Refrigerant Shortage - Daikin FTXS20K2V1B Service Manual

Troubleshooting
4.6

Refrigerant Shortage

U0
Error Code
Method of Error Detecting by discharge pipe temperature
Refrigerant shortage is detected by checking the discharge pipe temperature and the opening of
Detection
the electronic expansion valve. If the refrigerant is short, the discharge pipe temperature tends
to rise.
Detecting by the difference in temperature
Refrigerant shortage is detected by checking the difference between suction and discharge
temperature.
Error Decision Detecting by discharge pipe temperature
The following conditions continue for 80 seconds.
Conditions
Detecting by the difference in temperature
When the difference of the temperature is smaller than G°C, it is regarded as refrigerant
shortage.
Operation
mode
Cooling
Heating
Supposed
Causes
66
Opening of the electronic expansion valve ≥ D
Discharge pipe temperature > E × target discharge pipe temperature + F
D (pulse) E (–)
480 128/128
Description
room thermistor temperature – indoor heat exchanger temperature
outdoor heat exchanger temperature – outdoor temperature
indoor heat exchanger temperature – room thermistor temperature
outdoor temperature – outdoor heat exchanger temperature
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
Disconnection of the discharge pipe thermistor, indoor or outdoor heat exchanger thermistor,
room or outdoor temperature thermistor
Closed stop valve
Refrigerant shortage (refrigerant leakage)
Poor compression performance of compressor
Defective electronic expansion valve
F (°C)
30
SiBE041134EB
G (°C)
4.0
4.0
3.0
3.0
Service Diagnosis