Daikin FVKS25BVMB, Service Manual

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Troubleshooting SiBE06-514A
114 Service Diagnosis
4.24 Insufficient Gas
Remote
Controller
Display
U0
Method of
Malfunction
Detection Gas shortage detection I:
Gas shortage is detected by checking the input current value and the compressor running
frequency. If the gas is short, the input current is smaller than the normal value.
Gas shortage detection II:
Gas shortage is detected by checking the discharge temperature and the opening of the
electronic expansion valve. If the gas is short, the discharge temperature tends to rise.
Gas shortage detection III:
A gas shortage is detected by checking the difference between inhale and exhale temperature.
Malfunction
Decision
Conditions Gas shortage detection I:
The following conditions continue for 7 minutes.
Š
Input current × input voltage
≤
640 / 256 × output frequency
Š
Output frequency > 55 (Hz)
Gas shortage detection II:
The following conditions continue for 80 seconds.
Š
Target opening of the electronic expansion valve
≥
480 (pulse)
Š
Discharge temperature > 255 / 256 × target discharge tempe30 (°C)
Gas shortage detection III:
When the difference of the temperature is smaller than , it is regarded as insufficient gas.
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 outdoor air temperature thermistor disconnected
„
Stop valve closed
„
Electronic expansion valve defective
Cooling
room temperature – indoor heat exchanger temperature 4.0°C
outdoor heat exchanger temperature – outdoor temperature 4.0°C
Heating
indoor heat exchanger temperature – room temperature 3.0°C
outdoor temperature – outdoor heat exchanger temperature 3.0°C