Cleaning Heat Exchanger - Carrier 58DLA Installation, Start-Up, Operating And Service And Maintenance Instructions

The inducer and blower motors are pre- -lubricated and require no
additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.
Clean blower motor and wheel as follows:
1. Turn off electrical supply to furnace.
2. Remove outer door.
3. For downflow or horizontal furnaces having vent pipes
within the furnace that pass in front of the blower access
door:
a. Disconnect vent connector from furnace vent elbow.
b. Disconnect and remove short piece of vent pipe from
within furnace.
4. Remove two screws from blower access door and remove
blower access door.
5. All factory wires can be left connected, but field thermo-
stat connections may need to be disconnected depending
on their length and routing.
6. Remove two screws holding blower assembly to blower
deck and slide blower assembly out of furnace.
7. Clean blower wheel and motor using a vacuum with soft
brush attachment. Blower wheel blades may be cleaned
with a small paint or flux brush. Do not remove or disturb
balance weights (clips) on blower wheel blades.
8. Vacuum any loose dust from blower housing, wheel and
motor.
9. If a greasy residue is present on blower wheel, remove
wheel from the blower housing and wash it with an appro-
priate degreaser. To remove wheel:
NOTE: Before disassembly, mark blower motor, and blower
housing so motor and each arm is positioned at the same location
during reassembly.
a. Disconnect capacitor wires and ground wire attached to
blower housing.
b. Remove screws securing cutoff plate and remove cutoff
plate from housing.
c. Loosen set screw holding blower wheel on motor shaft
(160+/- -20 in.- -lb. when reassembling).
d. Remove bolts holding motor to blower housing and slide
motor out of wheel (40+/- -10 in.- -lb. when reassembling).
e. Remove blower wheel from housing.
f. Clean wheel and housing.
10. Reassemble motor and blower by reversing steps 9a
through 9f, finishing with 9a. Be sure to reattach ground
wire to the blower housing.
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 neces-
sary.
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 two screws holding blower assembly to blower
deck.
15. Refer to furnace wiring diagram, and connect thermostat
leads if previously disconnected.
16. To check blower for proper rotation:
a. Turn on electrical supply.
b. Manually close blower access door switch.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in shortened heat
exchanger life.
Heating fan speed(s) MUST be adjusted to provide proper
air temperature rise as specified on the rating plate.
Recommended operation is at the midpoint of the rise range
or slightly above. Refer to "SET TEMPERATURE RISE"
under START- -UP, ADJUSTMENT,
CHECK.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, or death.
Blower access door switch opens 115- -v power to
furnace control. No component operation can occur
unless switch is closed. Exercise caution to avoid
electrical shock from exposed electrical components
when manually closing this switch for service purposes.
NOTE: If thermostat terminals are jumpered at the time blower
access door switch is closed, blower will run for 90 sec before
beginning a heating or cooling cycle.
c. Perform component self- -test as shown at the bottom of
the SERVICE label, located on the front of blower access
door.
d. Verify blower is rotating in the correct direction.
17. If furnace is operating properly, RELEASE BLOWER
ACCESS DOOR SWITCH. Remove any jumpers or re-
connect any disconnected thermostat leads. Replace
blower access door.
18. 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.
19. Reinstall outer door.
20. Cycle furnace through one complete heating and cooling
cycle. Verify the furnace temperature rise as shown in
"Adjustments" Section. Adjust temperature rise as shown
in "Adjustments" Section. 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.

Cleaning Heat Exchanger

The following steps should be performed by a qualified
service agency:
NOTE: If the heat exchangers get a heavy accumulation of soot
and carbon, they should be replaced rather than trying to clean
them thoroughly. A heavy build- -up of soot and carbon indicates
that a problem exists which needs to be corrected, such as
improper adjustment of manifold pressure, insufficient or poor
quality combustion air, incorrect size or damaged manifold
orifice( s), improper gas, or a restricted heat exchanger. Action
must be taken to correct the problem.
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and SAFETY