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8.2.10 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 if the wiring between main
PCB and compressor connected
well?
Correct the connection or
replace the wires and
connectors.
No
Yes
Check if the IPM installed correctly.
Correct the installation,
tighten the screws and
apply silicon grease.
No
IPM continuity check. Check if the
IPM terminal resistance values are
uniform.
Yes
Replace the IPM board or replace
the main PCB if the IPM board and
main PCB are integrated together.
No
Check if the outdoor fan runs
properly or the outdoor unit
ventilation is good.
Yes
No
Please refer to the solution of
【
Fan
Speed Has Been Out Of Control
】
malfunction
Yes
Check if the compressor resistance
values are uniform .
No
Replace the compressor.
Yes
Replace the outdoor main PCB if the
main PCB and IPM are separate.
