Panasonic WH-SDC09H3E8 Service Manual page 182

16.5.22 Indoor/Outdoor Abnormal Communication (H90)
Malfunction Decision Conditions:
During operation of cooling and 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 (main).
2 Faulty indoor unit PCB (main).
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.
Troubleshooting:
Turn OFF the power and disconnect
terminal 3 wire. Turn ON the power
and measure Vdc between terminal
Turn OFF the power and reconnect
terminal 3 wire. Turn ON the power
and again measure Vdc between
terminal 2 & 3 from the outdoor unit.
Caution
Check the indoor-outdoor
units connection wires.
Is there any wiring error?
No
2 & 3 from the outdoor unit.
Is the Vdc fluctuate
between 45-60Vdc?
Yes
Is the Vdc fluctuate
between 15-60Vdc?
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Yes
Correct the indoor-outdoor
units connection wires.
No
Replace the outdoor unit
No
Replace the indoor unit
182
PCB (main).
PCB (main).