We are currently useing a Grasso RC4211 compound compressor in an industrial cooling and freezing installation. The RC4211 has six cylinders, four working in the low pressure stage and two in the high pressure stage. During normal operation, we need the two high pressure cylinders to be switched on and one or two low pressure cylinders. However, if we use the normal switching sequence recommended by the manufacturer, we can only switch on both high pressure cylinders if we also switch on all four low pressure ones. This gives too much cooling capacity in the low pressure stage.

Has anyone experience with switching of two low pressure cylinders on the RC4211 while both high pressure cylinders are under load? What could be the adverse effects if we do this?