Panasonic WH-UD30BE5-1 Service Manual page 50

16.5.7. Indoor/Outdoor Abnormal Communication (H90)
Malfunction Decision Conditions:
During standby and operation of heating, the data received from outdoor unit in indoor unit signal transmission is checked
whether it is normal.
Malfunction Caused:
1. Faulty outdoor unit PCB.
2. Faulty indoor unit PCB.
3. Indoor-outdoor signal transmission error due to wrong wiring.
4. Indoor-outdoor signal transmission error due to breaking of wire in the connection wires between the indoor and outdoor units.
5. Indoor-outdoor signal transmission error due to disturbed power supply waveform.
Abnormality Judgment:
Continue for 1 minute after operation.
Communication voltage measurement:
50