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 Information
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 instructions.
• If you cannot reach gas supplier, call the fire
department.
431570 G
Page 2
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.
TABLE OF CONTENTS
SECTION 1. IMPORTANT SAFETY RULES ............................................................................................................. 2
SECTION 25. OTHER INFORMATION AND PUBLICATIONS ..................................................................................32
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 furnace 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.
431570 G
Page 3
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.
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.
subject to continuous higher or lower temperatures.
Continuous operation outside of this range may shorten
furnace life.
WARNING : Do not install furnace on its back or
front. Doing so could cause heat exchanger blockage and
damage to heat exchanger.
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.
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 fu rnace in the downflow position in an
alcove, attic, basement, closet, garage or utility room. See
Figure 1.
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 furnace as near to the center of the air distribution
system as possible.
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 for
horizontal installations on wood flooring. You may also
install furnace on wood flooring in the downflow position
when using a combustible floor base, available from the
manufacturer. See parts list.
You may install this furnace in the horizontal air-left or
horizontal air-right position in an alcove, attic, basement,
garage or utility room. See Figure 1.
WARNING: Do not install fu rnace 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.
LEVELING FURNACE
Furnace must be installed level for proper condensate
drainage.
Figure 1. Furnace Installation Positions.
CAUTION: Do not install furnace in an area subject to
freezing temperatures. Doing so could cause condensate
to freeze.
This furnace operates best when return-air temperature is
between 55°F and 80°F. Do not install furnace in a location
Installer’s Information Manual Page 3
In DOWNFLOW POSITION, furnace must be level or tilted
to the front no more than 1/4 inch. Furnace must also be
level from side to side within 1/4 inch. See Figure 2.
Page 4
Figure 4. Level furnace or tilt toward front no more than 1/4
inch.
Figure 2. Level furnace or tilt toward front no more than 1/4
inch. Also, level from side to side within 1/4 inch.
In HORIZONTAL POSITIONS, furnace must be level or
tilted to the front no more than 1/4 inch and must also be
level from side to side or tilted toward burner end no more
than 1/4 inch. See Figures 3 and 4.
CAUTION: Furnace must be installed level. Failure to
properly level furnace may result in heat exchanger
damage.
OTHER LOCATION INFORMATION
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 return
air duct to avoid pulling air from furnace room.
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 requirements.
See Figure 5 for furnace dimensions and clearances.
Figure 3. Level furnace or tilt toward burner end no more
than 1/4 inch.
Page 4 Installer’s Information Manual
Page 5
GAS
INPUT*
(Btu/hr) (HP) “A” “B” “C” TOP SIDES FRONT*** VENT Inches
* See Furnace Rating Plate.
** These are furnace dimensions. See Sections 9 and 10 for proper ductwork and floor opening dimensions.
*** 30-inch front clearance required for service.
MOTOR
SIZE*
FURNACE
WIDTH**
RETURN-
AIR SIZE**
SUPPLY -
AIR SIZE**
Downflow
CLEARANCE TO COMBUSTIBLES
Horizontal
(Inches)
and
BACK Downflow
Horizontal
VENT
SIZE
Figure 5. Furnace Dimensions and Clearances.
Installer’s Information Manual Page 5
Page 6
ATTIC INSTALLATION
Line contact is permissible for furnaces installed in
horizontal positions. The intersection of furnace top and
sides forms a line as shown in Figure 6. This line may be in
contact with combustible material.
Figure 6. Typical Attic Installation.
Install a platform under furnace that extends a minimum 30
inches in front of furnace. This provides a work area and
keeps insulating materials away from combustion air
openings. Secure platform to joists.
Note: In horizontal position, condens ate trap hangs as low
as 5 inches below furnace. Provisions must be made for
condensate trap and drain lines. See Section 5 for details
on condensate trap installation.
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 all burner combustion air
openings. Failure to do so could cause fire.
Figure 7. Suspending Using Threaded Rod.
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.
CRAWL SPACE INSTALLATION
Furnace can be hung from floor joists or installed on
suitable blocks or pad. Pad or blocks must provide enough
height to eliminate potential for water damage. Maintain
clearances listed in Figure 5.
SUSPENDING FURNACE
Some installations require that the furnace be suspended
from rafters or floor joists. A common way to do this using
threaded rods is shown in Figure 7. Consider this means
when people may walk underneath furnace. Other means
that provide adequate support may be used.
Level furnace from front to back and from left to right and
maintain clearances as described previously.
Page 6 Installer’s Information Manual
GENERAL VENTING GUIDELINES
?? Vent system and combustion air supply components
must be constructed of schedule 40 PVC, PVC -DWV,
SDR26, SDR21 or ABS plastic. Use 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 toward
furnace from vent terminal.
Page 7
?? 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).
?? Protect vent from freezing. Long runs of vent pipe
installed in an unconditioned space may require
insulati on to prevent freezing of condensate.
PVC PIPE INSTALLATION INSTRUCTIONS
1. Cut ends of pipe square using a miter box or PVC
tubing cutter. 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, 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.
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 which can be
opened, a non-mechanical-air-supply inlet, or the
combustion-air inlet of any other appliance
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.
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 appliance
vents, or plumbing vents. Allow at least 3 feet 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.
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 condensa te, 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 dampers.
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.
Installer’s Information Manual Page 7
Page 8
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.
3. Cement 2” PVC pipe, 2” PVC elbow, and flue outlet
together as shown in Figure 8. Position flue outlet
such that street ell will be directly below vent elbow.
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 which 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
INSTALLATION” under the “NON-DIRECT VENTING”
instructions.
A non-direct vented furnace takes all air for combustion
from the room in which furnace 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.
VENTING INSTRUCTIONS: DOWNFLOW
1. Select venting option from Figure 9 that fits your
installation. Downflow furnaces can be vented through
top or either side. For direct venting, combustion air
can come through top or either side.
2. From parts package find the following parts: section of
2” PVC pipe, 2” PVC elbow, PVC flue outlet fitting, and
1/2” street ell.
Figure 8. Downflow Vent Connection.
4. Cement 1/2” street ell to flue-outlet drain. Position
street ell so that it will be angled down and toward front
of furnace at a 45° angle when assembly is installed in
furnace.
5. Install large hose clamp over rubber coupling on
furnace draft inducer. Do not tighten hose clamp.
6. Push vent assembly into rubber coupling until it
bottoms out and tighten hose clamp securely.
7. From parts package find long condensate hose and
two hose clamps.
8. Attach condensate hose and one hose clamp to
inducer-pan port A, located in upper right-hand corner
of inducer pan. Hose should be curved toward 1/2”
street ell in flue outlet.
9. Attach other end of hose and remaining hose clamp to
1/2” street ell.
10. Some models are shipped with a 3-inch to 2-inch
reducer bush ing. When venting with 2-inch pipe, install
reducer bushing in flue outlet fitting. See Table 1 or
Table 2 for correct vent diameter for your application.
11. Complete installation of venting system with field
supplied parts.
12. Support vent pipe at furnace. Do not allow draft
inducer and rubber coupling to support the weight of
the vent pipe.
Page 8 Installer’s Information Manual
Page 9
Left Vent Top Vent Right Vent
Downflow Position
Top Vent Right Vent
Horizontal Air-Left Position
Top Vent Left Vent
Horizontal Air-Right Position
Figure 9. Venting Options. Dashed lines show optional combustion air pipes for direct venting.
Installer’s Information Manual Page 9
Page 10
VENTING INSTRUCTIONS: HORIZONTAL
AIR-LEFT
1. Select venting option from Figure 9 that fits your
installation. Horizontal furnaces can be vented through
top or through blower end of furnace (in most
applications). For direct ve nting, combustion air can
come through top or bottom.
2. From parts package, get PVC flue outlet fitting and
large hose clamp.
3. Install large hose clamp over rubber coupling on
furnace draft inducer. Do not tighten hose clamp. See
Figure 10.
4. Push flue outlet fitting into rubber coupling until it
bottoms out. Rotate flue outlet fitting until drain is on
bottom as shown in Figure 10. Tighten hose clamp
securely.
5. From parts package, get long condensate hose and
two hose clamps.
6. Long condensate hose must be cut to fit between flue
outlet drain and street ell. Proper length is 6¼ inches
for 17½ or 20½ inch wide furnaces and 8½ inches for
23½ inch wide furnaces.
7. Attach condensate hose and one hose clamp to flue
outlet fitting.
8. From parts package, get 1/2” street ell. Attach hose
and remaining hose clamp to 1/2” street ell. Test fit
street ell and hose assembly to inducer-pan port A,
located in lower right -hand corner of inducer pan. Note
the angle of the street ell.
9. Solvent weld street ell to inducer-pan port A at angle
noted in previous step.
11. Complete installation of venting system with field
supplied parts.
12. Support vent pipe at furnace. Do not allow draft
inducer and rubber coupling to support the weight of
the vent pipe.
VENTING INSTRUCTIONS: HORIZONTAL
AIR-RIGHT
1. Select venting option from Figure 9 that fits your
installation. Horizontal furnaces can be vented through
top or through blower end of furnace (in most
applications). For direct venting, combustion air can
come through top or bottom.
2. Move inducer drain hose from middle drain port of
inducer to inducer drain port at bottom of inducer-located near pressure switch. To do this, remove cap
from inducer drain port near pressure switch. Save
cap. Move hose from middle inducer drain hole to
uncapped port. Install cap on open port.
3. Move pressure switch hose from inducer pan port “B”
to inducer-pan port E. To do this, remove cap from
inducer-pan pressure port E, at pressure switch end of
inducer pan. Save cap. Move h ose from inducer-pan
pressure port B to port E. Install cap on port B.
4. From parts package, get PVC flue outlet and 1/2” street
ell.
5. Cement 1/2” street ell to flue-outlet drain. Position
street ell so that it will be angled down and toward front
of furnace at a 45° angle when assembly is installed in
furnace.
6. Install large hose clamp over rubber coupling on
furnace draft inducer. Do not tighten hose clamp.
7. Push flue outlet into rubber coupling until it bottoms
out. Rotate flue outlet until street ell is on bottom as
shown in Figure 11. Tighten hose clamp securely.
Figure 10. Horizontal Air-Left Vent Connection.
10. Some models are shipped with a 3-inch to 2-inch
reducer bushing. When venting with 2-inch pipe, install
reducer bushing in flue outlet. See Table 1 or Table 2
for correct vent diameter for your application.
Figure 11. Horizontal Air-Right Vent Connection.
Page 10 Installer’s Information Manual
Page 11
8. Move rubber cap from inducer-pan port D (located in
lower left-hand corner) to inducer-pan port A (located in
top left corner).
9. From parts package, get long condensate hose and
two hose clamps.
10. Attach condensate hose and one hose clamp to
inducer-pan port D. Hose should be curved toward
1/2” street ell in flue outlet.
11. Attach hose and remaining hose clamp to 1/2” street
ell. Position hose on street ell so that hose does not
kink. On some models it will be necessary to reduce
condensate hose length for proper fit.
12. Some models are shipped with a 3-inch to 2-inch
reducer bushing. When venting with 2-inch pipe, install
reducer bushing in flue outlet fitting. See venting Table
1 or Table 2 for correct vent diameter for your
application.
13. Complete installation of venting system with field
supplied parts.
14. Support vent pipe at furnace. Do not allow draft
inducer and rubber coupling to support the weight of
the vent pipe.
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.
DIRECT VENTING (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 1 elbow.
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
(a) (b)
Figure 12. (a) Sweep 90? Elbow. (b) Hard 90? Elbow.
NOTE: Table 1 assumes Sweep 90? elbows like that in
Figure 12a. If using Hard 90? elbows similar to the one in
Figure 12b, decrease the vent length by 3 feet for every
elbow used.
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 intervals.
?? 126,000 BTU input furnaces may not be vented using a
concentric vent .
Installer’s Information Manual Page 11
Page 12
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
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' 90,000
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
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
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
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
108,000
3" 40 40 40 40 40 40 40 40
126,0
00 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
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
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
anadditional 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 12 Installer’s Information Manual
Page 13
DIRECT-VENT TERMINATION
You may terminate vent and combustion air pipes 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
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 13a for vertical direct vent termination.
Note: When venting with 3-inch pipe, a 3” X 2” reducer must
be used. Locate reducer as close as possible to
combustion-air inlet. You may use up to 20” of 2-inch pipe.
Figure 14. Combustion-Air Pipe Connection to Furnace for
Direct Vent.
NON-DIRECT VENTING (one pipe system)
Figure 13a. Vertical Termination for Direct Venting.
Combustion-air-inlet termination must always be pointed
downward to keep out rain and snow. Furnace will not
operate properly with water in combustion compartme nt.
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 13b.
Figure 13b. Horizontal Termination for Direct Venting.
Attach a combustion-air pipe to combustion-air-inlet collar
located on top of furnace burner enclosure. Seal air pipe to
collar with RTV silicone caulk. See Figure 14.
Installer’s Information Manual Page 13
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 1 elbow.
Table 2 shows the maximum allowable pipe lengths for
non-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 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 12a. If using Hard 90? elbows similar to the one in
Figure 12b, decrease the vent length by 3 feet for every
elbow used.
Page 14
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" 55 50 45 40 35 30 25 20
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" 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' 90,000
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" 36 31 26 21 16 11 - -
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" 55 50 45 40 35 30 25 20
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" 55 50 45 40 35 30 25 20
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" 55 50 45 40 35 30 25 20
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" 55 50 45 40 35 30 25 20
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" 53 48 43 38 33 28 23 18
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" 40 35 30 25 20 15 - -
54,000
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" 31 26 21 16 11 - - -
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 altit ude pressure switch in order to operate the furnace at the listed
vent lengths.
Page 14 Installer’s Information Manual
Page 15
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 15.
Figure 15. 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
above average snow accumulation. See Figure 16.
there must be a positive seal between furnace and returnair duct to avoid pulling air from furnace room.
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,
fluorine, bromine and iodine may result in safety and
performance related problems. The following types of
installation may require outdoor air for combustion (or direct
venting) due to chemical exposures:
?? Buildings with indoor pools
?? Furnaces installed in laundry rooms
?? Furnaces installed in hobby or craft rooms
?? Furnaces installed near chemi cal storage rooms
?? Furnaces installed near exhaust fans which 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
Figure 16. Horizontal Termination for Non-Direct Venting.
exchanger and may result in nausea or death by
asphyxiation.
UNCONFINED SPACE INSTALLATION (non-direct
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,
Installer’s Information Manual Page 15
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
Page 16
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.
?? "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 54,000 Btu/hr furnace and a 40,000 Btu/hr water
heater would require the minimum free area openings
of 100 square inches.
Figure 17. Confined Space, All Air From Inside The
Building.
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.
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.
ALL COMBUSTION AND VENTILATION AIR FROM
OUTDOORS
The fu rnace space mus t 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.
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 17.
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.
Page 16 Installer’s Information Manual
Figure 18. All Air Directly 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.
Page 17
For example: A 108,000 Btu per hour furnace requires two
openings of at least 108,000 ÷ 4,000 or 27 square inches.
See Figure 18 and Table 3.
Table 3. Free Opening Area Based On One Square Inch
Per 4000 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 19 and Table 3.
Figure 20 and Table 4.
Table 4. Free Opening Area Based On One Square Inch
Per 2000 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.
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
Figure 19. All Air Through Vertical Ducts From Spaces
That Freely Access The Outdoors.
Figure 20. 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
90,000 = 45 square inches
2,000
Each duct 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.
?? Field installed drain line from furnace must flow down
hill from furnace trap.
?? 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.
CAUTION: Make sure that drain connections do not leak.
Air leaks around drain hoses will prevent furnace from
draining and cause the furnace to shutoff. Make sure all
hos e clamps are installed correctly.
Installer’s Information Manual Page 17
Page 18
DRAIN TRAP INSTRUCTIONS-DOWNFLOW POSITION
1. Select drain location option from Figure 21 that best fits
your installation. In downflow position, condensate trap
can be mounted for draining through either side of
furnace.
2. From parts package find the following parts:
condensate drain trap, 8 1/2” section of 13/16” OD
drain hose, and two small hose clamps.
3. From inside of casing, insert drain trap through hole in
side of casing, port B end first. Slide trap down with
casing between first set of guides. Trap will protrude
from casing about 1 inch with port B pointed down.
Port A of trap will be inside of casing and pointed up.
4. Attach condensate hose and one hose clamp to port A
of drain trap. Attach other end of condensate hose and
hose clamp to inducer-pan drain port. For right-side
drain, use inducer-pan port C, located in lower righthand corner of inducer pan. For left-side drain, move
rubber cap from inducer-pan port F, (located in lower
left-hand corner) to port C. Attach condensate hose to
port F.
2. From parts package find the following parts:
condensate drain trap, 8 1/2” section of 13/16” OD
drain hose, and two small hose clamps.
3. From underside of casing, insert drain trap through
hole in casing, port B end first. Slide trap toward
inducer pan with casing between trap mounting guides.
Use first set of guides for 17 1/2” and 23 1/2” wide
models. Use second set of guides for 20 1/2” wide
models. Trap will protrude into casing with port B
pointed toward inducer-pan-drain port C. Port A of trap
will be outside of casing and pointed toward front of
furnace.
4. Cut condensate hose to a length of 4 1/2 inches.
Attach hose and one hose clamp to port B of drain trap.
Attach other end of condensate hose and hose clamp
to inducer pan drain port C.
5. Complete installation of condensate drain system from
condensate trap (port A) with field supplied parts.
DRAIN TRAP INSTRUCTIONS-HORIZONTAL AIR-RIGHT POSITION
Figure 21. Downflow Drain-Trap Installation.
5. Complete installation of condensate drain system from
condensate trap (port B) with field supplied parts.
1. See Figure 23 for drain trap location for your
installation. In horizontal positions, condensate drain
trap must be mounted through bottom side of furnace.
2. From parts package find the following parts:
condensate drain trap, 8 1/2” section of 13/16” OD
drain hose, and two small hose clamps.
DRAIN TRAP INSTRUCTIONS-HORIZONTAL AIR-LEFT POSITION
1. See Figure 22 for drain trap location for your
installation. In horizontal positions, condensate drain
trap must be mounted through bottom side of furnace.
3. Move cap from inducer-pan port F, located in lower
right-hand corner of inducer pan, to port C, located in
upper right -hand corner of inducer pan.
4. From underside of casing, insert drain trap through
hole in casing, port B end first. Slide trap toward
inducer pan with casing between trap mounting guides.
Use first set of guides for 17 1/2” and 23 1/2” wide
models. Use second set of guides for 20 1/2” wide
models. Trap will protrude into casing with port B
pointed toward inducer-pan-drain port F. Port A of trap
will be outside of casing and pointed toward front of
furnace.
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
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 24 and the following instructions.
1. Install a 4-inch long x 1/2” NPT black-iron pipe nipple
through gas entry grommet and into gas -control inlet
elbow. Install a black iron pipe elbow on 4-inch nipple.
Tighten gas tight. Do not over tighten.
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.
5. Cut condensate hose to a length of 4 1/2 inches.
Attach hose and one hose clamp to port B of drain trap.
Attach other end of condensate hose and hose clamp
to inducer pan drain port F.
6. Complete installation of condensate drain system from
condensate trap (port A) with field supplied parts.
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.
Installer’s Information Manual Page 19
Figure 24. Gas Line Installation (downflow position shown).
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.
Page 20
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.).
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 isolate 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, and size wire. Remember to renumber
wire ends. Verify proper operation after servicing.
Figure 25. Field Wiring Diagram.
115 VOLT WIRING
Wire furnace according to the Field Wiring Diagram shown
in Figure 25, local codes, and current National Electrical
Code ANSI/NFPA 70 or Canadian Electrical Code CSA
C22.1. Also, see Furnace Wiring Diagram in Figure 26.
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.
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 thermo stat following field-wiring diagram in Figure 25
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.
Page 20 Installer’s Information Manual
Page 21
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 switch 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 lock-out if the main blower fails in
heating mode. During lock-out, the Fan Timer's diagnostic
light signal will be 4 flash es. The furnace's Fan Timer can
be reset by cycling power to furnace.
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.
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 the 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.
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 ta bs located under
breakaway covers. Use insulated quick connects when
connecting to "HUM" terminals.
BURNER LIMIT CIRCUIT OPEN
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 seconds.
CONSTANT FAN MODE
Thermostat calls for constant fan ("R" and "G" terminals
connected). Fan Timer energizes main blower on heating
speed.
A call for cooling, 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.
Installer’s Information Manual Page 21
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.
VENT LIMIT CIRCUIT OPEN
If vent limit circuit opens: burners turn off, draft inducer runs
during call for heat, and main blower turns off after blower
off-delay. There is 24-volt power on the "R" terminal and no
diagnostic light signal.
Page 22
Figure 26. Furnace Wiring Diagram.
Page 22 Installer’s Information Manual
Page 23
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.
Note: A combustible floor base, available from the
manufacturer, is required for downflow furnace installation
on wood flooring.
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 prev ent leaks.
If you install furnace in horizontal position with a cooling
coil, an eighteen-inch transition between furnace and
cooling coil should be used to allow free airflow into the coil.
Also, consult cooling coil installation instructions.
Design duct system so furnace will operate at a static
pressure of less than 0.50 inches W.C. on high blower
speed. 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.
See Figure 27 for floor cutout dimensions for combustible
floor base.
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.
WARNING : Failure to seal return-air ductwork
could allow combustion products to enter circulating air
stream resulting in injury or death by asphyxiation.
In downflow position, return-air duct must have a minimum
inside depth of 19-7/8 inches for filters to fit. See Figure 28.
Figure 27. Floor Cutout Dimensions.
Installer’s Information Manual Page 23
Figure 28. Downflow Filter Application.
Page 24
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
INSTALLING FILTERS
Properly installed air filters keep blower motor, blower
wheel and cooling coil (if installed) clean. Filters and filter
mounting hardware are not supplied with this furnace.
Filter system must be field supplied. The manufacturer has
downflow filter kits available.
This furnace was designed for external filters. Do not
install air filters inside fu rnace 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 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.
FILTER MOUNTING
Use a downflow filter kit, field fabricated filter cabinet, or a
return-air filter grille. Field fabricated filter cabinets should
allow spacing between filter and fu rnace. Placing a fieldsupplied filter directly against furnace will decrease airflow
and adversely affect furnace operation.
When using manufacturer’s downflow filter kit, filters must
be at least 16” X 20” X 1”, high-velocity, washable filters
(included in kit). See Figure 28.
See Table 6 for minimum recommended filter size for field
fabricated filter cabinets or return-air filter grille.
54,000 1/3 16 X 25 X 1 16 X 25 X 1
72,000 1/2 16 X 25 X 1 16 X 25 X 1
90,000 1/2 16 X 25 X 1 16 X 25 X 1
72,000 3/4 20 X 25 X 1 20 X 25 X 1
90,000 3/4 20 X 25 X 1 20 X 25 X 1
108,000 3/4 20 X 25 X 1 20 X 25 X 1
126,000 3/4 20 X 25 X 1 20 X 25 X 1
* GAS INPUT and MOTOR HP can be found on fu rnace
rating plate.
MOTOR*
HORSE POWER
DISPOSABLE
AIR FILTER
- two required
HIGH-
VELOCITY
WASHABLE
AIR FILTER
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 fu rnace level or tilted forward within 1/4 inch from
front to back?
3. If Downflow, is furnace level within 1/4 inch from side to
side?
4. If Horizontal, is furnace level or tilted toward burner up
to 1/4”.
5. Have you cleared away all loose construction and
insulation materials?
6. Is furnace installed with proper clearances?
7. If furnace is in a crawl space, is it sufficiently elevated
above the ground.
8. Does furnace have sufficient combustion and
ventilation air?
9. Is the vent system sloped toward the fu rnace at least
1/4 inch per foot?
10. Have you checked the vent system for leaks?
11. Did you completely check gas pipe and controls for gas
leaks?
12. Does electrical wiring follow current National Electrical
Code ANSI/NFPA 70 or Canadian Electrical Code CSA
C22.1 as well as local codes?
13. Is furnace electrically grounded?
14. Is room thermostat properly installed and heat
anticipator set correctly?
15. Is duct system correctly sized and sealed?
16. Are air filters in place and correctly sized?
Page 24 Installer’s Information Manual
Page 25
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.
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 24.
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 valve
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.
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.
3. Pilot flame should cover 1/2 inch of tip of flame sensor
as shown in Figure 29.
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.
Figure 29. 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
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.
PILOT FLAME ADJUSTMENT
Check gas-supply pressure first. Follow instructions in
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.
Installer’s Information Manual Page 25
Section 12, "Gas Supply Pressure and Pilot Adjustment."
1. Turn off gas at equipment shut-off valve in gas su pply
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 24.
4. Install 1/8" NPT manual shut-off valve in hole vacated
by plug. Make sure shut -off valve is in off position.
Page 26
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" inside 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.
SECTION 14. CHECKING GAS
INPUT RATE
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.
Page 26 Installer’s Information Manual
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 fu rnace following "Operating Instructions" inside
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)
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."
Page 27
PROPANE (LP) GAS INPUT RATE
WARNING : Propane (LP) gas installations do not
have gas meters to double-check input rate. Measure
manifold pressure adjustment with an accurate manometer.
Failure to accurately adjust pressure could cause heat
exchanger failure.
WARNING : Do not set Propane (LP) manifold
pressure at 11.0 inches W.C. It could cause heat
exchanger failure.
SECTION 15. DERATING FOR HIGH
ALTITUDE
NOTE: NOx reducing screens must be removed from each
tube of California NOx furnaces when converting to
propane (LP) gas. See Figure 30.
Figure 30. California NOx Screen Removal.
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 fu rnace following "Operating Instructions" inside
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."
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 resp onsibility 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 furnace rating plate.
Table 7. Natural Gas Orifice Size. (Millimeters)
ELEVATION
GAS Up 2001 3001 4001 5001 6001* 7001* 8001* 9001*
HEATING to to to to to to to to to
VALUE ** 20003000 4000 5000 6000 7000 8000 9000 10000
* 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 sh ut-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 31.
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.
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.
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 secti ons, 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 32.
Figure 31. Main Burner Removal.
8. Check burner carry-over alignment. Burner carryovers may touch but not overlap adjacent burner carry overs. Replace screws.
Page 28 Installer’s Information Manual
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 32.
Factory setting for heating is listed in Table 9. Heating
speed should not be reduced below factory setting.
Page 29
Figure 32. Main Blower Speed Selection.
3. Connect two unused motor leads to terminals marked
"UNUSED MOTOR LEADS" on Fan Timer. See Figure
32.
WARNING : Failure to properly terminate unused
motor leads could cause electrical shock.
Table 9. Factory Heating Speed and Temperature Rise.
GAS*
INPUT
(Btu/hr)
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.
** 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 have 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 30-60 MH / BLUE
1/2 30-60 ML / YEL
3/4 25-55 ML / YEL
1/2 45-75 MH / BLUE
3/4 35-65 MH / BLUE
3/4 35-65 ML / YEL
3/4 40-70 MH / BLUE
1/3 LO ML MH HI -- -1/2 LO LO ML HI -- -3/4 LO ML MH HI -1/2 LO 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 -- 400 CFM PER TON
HEATING
OPERATION
**SPEED TAP /
WIRE COLOR
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.
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.
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 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.
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.
Page 30 Installer’s Information Manual
Page 31
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 33.
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 33. 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 operation, 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 openings 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 mus t be well supported without sagging,
cracks, or gaps around the base.
?? 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.
Heat exchanger flue gas passageways may be cleaned
using the following steps:
1. Remove heat exchanger from furnace.
2. Flush heat exchanger passageways with a highpressure water hose.
3. Replace heat exchanger.
The manufacturer recommends replacement of heat
exchanger with a new heat exchanger in the event that flue
gas passageways become blocked and cannot be cleaned.
NOTE: Blower motor and inducer motor do not require
oiling.
Follow these steps to remove blower assembly:
1. Turn off furnace electrical power.
2. Cut vent pipe and remove vent assembly from the
inducer-motor rubber coupling.
3. If necessary, cut and remove air-intake pipe.
4. Disconnect room thermostat wires from 24-volt terminal
strip on Fan Timer.
Installer’s Information Manual Page 31
Page 32
5. Locate five blower motor wires that feed through casing
hem.
6. Label blower motor wires for proper replacement.
7. Disconnect blower motor wires from Fan Timer. See
Figure 32.
8. Remove 2 screws holding blower door in place.
Remove blower door.
9. Pull blower motor wires through casing hem.
10. Remove power-disconnect assembly located in the
middle of blower deck.
11. Remove 2 screws holding blower assembly to blower
deck.
12. Slide blower assembly out.
13. After cleaning blower assembly, re-assemble in
reverse order making sure speed selections are in
original positions.
14. Install the vent assembly into the inducer rubber
coupling and tighten the hose clamps. The cut vent
pipes must be joined using a PVC coupling or rubber
coupling available from manufacturer.
SECTION 24. ACCESSORIES
panel in plenum. Includes two 16” x 20” x 1” high-velocity,
washable filters.
FILTERS: High-velocity washable filters, available in
cartons of 10.
RUBBER COUPLINGS AND CLAMPS: May be installed in
vent system to provide easier blower access. Each kit
contains five sets of 2 couplings and 4 hose clamps.
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
THERMOSTATS: Quality thermostats are available from
the furnace manufacturer. 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
6000 FEET): 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 6000 FEET): Includes natural gas regulator-spring
kit, natural gas pilot orifice, main burner orifices and highaltitude pressure switch.
COMBUSTIBLE FLOOR BASE: Required for downflow
installation on wooden flooring. (Not required for horizontal
installations).
DOWNFLOW FILTER KIT: Filter support mounts between
furnace and downflow return plenum. Requires an access
Standard For The Installation
Of Warm Air Heating And Air
Conditioning Systems.
For more information, contact these publishers:
ANSI:
CSA:
ASHRAE:
NFPA: National Fire Protection Association
American National Standards Institute Inc.
1430 Broadway
New York, New York 10018
(212) 642-4900
Canadian Standards Association
178 Rexdale Boulevard
Rexdale, Ontario, Canada M9W 1R3
(416) 447-4044
American Society Of Heating Refrigeration And
Air-Conditioning Engineers, Inc.
1791 Tullie Circle N.E.
Atlanta, GA 30329
(404) 636-8400
1 Batterymarch Park
Quincy, MA 02269
(617) 770-3000
ASHRAE/NFPA 90
Page 32 Installer’s Information Manual
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