Self-Diagnosis Method - Panasonic CS-Z25YKEA Service Manual

17.4 Self-diagnosis Method

17.4.1 H11 (Indoor/Outdoor Abnormal Communication)
Malfunction Decision Conditions

During startup 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 indoor unit PCB.

Faulty outdoor unit PCB.

Indoor unit-outdoor unit signal transmission error due to wiring error.

Indoor unit-outdoor unit signal transmission error due to breaking of wire in the connection wires between the
indoor and outdoor units.
Troubleshooting
When abnormality indication starts again
Measure the AC voltage at terminal 1 & 2 of outdoor unit
terminal board
Is the measured voltage 230/240V?
Measure the DC voltage at terminal 2 & 3 (communication
terminals) of outdoor unit terminal board
Is the measured DC voltage fluctuate between 10~70V?
(Value depend on multimeter accuracy)
Measure the AC voltage at terminal 1 & 2 of indoor unit
terminal board
Is the measured voltage 230/240V?
Measure the DC voltage at terminal 2 & 3 of indoor unit
terminal board
Is the measured DC voltage fluctuate between 10~70V?
YES
YES
YES
YES
125
For safety reason and to prevent
component breakdown, always switch
Caution
off the power before remove and
connect the component.
NO
● AC power supply abnormal fluctuation
● Defect in communication circuitry
NO
of outdoor unit PCB
● Replace the PCB
● Improper connection at terminals
NO
indoor/outdoor
●
Check indoor/outdoor connecting cable
● Improper connection at terminals
NO
indoor/outdoor
● Check indoor/outdoor connecting cable
● Defect in receiver/transmitter module of
the communication circuitry in indoor
unit PCB
● Replace the indoor unit PCB