Signal Transmission Error (Between Indoor Unit And Outdoor Unit) - Daikin FTKM-U Series Service Manual

Troubleshooting
4.8 Signal Transmission Error (Between Indoor Unit and
Outdoor Unit)
U4
Error Code
Method of Error
The signal transmission data received from the outdoor unit is checked whether it is normal.
Detection
Error Decision The data sent from the outdoor unit cannot be received normally, or the content of the data is
Conditions abnormal.
Supposed
 Power supply voltage out of specification
Causes  Reduction of power supply voltage
 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
66
SiMX042215E
Part 6 Service Diagnosis