8.2 General Troubleshooting
PROBLEM P OSSIBLE CAUSE REMARK
No power Check voltage at electrical outlet. Correct if
none.
Power supply cord Check voltage at the power cord terminal.
Replace the power cord if none.
Wire disconnected or
connection loose
Connect wire. Refer to wiring diagram for
terminal identification. Repair or replace
loose terminal.
Main switch failure Check and replace the main switch if failure.
Capacitor (Discharge
capacitor before testing)
Test capacitor. Replace if not within +/-10%
of manufacturer's rating. Replace if
shorted, open or damaged.
Fan motor doesn’t
run.
Will not rotate
Fan blade hitting shroud or blower hitting
scroll. Realign assembly. Check fan motor
bearings. Replace the motor if motor shaft
do not rotate.
Check voltage. Call an electrician if not
within limits.
Test capacitor. Replace if not within +/-10%
of manufacturer's rating.
Check bearings. Replace the motor if the
fan blade cannot rotate freely.
Fan motor runs
intermittently Cycles on overload.
Pay attention to any change from high
speed to low speed. Replace the motor if
the speed does not change.
Fan Replace the fan if cracked, out of balance,
or partially missing.
Blower Replace the blower if cracked, out of
balance, or partially missing.
Loose screws Tighten them.
Fan motor noise.
Worn bearings
Replace the motor if knocking sounds continue
when running or loose, or the motor hums or
noise appears to be internal while running.
Compressor does
not to stop although
room temperature
has reached set
temperature.
Thermostat Check and replace the thermostat.
Service Manual
Room Air Conditioner with R-410A
Heat Controller, Inc.
27