Daikin FVXG25K2V1B, Руководство по обслуживанию

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Troubleshooting SiBE061121_A
74 Service Diagnosis
4.8 Low-voltage Detection or Over-voltage Detection
Error Code
U2
Method of Error
Detection Indoor Unit
The zero-cross detection of the power supply is evaluated by the indoor unit PCB.
Outdoor Unit
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.
Error Decision
Conditions Indoor Unit
There is no zero-cross detection in approximately 10 seconds.
Outdoor Unit
Low-voltage detection:
„
The voltage detected by the DC voltage detection circuit is below 150 ~ 180 V (depending on
the model).
„
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
„
Power supply voltage is not as specified.
„
Defective DC voltage detection circuit
„
Defective over-voltage detection circuit
„
Defective PAM control part
„
Disconnection of compressor harness
„
Short circuit inside the fan motor winding
„
Noise
„
Momentary fall of voltage
„
Momentary power failure
„
Defective indoor unit PCB