Went to leak check this unit today. System held 225 psi for fifteen minutes. I soapy bubbled everything, nothing. Replaced the schraeders thinking that my be the problem and everything looks good. Hook up the vacuum and she pulled down and micron gauge started hanging up around 900 microns. Pump didn't sound right so I stopped and hit her again with nitrogen. By this time all the soap had ran into the condensate pan and there was a nice foamy mess down there. Removed the pan and this is what I saw.
The pan was a greasy mess as was the gas loop. I cleaned both and hit the loop with a stainless brush to get a better look at it. I thought that these stainless loops were put in to stop the leak problem.
I am guessing that awhile back someone used foam and clean on the condenser and when they rinsed it off it found its way into the pan and over an extended period of time the high temp of the loop and the sodium hydroxide did the damage. The entire loop does not look this way. Only two separate one inch sections.