7. Mark blower wheel, motor, and motor support in relation to
blower housing before disassembly to ensure proper reas-
sembly.
8. Loosen setscrew(s) 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. (Do not
remove motor belly band unless replacing motor.) Discon-
nect ground wire attached to blower housing before remov-
ing motor.
10. 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.
11. Clean blower wheel and motor using a vacuum with soft
brush attachment. Do not remove or disturb balance weights
(clips) on blower wheel blades.
CAUTION:
The blower wheel should not be dropped or
bent as balance will be affected.
12. Reinstall blower wheel by reversing items 10 a. through c.
Be sure wheel is positioned for proper rotation.
13. Reassemble motor and blower by reversing items 5 through
9. If motor has ground wire, be sure it is connected as
before.
CAUTION:
Be sure motor is properly positioned in
blower housing. The motor wires must exit the motor
below horizontal centerline of motor after blower assem-
bly has been reinstalled in the furnace. This applies to
upflow and downflow installations.
14. Reinstall blower assembly in furnace.
15. Reinstall control. (See item 12 for reassembly of vent pipe
and flue enclosure for downflow furnaces.)
16. Connect blower electrical leads to control. Please note that
connections are polarized for assembly. DO NOT FORCE.
C.
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 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 furnace only and
disconnect vent pipe from relief box.
4. Remove 2 screws that secure relief box. (See Fig. 5 or 6.)
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.
g. Flame-sensing electrode.
h. Wiring connectors leading to control.
6. Remove 8 screws that secure flue collector box to center
panel. Be careful not to damage sealant.
7. Remove complete inducer assembly from furnace, exposing
flue openings.
8. Using field-provided small wire brush, steel spring cable,
reversible electric drill, and vacuum cleaner, clean cells as
follows:
a. Assemble wire brush and steel spring cable.
(1.) Use 48 in. of 1/4-in. diameter high-grade steel
spring cable (commonly known as drain clean-out
or Roto-Rooter cable).
(2.) Use 1/4-in. diameter wire brush (commonly known
as 25-caliber rifle cleaning brush).
NOTE:
The materials needed in items (1.) and (2.) can usually be
purchased at local hardware stores.
(3.) Insert twisted wire end of brush into end of spring
cable, and crimp tight with crimping tool or strike
with ball-peen hammer. TIGHTNESS IS VERY
IMPORTANT.
(4.) Remove metal screw fitting from wire brush to
allow insertion into cable.
b. Clean each heat exchanger cell.
Fig. 6—Model 331JAV Downflow
A93394
PRESSURE
SWITCHES
VENT PIPE
ENCLOSURE
CONTROL
DRAFT
SAFEGUARD
SWITCH
AUXILIARY
LIMIT
SWITCH
MANUAL
RESET
LIMIT
SWITCHES
RELIEF
BOX
MOUNTING
SCREWS
—4—
Summary of Contents for 330JAV
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