The water-cooled screw chiller control system includes a compressor starting part and a control part. In the standard configuration, the compressor adopts an uninterrupted star-delta start method, which can effectively avoid the high switching current peaks during the start-up process.

Process control of water-cooled screw chiller on and off

1. Power on the control cabinet to preheat the compressor oil heater. The preheating time should be at least eight hours before starting.

2. The compressor can be turned on after the preheating time of the compressor reaches more than eight hours. Turn on the circulating water pump (cold water pump) first and then the cooling water pump.

3. After the cold water pump system and the cooling water pump system are circulated, the screw unit directly presses the start key;

4. Observe the start-up process by starting the chilled water pump first; the cooling water pump starts after the delay, and the unit starts after the water pump is delayed. The starting mode of the machine head is star-delta (Y- △) startup, and the conversion time is about 3.5 seconds. When starting, the compressor will run at 25% energy for 30 seconds, and then switch to 50% energy operation; then upload control according to temperature.

5. Check whether the inlet and outlet temperature of the cold water system is correct (the temperature of the inlet water is greater than the temperature of the outlet water in the refrigeration situation), and observe whether the operating current of the water-cooled screw chiller is within the range calibrated by the host.

6. Directly stop the machine by pressing the stop button. When the machine is stopped, the compressor will stop after 25% of its energy runs for 30 seconds; then the cooling water pump will be stopped after 1 minute delay and the frozen water pump will be stopped after 2 minutes.

7. If the cooling water pump and the chilled water pump are not interlocked, when the compressor is stopped, the cooling water pump must be manually stopped after a delay of 1 minute, and the refrigeration pump can be manually stopped after a delay of 2 minutes.