Part 5 – Diagnosis and Troubleshooting
5.23 P4 Troubleshooting
Digital display output
Procedure
P4: Compressor discharge temperature
too high protection
High pressure switch protection
Refer to P1 trouble shooting
Discharge temperature sensor is not
installed
Installed the discharge temperature
sensor
Discharge temperature sensor
1
connection on main PCB is loose
Ensure the sensor is connected properly
Discharge temperature sensor is affected
by moisture or water
Discharge Temperature sensor has short-
circuited or failed or big temperature
drift
Replace refrigerant system PCB
Notes:
1. Discharge temperature sensor (Tp) connection is port CN4 on the refrigerant system PCB.
Protection logic
Discharge temperature > 115°C
Discharge temperature < 95°C