Troubleshooting Si12-411A
202 Service Diagnosis
5.23 Insufficient Gas
Remote
Controller
Display
U0
Outdoor Unit LED
Display
A
5
1
1
2
1
3
4
4
4
Method of
Malfunction
Detection
Gas shortage detection I : A gas shortage is detected by checking the CT-detected input current
value and the compressor running frequency.
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
Decision
Conditions
Gas shortage detection I :
Input current < 8.78 / 256 (A/Hz) x Compressor running frequency + 0.25
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 :
If a gas shortage error takes place 4 times straight, the system will be 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
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