Troubleshooting For Outdoor Unit; Refrigerant Shortage - Daikin 4MXL-T Series Service Manual

SiUS121827E

7. Troubleshooting for Outdoor Unit

7.1

Refrigerant Shortage

U0
Error Code
Outdoor Unit LED A j 1 h 2 h 3 i 4 i 5 h
Display
Method of Error Refrigerant shortage is detected by checking the input current value and the compressor running
Detection frequency. If there is insufficient refrigerant, the input current tends to be lower than the normal
value.
Error Decision
The following conditions continue for 7 minutes.
Conditions
 Input current ≤ A × output frequency + B
 Output frequency > C
 If the error repeats, the system is shut down.
 Reset condition: Continuous run for about 60 minutes without any other error
Supposed
 The installation space not large enough
Causes  Dirty outdoor heat exchanger
 Defective outdoor fan motor
 Disconnection of the discharge pipe thermistor, indoor or outdoor heat exchanger thermistor,
 Closed stop valve
 Refrigerant shortage (refrigerant leakage)
 Poor compression performance of compressor
 Defective electronic expansion valve
Part 6 Service Diagnosis
A (coefficient) B (A)
2500/256 50
room or outdoor temperature thermistor

Troubleshooting for Outdoor Unit

C (Hz)
40
195