Troubleshooting
SiMT041509E
61
Service Diagnosis
4.7
Signal Transmission Error (Between Indoor Unit and
Outdoor Unit)
Error Code
U4
Method of Error
Detection
The data received from the outdoor unit in signal transmission is checked whether it is normal.
Error Decision
Conditions
The data sent from the outdoor unit cannot be received normally, or the content of the data is
abnormal.
Supposed
Causes
Power supply voltage is not as specified.
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
Summary of Contents for FTK(X)M-P Series
Page 16: ...SiMT041509E 1 List of Functions Part 1 List of Functions 1 Functions 2...
Page 18: ...SiMT041509E 3 Specifications Part 2 Specifications 1 Specifications 4...
Page 59: ...SiMT041509E Remote Controller 44 Part 5 Remote Controller 1 Remote Controller 45...
Page 118: ...Revision History Month Year Version Revised contents 07 2015 SiMT041509E First edition...