I have a Carrier FA4BNF048 that keeps icing up. I'm guessing (and please tell me if I'm off base) that this may be the result of something that happened a while ago:
I neglected to change the blue fiberglass filter (don't worry, I've switched to pleated paper since). The unit iced solid and when it thawed, it drenched the filter which disintegrated and got sucked up into the evaporator.
I took a grate of one of the returns and snaked the hose from my shop vac underneath, but then had to reach in though the little slot for the air filter to actually do the cleaning.
Is this something your layman should be able to do, or do I have to call in a professional?