Self-Diagnosis Method - Panasonic CU-4E24RBU Service Manual

15.2 Self-diagnosis Method

15.2.1 H11 (Indoor/Outdoor Abnormal Communication)
Malfunction Decision Conditions

During standby and operation of cooling and heating, the data received from outdoor unit in indoor unit signal
transmission is checked whether it is normal.
Malfunction Caused

Faulty outdoor unit PCB.

Faulty indoor unit PCB.

Indoor-outdoor signal transmission error due to wrong wiring.

Indoor-outdoor signal transmission error due to breaking of wire in the connection wires between the indoor and
outdoor units.

Indoor-outdoor signal transmission error due to disturbed power supply waveform.
Abnormality Judgment:

After operation for 1 minute.
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?
No
Disconnect terminal 3
wire and measure Vdc
between terminal 2 & 3
from the outdoor unit.
Is the Vdc fluctuate
between 10-70Vdc?
Yes
Reconnect terminal 3
wire and measure Vdc
between terminal 2 & 3
from the outdoor unit.
Yes
Is the Vdc fluctuate
between 10-70Vdc?
Yes
Correct the indoor-outdoor
units connection wires.
No
Replace outdoor unit
PCB.
No
Replace indoor unit PCB.
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