Carrier 58TMA - Manual (Page 4)

Lubricate motor every 5 years if motor is used on intermittent
operation (thermostat FAN switch in AUTO position), or every 2
years if motor is in continuous operation (thermostat FAN switch
in ON position).
Remember to disconnect the electrical supply before removing
access doors.
Clean and lubricate as follows:
1. Remove blower access door.
2. Disconnect vent pipe on downflow/horizontal furnace only.
a. Remove vent pipe enclosure.
b. Disconnect vent pipe and remove short piece of pipe from
furnace.
c. Disconnect wires from auxiliary limit on blower housing (if
present).
3. Disconnect blower electrical leads from control. (See Fig. 6
and 7.) Note location of wires for reassembly.
4. Remove control.
5. Remove screws holding blower assembly to blower deck and
slide blower assembly out of furnace.
6. Loosen a screw in strap holding motor capacitor to blower
housing and slide capacitor out from under strap.
7. Mark blower wheel, motor, and motor support in relation to
blower housing before disassembly to ensure proper reassem-
bly.
8. Loosen setscrew holding blower wheel on motor shaft.
9. Remove bolts holding motor and motor mount to blower
housing and slide motor and mount out of housing. Disconnect
ground wire attached to blower housing before removing
motor.
10. Lubricate motor (when oil ports are provided).
a. Remove dust caps or plugs from oil ports located at each
end of motor.
b. Use a good grade of SAE 20 nondetergent motor oil and
put 1 teaspoon, 5 cc, 3/16 oz, or 16 to 25 drops in each oil
port. Do not over-oil.
c. Allow time for total quantity of oil to be absorbed into each
bearing.
d. After oiling motor, be sure to wipe excess oil from motor
housing.
e. Replace dust cap or plugs on oil ports.
11. Remove blower wheel from housing.
a. Mark cutoff location to ensure proper reassembly.
b. Remove screws holding cutoff plate and remove cutoff
plate from housing.
c. Lift blower wheel from housing through opening.
12. Clean blower wheel and motor using a vacuum with soft brush
attachment. Do not remove or disturb balance weights (clips)
on blower wheel blades. The blower wheel should not be
dropped or bent as balance will be affected.
13. Reinstall blower wheel by reversing items 11 a. through c. Be
sure wheel is positioned for proper rotation.
14. Reassemble motor and blower by reversing items 5 through 9.
If motor has ground wire, be sure it is connected as before.
Be sure the motor is properly positioned in the blower
housing. The motor oil ports must be at a minimum of 45°
above the horizontal centerline of the motor after the blower
assembly has been reinstalled in the furnace.
15. Reinstall blower assembly in furnace.
16. Reinstall control. (See step C.13 for reassembly of vent pipe
and flue enclosure for downflow/horizontal furnaces.)
17. Connect blower electrical leads to control. Please note that
connections are polarized for assembly. DO NOT FORCE.
CLEANING HEAT EXCHANGER
The following steps should be performed by a qualified service
technician:
NOTE: Deposits of soot and carbon indicate the existence of a
problem which needs to be corrected. Take action to correct the
problem.
If it becomes necessary to clean the heat exchanger because of
carbon deposits, soot, etc., proceed as follows:
1. Turn gas and power to furnace to OFF.
2. Remove control and blower access doors.
3. Remove vent pipe enclosure on downflow/horizontal furnace
only and disconnect vent pipe from relief box.
4. Remove 2 screws that secure relief box. (See Fig. 6 or 7.)
5. Disconnect wires to the following components. Mark wires to
aid in reconnection of:
a. Draft safeguard switch.
b. Inducer motor.
c. Pressure switch(es).
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface ignitor.
Fig. 7—Model 58TMA Downflow
A93394
PRESSURE
SWITCHES
VENT PIPE
ENCLOSURE
CONTROL
DRAFT
SAFEGUARD
SWITCH
AUXILIARY
LIMIT
SWITCH
MANUAL
RESET
LIMIT
SWITCHES
RELIEF
BOX
MOUNTING
SCREWS
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