maintenance ( Controlling the compresssor )

Normally starts the comp.sometime immediately tripped off from the main panel breaker.sometime starts automatically machine without any trouble up to unloading pressure 7.9 bar(set point)loading pressure 6.9.But in stead of closing delivery v/v air leaking and net pre.decreasing through the inlet v/v.then air leaking from the air cleaner.Solenoid v/v's checked, it's not trouble. Pls give me clue of this problem. Electronikon setting are OK for programmed starting. Thanks GA 55 SCREW COMPRESSOR (NEW ONE) CURRENT RUNNING 54 Hrs. Power - 65.1Kw