The central air system in my house developed a refrigerant (R22) leak this year. It is a 19 year old York system, original to the house. It is leaking about 1# per month. Yesterday, I removed the fan from the condenser and cleaned the inside of it, didn't see any evidence of oil leaks. Today, I removed the filter for the attic mounted evaporator, stuck my leak detector probe up there, and bingo, that is what's leaking. Here is the question- is the evaporator coil serviceable, or does the whole air handler usually get replaced? It is a York unit as I mentioned, I don't know the model #, that will require a trip into the attic to find it. When properly charged, the system works great, easily cools the house even on the hottest days, and I've never had an electric bill over $100 for the month, even counting July of this year.