Panasonic WH-SXH09D0E8 Service Manual page 50

16.5.4 Compressor Low Pressure Protection (H42)
Malfunction Decision Conditions:
During operation of heating and after 5 minutes compressor ON, when outdoor pipe temperature below -29°C or
above 26°C is detected by the outdoor pipe temperature sensor.
Malfunction Caused:
1 Dust accumulation on the outdoor unit heat exchanger.
2 Air short circuit at outdoor unit.
3 2 way valve partially closed.
4 Faulty outdoor unit fan motor.
5 Refrigerant shortage (refrigerant leakage).
6 Clogged expansion valve or strainer.
7 Faulty outdoor pipe temperature sensor.
8 Faulty outdoor unit main PCB (main).
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