Service Manual -
VMH 9/12/18/24 SU & VMH30/36S D Series
42
45
9.3.1
1
Inverter compressor drive error diagnosis and solution
(P4)
Error Code
P4
Malfunction
c
onditions
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.
Possible
causes
●
Wiring
error
●
IPM malfunction
●
Outdoor fan ass
embl
y faulty
●
Compressor malfunction
●
Outdoor PCB faulty
Troubleshooting:
For 9K~18K:
Check that the wiring between
main PCB and compressor
are connected well.
Correct the connection
or replace the wires
and connectors.
Check the reactor or
inductor. Is it normal?
Replace the reactor
or inductor.
Check the IPM.
Is it installed correctly?
Correct the installation,
tighten the screws and
apply silicon grease.
IPM continuity check.
Make sure the IPM terminal
resistance values are uniform.
Replace the IPM board or replace the
main PCB if the IPM board and main
PCB are integrated together.
Check the outdoor fan to make
sure it runs properly and the
outdoor unit ventilation is good.
Please refer to the solution of
[Fan Speed Has Been Out Of
Control] malfunction
Check that the compressor
resistance values are uniform.
Replace the compressor.
Replace the outdoor main PCB if the
main PCB and IPM are separate.