Low-Voltage Detection Or Over-Voltage Detection - Daikin H Series Service Manual

Troubleshooting

4.24 Low-voltage Detection or Over-voltage Detection

U2
Remote
Controller
Display
Method of
Low-voltage detection:
Malfunction 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.
Malfunction Low-voltage detection:
 The voltage detected by the DC voltage detection circuit is below 150 V.
Decision
 The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Conditions
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.
 Supply voltage is not as specified.
Supposed
 Defective DC voltage detection circuit
Causes
 Defective over-voltage detection circuit
 Defective PAM control part
 Layer short inside the fan motor winding
Service Diagnosis
SiUS04-924_A
107