Insufficient Gas - Daikin CTXS09GVJU Service Manual

SiUS12-814

5.25 Insufficient Gas

5.25.1 18 Class
U0
Remote
Controller
Display
Outdoor Unit LED A 5
Display
Method of Gas shortage detection I :
Malfunction A gas shortage is detected by checking the CT-detected input current value and the compressor
running frequency.
Detection
Gas shortage detection II :
A gas shortage is detected by checking the difference between indoor unit heat exchanger
temperature and room temperature as well as the difference between outdoor unit heat exchanger
temperature and room temperature.
Malfunction Gas shortage detection I :
Decision The following conditions continue for 7 minutes.
DC current × DC voltage < 1756 / 256 (A/Hz) × Compressor running frequency + 50
Conditions
However, when the status of running frequency > 55 (Hz) is kept on for a certain time.
Note : The values are different from model to model.
Gas shortage detection II :
The following conditions continue for 80 seconds.
If a gas shortage error takes place 4 times straight, the system will shut down. The error counter
will reset itself if this or any other error does not occur during the following 60-minute compressor
running time (total time).
Supposed
Causes
Service Diagnosis
1 1 2 1 3 4 4 4
Target opening of the electronic expansion valve ≥ 450 (pulse)
Cooling: discharge temperature > 255 / 256 × target discharge temperature +20 (°C)
Heating: discharge temperature > 255 / 256 × target discharge temperature +40 (°C)
Refrigerant shortage (refrigerant leakage)
Poor compression performance of compressor
Discharge pipe thermistor disconnected, or indoor unit or outdoor unit heat exchanger
thermistor disconnected, room or outside air temperature thermistor disconnected
Stop valve closed
Electronic expansion valve defective
Troubleshooting
151