Refrigerant Shortage - Daikin FTXS09HVJU Service Manual

SiUS04-904

4.21 Refrigerant Shortage

4.21.1 09/12 Class
U0
Remote
Controller
Display
Method of Refrigerant shortage detection I :
Refrigerant shortage is detected by checking the compressor running frequency.
Malfunction
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 air suction and discharge
temperature.
Malfunction Refrigerant shortage detection I :
Input current <
Decision
However, when the status of running frequency >
Conditions
Note : The values are different from model to model.
Refrigerant shortage detection III :
When the difference of the temperature is smaller than
Cooling
Heating
If a refrigerant shortage error takes place 4 times successively, the system is shut down. The error
counter is reset if this or any other error does not occur during the following 60-minute compressor
running time (total time).
 Refrigerant shortage (refrigerant leakage)
Supposed
 Poor compression performance of compressor
Causes
 Discharge pipe thermistor disconnected, or indoor unit or outdoor unit heat exchanger
 Stop valve closed
 Electronic expansion valve defective
138
(A/Hz) x Compressor running frequency
640 / 256 0
room temperature – indoor heat exchanger temperature
outdoor heat exchanger temperature – outdoor temperature
indoor heat exchanger temperature – room temperature
outdoor temperature – outdoor heat exchanger temperature
thermistor disconnected, room or outdoor air temperature thermistor disconnected
Voltage +
(Hz) is kept on for a certain time.
55
, it is regarded as refrigerant shortage.
Troubleshooting

7.2°F

7.2°F

7.2°F

5.4°F
Service Diagnosis