Troubleshooting
SiBE04-808_B
143
Service Diagnosis
4.25 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 ~ 180 V (depending on
the model).
Over-voltage detection:
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer.
(The voltage is over 400 V.)
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 11 minutes (50 class: 5 minutes) without any
other error
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
