Daikin FTXS-L Series - Low-Voltage Detection or Over-Voltage Detection

Troubleshooting SiUS091133
107 Service Diagnosis
4.7 Low-voltage Detection or Over-voltage Detection
Remote
Controller
Display
U2
Method of
Malfunction
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.
Malfunction
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 ~ 200 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
 Supply voltage is not as specified.
 Defective DC voltage detection circuit
 Defective over-voltage detection circuit
 Defective PAM control part
 Disconnection of compressor harness
 Noise
 Momentary fall of voltage
 Momentary power failure
 Defective indoor unit PCB