Hello, I am hoping some one on here might be able to give me some advice. I work offshore as the engineer on an anchor handling tug supply boat. Currently off of Nigeria. We have a PBUCH S.A. compressor/condensing unit for the walk in coolers and freezer. There are two identicle units side by side. Over night the unit on line had tripped off on motor overload. I reset the overload and restarted but the unit seems to be seized up and hums for a few seconds and then trips again. It had the correct oil level in the compressor and was working fine until then. I lined up the other unit and started it up and it ran well for a few days and then did the same thing. It tripped on motor overload and will not run. I swapped that compressor out with a spare that we had on board and this one runs for about twenty minutes but gets very hot, runs rough and makes a squeeky noise and eventually trips on motor overload.
Does any one have any ideas? The compressor is a Bitzer semi hermetic reciprocating compressor using 404A. The condenser is cooled with a shell and tube sea water heat exchanger. The oil level in the compressor is correct, the condenser has good sea water flow, the charge seems correct. Is there more infor needed? Thanks for your time.