SiBE041025
Troubleshooting
Service Diagnosis
59
4.6
Signal Transmission Error (between Indoor and Outdoor
Unit)
Remote
Controller
Display
U4
Method of
Malfunction
Detection
The data received from the outdoor unit in indoor unit-outdoor unit signal transmission is
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.89
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
(R12023)
NO
YES
YES
NO
NO
Caution
Correct the indoor unit-outdoor
unit connection wires.
Diagnose the outdoor unit
PCB.
∗
Set the fan operation by
remote controller, and cancel
the standby electricity saving
function before you check the
LED A.
∗
Wait at least for 7 sec. after
turning on the power.
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.