It's really not as simple as it sounds. We have Cruise-Air systems in our coach which requires R-22 refrigerant. Called a couple of local RV service centers and one emphatically insisted that these were sealed units and not serviceable. No matter how many times I tried to explain that it has been serviced previously they disputed this and said they were sealed systems. The only service available was replacement. I finally said they should Google Cruise Air and learn a little more about their business before spewing incorrect information. I said goodbye and hung up. It's really amazing how poorly informed many of the RV service folks are about systems other than those installed in the majority of RVs.