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17.5.22 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:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Check the indoor-outdoor
units connection wires.
Is there any wiring error?
Is the Vdc fluctuate
between 45-60 Vdc?
Is the Vdc fluctuate
between 15-60 Vdc?
Turn OFF the power and disconnect
terminal 3 wire. Turn ON the power
and measure Vdc between terminal
2 & 3 from the outdoor unit.
Turn OFF the power and reconnect
terminal 3 wire. Turn ON the power
and again measure Vdc between
terminal 2 & 3 from outdoor unit.
Correct the indoor-outdoor
units connection wires.
Replace the outdoor unit
PCB (main).
Replace the indoor unit
PCB (main).
Yes
Yes
No
No
No
Caution