Midea M4OC-36HRFN1-M - Compressor Discharge Temperature Protection (P4) Diagnosis

9.4.2.12 P4(Temperature protection of compressor discharge) error diagnosis and solution.
Error Code
P4
Malfunction decision
conditions
When the compressor discharge temperature(Tp) is more
than 115℃ for 10 seconds, the compressor will stop and
restart till Tp is less than 90℃.
Supposed causes
● Refrigerant leakage
● Wiring mistake
● The discharge temperature sensor faulty
● Outdoor PCB faulty
Trouble shooting:
Temperature protection of
compressor discharge
Check whether the
compressor discharge temp.
is more than 115°C ?
Check whether the wiring
connection is right between
compressor discharge temp.
sensor and PCB according
to wiring diagrams?
Method: Check whether the
resistance of compressor
discharge temp. sensor is
right refer to the Appendix 2
No
Yes
Yes
Trouble is solved
No
Judge: The
discharge temp.
sensor is broken
Check whether the
refrigerant is leak
Correct the wiring connection
Stop leaking and add refrigerant
Replace the compressor discharge temp. sensor
No
Yes
Replace outdoor main board
Yes