I have a 2 stage Grasso package P & W frames, when the compressor stops suddenly the check valve doesn't close right and it rotates in the reversed direction with a noisy voice. when the service engineer arrived he changed the discharge pressure from 10.5 bar to 13 bar to avoid this action.
this change decreased the refrigeration capacity and made the oil temperature higher than 55 C
what should I do to solve these problems?