Troubleshooting
SiBE07-618_C
66
Service Diagnosis
4.6
Signal Transmission Error (between Indoor Unit and
Outdoor Unit)
Remote
Controller
Display
U4
Method of
Malfunction
Detection
The data received from the outdoor unit checked whether it is normal.
Malfunction
Decision
Conditions
The data sent from the outdoor unit cannot be received normally, or the content of the data is
abnormal.
Supposed
Causes
Wiring error
Breaking of the connection wires between the indoor and outdoor units (wire No. 3)
Defective outdoor unit PCB
Defective indoor unit PCB
Disturbed power supply waveform
Troubleshooting
Check No.10
Refer to P.98
Check No.10
Check the power supply
waveform.
Check the voltage of the
connection wires on the indoor
terminal board between No. 1
and No. 3, and between No. 2
and No. 3.
YES
YES
Replace the indoor unit PCB.
Locate the cause of the
disturbance of the power
supply waveform, and correct
it.
NO
(R12028)
NO
YES
YES
NO
NO
Caution
Correct the indoor unit -
outdoor unit connection wires.
Diagnose the outdoor unit
PCB.
Replace the connection wires
between the indoor and
outdoor units.
Is LED A blinking?
Properly insulated?
Is there any disturbance?
Is there any wiring error?
Check the indoor unit - outdoor
unit connection wires.
Check the LED A on the outdoor
unit PCB.
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.