Start and stop sequence of the refrigeration system
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I have been in charge of operating the refrigerators at the company for several years now (large-capacity screw compressors are used, and the low-pressure circulation tank is fed with liquid using an ammonia pump). Recently, the factory needs to prepare operating procedures, and after reviewing a lot of documents and the manufacturer’s instructions, I’m still not entirely sure about the sequence for starting and stopping the entire system. The instructions only mention the starting and stopping of the evaporative cooler and the compressor, but do not specify when the evaporator fan and the ammonia pump should be started. Summarizing the available information and personal opinions, the sequence for starting up at this stage is: evaporative cooling – evaporator fan – compressor – low-pressure circulation tank or economizer for liquid supply; as for shutting down, the order is reversed. There should be a delay between stopping each component: for example, after the ammonia pump stops, the compressor should be stopped after a few minutes, and evaporative cooling should be stopped yet another few minutes later. I’d like to ask the experienced seniors on this forum for their help; thank you in advance!
We use those from Yantai Binglun; it’s the same program
Stop the ammonia pump first and then delay stopping the compressor, in order to draw the ammonia liquid back into the compressor within the terminal system and prevent dangerous temperature rises in that system. Prevent excessive discharge pressure when evaporative cooling is finally stopped