I have a York screw chiller where circuit 1 compressor locks out on high discharge temp-runs 20 min to 1 hour. Have checked charge, subcooling superheat etc. all fans operational. History log shows that the capacity control is at or near the highest step 73 to 75 but the current is only 57 to 60% of full load. I suspect the slide valve is stuck and not opening fully.
Does anyone know the checkout procedure for this slide mechanism, solenoid valve etc.