![background image](http://html2.mh-extra.com/html/daikin/ftxr-t-series/ftxr-t-series_service-manual_3655463085.webp)
SiUS041829E
Troubleshooting
Part 6 Service Diagnosis
81
4.8 Signal Transmission Error (Between Indoor Unit and
Outdoor Unit)
Error Code
U4
Method of Error
Detection
The signal transmission data received from the outdoor unit 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 out of specification
Reduction of power supply voltage
Wiring error
Breaking of the connection 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 FTXR-T Series
Page 17: ...SiUS041829E Part 2 Specifications 13 1 Specifications 14 Part 2 Specifications...
Page 125: ...SiUS041829E Check Part 6 Service Diagnosis 121 18 class R25105 1 2 3 4 Multimeter...
Page 127: ...SiUS041829E Check Part 6 Service Diagnosis 123 18 class R20704 W V U DC_P1 DC_N1...
Page 143: ...SiUS041829E Operation Limit Part 8 Appendix 139 4 Operation Limit RX09 12 18RMVJU9 3D092209E...