Filter
Top Products
9
35 36
*Factory-provided with the furnace. Filters may be field modified by cutting-
filter material and support rods (3) in filters. Alternate sizes and additional
filters may be ordered from your dealer.
† Upflow only.
COMBUSTION AREA AND VENT SYSTEM
Visually inspect the combustion area and vent system before
each heating season. Make sure that all PVC pipes leading
into the combustion area and vent are free from any cracks
and sags. Check the combustion-air intake and vent pipe on
the outside of your home for blockage.
When dirt, soot, scale, or rust is allowed to build up, your fur-
nace can suffer a loss of efficiency and perform improperly.
Accumulations on the main burners can result in firing out of
normal sequence. This delayed ignition creates an alarmingly
loud sound.
To inspect the combustion area and vent system, you will
need a flashlight. Refer to Fig. 3 or 4, and proceed as follows:
1. Turn off the gas and electrical supplies to the furnace and
remove the main furnace door. (See Fig. 9, 10, and 11.)
2. Remove burner enclosure front. (See Fig. 37 or 38.)
Inspect the gas burners, igniter area, and remainder of furnace
for dirt, rust, soot, or scale.
3. Inspect the combustion-air and vent PVC pipes for sags,
holes, cracks, or disconnections. Horizontal portions of
pipes must slope downward toward furnace.
37 38
4. Reinstall burner enclosure front.
5. If your furnace is free of the above conditions, replace
main furnace door and turn on electrical and gas supplies
to the furnace. (See Fig. 16, 17, and 18.)
6. Start the furnace and observe its operation. Watch the
burner flames to see if they are clear blue, almost transpar-
ent. (See Fig. 36.) If you observe a suspected malfunction,
or the burner flames are not clear blue, call your dealer.
39
FURNACE AIR FILTER TABLE
AIR FILTER LOCATED IN BLOWER COMPARTMENT
FURNACE
CASING
WIDTH (IN.)
FILTER SIZE (IN)
FILTER
TYPESide Return† Bottom Return
17-1/2 (1) 16 x 25 x 1* (1) 16 x 25 x 1* Cleanable
21 (1) 16 x 25 x 1 (1) 20 x 25 x 1* Cleanable
24-1/2 (1 or 2) 16 x 25 x 1 (1) 24 x 25 x 1* Cleanable
AIR FILTER LOCATED IN FILTER CABINET
FILTER
CABINET
HEIGHT (IN)
FILTER
SIZE (IN)
FILTER
TYPE
16 (1) 16 x 25 x 1*
or (1) 16 x 25 x 4-5/16
Cleanable or
Disposable
20 (1) 20 x 25 x 1*
or (1) 20 x 25 x 4-5/16
Cleanable or
Disposable
24 (1) 24 x 25 x 1*
or (1) 24 x 25 x 4-5/16
Cleanable or
Disposable
CAUTION
Use care when cutting support rods in filters to
protect against flying pieces and sharp rod ends.
Wear safety glasses, gloves, and appropriate pro-
tective clothing. Failure to follow this caution
could result in personal injury.
DANGER
If holes are found in the pipes or if any portion has
become disconnected, toxic fumes can escape into
your home. DO NOT OPERATE YOUR FURNACE.
Call your dealer for service. Failure to follow this
warning could result in personal injury or death.
!
!
CAUTION
If your furnace makes an especially loud noise
when the main burners light, shut down your fur-
nace and call your dealer. Failure to follow this
caution would result in minor property damage.
CAUTION
If dirt, rust, soot, or scale accumulations are found,
call your dealer. Do not operate your furnace. Failure
to follow this caution would result in minor property
or product damage.
!
!
Upflow
Downflow