Filter
Top Products
Air Filter
Never operate the unit without a suitable air filter in the
return-air duct system. Always replace the filter with the
same dimensional size and type as originally installed.
See Tables 1 and 2 for recommended filter sizes.
Inspect air filter(s) at least once each month and replace
(throwaway-type) or clean (cleanable-type) at least twice dur-
ing each heating and cooling season or whenever the filter(s)
becomes clogged with dust and lint.
Unit Top Removal
NOTE: When performing maintenance or service proce-
dures that require removal of the unit top, be sure to perform
all of the routine maintenance procedures that require top
removal, including: inspection of the heat exchanger area,
coil inspection and cleaning, and condensate drain pan in-
spection and cleaning.
Only qualified service personnel should perform mainte-
nance and service procedures that require unit top removal.
Refer to the following top removal procedures:
1. Turn off gas supply, then turn off electric power to unit.
2. Remove all screws that secure unit top, including screws
around 4 sides and those on top that screw into internal
divider panels. Save all screws.
3. Lift top from unit carefully. Set top on edge.
4. Carefully replace and secure unit top to unit, using screws
removed in Step 2, when maintenance and/or service pro-
cedures are completed. (Be sure to use original screws
that have rubber washers to seal out water when securing
top to internal divider panels.)
Evaporator Blower and Motor
NOTE: Motors without oilers are prelubricated. Do not at-
tempt to lubricate these motors.
For longer life, operating economy, and continuing effi-
ciency, clean accumulated dirt and grease from the blower
wheel and motor annually.
Lubricate the motor every 5 years if the motor is used in-
termittently (thermostat FAN switch in AUTO. position), or
every 2 years if the motor is used continuously (thermostat
FAN switch in ON position).
Turn off the gas supply, then disconnect and tag elec-
trical power to the unit before cleaning and lubricating
the blower motor and wheel. Failure to adhere to this
warning could cause personal injury or death.
To clean and lubricate the blower motor and wheel:
1. Remove and disassemble blower assembly as follows:
a. Remove blower access door.
b. On standard non-ICM units disconnect motor lead from
blower relay (BR). Disconnect yellow lead from ter-
minal L2 of the contactor.
c. On all units remove blower assembly from unit. Re-
move screws securing blower to gas partition and slide
assembly out. Be careful not to tear insulation in blower
compartment.
d. Ensure proper reassembly by marking blower wheel
and motor in relation to blower housing before dis-
assembly.
e. Loosen setscrew(s) that secures wheel to motor shaft,
remove screws that secure motor mount brackets to
housing, and slide motor and motor mount out of
housing.
2. Lubricate motor as follows:
a. Thoroughly clean all accumulations of dirt or grease
from motor housing.
b. Remove dust caps or plugs from oil ports located at
each end of motor.
c. Use a good grade of SAE 20 nondetergent motor oil
and put one teaspoon (
3
⁄
16
oz. or 16 to 25 drops) in
each oil port.
d. Allow time for oil to be absorbed by each bearing,
then wipe excess oil from motor housing.
e. Replace dust caps or plugs in oil ports.
3. Remove and clean blower wheel as follows:
a. Ensure proper reassembly by marking wheel
orientation.
b. Lift wheel from housing. When handling and/or clean-
ing blower wheel, be sure not to disturb balance weights
(clips) on blower wheel vanes.
c. Remove caked-on dirt from wheel and housing with a
brush. Remove lint and/or dirt accumulations from wheel
and housing with vacuum cleaner, using soft brush at-
tachment. Remove grease and oil with mild solvent.
d. Reassemble wheel into housing.
e. Reassemble motor into housing. Be sure setscrews are
tightened on motor shaft flats and not on round part of
shaft.
f. Reinstall blower access door.
4. Restore electrical power, then gas supply to unit. Start
unit and check for proper blower rotation and motor speeds
during heating and cooling cycles.
Flue Gas Passageways — To inspect the flue col-
lector box and upper areas of the heat exchanger:
1. Remove the combustion blower wheel and motor assem-
bly according to directions in Combustion-Air Blower sec-
tion on page 46.
2. Remove the 3 screws holding the blower housing to the
flue collector box cover (see Fig. 34).
3. Remove the 12 screws holding the flue collector box cover
(Fig. 34) to the heat exchanger assembly. Inspect the heat
exchangers.
4. Clean all surfaces as required using the wire brush.
INDUCED
DRAFT MOTOR
MOUNTING PLATE
BLOWER
HOUSING
FLUE COLLECTOR
BOX
BURNER
RACK
MOUNTING
SCREW
Fig. 34 — Blower Housing and Flue Collector Box
45