Due to the improper operation of low temperature chiller system, there is the possibility of  water entering into refrigerant system. Therefore, in view of the problem of water supply in low temperature chiller system, process guidance is formulated to serve as a reference for maintenance.
1. Analyse the reasons. Check the whole low temperature chiller system to confirm the cause of freezing damage and find out the leak point.
2. Blow dirt in sections.
(1) First, air compressor can be used to blow water (save nitrogen), until no water mist precipitate. Then blow with high pressure nitrogen, at the same time, heat the nitrogen (the nitrogen cylinder is prohibited from heating).
(2) Because the pipeline of low temperature chiller system is complex, water can be blown out in segments by using welding torch in some parts according to specific conditions.
(3) Heat and dry. The capillary, thermal expansion valve, compressor and other small components can be placed in the oven to bake and dry. Do replace the refrigerating oil in the compressor after the water is dried.
1. Vacuum drying
(1) Restore the pipeline and maintain the nitrogen pressure to ensure the air tightness of the system. Then connect the vacuum pump to the system for vacuum drying. (Dry filter barrel should be added to the front end of vacuum pump to avoid excessive water and gas entering the vacuum pump)
(2) In the process of vacuum drying, heat the place where water is easily stored in the pipeline, and the time can be determined according to the site.
2. Debugging and running.
(1) Make sure that the water in the system is basically removed.
(2) Connect the external drying filter barrel to the system and replace the desiccant after running for 5 minutes. At the same time, observe the operating parameters of the unit and pay attention to the sound of the compressor. If the dry filter is cold, the expansion valve frosts, and there is a pressure difference of more than 0.5 kg before and after the return air filter, stop the compressor   immediately.
3. Completion of maintenance
(1) Remove the refrigerant pipe from the drying filter barrel and restore it.
(2) Check the supplementary refrigerant quantity. Turn on and check the machine running parameters to confirm normal.