Screw chillers have many industrial application scenarios, such as machinery industry, food refrigeration, pharmaceutical and chemical industry, beverage and wine brewing, etc. There are roughly two classification methods. One is divided into air-cooling and water-cooling methods according to the condensation method; the other is divided into single-screw unit and twin-screw unit according to compressor type.

Screw compressor is a kind of compressor with adjustable energy. The main components include rotor, bearing, body, energy regulating device, etc. Through the rotation of the rotor, a periodic volume change is formed to realize the compression and work of the gas.

For the screw chiller, its operation is stable, but due to other reasons, such as year-round operation or insufficient maintenance, it will also cause common failures of the screw chiller.

Common fault types

1: High voltage failure

High-voltage failures usually have the following reasons:

1. The water temperature is too high. Mainly occurs in the high temperature season, cooling tower fan failure, cooling tower valve, cooling pipe blockage, will cause poor cooling water heat dissipation, water temperature will rise, causing high pressure to trigger an alarm.

2. Too much refrigerant. Refrigerant is a substance compressed in the refrigerant system. Too much addition will cause excessive suction and discharge pressure. As a result, the compressor current rises and high pressure appears.

3. Insufficient cooling water. If the system lacks cooling water, the system water flow will decrease, and the water pressure difference between the inlet and outlet of the unit will decrease. The temperature difference increases, causing high pressure.

4. The condenser is malfunctioning. The fouling and clogging of the condenser will cause poor operation of the cooling water system, poor water flow, reduced water flow, reduced heat dissipation area, and low condensation efficiency. Especially the common failure causes of chillers that have not been cleaned for a long time.

Common fault types

2:Low voltage fault

There are several reasons for low voltage failures.

1. The refrigerant charge is insufficient. The less refrigerant is added, the lower the working pressure of the refrigerant system will be, resulting in a decrease in compressor current and low pressure failure.

2. The cooling water temperature is too low. The usual solution is to close the cooling tower valve, reduce the cooling water flow, and increase the cooling water temperature. Especially in winter, it will cause the temperature of the refrigerating oil to drop, affect the separation, and cause low pressure.

3. Too little chilled water. Insufficient chilled water flow is usually caused by air in the system, water in the system, and damaged water pumps.

Other failures: such as blockage of expansion valve, blockage of evaporator, insufficient refrigerant charge, etc., can also cause unit failure or shutdown. Pay special attention to the temperature of the compressor during operation to avoid overheating.

The following are common troubleshooting methods.

1. Clean the condenser and evaporator.

Common faults include internal scaling, rust, corrosion, etc., which cause internal blockage and water pollution. Especially in an operating environment with poor cooling water quality, a water processor should be installed or the cleaning frequency should be increased.

2. Replace lubricating oil and filter drier.

Long running time of lubricating oil will cause deterioration of oil quality, penetration of moisture and impurities, and poor lubrication. The compressor overheated, causing serious failure in the later stage. Therefore, the lubricating oil and filter drier should be replaced regularly.

3. Regularly check the safety valve

The condenser evaporator container is equipped with a safety valve to avoid accidents caused by overpressure. Therefore, the working efficiency of the safety valve should be checked regularly to see if it is normal. Avoid accidents caused by damage.