Low-Voltage Detection Or Over-Voltage Detection - Daikin FTKN09NMVJU Service Manual

SiUS041501E
4.6

Low-voltage Detection or Over-voltage Detection

U2
Error Code
Method of Error Low-voltage detection:
An abnormal voltage drop is detected by the DC voltage detection circuit.
Detection
Over-voltage detection:
An abnormal voltage rise is detected by the over-voltage detection circuit.
Error Decision Low-voltage detection:
Conditions
Over-voltage detection:
Supposed
Causes
Service Diagnosis
The voltage detected by the DC voltage detection circuit is below 180 ~ 196 V (depending on
the model).
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer (over
458 ~ 500 V, depending on the model).
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
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 drop of voltage
Momentary power failure
Defective outdoor unit PCB
Troubleshooting
66