Three compressor chiller unit problem

There are three compressors No1,2,3. You can choose to work 1/2/3, 2/1/3, 3/2/1 as lead and lag compressors. There is also a sea water pump feeding the condenser and a chilled water pump feeding the evaporator. Each compressor has its own chilled water line with a magnet valve before each evaporator. To save our generators from overloading in winter we used to cut the electrical power to the first compressor and the third one with the selection 2/1/3 so the second one would work alone. During the last days the second compressor can not work alone, when it prepares to take load the chilled pump has a slight change in speed and amperes and the compressor never takes any load with no fault indications. When we feed all the compressors and 2/1/3 plays fully then the second compressor works fine.
Might be a stuck chilled water valve?

source https://hvac-talk.com/vbb/threads/2227401-Three-compressor-chiller-unit-problem?goto=newpost