Service Manual

Troubleshooting SiUS091133
109 Service Diagnosis
4.8 Signal Transmission Error (between Indoor Unit and
Outdoor Unit)
Remote
Controller
Display
U4
Method of
Malfunction
Detection
The data received from the outdoor unit in indoor unit-outdoor unit signal transmission is checked
whether it is normal.
Malfunction
Decision
Conditions
The data sent from the outdoor unit cannot be received normally, or the content of the data is
abnormal.
Supposed
Causes
 Wiring error
 Breaking of the connection wires between the indoor and outdoor units (wire No. 3)
 Defective outdoor unit PCB
 Defective indoor unit PCB
 Disturbed power supply waveform