Self-Diagnosis Method - Panasonic CS-MS9SD3H Service Manual

13.5 Self-diagnosis Method

13.5.1 H11 (Indoor/Outdoor Abnormal Communication)
Malfunction Decision Conditions

During startup and operation of cooling, 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 20~70Vdc?
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 20~50Vdc?
YES
YES
YES
YES
Caution
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
43
For safety reason and to prevent
component breakdown, always switch
off the power before remove and
connect the component.