Daikin AT12BV1LS Pocket Manual page 143

Troubleshooting
5.3.9 Signal Transmission Error (between Indoor
and Outdoor Units)
Remote
Controller
Display
Method of
Malfunction
Detection
Malfunction
Decision
Conditions
Supposed
Causes
142
U4
The data received from the outdoor unit in indoor unit-
outdoor unit signal transmission is checked whether it is
normal.
When the data sent from the outdoor unit cannot be
received normally, or when the content of the data is
abnormal.
Faulty outdoor unit PCB.
Faulty indoor unit PCB.
Indoor unit-outdoor unit signal transmission error due
to wiring error.
Indoor unit-outdoor unit signal transmission error due
to disturbed power supply waveform.
Indoor unit-outdoor unit signal transmission error due
to breaking of wire in the connection wires between
the indoor and outdoor units (wire No. 2).
Si10-417
Service Diagnosis