General Information

Simultaneous Compressor Start/ Stop

Both compressors will start in close succession to minimize the time it takes for the chiller to reach full load. Some process applications need the chiller to start and generate capacity as fast as possible. This method will start both compressors, slightly staggered to prevent doubling of the current inrush, but will generally control the chiller as if there were only one compressor.

If the chiller is in the Auto mode and all interlocks have been satisfied, compressor 1 will be started based on the leaving water temperature rising above the “Differential to Start” setting. When compressor 1 is at speed, compressor 2 will start. Both compressors will run until water temperature falls below the differential to stop, at that time both compressors will be shut down.

Figure 15. CDHF/G sequence of operation: combined start

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American Standard CH530 manual Simultaneous Compressor Start/ Stop, CDHF/G sequence of operation combined start