Low-Voltage Detection Or Over-Voltage Detection - Daikin 2MXS40H2V1B Service Manual

SiBE121123_A
7.2

Low-voltage Detection or Over-voltage Detection

U2
Error Code
Method of Error
Detection
Evaluation of zero-cross detection of power supply by the indoor unit PCB.
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
There is no zero-cross detection in approximately 10 seconds.
Low-voltage detection:
Over-voltage detection:
Supposed
Causes
Service Diagnosis
Indoor Unit
Outdoor Unit
Indoor Unit
Outdoor Unit
The voltage detected by the DC voltage detection circuit is below 180 V.
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.
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
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 outdoor unit PCB
Defective indoor unit PCB
Troubleshooting for Outdoor Unit
180