Carrier 40QSM009DS Service Manual page 98

16.3.3 Fan speed malfunction diagnosis and solution (E3)
Error Code
Malfunction conditions
Potential Causes
Trouble shooting:
Power off, then restart the
unit after 2 minutes. Does
a problem remain?
Yes
Shut off the power supply,
Rotate the fan by hand.
Does it turn easily?
Yes
Check the wiring of fan
motor. Is it improperly
wired?
Yes
Measure the voltage for the
fan motor from the main
PCB. Is it within normal
parameters?
Yes
Replace the fan motor
E3
When indoor fan speed is too low (300RPM) for a certain period
of time, the unit ceases operation and the LED displays a failure
code.
Wiring mistake
●
Faulty fan assembly
●
Faulty fan motor
●
Faulty PCB
●
No
No
No
No
The unit is operating normally
Find the cause of the
problem and resolve it
Correct the connections.
Replace the main PCB
No
95