Loose Fittings
We have a SuperCold Machine with a holdover plate in a Catalina 42 MKII. After the first year of operation we started to loose cooling even though the compressor was running almost continuously. The classic symptom of low refrigerant. All the fittings were tightened and the system was recharged and it worked fine for almost the second year. Then the same thing happened - loss of cooling. We finally found a local refrigeration service person who identified the problem. When charging the system, ice on the refrigerant line should retreat into the icebox. When ice forms on the fittings of the holdover plate the expansion of the ice causes the fittings to loosen slowly over time. Both times that we had to recharge the system we found the the fittings at the hold over plate were loose and leaking refrigerant as detected by a gas sniffer. The service person said that this was not an uncommon problem with threaded fittings when they ice up. He suggested that we wrap the fittings with common asphalt impregnated cork insulating tape used on refrigeration and air conditioning systems. The key to a successful wrapping is to make sure that the tape makes an air tight seal around the fittings so that frost and ice cannot form directly on the threaded fittings. We wrapped the fittings, some frost and ice still form on the outside of the tape, but we have not have any further problems with loose fittings and have not lost any refrigerant since. Hope this helps! Good luck!
