Carrier 38MGRBQ18B-3 - SPECIFIC ERROR DIAGNOSES; Outdoor DC Fan Motor Lack Phase Failure (EC72)

38MGRBQ: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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Lack phase failure of outdoor DC fan motor (EC72)
Check the fan three-phase
output for obvious open
circuit
Power off
,then restart the unit
2 minutes later.Is it still
displaying the error code?
The unit operates
normally
Check the fan motor wiring
Are all the connections good?
Correct the connections
Check whether the three-
phase resistance of the fan is
symmetrical
Replace the fan motor
Yes
Yes
Yes
No
No
No
Replace the main PCB
No
Problem solved
Yes