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WARNING: Turn OFF the gas and electrical supplies to the
unit before performing any maintenance or service. Follow
the operating instructions on the label attached to the
furnace. Failure to follow this warning could result in
personal injury.
The minimum maintenance that should be performed on this equip-
ment is as follows:
1. Check and clean or replace air filter each month, or as required.
(See Section 1.)
2. Check blower motor and wheel for cleanliness and lubrication
each heating and cooling season. Clean and lubricate as
necessary. (See Section 2.)
3. Check electrical connections for tightness and controls for
proper operation each heating season. Service as necessary.
4. Check for blockages of vent pipe.
CAUTION: As with any mechanical equipment, personal
injury could result from sharp metal edges, etc. Be careful
when removing parts, panels, or components.
I. AIR FILTER CLEANING AND REPLACEMENT
The air filter arrangement may vary depending on the application.
Each furnace may be supplied with a permanent, washable filter and
wire filter retainer option. If so, the filter is normally located in the
return-air plenum opening before the blower. (See Fig. 2.)
Fig. 2—Blower Compartment
TABLE 1—HORIZONTAL FURNACE FILTERS
FURNACE SIZE
FILTER SIZE
(INPUT BTUH)
50,000
(1) 13x23x1
75,000
(1) 13x23x1
100,000
(1) 16x23x1
125,000
(1) 20x23x1
CAUTION: Never operate unit without a filter or with filter
access door removed. Failure to follow this warning could
result in a fire or personal injury.
To clean or replace the filters, proceed as follows:
1. Turn OFF electrical supply to unit.
A91175
FILTER TYPE
(IN.)
Cleanable
Cleanable
Cleanable
Cleanable
2. Remove blower access door located at inlet (return air) end of
furnace; 4 screws must be removed.
3. Bend wire filter retainer until it clears furnace flange and swing
it toward the blower.
4. Remove filter from furnace. If filter is torn, replace it.
5. Furnaces may be equipped with permanent, washable filters.
Clean these filters by spraying cold tap water through filter in
opposite direction of airflow. A mild liquid detergent may be
used if necessary.
6. Rinse filters and let dry. Oiling or coating of filters is not
recommended or required for factory-supplied filters.
7. Reinstall filters with cross-mesh binding facing blower.
8. Replace blower access door and reinstall 4 screws.
9. Turn ON electrical supply to furnace.
II. BLOWER MOTOR AND WHEEL MAINTENANCE
For long life, economy, and high efficiency; clean accumulated dirt
and grease from blower wheel and motor annually.
The following items should be performed by a qualified service
technician:
Some motors have prelubricated, sealed bearings and require no
lubrication. These motors can be identified by the absence of oil ports
on each end of the motor. For motors with oil ports, lubricate as
follows:
Lubricate motor every 5 years if motor is used for intermittent
operation (thermostat FAN switch in AUTO position), or every 2
years if motor is in continuous operation (thermostat FAN switch in
ON position).
Clean and lubricate as follows:
1. Turn OFF electrical supply to unit.
2. Remove blower access door; 4 screws must be removed.
3. Remove blower assembly as follows:
a. Remove 4 screws securing front blower support bracket and
remove bracket. (See Fig. 2.)
b. Using a 3/8-in. ratchet with a 3-in. extension, reach through
4-in. diameter holes in rear blower support bracket and
remove 2 screws securing bracket to blower shelf. (See Fig.
2.)
c. Disconnect motor leads from motor speed selector. (See Fig.
2.)
d. Remove blower assembly from unit.
4. Mark blower wheel location on shaft before disassembly to
insure proper reassembly.
5. Loosen setscrew holding blower wheel on motor shaft.
6. Disconnect ground wire from blower housing.
7. Remove bolts holding motor mount to blower housing and
slide motor and mount out of housing.
8. Lubricate motor (when oil ports are provided).
a. Remove dust caps or plugs from oil ports located at each
end of motor. If motor does not have these caps or plugs,
bearings are sealed and need no further lubrication.
b. Use a good grade of SAE 20 nondetergent motor oil and add
1 teaspoon (5 cc, 3/16 oz, or 16 to 25 drops) in each oil port.
The use of other types or grades of oil will damage the
motor. Excessive oiling can cause premature bearing fail-
ures.
c. Allow time for total quantity of oil to be absorbed by each
bearing.
—2—
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