Low-Voltage Detection Or Over-Voltage Detection - Daikin CTXS07LVJU Service Manual

Troubleshooting for Outdoor Unit
7.2

Low-voltage Detection or Over-voltage Detection

U2
Error Code
Outdoor Unit LED A
Display
Method of Error
Detection
The zero-cross detection of the power supply is evaluated 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
136
j i h h i
1 2 3 4
Indoor Unit
Outdoor Unit
Indoor Unit
Outdoor Unit
The voltage detected by the DC voltage detection circuit is below 150 V for 0.1 second.
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
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.
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
Defective indoor unit PCB
h
5
SiUS121602E
Service Diagnosis