Carrier N92ESN Installation, Start-Up, Operating And Service And Maintenance Instructions page 57

N92ESN: Installation, Start-up, Operating and Service and Maintenance Instructions
2. Remove blower door.
3. All factory wires can be left connected, but field thermostat and
accessory wiring may need to be disconnected depending on their
length and routing.
4. If the vent and combustion air pipe passes through the blower
compartment, it will be necessary to remove the pipes from the
blower compartment.
Disconnect the vent and combustion air pipe by:
a. Loosen the clamps on the vent couplings and combustion air
pipe external to the furnace.
b. Separate the pipes from the couplings and move them aside.
c. Loosen the clamps on the vent couplings and combustion air pipe
located on the blower shelf.
d. Separate the pipes from the blower compartment and set aside.
e. Remove the couplings from the pipe adapters and set aside.
f. After servicing the blower, reverse steps a through e.
g. Tighten all clamps 15 lb -in.
See Fig. 65 for steps 5 through 14.
5. Remove screws securing blower assembly to blower shelf and slide
blower assembly out of furnace. Detach ground wire and
disconnect blower motor harness plugs from blower motor.
NOTE: Blower wheel is fragile. Use care.
6. Clean blower wheel and motor by using a vacuum with soft brush
attachment. Be careful not to disturb balance weights (clips) on
blower wheel vanes. Do not bend wheel or blades as balance will be
affected.
7. If greasy residue is present on blower wheel, remove wheel from
the blower housing and wash it with an appropriate degreaser. To
remove wheel:
a. Mark blower wheel location on shaft before disassembly to
ensure proper reassembly.
b. Loosen setscrew holding blower wheel on motor shaft.
NOTE: Mark blower mounting arms and blower housing so each arm is
positioned at the same hole location during reassembly.
c. Mark blower wheel orientation and cutoff plate location to
ensure proper reassembly.
d. Remove screws securing cutoff plate and remove cutoff plate
from housing.
e. Remove bolts holding motor mounts to blower housing and slide
motor and mounts out of housing.
f. Remove blower wheel from housing.
g. Clean wheel per instructions on degreaser cleaner. Do not get
degreaser in motor.
8. Reassemble motor and blower wheel by reversing items 7b through
7f. Ensure wheel is positioned for proper rotation.
9. Torque motor mounting bolts to 40 +/- 10 lb-in. when reassembling.
10. Torque blower wheel set screw to 160 +/- 20 lb-in. when
reassembling.
11. Verify that blower wheel is centered in blower housing and set
screw contacts the flat portion of the motor shaft. Loosen set screw
on blower wheel and reposition if necessary.
12. Spin the blower wheel by hand to verify that the wheel does not rub
on the housing.
13. Reinstall blower assembly in furnace.
14. Reinstall 2 screws securing blower assembly to blower deck.
15. Reconnect blower leads to furnace control. Refer to furnace wiring
diagram, and connect thermostat leads if previously disconnected.
NOTE: Be sure to attach ground wire and reconnect blower harness
plugs to blower motor.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
!
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or death.
Blower door switch opens 115-v power to control. No component
operation can occur unless switch is closed. Caution must be taken
when manually closing this switch for service purposes.
16. Downflow or horizontal furnaces with vent pipe through furnace
only:
a. Install and connect short piece of vent pipe inside furnace to
existing vent.
b. Connect vent connector to vent elbow.
17. Turn on electrical supply. Manually close blower door switch. Use a
piece of tape to hold switch closed. Check for proper rotation and
speed changes between heating and cooling by jumpering R to G
and R to Y on furnace control thermostat terminals. If outdoor
temperature is below 70_F (21_C), turn off circuit breaker to
outdoor unit before running furnace in the cooling cycle. Turn
outdoor circuit breaker on after completing cooling cycle. See
Fig. 36.
NOTE: If R-W/W1 thermostat terminals are jumpered at the time
blower door switch is closed, blower will run for 90 sec before
beginning a heating cycle.
a. Perform component self-test as shown at the bottom of the
SERVICE label, located on the control door.
b. Verify blower is rotating in the correct direction
18. If furnace is operating properly, RELEASE BLOWER DOOR
SWITCH. Remove any jumpers or reconnect any disconnected
thermostat leads. Replace blower door.
19. Turn on gas supply and cycle furnace through one complete heating
cycle. Verify the furnace temperature rise as shown in Adjustments
Section. Adjust temperature rise as shown in Adjustments Section.
MOTOR SHAFT FLAT
SET SCREW
SEE DETAIL
SCREW LOCATION
BLOWER HSG ASSY
BRACKET
BRACKET
ENGAGEMENT
A
DETAIL
BRACKET
CAPACITOR
OR POWER CHOKE
(WHEN USED)
Fig. 65 – Blower Assembly
57
WARNING
GROMMET
MOTOR WHEEL HUB
A
CUTOFF, BLOWER
WHEEL, BLOWER
BLOWER HSG ASSY
MOTOR, BLOWER
SCREW
(GND)
MOTOR ARM
SCREW
A11584