Carrier 38MBRQ36A-3 - Inverter Compressor Drive Error Diagnosis and Solution (P4)

38MBR: Service Manual
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Inverter Compressor Drive Error Diagnosis and Solution (P4)
Troubleshooting
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 assembly fault
• Compressor malfunction
• Outdoor PCB faulty
Check the wiring between the
main PCB and compressor.
Is it improperly wired?
Check the IPM.
/ƐŝƚĨƵŶĐƟŽŶŝŶŐƉƌŽƉĞƌůLJ
No
Yes
Check the outdoor fan and the
ŽƵƚĚŽŽƌƵŶŝƚǀĞŶƟůĂƟŽŶ
/ƐŝƚĨƵŶĐƟŽŶŝŶŐƉƌŽƉĞƌůLJ
Yes
Check the compressor resistance values.
Are they within acceptable parameters?
Yes
Replace the
outdoor main PCB.
ŶƐƵƌĞƉƌŽƉĞƌĐŽŶŶĞĐƟŽŶŽƌ
replace the wires and connectors.
Yes
Replace the IPM board
or replace the main PCB.
No
Please refer to
&ĂŶ^ƉĞĞĚDĂůĨƵŶĐƟŽŶƐĞĐƟŽŶ
No
Replace the compressor.
No