Panasonic WH-UD28AE Service Manual page 52

16.5.10. Water Flow Switch Abnormality (H62)
Malfunction Decision Conditions:
During operation of heating, the water flow detected by the indoor water flow switch is used to determine water flow error.
Malfunction Caused:
1. Water leak in system.
2. Faulty connector connection.
3. Faulty switch.
4. Faulty PCB.
Abnormality Judgment:
Continue for 1 minute (but no judgment for 9 minutes after compressor startup/restart).
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