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SiBE12-933_A
Troubleshooting
Service Diagnosis
207
4.22 Over-voltage Detection / Low-voltage Detection
Remote
Controller
Display
U2
Method of
Malfunction
Detection
An abnormal voltage rise (or drop) is detected by checking the over-voltage detection circuit or
DC voltage detection circuit.
Malfunction
Decision
Conditions
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer, or
the voltage being detected by the DC voltage detection circuit is judged to be below 150V for
0.1 second.
The system is shut down if the error occurs 255 times.
Clearing condition: Continuous run for about 60 minutes (normal)
Supposed
Causes
Supply voltage not as specified
Over-voltage detector or DC voltage detection circuit defective
PAM control part(s) defective
Short circuit inside the fan motor winding.
Troubleshooting
(R7150)
Caution
Be sure to turn off power switch before connect or disconnect connector,
or parts damage may be occurred.
Check the supply voltage.
Supply voltage as
specified?
YES
Rotate fan by hand.
Does fan rotate
smoothly?
YES
NO
NO
Correct the power supply.
Replace fan motor and
outdoor unit PCB.
Turn on the power
again. System
restarted?
Repeat a
couple of times.
NO
YES
(Precaution before turning on the power again)
Make sure the power has been off for
at least 30 seconds.
Disturbance factors
∗
Noise
∗
Power supply distortion
Check for such factors for a
long term.
∗
Try to get restarted a
couple of times.
Replace the outdoor unit
PCB.