Mammoth- FuSheng compressors

[chi 597]

Any advice on these screw compressors, I have 2 that are approximately 15 years old, suction gas 57 degrees F. Compressor body around motor is 106 and 160, compressor will not load. Is there an internal relief of some sort that could be bypassing refrigerant back to the suction of the compressor? I recently replaced a compressor and I have no issues running it unloaded the motor core stays roughly the same as the suction temp.

[Mike Doran]

try looking at the oil passages on the side of the compressor on(sv2) they sometimes get blocked and wont allow compressor to load