First: normal shutdown 1. Slowly close the suction valve of the compressor; 2. Turn off the condenser to the liquid supply valve of the evaporator and the outlet valve of the condenser; 3. The pressure in the crankcase is reduced and then uninstalled step by step;4. After the unloading is completed, stop the operation of the compressor and the oil pump; 

5. Turn off the exhaust valve of the refrigeration compressor; 6. After the compressor has stopped running for 15 minutes, the cold water system and the cooling water system are turned off. Second: accident shutdown 

1. Stop the operation of the compressor, close the suction valve of the compressor, and investigate the cause of the accident;

2. Stop the operation of the oil pump and close the cooling water inlet valve of the oil cooler; 

3. Turn off the cold water system and the cooling water system;

4. Cut off the main power supply and eliminate the accident.

third: long-term downtime
1. close the shutoff valve on the supply pipe;
2. disconnect the unit power;
3. close the compressor suction and exhaust valves;
4. Note on all closed valves: Open before turning on again;
5. cut off the waterway and drain all the water in the evaporator, condenser and water pipeline to prevent the pipeline from freezing at low temperatures;
6. During the shutdown period, start the lubricating oil pump regularly to lubricate the working face of the compressor to facilitate the next startup.

7. Gradually close the unit's outlet valve to unload the unit and pump all of the refrigerant into the condenser. In order to prevent the unit from stopping due to too low suction pressure, the low pressure pressure relay setting can be adjusted to 0.15 MPa. When the suction pressure is reduced to 0.15 MPa, the compressor is stopped, and the pressure set value is adjusted back to the specified value;

This article sources industrial chiller manufacturers www.dgcarno.com.cn