Hey all,
Sabroe 202LF, -30/+30degC, Ammonia, 3000rpm, manual fixed VI has a strange rattle emanating from the suction intake area on the compressor body and a strong side to side vibration. We have had the compressor on the ground and checked the suction check valve which has some wear but not excessive and also removed and checked the POV assembly which also appeared in reasonable order. This compressor runs part loaded, 30-40%. Is it possible for discharge gas to be redirected back into the suction intake area and overcome the suction check valve causing it to chatter? Say if the rotors were not sealing? The suction pressure transmitter is upstream from the suction check valve and reads stable, all other temperatures and pressures are normal. The compressor shaft turns freely by hand. The oil pump is prelube only. The compressor was re-aligned when re-installed. The coupling was checked and is fine. Thoughts?