Carrier 38QHC009D8S Series, Service Manual

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10.2.10 Inverter compressor drive error diagnosis and solution(P4)
Error Code
P4
Malfunction decision
conditions
An abnormal inverter compressor drive is detected by a special
detection circuit, including communication signal detection,
voltage detection, compressor rotation speed signal detection
and so on.
Supposed causes
●
Wiring mistake
●
IPM malfunction
●
Outdoor fan ass’y faulty
●
Compressor malfunction
●
Outdoor PCB faulty
Trouble shooting:
Check the wiring between main PCB
and compressor
Correct the connection or replace
the wires and connectors.
Yes
No
Check the IPM No
Yes
Replace the IPM board or replace
the main PCB
Check the outdoor fan and the
outdoor unit ventilation
No
Please refer to the solution of
【
Fan
Speed Has Been Out Of Control
】
malfunction
Yes
Check the compressor resistance
values
No Replace the compressor.
Yes
Replace the outdoor main PCB