Oil left over from old compressor
How do you check if a compressor or condenser that you are replacing has left oil in a system? I recently helped replace a compressor in a package unit and it ended up with fluctuating pressures that eventually caused it to over heat. We thought it was a txv issue at first, but it has a piston. I asked around and the most likely cause i can find is oil was left in the system from the d comp so now there is too much oil in the system.
So how do you check for this and resolve the issue when replacing a compressor? I guess you could dump out oil from the old compressor and see how much comes out but that only solves half of the problem at best. I have not had much luck trying to flush it out with rx11. It worked great the first time i tried it but a dozen or so times after that it doesn’t push anything out the other end.