The core problem of compressor oper
Introduction to five common failures of screw chillers
1. Screw chiller communication failure
The control of each module by the computer controller is realized through the communication line and the main interface board. The main cause of communication failure is the poor contact or open circuit of the communication line, especially the poor contact caused by the interface damp and oxidation, and the unit electronic board or the main interface Board failure, improper selection of the address dial switch, and power failure can cause communication failure.
2. Screw chiller low pressure failure
The suction pressure of the compressor is too low, causing the low-pressure protection relay to operate. The compressor suction pressure reflects the evaporation pressure, the normal value should be 0.4~0.6MPa, and the protection value is set to 0.2MPa. If the suction pressure is low, the return air volume is small, and the refrigeration capacity is insufficient, resulting in a waste of electric energy. For the return air cooling compressor motor, the heat dissipation is poor and the motor is easily damaged.
3. Screw chiller high pressure failure
The compressor discharge pressure is too high, causing the high-pressure protection relay to operate. The compressor discharge pressure reflects the condensing pressure, the normal value should be 1.4~1.6MPa, and the protection value is set to 2.0MPa. If the pressure is too high for a long time, it will cause the compressor to run too much current, easily burn the motor, and easily damage the compressor exhaust valve.
4. Screw chiller compressor overheat failure
Thermistor is embedded in the winding of the compressor motor, the resistance is generally 1kΩ. When the winding is overheated, the resistance value will increase rapidly. When it exceeds 141kΩ, the thermal protection module SSM will act to cut off the operation of the unit, and the overheating fault will be displayed at the same time, and the TH fault indicator will be on.
5. Screw chiller low valve temperature failure
The outlet temperature of the expansion valve reflects the evaporation temperature, which is a factor that affects the heat exchange. Generally, the difference between it and the outlet temperature of the refrigerant water is 5-6°C. When a low valve temperature failure occurs, the compressor will stop, and when the valve temperature rises, it will automatically resume operation with a protection value of -2°C.
