Quote Originally Posted by stepperider
When the discharge pressure goes above 10 bars, the fans turns on, and we have combined cooling from water/fan. Then I see discharge pressure at around 8.5 bars on one compressor full load, and 10-11 bars on two compressors full load (depending on the outside air temperature).
One other item you need to be careful of is; at what discharge pressure will the pressure be low enough to cause problems with feeding liquid refrigerant. If the liquid feed pressure drops too low, the pressure will not be high enough to push liquid through the expansion valves (hand or thermostatic).

You need to find out what this pressure is and balance it with the desire to save energy.