards, we use the signal words
"WARNING" and "CAUTION" throughout this manual.
"WARNING" alerts you to situations that could cause or
result in serious injury or death. "CAUTION" alerts you to
situations that could cause or result in minor or moderate
injury or property damage. For a safe and reliable
installation be sure to read and follow all warnings and
cautions.

We also use the words "must" and "should" in this manual.
"Must" is mandatory. "Should" is advisory.

WARNING: Read and follow the safety rules in
this section and throughout this manual. Failure to do so
could cause improper furnace operation, resulting in

damage, injury or death.

Rule 1. Use only gas approved for use in this fu rnace, as
indicated on fu rnace rating plate. Use only natural gas in
furnaces designed for natural gas. Use only propane (LP)
gas in furnaces designed for propane (LP) gas. Make sure
furnace will operate properly on the gas type available to
user. Do not use butane gas in this furnace.

WARNING: Use of a non-approved gas (such as
butane) in this furnace could cause sooting or overheating
of heat exchanger.

Rule 2. Do not install this fu rnace outdoors or in a mobile
home, trailer or recreational vehicle. It is not design
certified for these installations. This furnace is suitable for
a home built on site or a manufactured home completed at

the final site.
Rule 3. Air for combustion must not come from a corrosive

or contaminated atmosphere. Make sure all combustion
and ventilation air requirements are adhered to in addition
to local codes and ordinances.

Rule 4. This furnace is not to be used for temporary
heating of buildings or structures under construction.

Rule 5. Provide adequate combustion and ventilation air to
space where furnace is being installed unless combustion
air is provided directly through an inlet air pipe. Connect
this furnace to an approved vent system--venting
combustion products outdoors.

Rule 6. Check for gas leaks anytime work is done on gas
supply line, fu rnace gas control, pilot and pilot line or main
burner manifold.

Rule 7. Never test for gas leaks with an open flame. Use a
commercial soap solution made specifically for leak
detection to check all connections.

Page 2 Installer’s Information Manual

Rule 8. Completely seal supply and return air ducts to
furnace casing. Duct system must run to an area outside
furnace room or closet. Seal duct work wherever it runs
through walls, ceilings or floors of furnace room or closet.

SECTION 2. MEETING CODES

This furnace complies with American National Standard
and National Standard of Canada for Gas Fired Central
Furnaces, ANSI Z21.47 ? CAN/CGA-2.3. It is certified for
operation with either natural gas or propane (LP) gas for
indoor installation in a building constructed on site. It meets
the requirement for a 100% shut -off gas control system.

Provide ample space for servicing and cleaning. Location
must allow 30 inches minimum front clearance for service.

WARNING : Some insulating materials are
combustible. When a furnace is installed in an attic or other
insulated space, keep all insulating materials at least 12
inches away from furnace and combustion air inlet. Failure

to do so could cause a fire.

You may install fu rnace on non-combustible flooring or on
wood flooring.

Before installing this furnace, make sure you know all
applicable codes. Be sure to consult local authorities
having jurisdiction over furnaces for information on
electrical wiring, gas piping and venting. The installation of
this furnace must conform with local building codes or in the
absence of local codes, with ANSI Z223.1, National Fuel
Gas Code or CAN/CGA B149, Canadian Installation Codes.

Electrical wiring must conform with local building codes or
in the absence of local codes, with the current National
Electrical Code, ANSI/NFPA 70 or current Canadian
Electrical Code, CSA C22.1.

SECTION 3. DETERMINING BEST
FURNACE LOCATION

You may install this upflow furnace in an alcove, attic,
basement, closet, garage or utility room. Do not install
furnace in an area subject to freezing temperatures.

This furnace operates best when return-air temperature is
between 55°F and 80°F. Do not install furnace in a location
subject to continuous higher or lower temperatures.
Continuous operation outside of this range may shorten
furnace life.

WARNING : Do not install furnace in any other
position other than upflow. Doing so could cause heat
exchanger blockage and damage to heat exchanger.

Select a location that meets all requirements described in
this manual for the following:

?? Safety
?? Minimum Clearances
?? Combustion and Ventilation Air
?? Venting
?? Duct System
?? Gas Piping
?? Electrical Wiring

Locate fu rnace as near to the center of the air distribution
system as possible.

WARNING : Do not install furnace on carpeting,
tile or other combustible material except wood flooring.

Doing so could cause a fire.

Install fu rnace so all electrical components are protected
from water.

Level fu rnace from front to back and from left to right within
1/4 inch. Furnace must be installed level for proper
condensate drainage. Furnace will not operate if
condensate does not drain.

When fu rnace is located within the heated space, exhaust
fans can adversely affect its operation. Exhaust fans in
kitchen, bathrooms, clothes dryers or anywhere within
heated space, increase combustion air requirements of
non-direct vented fu rnaces. This is because exhaust fans
reduce the amount of combustion air available to the
furnace. A fireplace also reduces amount of combustion
air.

Sufficient air must be provided to ensure there will not be a
negative pressure in fu rnace room or space. In addition,
there must be a positive seal between fu rnace and return
air duct to avoid pulling air from burner area.

When a cooling unit is installed with this furnace, the
furnace must be installed parallel with or on the upstream
side of the cooling unit to avoid condensation in fu rnace
heat exchanger. With a parallel flow arrangement, the
dampers or other means used to control flow of air must be
adequate to prevent chilled air from entering the fu rnace
and, if manually operated, must be provided with a means
to prevent operation of either unit unless damper is in the

full heat or cool position.
When furnace is in a residential garage, it must be installed

so that pilot and main burners are located no less than 18
inches above the floor. Also, fu rnace should be protected
from physical damage by vehicles.

When fu rnace is in a public garage, airplane hanger, or
other building having hazardous atmosphere, install unit in
accordance with recommended good practice requirements
of the National Fire Protection Association, Inc. Consult

local code authorities for additional location requirement s.
See Figure 1 for furnace dimensions and clearances.

Installer’s Information Manual Page 3

GAS

INPUT*

(Btu/hr) (HP) “A” “B” “C” TOP SIDES BACK FRONT VENT (INCHES)

54,000 1/3 17 1/2 15 3/4” 15 15/16” 1 0 0 2 0 2
72,000 1/2 17 1/2 15 3/4” 15 15/16” 1 0 0 2 0 2 OR 3
72,000 3/4 20 1/2 18 3/4” 18 15/16” 1 0 0 2 0 2 OR 3
90,000 1/2 17 1/2 15 3/4” 15 15/16” 1 0 0 2 0 2 OR 3

90,000 3/4 20 1/2 18 3/4” 18 15/16” 1 0 0 2 0 2 OR 3
108,000 3/4 23 1/2 21 3/4” 21 15/16” 1 0 0 2 0 3
126,000 3/4 23 1/2 21 3/4” 21 15/16” 1 0 0 2 0 3

* See Furnace Rating Plate located on blower door.
** These are furnace dimensions. See Sections 9 and 10 for proper ductwork and floor opening dimensions.
*** Certified for installation on wood flooring. 30-inch front clearance required for service. 18-inch front clearance required in an alcove.

MOTOR

SIZE*

FURNACE

WIDTH**

RETURN AIR

SIZE**

SUPPLY AIR

SIZE**

CLEARANCE TO COMBUSTIBLES***

(INCHES)

VENT SIZE

Figure 1. Furnace Dimensions and Clearances.

Page 4 Installer’s Information Manual

SECTION 4. PROVIDING VENTING
AND COMBUSTION AIR

This furnace must be connected to a plastic venting system
adequate to remove flue gases to the outside atmosphere.
It must be vented in accordance with these instructions and
local building codes.

The fu rnaces covered by this manual are design-certified
as Category IV appliances. Category IV appliances operate
with a positive vent static pressure and with a flue gas
temperature that will produce significant condensate in the
vent. The vent system for this furnace must be installed so
as to prevent leakage of flue gases into the building. This
furnace may be installed using either direct venting or non­direct venting.

WARNING : Do not connect this furnace to a vent
system shared by any other appliance. Do not connect it to
any other type of vent system other than described by these
instructions. Improper venting could allow combustion
products to collect in building during use resulting in nausea

or death by asphyxiation.

GENERAL VENTING GUIDELINES

?? Vent system and combustion air supply components

must be constructed of schedule 40 PVC, PVC -DWV,
SDR26, SDR 21 or ABS plastic pipe, fittings, sealants,
and installation procedures that conform to the
following ANSI/ASTM standards:

PVC ASTM D-1785
SDR26, SDR21 ASTM D-2241
PVC-DWV ASTM D-2665
PVC-DWV Cellular Core ASTM F-891
PVC Primer And Solvent Cement ASTM D-2564
ABS Pipe And Fittings ASTM D-2235
Procedure For Cementing Joints ASTM D-2855

?? All condensate formed in the vent must run back

toward fu rnace for proper drainage. Install vent pipe
with no less than a 1/4 inch per foot slope from furnace
to vent terminal.

?? Install vent pipe without dips or sags that may hold

water. Support horizontal portions of vent pipe every 5
feet (3 feet for SDR-21 or SDR-26 pipe).

?? Some models are shipped with a 3-inch to 2-inch

reducer bushing. When venting with two-inch pipe,
install reducer bushing in flue outlet fitting.

Figure 2. Vent Connection to Furnace.

PVC PIPE INSTALLATION INSTRUCTIONS

1. Cut ends of pipe square using a miter box, power saw
or PVC tubing cutter. Put a 10 to 15 degree chamfer
on end of pipe. Remove any burrs, dirt, grease, and
moisture. Check joint for proper fit.

2. Freely coat outside end of pipe and inside of fitting
socket with cleaner-primer. The purpose of the primer
is to dissolve and penetrate the surface of the pipe.

Several coats may be necessary to do this.

3. While primer is still wet, apply a heavy coat of solvent
cement to outside of pipe. Next, using outward strokes
to keep excess cement out of socket, apply a generous
coat of cement to the inside of socket.

4. While both surfaces are still wet with cement, insert
pipe into fitting socket until it bottoms out, using a slight
twisting motion (1/4 turn). Hold pipe in socket 30

seconds to allow cement to set.

5. Allow joint to cure before handling.

Caution: Keep solvent cement container sealed when not
in use. Do not use solvent cement that has thickened or is
gel-like.

WARNING : PVC cements are highly flammable.
Do not use near open flames. A fire or explosion could
result. Avoid prolonged breathing or contact with skin or

eyes.

?? Protect vent from freezing. Long runs of vent pipe

installed in an unconditioned space may require
insulation to prevent freezing of condensate.

?? Furnace can be vented from either left or right side.

See Figure 2. As shipped, furnace is setup for venting
through the left side. Right side venting is
accomplished by rotating flue outlet fitting and adding a
street elbow to the drain fitting. Street elbow and
instructions are supplied in the furnace parts package.

Installer’s Information Manual Page 5

TERMINATION LOCATION AND CLEARANCES

Vent pipe and combustion-air-supply pipe (when direct
vented) may terminate through a roof or through a sidewall.
Roof termination has the advantages of better pipe
protection and fewer condensate -damage concerns. Use

the following guidelines when choosing a vent location:
?? Flue gases can be corrosive. When sidewall venting,

protect walls with a corrosion resistant material. Also,
terminate away from plants and shrubs.

?? Locate termination consistent with the National Fuel

Gas Code, ANSI Z223.1/NFPA 54 or the CAN/CGA
B149 Installation Codes.

?? Locate termination away from other air intake or

exhaust vents such as dryer vents, other gas appli ance
vents, or plumbing vents. Allow at least 3 foot to any

other vent.

?? Terminal must not be located above a walkway,

driveway or within 10 feet of an adjacent building.

?? Do not locate termination underneath a veranda,

porch, or deck.

IN THE UNITED STATES:

?? Allow a minimum clearance of 4 feet from electric

meters, gas meters, regulators, and relief equipment.

?? When non-direct venting, terminal must be at least 4

feet below, or 4 feet horizontally from or one foot above
any door, window or gravity air inlet into a building.
Terminal must also be at least 3 feet above any forced­air inlet located within 10 feet horizontally.

?? When direct venting, vent terminal must be at least one

foot from any opening through which flue gases could
enter a building.

IN CANADA:

?? Allow 6 feet clearance to any mechanical air supply or

service regulator vent and 6 feet horizontally to any gas
meter, electric meter, or relief device.

?? Do not terminate above a meter/regulator assembly

within 3 feet horizontally of the vertical center line of
the regulator

?? Do not terminate within one foot (3 feet for 108,000 and

126,000 Btu models) of a window or door that can be
opened, a non-mechanical-air-supply inlet, or the
combustion-air inlet of any other appliance

EXISTING VENT CONSIDERATIONS

When a Category I fu rnace is removed or replaced, the old
venting system may not be properly sized to vent the
remaining appliance(s), for example, a gas water heater.
An improperly sized venting system may promote the

formation of condensate, leakage or spillage.

The following steps shall be followed with each appliance
connected to the old venting system placed in operation,
while any other appliances connected to the venting system
are not in operation:

1. Seal any unused openings in the venting system;

2. Inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 or the CAN/CGA B149
Installation Codes. Determine that there is no
blockage or restriction, leakage, corrosion and other

deficiencies which could cause an unsafe condition;

3. In so far as is practical, close all building doors and
windows and all doors between space in which
appliance(s) connected to the venting system are
located and other spaces of building.

4. Close fireplace damp ers.

5. Turn on clothes dryers and any appliance not
connected to the venting system. Turn on any exhaust
fans, such as range hoods and bathroom exhausts, so
they shall operate at maximum speed. Do not operate
a summer exhaust fan.

6. Follow the lighting instructions. Place the appliance
being inspected in operation. Adjust thermostat so
appliance shall operate continuously;

7. Test for drafthood equipped appliance spillage at the
drafthood relief opening after 5 minutes of main burner

operation. Use the flame of a match or candle;

8. After it has been determined that each appliance
connected to the venting system properly vents when
tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas ­burning appliance to their previous conditions of use;

9. If improper venting is observed during any of the above
tests, the venting system must be corrected. Follow
the National Fuel Gas Code, ANSI Z223.1/NFPA 54 or
CAN/CGA B149 Installation Codes to correct improper
vent operation. Any "common vent" re-sizing must
approach minimum size determined using current
venting tables.

DIRECT OR NON-DIRECT VENTING?

This furnace may be installed using either direct venting or
non-direct venting.

A direct-vented fu rnace takes all air for combustion directly
into the fu rnace through a pipe from outdoors. To direct
vent this furnace you must install two pipes to the outdoors.
One pipe supplies combustion air that the furnace needs to
operate. The other pipe vents flue gases to the outdoors.

Use direct venting when indoor air may be contaminated
with chemicals such as chlorine, fluorine, bromine or iodine.
When these chemicals are burned with natural gas or
propane gas, acids are produced that may decrease heat
exchanger life. You should also consider direct venting
when furnace is installed in a space with limited combustion
and ventilation air. See “CONFINED SPACE

Page 6 Installer’s Information Manual

INSTALLATION” under the “NON-DIRECT VENTING”
instructions.

A non-direct vented furnace takes all air for combustion
from the room in which fu rnace is installed. Non-direct
venting requires only one pipe for venting the flue gases to
the outdoors but you must make sure there is enough air for
combustion and ventilation.

DIRECT VENTING INSTRUCTIONS (two
pipe system)

DETERMINING VENT LENGTH

See Table 1 for maximum vent and combustion-air pipe
length. Include any termination elbows when determining
maximum allowable vent length. Minimum vent length is
five feet with 0 elbows.

Table 1 shows the maximum allowable pipe lengths for
direct vent systems depending on:

?? altitude (elevation) of the installation
?? gas input rating of furnace
?? diameter of the air and vent pipes
?? number of elbows

Note that some of the larger furnace models may require a
high altitude pressure switch at elevations between 3000
and 6000 feet. For example, the table shows that the
126,000 Btu/hr model may need a high altitude pressure
switch when installed at elevations between 3000 and 4000
feet. Above 4000 feet, this model requires a high altitude
switch for all installations.

All furnace models require the high altitude pressure switch
when installed at elevations above 6000 feet.

The high-altitude pressure switch is supplied with the LP
Conversion Kit #4226000 and the Natural Gas Conversion
Kit #4225600. These kits also contain the other
components required for furnace installation at high
elevations.

NOTE: Table 1 assumes Sweep 90? elbows like that in
Figure 3a. If using Hard 90? elbows similar to the one in

Figure 3b, decrease the vent length by 3 feet for every
elbow used.

(a) (b)
Figure 3. (a) Sweep 90? Elbow. (b) Hard 90? Elbow.

When using a concentric vent kit the following exceptions
apply:

?? 90,000 BTU input furnaces must be vented with 3-inch

pipe.

?? For 108,000 BTU input furnaces, reduce the maximum

vent length by 5 feet when 2 sweep elbows are used,
10 feet when 3 sweep elbows are used, 15 feet when 4
sweep elbows are used and so on. For hard 90°
elbows reduce vent length in 8-foot interv als.

?? 126,000 BTU input furnaces may not be vented using a

concentric vent.

Installer’s Information Manual Page 7

Table 1. Maximum Pipe Length--Direct Vent

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 40 40 37 33 30 27 23 20

72,000

3" 40 40 40 40 40 40 40 40 0'-1000' 90,000

2" 30 26 22 19 15 11 - -

90,000

3" 40 40 40 40 40 40 40 40

108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 40 40 40 40 35 30 25 20

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 40 37 33 29 25 21 19 15

72,000

3" 40 40 40 40 40 40 40 40 1001'-2000' 90,000

2" 25 22 19 16 12 - - -

90,000

3" 40 40 40 40 40 40 40 40

108,000

3" 40 40 40 40 40 40 40 40 126,000

3" 40 38 33 28 22 16 11 -

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 35 33 29 25 21 17 13 -

72,000

3" 40 40 40 40 40 40 40 40 2001'-3000' 90,000

2" 22 19 16 14 - - - -

90,000

3" 40 40 40 40 40 40 40 40 108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 35 30 25 20 15 10 - -

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 30 28 26 24 22 20 18 17

72,000

3" 40 40 40 40 40 40 40 40 3001'-4000' 90,000

2" 15 13 11 - - - - -

90,000

3" 40 40 40 40 40 40 40 40 108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 30 25 20 15 10 - - -

126,000

3" 40 40 40 40 35 30 25 20

See Note 2 below.

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 26 22 17 14 12 - - -

72,000

3" 40 40 40 40 40 40 40 40 4001'-5000' 9

0,000

3" 40 40 40 40 40 40 40 40

108,000

3" 40 40 40 35 30 25 20 15

108,000

3" 40 40 40 40 40 40 40 40

See Note 2 below.

126,000

3" 40 40 40 40 35 30 25 20

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 21 18 14 11 - - - -

72,000

3" 40 40 40 40 40 40 40 40 5001'-6000' 90,000

3" 40 40 40 40 40 40 40 40

108,000

3" 40 35 30 25 20 15 10 -

108,000

3" 40 40 40 40 40 40 40 40

See Note 2 below.

126,000

3" 40 40 40 40 35 30 25 20

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 40 40 40 40 36 32 28 24 72,000

3" 40 40 40 40 40 40 40 40 6001'-7000' 90,000

3" 40 40 40 40 40 40 40 40

See Note 2 below.

108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 40 40 40 40 35 30 25 20

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 40 40 40 37 35 32 28 24

72,000

3" 40 40 40 40 40 40 40 40 7001'-8000' 90,000

3" 40 40 40 40 40 40 40 40

See Note 2 below.

108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 40 40 40 40 35 30 25 20

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 40 40 37 34 31 28 24 21

72,000

3" 40 40 40 40 40 40 40 40 8001'-9000' 90,000

3" 40 40 40 40 40 40 40 40

See Note 2 below.

108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 40 40 40 35 30 25 20 15

54,000

2" 40 40 40 40 40 40 40 40

72,000

2" 40 37 35 31 27 24 21 18

72,000

3" 40 40 40 40 40 40 40 40 9001'-10000'

90,000

3" 40 40 40 40 40 40 40 40

See Note 2 below.

108,000

3" 40 40 40 40 40 40 40 40

126,000

3" 40 35 30 25 20 15 - -

ALLOWABLE PIPE LENGTH (feet of each pipe)

ALTITUDE FURNACE PIPE

NUMBER OF SWEEP ELBOWS (each pipe) (SEE NOTE 1)

INPUT DIA. 1 2 3 4 5 6 7 8

NOTE 1: The table assumes the use of sweep elbows. If using hard 90? elbows , the vent length should be decreased an

NOTE 2: The shaded portions of the table require the high altitude pressure switch in order to operate the furnace at the listed

Page 8 Installer’s Information Manual

additional 3 feet for every elbow used.

vent lengths.

DIRECT-VENT TERM INATION

You may terminate vent and combustion air pipes either
vertically (through the roof) or horizontally (through a side
wall). Vertical (through the roof) venting is preferred
because it offers protection from pipe damage and
condensate damage. You may use concentric vent
termination except on 126,000 BTU input furnaces. Follow
the instructions supplied with the concentric-vent kit.

For vertical direct venting, combustion air inlet pipe must
terminate next to vent pipe and 12 inches above roof (18” in
Canada) or highest expected snow accumulation. Extend
vent pipe at least 6 inches above combustion air inlet. See
Figure 4a for vertical direct vent termination.

Attach a combustion air pipe to combustion-air-inlet collar
on top of fu rnace. Use rubber coupling and hose clamps
supplied with furnace. See Figure 5.

Figure 5. Combustion Air Pipe Connection to Fu rnace for
Direct Vent.

NON-DIRECT VENTING INSTRUCTIONS
(one pipe system)

Figure 4a. Vertical Termination for Direct Venting.
Combus tion-air-inlet termination must always be pointed

downward to keep out rain and snow. Furnace will not
operate properly with water in combustion compartment.

Note: When properly installed, vent pipe is designed to
drain condensate and will not be affected by rainwater.

For horizontal direct venting, combustion air inlet must
terminate next to vent pipe and at least 12 inches above
grade or highest expected snow accumulation. Extend vent
pipe at least 12 inches above combustion air inlet. See
Figure 4b.

Figure 4b. Horizontal Termination for Direct Venting.

DETERMINING VENT LENGTH

See Table 2 for maximum vent pipe length. Include any
termination elbows when determining maximum allowable
vent length. Minimum pipe length is five feet with 0 elbows.

Table 2 shows the maximum allowable pipe length for non­direct vent systems depending on:

?? altitude (elevation) of the installation
?? gas input rating of furnace
?? diameter of the vent pipe
?? number of elbows

Note that some of the larger furnace models may require a
high altitude pressure switch at elevations between 3000
and 6000 feet. For example, the chart shows that the
126,000 Btu/hr model may need a high altitude pressure
switch when installed at elevations between 3000 and 4000
feet. Above 4000 feet, this model requires a high altitude
switch for all installations.

All furnace models require the high altitude pressure switch
when installed at elevations above 6000 feet.

The high-altitude pressure switch is supplied with the LP
Conversion Kit #4226000 and the Natural Gas Conversion
Kit #4225600. These kits also contain the other
components required for furnace installation at high
elevations.

NOTE: Table 2 assumes Sweep 90? elbows like that in
Figure 3a. If using Hard 90? elbows similar to the one in
Figure 3b, decrease the vent length by 3 feet for every
elbow used.

Installer’s Information Manual Page 9

Table 2. Maximum Pipe Length--Non-Direct Vent

54,000

2"

112 108 104 100 96 92 88 84 72,000

2" 55 51 47 43 39 35 31 27

72,000

3"

150 150 150 150 150 150 150 150 0'-

1000' 90,000

2" 36 32 28 24 20 16 - -

90,000

3"

150 150 150 145 140 135 130 125 108,000

3" 85 80 75 70 65 60 55 50

126,000

3" 62 57 52 47 42 37 32 27

54,000

2" 97 93 90 86 83 80 76 73

72,000

2" 44 40 36 33 30 26 23 19

72,000

3"

150 150 150 150 150 150 150 150

1001'-2000' 90,000

2" 30 26 23 19 16 - - -

90,000

3"

140 135 130 125 120 115 110 105 108,000

3" 75 70 65 60 55 50 45 40

126,000

3" 50 45 40 35 30 25 20 15

54,000

2" 84 81 78 74 71 67 64 61

72,000

2" 37 34 30 27 24 21 18 15

72,000

3"

150 150 150 150 150 150 150 150

2001'-3000' 90,00

0 2" 24 21 18 14 11 - - - 90,000

3"

125 120 115 110 105 100 95 90 108,000

3" 50 45 40 35 30 25 20 15

126,000

3" 40 35 30 25 20 15 - -

54,000

2" 71 68 64 61 58 55 51 48

72,000

2" 30 27 23 20 17 13

72,000

3"

150 150 150 150 150 150 150 150 3001'-4000' 90,000

2" 19 16 12 - - - - -

90,000

3"

100 95 90 85 80 75 70 65 108,000

3" 37 32 27 22 17 12 - -

126,000

3" 30 25 20 15 10 - - -

126,000

3" 62 57 52 47 42 37 32 27

See Note 2

54,000

2" 57 54 50 47 44 40 36 33

72,000

2" 25 22 19 16 12 - - -

72,000

3"

150 150 150 150 150 150 150 150

4001'-5000' 90,000

3" 85 80 75 70 65 60 55 50

108,000

3" 85 80 75 70 65 60 55 50

See Note 2

126,000

3" 62 57 52 47 42 37 32 27

54,000

2" 43 40 37 33 30 27 24 20

72,000

2" 21 18 14 11 - - - -

72,000

3"

150 150 150 150 150 150 150 150

5001'-6000' 90,000

3" 70 65 60 55 50 45 40 35

108,000

3" 85 80 75 70 65 60 55 50

See Note 2

126,000

3" 62 57 52 47 42 37 32 27

54,000

2"

110 106 104 100 96 92 88 84

72,000 2" 50 46 43 40 36 32 29 25 72,000

3"

150 150 150 150 150 150 150 150

6001'-7000' 90,000

3"

150 150 150 145 140 135 130 125 See Note 2

108,000

3" 85 80 75 70 65 60 55 50

126,000

3" 62 57 52 47 42 37 32 27

54,000

2" 97 93 90 86 83 80 76 73

72,000

2" 50 46 43 40 36 32 29 25

72,000

3"

150 150 150 150 150 150 150 150

7001'-8000' 90,000

3"

150 150 150 145 140 135 130 125 See Note 2

108,000

3" 85 80 75 70 65 60 55 50

126,000

3" 60 55 50 45 40 35 30 25

54,000

2" 84 81 78 74 71 67 64 61

72,000

2" 41 38 34 31 28 24 21 17

72,000

3"

150 150 150 150 150 150 150 150

8001'-9000' 90,000

3"

150 150 150 145 140 135 130 125 See Note 2

108,000

3" 70 65 60 55 50 45 40 35

126,000

3" 45 40 35 30 25 20 15

54,00

0 2" 71 68 64 61 58 55 51 48

72,000

2" 35 31 28 25 21 18 15 -

72,000

3"

150 150 150 150 150 150 150 150

9001'-10000'

90,000

3"

150 150 150 145 140 135 130 125 See Note 2

108,000

3" 55 50 45 40 35 30 25 20

126,000

3" 35 30 25 20 15 10 - -

ALLOWABLE PIPE LENGTH (feet)

ALTITUDE FURNACE PIPE

NUMBER OF SWEEP ELBOWS (SEE NOTE 1)

INPUT DIA. 1 2 3 4 5 6 7 8

NOTE 1: The table assumes the use of sweep elbows. If using hard 90? elbows, the vent length should be decreased an

additional 3 feet for every elbow used.

NOTE 2: The shaded portions of the table require the high altitude pressure switch in order to operate the furnace at the listed

vent lengths.

Page 10 Installer’s Information Manual

NON-DIRECT VENT TERMINATION

You may terminate vent pipe either vertically (through the
roof) or horizontally (through a sidewall). Vertical (through
the roof) venting is preferred because it offers protection
from pipe damage and is less likely to cause condensate
damage.

For vertical non-direct venting, extend PVC vent pipe at
least 12 inches above roof or average snow accumulation.
In Canada, vent pipe must extend at least 18 inches above
roof. See Figure 6.

Figure 6. Vertical Termination for Non-Direct Venting.

Note: When properly installed, vent system is designed to
drain condensate and will not be affected by rainwater.

For horizontal non-direct venting, extend PVC pipe at least
6 inches from structure and 12 inches above grade or
average snow accumulation. See Figure 7.

Figure 8. Combustion-Air-Inlet Elbow for Non-Direct (one
pipe) Venting.

COMBUSTION AND VENTILATION AIR (non-direct
vent)

The total amount of combustion and ventilation air provided
within the building must equal the requirements of all gas
appliances in the building. You must also allow for
reduction of air available for combustion and ventilation
caused by exhaust fans, range hoods and fireplaces.
Sufficient air must be provided to ensure there will not be a
negative pressure in fu rnace room or space. In addition,
there must be a positive seal between furnace and return­air duct to avoid pulling air from burner area.

Provide for adequate combustion and ventilation air in
accordance with Section 5.3, Air for Combustion and
Ventilation, of the National Fuel Gas Code, ANSI
Z223.1/NFPA 54, or Sections 7.2, 7.3 or 7.4 of CAN/CGA
B149 Installation Codes, or applicable provisions of local
building codes.

WARNING : Furnaces and any other fuel burning
appliances must have enough fresh air for proper
combustion. Lack of adequate combustion air could cause
the fu rnace to produce carbon monoxide and may result in

nausea or asphyxiation.

Excessive exposure to air contaminated with chlorine,

Figure 7. Horizontal Termination for Non-Direct Venting.

Attach a PVC elbow to combustion-air-inlet collar on top of
furnace to prevent accidental blockage. Use rubber
coupling and hose clamps supplied with furnace. See
Figure 8.

Installer’s Information Manual Page 11

fluorine, bromine and iodine may result in safety and
performance related problems. The following types of
installation may require outdoor air for combust ion (or direct
venting) due to chemical exposures:

?? Commercial buildings, repair garages, beauty parlors,

and so on

?? Buildings with indoor pools
?? Furnaces installed in laundry rooms
?? Furnaces installed in hobby or craft rooms
?? Furnaces installed near chemical storage rooms
?? Furnaces installed near exhaust fans that vent the

above areas

Exposure to the following substances in the combustion air
supply may also require outdoor air for combustion:

?? Aerosols
?? Permanent wave solutions
?? Chlorinated waxes, bleaches and cleaners
?? Cat litter
?? Chlorine-based swimming pool chemicals
?? Cleaning solvents
?? Paint removers and varnishes
?? Adhesives
?? Anti-static fabric softeners
?? Most refrigerants

WARNING : Combustion air that contains chlorine,
fluorine, bromine or iodine could cause corrosion in heat
exchanger and may result in nausea or death by
asphyxiation.

UNCONFINED SPACE INSTALLATION (non-direct
vent)

The National Fuel Gas Code, ANSI Z223.1/NFPA 54 and
CAN/CGA B149 Installation Codes do not require that you
make special provisions for combustion and ventilation air
when fu rnace is in an "unconfined space" and building is
not of "unusually tight construction."

?? "Unconfined spaces" have a volume of at least 50

cubic feet per 1000 Btu per hour combined input rating
of all appliances installed in the space. For example: a
100,000 Btu/hr furnace and a 40,000 Btu/hr water
heater would require a volume of at least 140,000 X 50
÷ 1,000 or 7,000 cubic feet.

WARNING : You must provide permanent air
openings to a confined furnace installation space from
another area as described below. Failure to do so could
cause inadequate combustion and ventilation air and may

result in nausea or death by asphyxiation.

ALL COMBUSTION AND VENTILATION AIR FROM
INSIDE THE BUILDING

The confined furnace space must be provided with two
permanent openings to an additional room of sufficient
volume so that the combined volumes of the spaces meet
the criteria above for an unconfined space not of unusually
tight construction. The total input of all gas appliances
within the combined space must be considered in making
this determination.

Each opening must have minimum free area of one square
inch per 1,000 Btu per hour of the total combined input
rating of all gas appliances within the confined furnace
space, but not less than 100 square inches. One opening
must be within 12 inches of the top and one opening within
12 inches of the bottom of the furnace space. The shortest
side of each air opening must be at least 3 inches long.
See Figure 9.

For example:
?? A 90,000 Btu/hr furnace and a 40,000 Btu/hr water

heater would require free area openings of 130,000 ÷
1,000 or 130 square inches.

?? A 54,000 Btu/hr furnace and a 40,000 Btu/hr water

heater would require the minimum free area openings
of 100 square inches.

?? "Unusually tight construction" means windows and

doors are either tight fitting or are sealed construction
and that walls are covered with a continuous, sealed
vapor barrier and drywall or similar materials having
sealed joints.

If you meet the volume requirements for unconfined space,
the building is not of unusually tight construction and there
are no airborne contaminants, as listed above, you may
install this fu rnace without making special provisions for
combustion and ventilation air. Otherwise, follow the
instructions for "confined space installation" below or direct
vent the furnace using two pipes.

CONFINED SPACE INSTALLATION (non-direct
vent)

A non-direct vented fu rnace installed in a confined space
must take combustion and ventilation air from an
unconfined space within the building or from outdoors.
However, if the building is of unusually tight construction all
combustion air must come from outdoors. Also, if return air
is taken directly from a hallway or space next to fu rnace
that communicates with furnace spaces, all combustion air
must come from outdoors.

Page 12 Installer’s Information Manual

Figure 9. Confined Space, All Air From Inside The Building.

ALL COMBUSTION AND VENTILATION AIR FROM
OUTDOORS

The fu rnace space must be provided with two permanent
air openings communicating directly, or by ducts, with the
outdoors or spaces that freely access the outdoors. Well­ventilated attics or crawl spaces usually satisfy this
requirement. These openings will give furnace free access

to fresh air for combustion and ventilation.

You must provide air sufficient for all gas appliances within
furnace space. Locate one combustion and ventilation air
opening within 12 inches of top of fu rnace space. Locate
another within 12 inches of bottom of furnace space.

Ducts that supply air from outdoors must have the same
cross-sectional area as the free area of openings to which

they connect.

Figure 10. All Air Directly From Spaces That Freely Access
The Outdoors.

Figure 11. All Air Through Vertical Ducts From Spaces
That Freely Access The Outdoors.

When directly communicating with the outdoors, each
opening must have a minimum free area of one square inch
per 4,000 Btu per hour of total combined input rating of all
gas appliances within furnace space. For example: A
108,000 Btu per hour fu rnace requires two openings of at
least 108,000 ÷ 4,000 or 27 square inches. See Figure 10
and Table 3.

Table 3. Free Opening Area Based On One Square Inch
Per 4000 Btu/hr.

TOTAL

INPUT

(Btu/hr)

54,000 13.5 5 78,000
72,000 18 5 78,000

90,000 22.5 6 113,000
108,000 27 6 113,000
126,000 31.5 7 153,000
144,000 36 7 153,000

REQUIRED

FREE

AREA PER

OPENING

(square inches)

MINIMUM

ROUND PIPE

DIAMETER

(inches)

MAXIMUM
INPUT FOR

GIVEN PIPE

DIAMETER

(Btu/hr)

When communicating with the outdoors through vertical
ducts, openings and ducts must have a minimum free area
of one square inch per 4,000 Btu per hour of total combined
input rating of all gas appliances within furnace space. See
Figure 11 and Table 3.

Figure 12. All Air From The Outdoors Through Horizontal
Ducts.

When communicating with the outdoors through horizontal
ducts, openings and ducts must have a minimum free area
of one square inch per 2,000 Btu per hour of total combined
input rating of all gas appliances within furnace space. See
Figure 12 and Table 4.

Table 4. Free Opening Area Based On One Square Inch
Per 2000 Btu/hr.

TOTAL

INPUT

(Btu/hr)

54,000 27 6 56,000
72,000 36 7 76,000

90,000 45 8 100,000
108,000 54 9 127,000
126,000 63 9 127,000
144,000 72 10 157,000

REQUIRED

FREE

AREA PER

OPENING

(square inches)

MINIMUM

ROUND

PIPE

DIAMETER.

(inches)

MAXIMUM
INPUT FOR

GIVEN PIPE

DIAMETER

(Btu/hr)

Example: Furnace is 90,000 Btu per hour input and is to be
installed in a confined space that contains no other gas
appliances. Rectangular combustion and ventilation air
ducts will run horizontally from outdoors to furnace space.

Installer’s Information Manual Page 13

Calculate the free area required.
Because combustion and ventilation air ducts run

horizontally, allow 2,000 Btu per hour.
Furnace input (Btu/hr) = Free area required

2,000 Btu/hr
per square inch

90,000 = 45 square inches
2,000

Both of the ducts must have a minimum cross sectional
area of 45 square inches.

SECTION 5. CONDENSATE DRAIN

This fu rnace produces water as a product of combustion.
Much of this water condenses on the stainless steel tubing
of the heat exchanger and in the vent system. This water
(referred to as condensate) must be drained from the
furnace into a household drain. The following notes should
be considered when connecting condensate drain:

?? The furnace’s drain trap must be primed. This is easily

done by pouring a few cups of water into fu rnace vent
pipe after drain installation is complete.

?? A frozen or blocked drain line will cause furnace

shutdown and no-heat complaints. Protect drain trap
and drain tubing from freezing.

?? When a condensate pump is used, select a pump

designed for furnace condensate.

compound to all joints on male threads only, starting two
threads from the end.

INSTALLATION

Gas supply piping can be installed from either side of
furnace casing. Install gas supply piping according to
Figure 13 and the following instructions.

Figure 13. Gas Line Installation.

1. Install a 3-inch long x 1/2” NPT black-iron pipe nipple
through gas entry grommet and into gas -control inlet
elbow. Inst all a black iron pipe elbow on 3-inch nipple.

Tighten gas tight. Do not over tighten.

SECTION 6. INSTALLING GAS
PIPING

PREPARATION

Refer to the current National Fuel Gas Code ANSI
Z223.1/NFPA 54 or CAN/CGA B149 Installation Codes and
local codes for gas piping requirements and sizing. Pipe
size running to furnace depends on:

?? Length of pipe
?? Number of fittings
?? Specific gravity of gas
?? Input requirements (Btu per hour) of all gas-fired

appliances attached to same main supply line.

Plan fu rnace gas supply piping so it will not interfere with
removal of burner assembly, front door or blower door for
servicing.

Make sure gas piping is large enough for all appliances
connected to it to operate at once without lowering gas
supply pressure. Failure to do so could cause lighting or
burning problems on any of the appliances.

Always use a pipe thread compound that is resistant to
propane (LP) gas solvent action. Sparingly apply thread

2. Install a ground-joint union and a drip leg immediately
upstream of the fu rnace. Ground-joint union allows
easy servicing of burner assembly and fu rnace gas
control. Ground-joint union must be listed by a
nationally recognized testing laboratory.

3. Install a manual “equipment” shut-off valve in gas
supply line immediately upstream of ground-joint union.
Equipment shut -off valve must be listed by a nationally
recognized testing laboratory.

TESTING FOR LEAKS

Isolate furnace and its gas control from gas supply line
during leak checks. Gas-supply line test pressure
determines how you isolate gas control.

The furnace and its gas control must be disconnected from
gas supply piping system at ground joint union during any
pressure testing of the system at test pressures greater
than 1/2 psi (14 inches W.C.).

The furnace must be isolated from gas supply piping
system by tu rning off equipment shut-off valve during any
pressure testing of the system at test pressures equal to or
less than 1/2 psi (14 inches W.C.).

Page 14 Installer’s Information Manual

WARNING : When test pressure is above 1/2 psi
(14 inches W.C.), completely disconnect fu rnace and gas
control from gas supply line. Failure to isolat e furnace and
gas control from test pressure could damage them, causing

gas to leak, resulting in fire or explosion.

Use a commercial soap solution made to detect leaks and
check all gas piping connections. Bubbles indicate gas
leakage. Seal all leaks before proceeding.

SECTION 7. INSTALLING
ELECTRICAL WIRING

CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper and
dangerous operation. When replacing original wire, use
same type, color, or equivalent wire. Remember to
renumber wire ends. Verify proper operation after
servicing.

115 VOLT WIRING

Wire furnace according to the Field Wiring Diagram shown
in Figure 14, local codes, and current National Electrical
Code ANSI/NFPA 70 or Canadian Electrical Code CSA
C22.1. Also, see Furnace Wiring Diagram in Figure 15.

Install proper electrical grounding by attaching grounding
source to green wire in fu rnace junction box. Follow local
codes or in the absence of local codes, the current National
Electrical Code ANSI/NFPA 70 or Canadian Electrical Code
CSA C22.1.

WARNING : Failure to provide a proper electrical
ground could result in electric shock or fire.

Provide fu rnace with its own separate electrical circuit and
means of circuit protection. Furnace must have an
electrical disconnect switch located at furnace.

WARNING : Failure to provide the above shut-off
means could result in electrical shock or fire.

Use electrical wiring that meets current National Electrical
Code ANSI/NFPA 70 or Canadian Electrical Code CSA
C22.1 and local codes. Use Type T (63 degrees C rise)

wire or equivalent.

Figure 14. Field Wiring Diagram.

24 VOLT WIRING

Select a location for room thermostat on a draft-free interior
wall that is away from supply and return air registers, lights,
television, direct sunlight, or other heat sources.

Install thermostat following field-wiring diagram in Figure 14
and thermostat manufacturer's instructions. Thermostat
wire should be 18 AWG wire for best results.

NOTE: For proper cooling operation, “Y” wire must be
connected to Fan Timer. “Y” wire controls cooling
speed blower operation.

Set the thermostat's heat anticipator following instructions
provided with thermostat. This furnace will have heat
anticipator current of approximately 0.4 amps.

CAUTION: 24 VAC accessories that draw power from the
furnace's transformer should not be installed on this
furnace. Addition of such accessories may cause improper

furnace operation and limit transformer life.

Installer’s Information Manual Page 15

Figure 15. Furnace Wiring Diagram.

Page 16 Installer’s Information Manual

SECTION 8. SEQUENCE OF
OPERATION

HEATING MODE

1. Thermostat calls for heat ("R" and "W" terminals
connected). Fan Timer verifies that burner limits,
primary limit and pressure switches are in normally
closed (NC) position.

2. Draft-inducer relay is energized and draft inducer motor
starts. Pressure switch normally open contacts close
after a short delay, energizing gas control.

3. Gas control provides power to igniter and pilot valve to
light pilot. After proving pilot flame, the main valve
opens and igniter turns off.

NOTE: If the gas control does not sense a pilot flame
within 30 seconds, it will turn off the igniter while continuing
to purge the gas line. After 30 seconds, the igniter will turn
on again. If a pilot is not sensed in the next 30 seconds,
the gas control will turn off for 5 minutes. This sequence

will continue as long as there is a call for heat.

4. Fan Timer energizes main blower in 30 seconds.

5. After thermostat is satisfied, gas control is de­energized. After a 5 second post-purge, draft inducer
de-energizes and retu rns pressure switch to normally
closed (NC) position.

6. Main blower remains energized for 60 to 180 seconds
depending on heating blower off-delay setting.

NOTE: This fu rnace will lockout if the main blower fails in
heating mode. During lockout, the Fan Timer's diagnostic
light signal will be 4 flashes. The furnace's Fan Timer can
be reset by cycling 115-volt power to furnace.

A call for cooling mode while in constant fan mode causes
main blower to change from heating to cooling speed. Sixty
seconds after the call for cooling mode ends, main blower
changes back to heating speed. A call for heating mode
while in constant fan mode does not effect main blower
operation. The main blower runs constantly on heating
speed.

CONTINUOUS LOW-SPEED FAN OPTION

Some models are equipped with a fan timer that allows
continuous low-speed fan as an option. When available,
this option can be used to operate the blower on low speed
anytime the blower is not otherwise running on heating or
cooling speed. These models do not have electronic air
cleaner terminals on the fan timer.

To use this option, follow these steps:

1. Disconnect electrical power

2. Remove insulator cap from “CONT” terminal on Fan
Timer.

3. Plug blower low-speed wire (red wire) into “CONT”
terminal.

4. Place insulator cap on “UNUSED MOTOR LEAD”
terminal on Fan Timer.

5. Reconnect power. Motor will start on low speed
immediately.

ELECTRONIC AIR CLEANER OPTION

For models with Electronic Air-Cleaner (EAC) terminals, the
Fan Timer "EAC" terminals are energized with 115 VAC
when main blower is energized. "EAC" terminals are 1/4
inch quick connect tabs located under breakaway covers.
Use insulated quick connects when connecting to "EAC"
terminals. Limit total "EAC" current plus main blower

current to 15 amps max.

NOTE: On each heating cycle, this fu rnace verifies that the
pressure switch did not stick closed on the previous cycle.
This condition is detected by checking the pressure switch's
normally closed circuit. If the normally closed circuit is
open, furnace will not operate and the Fan Timer's
diagnostic light signal will be 3 flashes.

HUMIDIFIER

Fan Timer "HUM" terminals are energized with 115 VAC (1
amp. Max.) when draft inducer is energized. "HUM"
terminals are 1/4 inch quick connect tabs located under
breakaway covers. Use insulated quick connects when
connecting to "HUM" terminals.

COOLING MODE

Thermostat calls for cooling ("R", "Y" and "G" terminals
connected). Condensing unit contactor closes, energizing
condensing unit. Fan Timer energizes main blower on
cooling speed after a short delay. After thermostat is
satisfied, condensing unit contactor is de-energized. Main
blower remains energized for 60 se conds.

CONSTANT FAN MODE

Thermostat calls for constant fan ("R" and "G" terminals
connected). Fan Timer energizes main blower on heating

speed.

Installer’s Information Manual Page 17

BURNER LIMIT CIRCUIT OPEN

If the burner limit circuit opens: burners turn off, draft
inducer stays on, main blower stays on, there is no 24 volt
power on the "R" terminal and diagnostic light signal is 1

flash.

PRIMARY LIMIT CIRCUIT OPEN

If the primary limit circuit opens: burners turn off, draft
inducer tu rns off, main blower stays on, there is no 24 volt
power on the "R" terminal and the diagnostic light signal is
2 flashes.

SECTION 9. INSTALLING DUCT
SYSTEM

Properly size duct system based on heat loss and heat gain
calculations to ensure good heating and cooling
installations, potentially fewer call-backs, and delivery of
required circulating air. Install duct system to meet current
Standard for Installations of Warm Air Heating and Air
Systems ASHRAE/NFPA 90 and local codes.

CAUTION: Failure to follow these standards could reduce
airflow or increase air leakage, resulting in reduced system
performance or furnace damage.

Design duct system so furnace will operate at a static
pressure of 0.50 inches W.C. or less. This static pressure
limitation includes the total pressure losses on both supply
air side and return air side of system. Supply side pressure
loss includes cooling coil, ducts and room registers. Return
side pressure loss includes return grilles and ducts.
Pressure losses are calculated based on 400 CFM per ton
of cooling.

SUPPLY AIR DUCT WORK

Supply air duct (plenum) connections must be at least as
big as furnace supply opening. Seal supply -air ductwork to
furnace casing, walls, ceilings or floors it passes through.
End ductwork outside furnace space.

On fu rnaces not equipped with a cooling coil, a removable
access panel that is large enough to allow viewing of the
heat exchanger should be provided in the supply duct. The
access panel should be accessible when the fu rnace is
installed. Seal access-panel cover to prevent leaks.

RETURN AIR DUCT WORK

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

Table 5. Bottom Closure Part Numbers.

GAS

INPUT*

(Btu/hr)

54,000 1/3 4045901
72,000
90,000
72,000

90,000
108,000
126,000

* GAS INPUT and MOTOR HP can be found on fu rnace
rating plate.

WARNING : Failure to install bottom closure panel
could allow combustion products to enter circulating air

stream, resulting in injury or death by asphyxiation.

MOTOR*

HORSE ­POWER

1/2
3/4 4045902
3/4 4045903

BOTTOM CLOSURE

PART NUMBER

4045901

DUCT DAMPERS

You may balance airflow with dampers installed in each
branch run duct and adjust for even temperature throughout
the heated space. For proper furnace operation, make sure
of the following:

?? Supply air registers and return air grilles are open;
?? Rugs, carpets, drapes or furniture are clear of registers

and grilles;

?? Size and shape of supply air plenum is correct;
?? Number of supply air ducts is correct.

LOCATION OF COOLING COIL

If fu rnace will share common duct system with a separate
cooling unit, install furnace parallel to or upstream of
cooling unit. This avoids condensation in heating element.
Do not install cooling coil in return-air ductwork. With
parallel flow, dampers must be installed to prevent chilled
air from entering fu rnace. If dampers are not in full heat or
full cool position, furnace or cooling unit must not operate.

SECTION 10. SELECTING AND

WARNING : Failure to seal return-air ductwork
could allow combustion products to enter circulating air
stream resulting in injury or death by asphyxiation.

Air delivery above 1800 CFM requires that both sides of
furnace be used for return air, or a combination of one side
and bottom or bottom only.

If bottom return air is not used, you must attach a solid
bottom-closure panel to bottom return-air opening. Bottom
closure panel is available from manufacturer. See Table 5
for bottom closure part numbers.

Page 18 Installer’s Information Manual

INSTALLING FILTER CABINETS

Properly installed air filters keep blower motor, blower
wheel and cooling coil (if installed) clean. Filters and filter
cabinets are not supplied with this furnace. Filters and filter
cabinets must be field supplied or obtained from the
manufacturer. The manufacturer has bottom and side filter
cabinets available. This furnace was designed for an
external filter(s). Do not install air filters inside furnace
casing. Obtain and install proper filter frames and correctly
sized filters. To inspect, clean or replace air filters, follow
the instructions in the User’s Information Manual.

CAUTION: You must install air filters to keep blower motor,
blower wheel and cooling coil (if installed) clean. Dirty
equipment may reduce system efficiency or cause erratic
control performance and can result in damage to blower

motor, heat exchanger or air conditioner (if installed).

Follow these instructions and the filter manufacturer's
instructions for minimum size and quantity
recommendations. Air velocity must not exceed 300 feet
per minute through low velocity disposable filters. Air
velocity must not exceed 650 feet per minute through high
velocity washable filters. Undersized filters reduce airflow
and can adversely affect furnace and cooling system
operation.

See Table 6 for recommended filter size for bottom return
installations. Side return filters must be at least 16" X 25" X
1", high-velocity washable filters.

Table 6. Recommended Filter Size--Bottom Return.

GAS

INPUT*

(Btu/hr)

54,000 1/3 16 X 25 X 1 16 X 25 X 1
72,000
90,000
72,000

90,000
108,000
126,000

* GAS INPUT and MOTOR HP can be found on furnace
rating plate.

MOTOR*

HORSE ­POWER

1/2
3/4 20 X 25 X 1 20 X 25 X 1

DISPOSABLE

AIR FILTER

- two required
(inches)

16 X 25 X 1 16 X 25 X 1

HIGH-

VELOCITY

WASHABLE

AIR FILTER

Manufacturer's bottom filter cabinet and upflow side filter
cabinets are shown in Figures 16 and 17 respectively. See
Figure 18 for floor cutout dimensions for bottom filter
cabinet.

Air delivery above 1,800 CFM requires returns on both
sides, a combination of side and bottom returns, or bottom
return only. Use appropriate filter cabinets with these

combinations.

FILTER CABINETS

Use a bottom filter cabinet, side filter cabinet, or retu rn-air
filter grille. Field fabricated filter cabinets should allow 1
inch spacing between filter and fu rnace. Placing a field
supplied filter directl y against furnace bottom or side will
decrease airflow and adversely affect furnace operation.
Filter cabinets that provide correct filter spacing to ensure
designed airflow are available from the manufacturer.

Figure 17. Side Filter Cabinet.

Figure 16. Bottom Filter Cabinet.

Installer’s Information Manual Page 19

Figure 18. Floor Cutout Dimensions.

SECTION 11. CHECKS BEFORE
STARTING FURNACE

Before starting fu rnace for the first time, be sure you can
answer "Yes" to each of these questions:

1. Is fu rnace properly equipped to operate with available
fuel?

2. Is furnace level?

3. Have you cleared away all loose construction and
insulation materials?

4. Is furnace installed with proper clearances?

5. Does furnace have sufficient combustion and
ventilation air?

6. Is the vent system sloped toward the fu rnace at least
1/4 inch per foot?

7. Have you checked the vent system for leaks?

8. Did you completely check gas pipe and controls for gas
leaks?

9. Does electrical wiring follow current National Electrical
Code ANSI/NFPA 70 or Canadian Electrical Code CSA
C22.1 as well as local codes?

10. Is furnace electrically grounded?

11. Is room thermostat properly installed and heat
anticipator set correctly?

12. Is duct system correctly sized and sealed?

13. Are proper air filter cabinets installed?

14. Are air filters in place and correctly sized?

SECTION 12. GAS SUPPLY
PRESSURE AND PILOT
ADJUSTMENT

You will need a 0 to 15 inch water manometer with 0.1 inch
resolution and a 1/8" NPT manual shut -off valve to measure
actual gas pressure.

9. With fu rnace operating, read gas supply pressure on
manometer.

?? Natural gas supply pressure must be between 5

and 7 inches W.C.

?? Propane gas (LP) supply pressure must be

between 11 and 13 inches W.C.

10. If gas supply pressure is not within these limits, call gas
supplier. Tu rn off all gas appliances attached to gas
supply line.

11. Shut off furnace.

12. Turn off gas at equipment shut-off valve in gas supply
line just ahead of furnace. Remove shut -off valve from
gas -control inlet pressure tap. Install pressure tap
plug. Turn on gas.

13. Replace burner access panel using three screws
removed in step 2.

PILOT FLAME ADJUSTMENT

Before adjusting pilot flame, confirm that gas supply
pressure is correct, as explained above.

NOTE: Pilot flame adjustment was checked at the factory
and should not require adjustment. However; pilot
adjustment is possible if necessary.

1. Remove three screws holding burner access panel in
place. Remove burner access panel.

2. Start furnace following "Operating Instructions" on front
door.

3. Pilot flame should cover 1/2 inch of tip of flame sensor
as shown in Figure 19.

4. If you need to adjust pilot flame, remove pilot­adjustment cover screw on gas control. Save cover
screw for re-installation. Turn inner adjustment screw
clockwise to decrease pilot flame; counter-clockwise to
increase pilot flame. Install cover screw and tighten to
torque of 5 inch-pounds to prevent gas leakage.

CHECKING GAS SUPPLY PRESSURE

1. Turn off gas at equipment shut-off valve in gas supply
line just ahead of furnace.

2. Remove three screws holding burner access panel in
place. Remove burner access panel.

3. Remove inlet pressure plug from gas control. See
Figure 13.

4. Install 1/8" NPT manual shut-off valve in hole vacated
by plug. Make sure valve is in off position.

5. Attach manometer to 1/8" NPT manual shut-off va lve
just installed.

6. Slowly open equipment shut -off valve in gas supply line
just ahead of furnace.

7. Slowly open 1/8" NPT manual shut -off valve leading to
manometer.

8. Turn on all gas appliances attached to gas supply line.

Page 20 Installer’s Information Manual

Figure 19. Pilot Flame Adjustment.

5. Check pilot-adjustment cover screw and gas -control
inlet-pressure-tap plug for gas leaks. Use a
commercial soap solution made for leak detection.

6. Replace burner access panel using three screws
removed in step 1.

SECTION 13. MANIFOLD
PRESSURE ADJUSTMENT

SECTION 14. CHECKING GAS
INPUT RATE

You will need a 0 to 15 inch water manometer with 0.1 inch
resolution and a 1/8" NPT manual shut -off valve to measure
actual manifold pressure.

WARNING : Correct manifold pressure is
necessary for proper ignition and burner operation. Failure
to accurately adjust pressure could cause heat exchanger
failure.

Check gas-supply pressure first. Follow instructions in
Section 12, "Gas Supply Pressure and Pilot Adjustment."

1. Turn off gas at equipment shut-off valve in gas supply
line just ahead of furnace.

2. Remove three screws holding burner access panel in
place. Remove burner access panel.

3. Remove plug from manifold pressure tap in gas
control. See Figure 13.

4. Install 1/8" NPT manual shut-off valve in hole vacated
by plug. Make sure shut -off valve is in off position.

5. Attach manometer to 1/8" NPT manual shut-off valve
just installed.

6. Slowly open equipment shut -off valve in gas supply line
just ahead of furnace. Start furnace following
"Operating Instructions" on front door.

7. Slowly open 1/8" NPT manual shut -off valve leading to
manometer.

8. Read manifold pressure on manometer.

9. Adjust manifold pressure by turning gas control
regulator adjusting screw clockwise to increase
pressure or turning counter-clockwise to decrease
pressure. Manifold pressure must be within allowable
range below:

?? Natural gas manifold pressure must be between

3.2 and 3.8 inches W.C.

?? Propane gas (LP) manifold pressure must be

between 9.7 and 10.3 inches W.C.

NOTE: For natural gas, if gas flow rate cannot be properly

set within these pressure ranges then you must change
main burner orifices to obtain proper gas flow rate.

10. Shut off fu rnace. Turn off gas at equipment shut-off
valve in gas supply line just ahead of fu rnace. Install
outlet-pressure-tap plug in gas control. Turn on gas.

11. Check regulator-adjustment-cover screw and gas
control plug for gas leaks. Use a commercial soap
solution made for leak detection.

12. Replace burner access panel using three screws
removed in step 2.

It is the installer's responsibility to see that the Btu input
rate of the fu rnace is properly adjusted. Under-firing could
cause inadequate heat, primary heat exchanger corrosion
and/or ignition problems. Over-firing could cause sooting,
flame impingement and/or overheating of heat exchanger.

WARNING : Failure to adjust furnace to the proper
firing rate could cause heat exchanger failure.

Depending on your local gas heating value and elevation,
you may need to adjust manifold pressure or change
orifices to get proper gas input rate. Check with your local
gas supplier to determine heating value (Btu/cu.ft.) of
natural gas in your area.

NOTE: If fu rnace is being installed at an altitude of more
than 2000 feet above sea level, you must derate the
furnace. See Section 15, "Derating For High Altitude."

NATURAL GAS INPUT RATE

Natural gas heating value (Btu/cu.ft.) can vary significantly.
Before starting natural gas input check, obtain gas heating
value at your location from local supplier. You will need a
stopwatch to measure actual gas input.

1. Gas supply pressure must be between 5 and 7 inches
W.C. for natural gas. See Section 12, "Gas Supply
Pressure and Pilot Adjustment."

2. Turn off all other gas appliances. You may leave pilots
on.

3. Start furnace following "Operating Instructions" on front
door. Let furnace warm up for 6 minutes.

4. Locate gas meter. Determine which dial has the
fewest cubic feet of gas and how many cubic feet per
revolution it represents. This is usually one-half, one or
two cubic feet per revolution.

5. With stopwatch, measure time it takes to consume two
cubic feet of gas.

?? If dial is one cubic foot per revolution, measure

time for two revolutions.

?? If dial is two cubic feet per revolution, measure

time for one revolution.

6. Divide this time by two. This gives average time for
one cubic foot of gas to flow through meter. Example:
If it took 58 seconds for two-cubic feet to flow, it would
take 29 seconds for one-cubic foot to flow.

7. Calculate gas input using this formula:

Gas Heating Value (Btu/cu.ft.)
X 3,600 sec/hr
Gas input = = Btu/hour
Time (Seconds for
one cubic foot of gas)

Installer’s Information Manual Page 21

Example:
Assume it took 29 seconds for one cubic foot of gas to flow

and heating value of 1,000 Btu/cu.ft.
1,000 x 3,600

Gas Input = = 124,138 Btu per hour
29

If you left no other pilots on, this is the furnace gas input.

8. If you left water heater, dryer or range pilots on, allow
for them in calculating correct furnace gas input. A
quick way is to allow 1,000 Btu per hour for a water
heater, 500 Btu per hour for dryer and 500 Btu per hour

for each range burner pilot.

Example:

If you left gas water heater, dryer, two range burner pilots

and one oven pilot on, allow:

Water heater pilot 1,000 Btu per hour
Dryer pilot 500 Btu per hour
2 range burner pilots 1,000 Btu per hour
1 range oven pilot 500 Btu per hour

3,000 Btu per hour
Subtracting 3,000 Btu per hour from 124,138 Btu per hour

measured above equals 121,138 Btu per hour. This would
be the correct furnace gas input after allowing for pilots left
on.

9. Manifold pressure may be adjusted within the range of

3.2 inches W.C. to 3.8 inches W.C. to get rated input ±
2 percent. See Section 13, "Manifold Pressure
Adjustment." If you cannot get rated input with
manifold pressure within the allowable range, you must
change orifices. See Section 17, "Changing Main
Burner Orifices."

PROPANE (LP) GAS INPUT RATE

WARNING : Propane (LP) gas installations do not
have gas meters to double-check input rate. Measure
manifold pressure with an accurate manometer. Failure to
accurately adjust pressure could cause heat exchanger

failure.

1. Make sure you have correct pilot orifice and main
burner orifices.

2. Gas supply pressure must be between 11 and 13
inches W.C. for propane (LP) gas. See Section 12,
"Gas Supply Pressure and Pilot Adjustment."

3. Start furnace following "Operating Instructions" on front
door.

4. Let furnace warm up for 6 minutes.

5. Adjust manifold pressure to 10.0 inches W.C. ± 0.3
inches W.C. See Section 13, "Manifold Pressure
Adjustment."

WARNING : Do not set Propane (LP) manifold
pressure at 11.0 inches W.C. It could cause heat
exchanger failure.

NOTE: NOx reducing screens must be removed from each
tube of California NOx furnaces when converting to
propane (LP) gas. See Figure 20.

Figure 20. California NOx Screen Removal.

SECTION 15. DERATING FOR HIGH
ALTITUDE

At higher altitudes, the density of the air is lower.
Therefore, for proper combustion, the quantity of gas
burned in the furnace must be reduced. This is called
derating. Furnaces must be derated when installed at
altitudes greater than 2,000 feet above sea level.

Derating the fu rnace by adjusting the manifold pressure
lower than the range specified in the Section 13, "Manifold
Pressure Adjustment" is considered to be an improper
procedure.

At elevations above 2,000 feet, the furnace must be
derated 4% for each 1,000 foot above sea level. It is the
installer’s responsibility to see that the furnace input rate is
adjusted properly. Derating must be achieved by reducing
the size of the main burner orifices. Choose the proper
orifices for your altitude and gas heating value from orifice
size Table 7 or 8. In Canada, high-altitude models may be
available that are rated for 2,000 to 4,500 feet above sea
level.

SECTION 16. DETERMINING
CORRECT ORIFICE SIZE

See Table 7 or Table 8 to determine correct orifice size for
your gas type, gas heating value, and altitude. Natural gas
and propane (LP) gas orifice kits are available through your
supplier. Individual orifices are also available in convenient
lot sizes. To ensure proper performance, use only
manufacturer supplied orifices. To determine which orifices
are installed in furnace, see rating plate--located on blower
door.

Page 22 Installer’s Information Manual

Table 7. Natural Gas Orifice Size.

ELEVATION

GAS Up 2001 3001 4001 5001 6001* 7001* 8001* 9001*
HEATING to to to to to to to to to
VALUE** 2000 3000 4000 5000 6000 7000 8000 9000 10000

(Btu/cu. ft.) Feet Feet Feet Feet Feet Feet Feet Feet Feet

800-849 2.25 2.20 2.15 2.15 2.10 2.05 2.05 2.00 1.95
850-899 2.20 2.15 2.10 2.10 2.05 2.00 2.00 1.95 1.90
900-949 2.15 2.10 2.05 2.05 2.00 1.95 1.95 1.90 1.85

950-999 2.10 2.05 2.00 2.00 1.95 1.90 1.90 1.85 1.80
1000-1049 2.05 2.00 1.95 1.95 1.90 1.85 1.85 1.80 1.75
1050-1099 2.00 1.95 1.90 1.90 1.85 1.80 1.80 1.75 1.75
1100-1149 1.95 1.90 1.85 1.85 1.80 1.80 1.75 1.75 -­1150-1199 1.90 1.85 1.85 1.80 1.75 1.75 -- -- --

* Above 6000 feet, a high-altitude gas conversion kit must be used.
** At standard conditions: 30.0 inches Mercury, 60°F, Saturated.

Table 8. Propane (LP) Gas Orifice Size.

ELEVATION

GAS Up 2001 3001 4001 5001 6001* 7001* 8001* 9001*

HEATING* to to to to to to to to to

VALUE 2000 3000 4000 5000 6000 7000 8000 9000 10000

(Btu/cu. ft.) Feet Feet Feet Feet Feet Feet Feet Feet Feet

2500-2550 1.20 1.15 1.15 1.15 1.15 1.10 1.10 1.10 1.05

* Above 6000 feet, a high-altitude gas conversion kit must be used.

SECTION 17. CHANGING MAIN
BURNER ORIFICES

WARNING : To prevent electrical shock and gas
leaks, tu rn off electrical power and gas before changing

orifices.

Follow this procedure:

1. Turn off electricity at electrical disconnect switch next
to furnace.

2. Turn off equipment shut -off valve in gas supply line just
ahead of furnace.

3. Remove three screws holding burner access panel in
place. Remove burner access panel.

4. Starting with burner farthest from gas control, remove
main burner screws and main burners. Note how
burners overlap. Burner farthest from gas control is on
top. See Figure 21.

5. Remove original main burner orifices from manifold
pipe.

6. Carefully, hand thread new orifices into manifold pipe.
Do not cross-thread. Tighten to torque of 50 inch­pounds.

7. Starting with burner closest to gas control, replace
main burners and main burner screws. Burner
mounting flange of burner farther from gas control
overlaps burner-mounting flange of burner closest to
gas control.

Figure 21. Main Burner Removal.

8. Check burner carry-over alignment. Burner carry­overs may touch but not overlap adjacent burner carry ­overs. Replace screws.

9. Replace burner access panel using three screws
removed in step 3.

10. Open equipment shut-off valve in gas supply line just
ahead of furnace.

11. Set room thermostat to highest setting and to heating
mode.

12. Turn on electricity at electrical disconnect switch
located next to furnace. Furnace will light.

13. Visually check that each burner lights promptly.

14. Check gas input following Section 14, "Checking Gas
Input Rate."

15. Reset room thermostat to desired setting.

Installer’s Information Manual Page 23

SECTION 18. ADJUSTING
BLOWER SPEED

Determine initial heating and cooling speeds in system
design stage. See Specification Sheet for airflow data.
Depending on tests performed in following sections, you
may need to change blower motor speed.

CAUTION: Heating speed tap should not be reduced below
factory setting. Doing so may result in inadequate air
circulation, and could cause excessive air temperature rise
through furnace. This could cause a high-temperature limit
switch to cycle burners on and off, reducing furnace
efficiency and shortening heat exchanger life.

All models have these four motor speed designations:
High Speed (HI) Black wire

Medium High Speed (MH) Blue wire
Medium Low Speed (ML) Yellow wire
Low Speed (LO) Red wire

WARNING : To prevent electric shock, turn off

electrical power to fu rnace before changing blower motor
speed.

1. To change cooling speed, move desired motor lead to
terminal marked 'COOL' on Fan Timer. See Figure 22.
Initial factory setting for cooling is high speed (black
wire).

2. To change heating speed, move desired motor lead to
terminal marked 'HEAT' on Fan Timer. See Figure 22.
Factory setting for heating is listed in Table 9. Heating
speed should not be reduced below factory setting.

Table 9. Factory Heating Speed and Temperature Rise.

GAS*

INPUT

(Btu/hr)

54,000 1/3 35-65 MH / BLUE
72,000 1/2 35-65 ML / YEL
72,000 3/4 30-60 ML / YEL
90,000 1/2 45-75 MH / BLUE

90,000 3/4 35-65 MH / BLUE
108,000 3/4 35-65 MH / BLUE
126,000 3/4 45-75 MH / BLUE

* Gas Input and Motor HP can be found on rating plate.
** These are factory settings.

Table 10. Cooling Speed Selection.

GAS* MOTOR AIR CONDITIONING TONNAGE

INPUT SIZE

(Btu/hr) (HP) 1.5 2 2.5 3 3.5 4 5

54,000
72,000
72,000
90,000

90,000
108,000
126,000

* Gas Input and Motor HP can be found on rating plate.
This table gives speed tap settings for installations with duct
static pressure of 0.5” W.C. Duct work with a static pressure

less than 0.5” W.C. will hav e increased airflow. To determine
correct speed tap settings at ductwork static pressures other
than 0.5” W.C., see specification sheet.

MOTOR

SIZE

(HP)

1/3 LO ML MH HI -- -- -­1/2 -- LO ML HI -- -- -­3/4 -- -- LO ML MH HI -­1/2 -- LO ML HI -- -- -­3/4 -- -- LO ML MH HI -­3/4 -- -- -- -- LO ML HI
3/4 -- -- -- -- LO ML HI

AIR

TEMPERATURE

RISE RANGE

(°F)

AT 0.5 INCHES WC

HEATING

OPERATION

**SPEED TAP /

WIRE COLOR

Figure 22. Main Blower Speed Selection.

3. Connect two unused motor leads to terminals marked
"UNUSED MOTOR LEADS" on Fan Timer. See Figure

22.

WARNING : Failure to properly terminate unused

motor leads could cause electrical shock.

SECTION 19. MEASURING DUCT
SYSTEM STATIC PRESSU RE

You will need a 0 to 1 inch W.C. slope gauge with 0.01-inch
resolution and two pressure measurement taps to measure
duct system static pressure.

System airflow can be determined from Specification Sheet
when duct system static pressure is known. Improper
airflow in heating mode may result in poor heating
performance and reduced heat exchanger life. Improper
airflow in cooling mode may cause poor cooling
performance or air-conditioning coil freeze-up.

High duct system static pressure is an indication of an
overly restrictive duct system. Static pressure in excess of

0.5 inches W.C. indicates a need for duct system redesign
to ensure proper volume of airflow.

Follow this procedure:

1. Open supply-air registers and retu rn-air grilles. Make
sure registers and grilles are free of obstruction from
rugs, carpets, drapes or furniture.

2. Set balancing dampers in supply duct system.

3. Check ductwork for obstructions or leaks.

4. Make sure filters are clean and in place.

Page 24 Installer’s Information Manual

5. Make sure that blower speed taps are set for proper
heating and cooling. Refer to Section 18, "Adjusting
Blower Speed." Heating speed should be set
according to Table 9. Cooling speed should be set to
meet cooling equipment requirements. See Table 10
for cooling airflow capacities at 0.5 inch W.C.

6. Place slope gauge near furnace, level and adjust scale
to read 0.00 inches W.C.

7. Insert one static pressure tap into supply-air duct
between furnace and cooling coil or in supply air
plenum for heating only systems. Connect this
pressure tap to positive pressure side of slope gauge.

8. Insert other static pressure tap in retu rn air plenum.
Connect this pressure tap to negative pressure side of

slope gauge.

9. Start blower.

?? Blower heating speed can be run by jumping

terminals "R" and "G" on 24-volt terminal block
located on Fan Timer.

?? Blower cooling speed can be run by jumping

terminals "R" and "Y" on 24-volt terminal block
located on Fan Timer.

NOTE: On cooling speed, there is a short on-delay before

blower starts and a 60-second off-delay before blower
stops.

10. Read duct system static pressure from slope gauge.

NOTE: If air filter location is upstream of return-air pressure

tap, static pressure must be adjusted to exclude filter
pressure drop. Do this by subtracting 0.08 inches W.C.
from the measured static pressure.

Duct System = Measured - 0.08 inches W.C.
Static Pressure Pressure

11. Remove jumper wire from 24-volt terminal strip.
Remove pressure taps and seal holes in ductwork.

SECTION 20. MEASURING AIR
TEMPERATURE RISE

You will need 2 thermometers with 1-degree resolution
capable of reading up to 175 degrees F.

Air temperature rise (supply air temperature minus retu rn
air temperature) must be within allowable air-temperature

rise range specified on furnace rating plate and in Table 9.
Follow this procedure:

1. Open supply air registers and retu rn air grilles. Make
sure registers and grilles are free of obstruction from
rugs, carpets, drapes or furniture.

2. Set balancing dampers in supply duct system.

3. Check ductwork for obstructions or leaks.

4. Make sure filters are clean and in place.

5. Make sure that blower speed taps are set for proper
heating and cooling. Refer to Section 18, "Adjusting
Blower Speed." Heating speed should be set
according to Table 9. Cooling speed should be set to

meet cooling equipment requirements. See Table 10
for cooling airflow capacities at 0.5 inch W.C.

6. Place one thermometer in supply air plenum
approximately 2 feet from furnace. Locate
thermometer tip in center of plenum to ensure proper
temperature measurement.

7. Place second thermometer in return-air duct
approximately 2 feet from furnace. Locate
thermometer tip in center of duct to ensure proper
temperature measurement.

8. Set room thermostat on highest temperature setting.
Operate furnace 6 minutes. Record supply air and
return air temperatures.

9. Calculate air temperature rise by subtracting return air
temperature from supply air temperature.

?? If air temperature rise is above temperature rise

range specified in Table 9, furnace is overfired or
has insufficient airflow. Check gas input following
the instructions in Section 14, "Checking Gas
Input Rate." If air temperature rise is still above
temperature rise range specified, more heating
airflow is needed. Change blower heating speed
to a higher setting following instructions in
Section 18, "Adjusting Blower Speed."

?? If air temperature rise is below temperature rise

range specified in Table 9, fu rnace is underfired
or has too much airflow. Check gas input
following the instructions in Section 14, "Checking
Gas Input Rate." If air temperature rise is still
below temperature rise range specified, less
heating airflow is needed. Change blower
heating speed to a lower setting following
instructions in Section 18, "Adjusting Blower

Speed."

?? After making adjustments, you must check air

temperature rise to verify that resulting air
temperature rise is within allowable range. If air
temperature rise is still outside temperature rise
range specified in Table 9, check duct system
design with a qualified heating engineer. It may
be necessary to re-size duct work. Recheck air
temperature rise after revising duct systems.

10. Set room thermostat to desired setting.

11. Remove thermometers and seal ductwork holes.

SECTION 21. CHECKING
CONTROLS

Before leaving work site, check to see that all controls are
functioning properly.

You will need a 0 to 15 inch water manometer with 0.1 inch
resolution and a 1/8" NPT manual shut -off valve.

Follow this procedure:

1. Turn off electricity at electrical disconnect switch next
to furnace.

2. Remove three screws holding burner access panel in
place. Remove burner access panel.

3. Turn gas control switch to OFF position.

Installer’s Information Manual Page 25

4. Connect a manometer to gas control outlet (manifold)
pressure tap.

5. Set room thermostat to its highest temperature.

6. Turn on electricity at electrical disconnect switch
located next to furnace.

7. Diagnostic light on Fan Timer should be on and cycling
bright-dim -bright-dim...

8. Draft inducer should run and pilot igniter should glow
but pilot burner should not light. Manifold pressure
should remain at zero.

9. Turn gas control switch to ON position.

10. Pilot burner should light and ignite main burners. It
may take several minutes to purge gas line before pilot
burner lights. Wait 30 seconds after main burner
ignition for main blower to start.

11. Cycle electrical disconnect switch next to fu rnace on
and off. Watch at least three ignition cycles. Pilot
should ignite main burners smoothly.

12. Burner flames should look the same with circulation
blower on and off.

13. Remove manometer from gas control and replace
outlet pressure tap

14. Use a commercial soap solution made to detect leaks
and check all gas piping connections. Bubbles indicate
gas leakage. Seal all leaks before proceeding.

15. Replace burner access panel using three screws
removed in step 2.

16. Set room thermostat to desired setting.

SECTION 22. SETTING BLOWER
TIMINGS

Heating blower on-delay is fixed at 30 seconds from when
main valve opens. It is not adjustable.

Heating blower off-delay is adjustable to one of four times:
60, 100, 140 or 180 seconds. Heating blower off-delay is
factory set at 140 seconds. If a different blower off-delay is
desired, do the following:

1. Find two small switches located near 24-volt terminal
strip on Fan Timer.

2. Determine switch settings for desired heating blower
off-delay. See Figure 23.

3. Set switches on Fan Timer using a small screwdriver.

NOTE: Cooling blower off-delay is fixed at 60 seconds and
is not adjustable.

Figure 23. Heating Blower Off-Delay.

SECTION 23. MAINTAINING
FURNACE IN GOOD WORKING
ORDER

WARNING : Use replacement parts listed in parts
list only. Use of incorrect parts on this furnace could cause
improper fu rnace operati on, resulting in damage, injury or
death.

WARNING : Failure to disconnect electrical power
before servicing fu rnace could result in electrical shock or
death.

Inspection and cleaning by a qualified service person
should be performed once each heating season. Make
sure the inspection includes each of the items listed below.

?? An operational check of the entire system. Assure that

furnace is operating properly and safely.

?? Vent pipe must be in place, slope upward at least 1/4

inch per foot and must be physically sound, without
holes or loose connections.

?? All venting components including vent pipe and vent

terminal must be clear and free of obstructions.

?? Condensate drain system must be clear and free

including all internal and external hoses and
condensate trap. Check for signs of condensate
leakage.

?? Furnace-room - or closet- combustion and ventilation

air openings must be clear and free.

?? Furnace combustion-air opening must be clear and

free.

?? Return air duct must be physically sound, sealed to

furnace casing and ending outside the space
containing furnace.

?? Supply air ducts and return air ducts must be clear and

free, and without air leaks.

?? Registers and return grilles must be open and

unobstructed by rug, carpet or furniture.

?? The fu rnace must be well supported without sagging,

cracks, or gaps around the base.

Page 26 Installer’s Information Manual

?? There must be no obvious signs of deterioration of the

furnace. Inspection must include burners, pilot, heat
exchanger, inducer pan, and draft inducer.

?? Flame holders, located inside the main burners, should

be free of lint or dirt. Burners can be cleaned with
compressed air.

?? Inspect all electrical wiring and connections, including

electrical ground.

?? Gas pipes must be checked for leaks using a

commercial soap solution made to detect leaks.

?? Main burners and pilot burner must be in good

adjustment as shown in the User’s Information Manual.
Main burner flame must be clear blue and centered
within heat exchanger openings.

?? Check furnace area for combustible materials,

flammable liquid near furnace, corrosive materials,
insulation material within 12 inches of furnace, and

signs of high water levels.

?? Inspect, clean, or repair as needed the following items:

blower housing, blower motor, blower wheel, air filters,
draft inducer, and cooling coil.

NOTE: Blower motor and inducer motor do not require
oiling.

Follow these steps to remove blower assembly:

1. Turn off furnace electrical power.

2. Disconnect room thermostat wires from 24-volt terminal
strip on Fan Timer.

3. Locate five blower mot or wires that feed though casing
hem.

4. Label blower motor wires for proper replacement.

5. Disconnect blower motor wires from Fan Timer. See
Figure 22.

6. Remove 2 screws holding blower door in place.
Remove blower door.

7. Pull blower motor wires through casing hem.

8. Remove power-disconnect assembly located in the
middle of blower deck.

9. Remove 2 screws holding blower assembly to blower
deck.

10. Slide blower assembly out.

11. After cleaning blower assembly, re-assemble in
reverse order making sure speed selections are in
original positions.

SECTION 24. ACCESSORIES

THERMOSTATS: These are quality thermostats with the
Consolidated Industries name. Choose from the T87
(round w/subbase), T834 (heating and cooling) or the
T8699 (Chronotherm III)--available in white only.

PROPANE CONVERSION KIT (BELOW 6,000 ft): Includes
propane regulator-spring kit, propane pilot orifice and main

burner orifices.
HIGH-ALTITUDE PROPANE CONVERSION KIT (ABOVE

6,000 ft): Includes propane regulator-spring kit, propane
pilot orifice, main burner orifices, and high-altitude pressure
switch.

NATURAL GAS CONVERSION KIT (BELOW 6,000 ft):
Includes natural gas regulator-spring kit, natural gas pilot
orifice and main burner orifices.

HIGH-ALTITUDE NATURAL GAS CONVERSION KIT
(ABOVE 6,000 ft): Includes natural gas regulator-spring kit,
natural gas pilot orifice, main burner orifices and high­altitude pressure switch.

BOTTOM FILTER CABINET: Three sizes - one size for
each furnace casing size.

SIDE FILTER CABINET: Attaches to either side of fu rnace.
One size fits all.

BOTTOM CLOSURE: Seals bottom of fu rnace when only
side return is used.

FILTERS: High-velocity washable filters, available in
cartons of 10. Sizes include 16 x 25 x 1 and 20 x 25 x 1.

SECTION 25. OTHER
INFORMATION AND
PUBLICATIONS

These publications can help you install the fu rnace. You
can usually find these at your local library or buy them
directly from the publisher. Be sure to consult current
edition of each standard.

National Fuel Gas Code
Canadian Installation Codes
National Electrical Code
Canadian Electrical Code
Standard For The Installation

Of Warm Air Heating And Air
Conditioning Systems.

For more information, contact these publishers:
ANSI: American National Standards Institute Inc.

1430 Broadway
New York, New York 10018
[phone]

CSA: Canadian Standards Association

178 Rexdale Boulevard
Rexdale, Ontario, Canada M9W 1R3
[phone]

ASHRAE: American Society Of Heating Ref rigeration And

Air-Conditioning Engineers, Inc.
1791 Tullie Circle N.E.
Atlanta, GA 30329
[phone]

NFPA: National Fire Protection Association

1 Batterymarch Park

Quincy, MA 02269

[phone]

ANSI Z223.1/NFPA 54
CAN/CGA B149
ANSI/NFPA Code 70
CSA C22.1
ASHRAE/NFPA 90

Installer’s Information Manual Page 27