Signal Transmission Error (Between Indoor Unit And Outdoor Unit) - Daikin FTX20K(2)V1B Service Manual

Troubleshooting
4.7 Signal Transmission Error (Between Indoor Unit and
Outdoor Unit)
U4
Error Code
The data received from the outdoor unit in signal transmission is checked whether it is normal.
Method of Error
Detection
The data sent from the outdoor unit cannot be received normally, or the content of the data is
Error Decision
abnormal.
Conditions
 Power supply voltage is not as specified.
Supposed
 Reduction of power supply voltage
Causes
 Wiring error
 Breaking of the connecting wires between the indoor and outdoor units (wire No. 3)
 Defective outdoor unit PCB
 Short circuit inside the fan motor winding
 Defective indoor unit PCB
 Disturbed power supply waveform
57
SiBE041525F
Service Diagnosis