Maintenance of Screw Chiller

2024-09-23

Main contents of maintenance for screw chiller units include daily maintenance and regular overhaul. Regular overhaul and maintenance can ensure the long-term normal operation of the unit, extend the service life of the unit, and also save refrigeration energy consumption. For screw chiller units, there should be operation records to record the operation status of the unit, and a maintenance technical file should be established. Complete technical data is helpful to find potential faults and take measures in advance to prevent faults.

Screw compressor
The screw compressor is a very critical component in the unit. The quality of the compressor is directly related to the stability of the unit.
If the compressor fails. Due to the high installation accuracy requirements of the screw compressor, it is generally necessary to ask the manufacturer to carry out maintenance.
Cleaning of condenser and evaporator
The cooling water of the water-cooled condenser is an open circulation loop. Generally, tap water is used and circulated through the cooling tower. When the content of calcium salts and magnesium salts in the water is large, it is easy to decompose and deposit on the cooling water pipe to form scale, affecting heat transfer. Excessive scale formation will also reduce the circulation cross-section of the cooling water, reduce the water volume, and increase the condensing pressure. Therefore, when the quality of the cooling water used is poor, the cooling water pipe should be cleaned at least once a year to remove scale and other dirt in the pipe. There are usually the following two methods for cleaning condenser water pipes:
(1) Use a special pipe cleaning gun to clean the pipe.
(2) Use a special cleaning agent for cyclic flushing or fill it in the cooling water. Replace the solution after 24 hours until it is cleaned.
Changing lubricating oil
After the unit is used for a long time, the quality of the lubricating oil deteriorates, and the impurities and moisture inside the oil increase. Therefore, it is necessary to observe and check the quality of the oil regularly. Once a problem is found, it should be replaced in time. The brand of the replaced lubricating oil must conform to the technical data.
Replacement of drying filter
The drying filter is an important component to ensure the normal circulation of the refrigerant. Since water and refrigerant are immiscible, if there is moisture in the system, it will greatly affect the operating efficiency of the unit. Therefore, it is very important to keep the system interior dry. The filter element inside the drying filter must be replaced regularly.
Calibration of safety valve
The condenser and evaporator on the screw chiller unit belong to pressure vessels. According to regulations, a safety valve should be installed on the high-pressure end of the unit, that is, the condenser body. Once the unit is in an abnormal working environment, the safety valve can automatically relieve pressure to prevent possible high pressure from causing harm to the human body. Therefore, the regular calibration of the safety valve is very important for the safety of the entire unit.
Charging of refrigerant:
If there is no other special reason, generally the unit will not generate a large amount of leakage. If a certain amount of refrigerant leaks due to improper use or after maintenance, it is necessary to add refrigerant again. When charging refrigerant, attention must be paid to the brand of refrigerant used by the unit.