Low-Voltage Detection Or Over-Voltage Detection - Daikin FTX-N Series Service Manual

Troubleshooting for FTX, FVXS Series
5.5

Low-voltage Detection or Over-voltage Detection

U2
Error Code
Method of Error
Low-voltage detection:
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
Low-voltage detection:
Conditions  The voltage detected by the DC voltage detection circuit is below 150 ~ 200 V (depending on
 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 (over
 The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Supposed  Power supply voltage out of specification
Causes  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
133
the model).
458 ~ 500 V, depending on the model).
SiUS091601EA
Part 6 Service Diagnosis