Kaisai KOU-12HDN1 Service Manual page 123

MLCAC-UTSM-2010-10
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.
Discharge temperature protection of compressor
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
Judge: The discharge temp. sensor is broken
Method: Check whether the resistance of compressor discharge
temp. sensor is right refer to the Annex 2
Outdoor Units
P4 display
No
Yes
Yes
Replace outdoor main board
No
Correct the wiring connection
Check whether the refrigerant is leak
Stop leaking and add refrigerant
No
Replace the compressor
discharge temp. sensor
Troubleshooting
Yes
Yes
119