Refrigerant Shortage - Daikin FTXS20K2V1B Service Manual

SiBE041134
4.6

Refrigerant Shortage

U0
Remote
Controller
Display
Method of
Refrigerant shortage detection I:
Malfunction Refrigerant shortage is detected by checking the input current value and the compressor
running frequency. If the refrigerant is short, the input current is lower than the normal value.
Detection
Refrigerant shortage detection II:
Refrigerant shortage is detected by checking the discharge pipe temperature and the opening of
the electronic expansion valve. If the refrigerant is short, the discharge pipe temperature tends
to rise.
Refrigerant shortage detection III:
Refrigerant shortage is detected by checking the difference between suction and discharge
temperature.
Malfunction
Refrigerant shortage detection I:
Decision The following conditions continue for 7 minutes.
Conditions
Refrigerant shortage detection II :
The following conditions continue for 80 seconds.
Refrigerant shortage detection III :
When the difference of the temperature is smaller than G°C, it is regarded as refrigerant
shortage.
Cooling
Heating
Supposed
Causes
Service Diagnosis
Input current × input voltage
Output frequency > C
A B (W)
(–)
640/256 0
Opening of the electronic expansion valve ≥ D
Discharge pipe temperature > E × target discharge pipe temperature + F
D (pulse) E (–)
480 128/128
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
≤
A × output frequency + B
C (Hz)
55
F (°C)
30
Troubleshooting
G (°C)
4.0
4.0
3.0
3.0
73