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SiBE041010
Troubleshooting
Service Diagnosis
89
4.24 Low-voltage Detection or Over-voltage Detection
Remote
Controller
Display
U2
Method of
Malfunction
Detection
Low-voltage detection:
An abnormal voltage drop is detected by the DC voltage detection circuit.
Over-voltage detection:
An abnormal voltage rise is detected by the over-voltage detection circuit.
Malfunction
Decision
Conditions
Low-voltage detection:
The voltage detected by the DC voltage detection circuit is below 150 V.
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Over-voltage detection:
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer.
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Supposed
Causes
Supply voltage is not as specified.
Defective DC voltage detection circuit
Defective over-voltage detection circuit
Defective PAM control part
Layer short inside the fan motor winding
Troubleshooting
Correct the power supply.
Replace the PM1. (Replace
the outdoor unit PCB.)
Check for such factors for a
long term.
∗
Try to restart a few times.
(R8402)
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
NO
YES
YES
NO
YES
(Precaution before turning on the power again)
NO
Replace the fan motor or
the outdoor unit PCB.
Check the supply voltage.
Rotate the fan by hand.
Disturbance factors
∗
Noise
∗
Power supply distortion
Repeat a few
times.
Make sure the power has been off for
at least 30 seconds.
Turn on the
power again. System
restarted?
Does the fan rotate
smoothly?
Supply voltage as
specified?