Have an approx 2002 Carrier Evaporator 5BXA042021AAAA in really good condition (well air handler is but can't see the coil yet!) and it's on R22. Condensor is about shot and need to change out so will go with R410A of course. BUT. Evaporator says on it (model above) for use with R22 or R410A in "Listed" units. So question is how do I determine if it's an easy swap, or maybe change expansion valve too? Anyone seen this before? Actually believe the right approach would be new evap coil...anyone know of a direct swap model number for same size A coil to replace this one CK5BXA042021AAAA. So minimal modifications to box.

Earlier today, my air conditioner turned off. I realized that the water switch had activated. There was water leaking out of the area where the condensate drain connects. I heard my condensate pump activating, and there didn’t seem to be any backup in that area of the line (from the the pump to outside). After drying everything off and resetting the switch, I put the AC back on. Water almost immediately started leaking from the unit (near the condensate connection). I took the front panel off, and there didn’t seem to be any water in the pan. It is badly rusted, which may be a concern. I got a brush and cleaned the condensate connection line. I was thinking about starting the unit with the cover off, so I could see the water. However, I wasn’t sure if it’s okay to put the AC on with the coil exposed. I put it back in place, started the unit, and there has been no leak. Is it really this simple? Maybe there was algae or mold at the connection point? If this were clogged, would water leak that quickly? The pan seemed deep enough that it would take more than a few seconds for it to overflow. I appreciate any help. I apologize in advance for the poor explanation. I am very new at working with HVAC, so I have a lot to learn.