The outlet temperature of the expansion valve reflects the evaporation temperature, which is a factor affecting heat transfer. Generally, it is 5~6°C different from the outlet temperature of the refrigerant water. When a low valve temperature fault occurs, the compressor will stop. When the valve temperature rises, it will automatically resume operation with a protection value of -2°C.

The reasons for low valve temperature failure of the chiller are as follows:

1 A small amount of refrigerant leakage usually manifests itself as a low valve temperature fault rather than a low pressure fault. Insufficient refrigerant will evaporate at the outlet of the expansion valve, causing cooling, which is manifested as frost at the outlet of the expansion valve. At the same time, the temperature of the suction port is high (superheated steam), the cooling capacity decreases, and the cooling is slow.

2. The expansion valve is clogged or the opening is too small, and the system is not clean. If the refrigerant pipeline is not cleaned after maintenance, the refrigerant is impure or contains moisture.

3. Insufficient refrigerant water flow or clogged evaporator. Poor heat exchange results in low evaporation temperature and low suction temperature. The opening of the expansion valve is adjusted according to the suction temperature. When the temperature is low, the opening is small, resulting in a low valve. temperature failure.

4. False alarms caused by electrical faults, such as poor contact of the valve temperature line, causing the display to remain unchanged at -5°C.