2.4.4.11. P4 malfunction
When compressor discharge temperature is higher than 115°C, the unit will stop, and unit runs again when
compressor discharge temperature is lower than 90°C.
P4 display
Temperature protection of
compressor discharge
Check whether the
compressor discharge temp. is
more than 115°C ?
No
Check
whether
connection is right between
compressor discharge temp.
sensor and PCB according
to wiring diagrams?
Yes
Measure the resistance value
of compressor discharge
temp. sensor. If the value is
not normal is normal refer to
the Appendix 2?
Yes
Replace outdoor main PCB
No
Replace high pressure valve assy
Electrical Control System
Check whether the
Yes
refrigerant is leak
No
the
No
No
Replace the compressor discharge temp. sensor
Yes
Correct the wiring connection
Troubleshooting
Stop leaking and add refrigerant
155