We recently purchased a couple of mobile homes for rental properties. When we hade them inspected they said everything was in working order. When we moved in a tenet the first thing they complained about was that the a/c was not cooling during the day, but at night it was fine. We sent out a company to service the unit and received a $300 bill with an est. for $4000 to replace the unit. He claimed that the evaporator coils were damaged and needed to be replaced. When I asked him to show me what he was talking about he opened the panel to show me that he cleaned the coils with an acid based cleaner but they still needed to be replaced this was in march the coils looked fine, they were separated and in a fine shape air flow was going through. Still we had a problem with the cooling. I had another tech come out,( this time I stood there and watched him) and he found that the first tech had set the blower speed to the lowest setting, once he changed it it worked fine. Cooled during the day till about yesterday. When I opened up the access panel I saw that the coils that were fine in march were now deteriorating and brittle they fell apart with just the lightest touch. Now there is very little air flow. Now for my questions, can I change just the outside package air cooling unit without messing with the stuff inside? And what is the stuff inside? The unit is a Heil PA5536AKA2 model and the serial # is L9731 26080 any kind of help would be great.

You can replace the out door unit without replacing the indoor unit, but if it is the indoor coil that is deteriorating then you should also replace that, it is an important part of the a/c system. The furnace is the other componet that can also be changed by itself.