Low-Voltage Detection Or Over-Voltage Detection - Daikin 2MXS-W Series Service Manual

Troubleshooting for Outdoor Unit
7.2

Low-voltage Detection or Over-voltage Detection

U2
Error Code
Outdoor Unit LED A j 1 i 2 h 3 h 4 i 5 h
Display
Method of Error
 Indoor Unit
Detection
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.
Error Decision  Indoor Unit
Conditions
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 A 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
A (V)
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  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
 Defective indoor unit PCB
188
2/3/4MXS 5MXS
150 180
2/3MXL(H) 4MXL(H)
150 180
SiUS122226E
Part 6 Service Diagnosis