BGH BSBSIC24CTK Manual page 48

Troubleshooting
12. 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
Discharge temperature protection of compressor
Yes
Check whether the compressor discharge temp. is more than 115°C ?
No
No
Check whether the wiring connection is right
between compressor discharge temp. sensor and
Correct the wiring connection
PCB according to wiring diagrams
Check whether the refrigerant is leak
Yes
Yes
Judge: The discharge temp. sensor is broken
Stop leaking and add refrigerant
No
Method: Check whether the resistance of compressor discharge Replace the compressor
temp. sensor is right refer to the Annex 2 discharge temp. sensor
Yes
Replace outdoor main board
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