Carrier 48KHA - Manual (Page 20)

3. Remove and clean blower wheel.
a. Ensure proper reassembly by marking wheel
orientation and cutoff plate location.
b. Remove screws holding cutoff plate, and
remove plate from housing.
c. Lift wheel from housing. When handling and/
or cleaning blower wheel, be sure not to
disturb balance weights (clips) on blower
wheel vanes.
d. Remove caked-on dirt from wheel and hous­
ing with a brush. Remove lint and/or dirt
accumulation from wheel and housing with
vacuum cleaner, using soft brush attachment.
Remove grease and oil with mild solvent.
e. Reassemble wheel and cutoff plate into
housing.
f. Reassemble motor into housing. Be sure set­
screws are tightened on motor shaft flats and
not on round part of shaft.
4. Reinstall blower assembly into unit. Route
blower motor leads into control compartment
and reconnect all blower motor leads to proper
termination points in unit control box. Replace
panels.
5. Restore electrical power, then gas supply, to unit.
Start unit and check for proper blower rotation
and motor speeds during heating and cooling
cycles.
Heating Section — Ensure dependable and effi­
cient heating operation by inspecting heating section
before each heating season and cleaning when neces­
sary. Proceed as follows:
1. Turn off gas supply, then disconnect electrical
power to unit.
2. Inspect and clean heating section.
a. Remove control access door.
b. Remove unit top following procedures under
Top Removal.
c. Remove secondary-air shield, flue baffles,
pilot and burners. Flue baffles may be re­
moved after partial loosening of collector
front panel. Inspect and clean all of these com­
ponents. Be sure to remove any residue that
may have collected on a component.
d. Clean flue ways with brush and/or vacuum,
and inspect heat exchanger for leaks and
cracks.
e. Inspect indoor-air passages in unit for cleanli­
ness and check tightness of screws and parts.
f. Replace all components removed in step c,
and replace unit top.
3. Restore electrical power, then gas supply to unit.
Start heating cycle and adjust burner air shutters.
See Heating Section Start-Up and Adjustments
— Adjusting Burner Air Shutters.
4. Inspect gas control area for gas leaks, using a
soap-and-water solution.
5. Replace control access panel.
Pilot — Inspect the pilot and clean (when necessary)
at beginning of each heating season. Remove accu­
mulation of soot and carbon from pilot. The pilot
flame must be high enough to properly touch
flame-sensing element and to light burners.
Condenser Coil, Evaporator Coil and Con­
densate Drain Pan
— Inspect condenser coil,
evaporator coil and condensate drain pan at least
once each year. Proper inspection and cleaning
requires removal of unit top. See Top Removal
section.
Coils are easily cleaned when dry; therefore, in­
spect and clean coils either before or after each
cooling season. Remove all obstructions including
weeds and shrubs that interfere with airflow through
condenser coil. Straighten bent fins with a fin comb.
If coated with dirt or lint, clean coils with a vacuum
cleaner, using soft brush attachment. Be careful not
to bend fins. If coated with oil or grease, clean coils
with mild detergent and water solution. Rinse coils
with clear water, using a garden hose. Be careful not
to splash water on motors, insulation, wiring or air
filter(s). For best results, spray condenser coil fins
from inside to outside of unit. On units with an outer
and inner condenser coil, be sure to clean between
coils. Be sure to flush all dirt and debris from unit
base.
Inspect drain pan and condensate drain line when
inspecting the coils. Clean drain pan and condensate
drain by removing all foreign matter from pan.
Flush pan and drain tube with clear water. Do not
splash water on insulation, motor, wiring or air
filter(s). If drain tube is restricted, clear it with a
plumber’s snake or similar probe device.
The bottom of drain tube has a 1/8-in. diameter
hole. This hole is located in the portion of the drain
tube that runs through drain pan. Clean this hole
with a stiff wire that has a 3/8-in. long, 90 degree
bend.
Condenser Fan
Inspect fan blades for cracks or bends each year.
Ensure that blades clear the motor by exactly 114
inch. If blade assembly has slipped down motor
shaft, adjust fan position on motor shaft by loosen­
ing setscrew(s), then moving blade assembly up. Be
sure setscrew(s) is on flat(s) of shaft before tightening.
Electrical Controls and Wiring — Inspect and
check electrical controls and wiring annually. Be
sure to turn off gas supply and then electrical power
to unit.
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