Daikin 4MXS-R Series, Руководство по обслуживанию

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Troubleshooting for Outdoor Unit SiUS121736EA
181 Service Diagnosis
7.2 Low-voltage Detection or Over-voltage Detection
Error Code
U2
Outdoor Unit LED
Display A
j
1
i
2
h
3
h
4
i
5
h
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 V for 0.1 second.
„
If the error repeats, the system is shut down.
„
Reset condition: Continuous run for about 60 minutes without any other error
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 out of specification
„
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 drop of voltage
„
Momentary power failure
„
Defective outdoor unit PCB
„
Defective indoor unit PCB