Panasonic WH-SHF09F3E5 Service Manual page 104

16.5.18 Outdoor High Pressure Switch Activate (F12)
Malfunction Decision Conditions:
During operation of heating, when pressure 4.5MPa and above is detected by outdoor high pressure switch.
Malfunction Caused:
1 Faulty water pump.
2 Insufficient water flow rate in system.
3 Water leak in system.
4 3 way valve closed.
5 Clogged expansion valve or strainer.
6 Excessive refrigerant.
7 Faulty outdoor high pressure sensor and switch.
8 Faulty outdoor unit PCB.
Abnormality Judgment:
Continue 4 times in 20 minutes.
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