I have checked all filters and replaced them (very dirty) and also cleaned condensing unit. This morning the line outside was frosted so I turned my unit off. I waited about 2 hours and turned it back on everything working fine but I do hear "water noises" inside the furnace closet when I opened it. Pipe has little water drips on it and I feel very cold air around return air area. Any ideas? Do I really need to call someone? I would really like to do this myself. I am wondering if maybe the blower fan needs to be cleaned? Any help would be great!