Panasonic WH-UD28AE Service Manual page 44

To determine if outdoor PCB or indoor PCB is faulty:
1. Start with outdoor terminal first.
2. Remove terminal 3 wire.
3. Measure with a multimeter (voltage in DC range).
4. If it is never constant, outdoor PCB is good fluctuating in between 20-70Vdc, outdoor PCB is in good condition.
16.5.2. Indoor Water Outlet Temperature Sensor Abnormality (H14)
Malfunction Decision Conditions:
During startup and operation of heating, the temperatures detected by the indoor water outlet temperature sensor are used to
determine sensor error.
Malfunction Caused:
1. Faulty connector connection.
2. Faulty sensor.
3. Faulty PCB.
Abnormality Judgment:
Continue for 5 seconds.
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