Refrigerant Shortage Warning - Daikin RXQ12AHR Service Manual

Troubleshooting by Error Code

5.47 Refrigerant Shortage Warning

Applicable All outdoor unit models
Models
U0
Error Code
Sub code: 05
Method of Error
Detects refrigerant shortage according to the ending conditions of cooling oil return operation.
Detection
Error Decision
Cooling oil return operation does not finish according to the ending conditions, and the time is
Conditions up for 3 consecutive times.
 No abnormality is determined, and the operation continues.
Supposed
 Refrigerant shortage and refrigerant clogging (wrong piping)
Causes  Defective thermistor
 Defective low pressure sensor
 Defective outdoor unit main PCB
Troubleshooting
Reference
CHECK 2 Refer to page 288.
Reference
CHECK 3 Refer to page 289.
260
Be sure to turn off the power switch before connecting or disconnecting
Caution
connectors, or parts may be damaged.
Are the
NO
characteristics of the
suction air thermistor
normal?
YES
Are the
NO
characteristics of the
low pressure sensor
normal?
YES
CHECK 2
NO
Is refrigerant shortage detected
as a cause of abnormally
low pressure?
YES
CHECK 3
NO
Is refrigerant shortage detected
as a cause of superheat
operation?
YES
CHECK 7
YES
Is refrigerant
insufficient?
NO
CHECK 2
YES
Is another cause detected as a
cause of abnormally low
pressure?
NO
CHECK 3
YES
Is another cause detected
as a cause of superheat
operation?
NO
SiAF341904E
Replace the thermistor.
Replace the low pressure
sensor.
Correct the abnormally low
pressure.
Correct the superheat
operation.
Correct the insufficient low
refrigerant condition.
Replace the outdoor unit
main PCB (A1P).
Part 6 Service Diagnosis