Replaced a condensing unit for a friend. Did the startup and the suction pressure/temp crashes hard. Well, I tell the owner, looks like we're onto what killed your old compressor.
Head out to the garage where his furnace and coil are and open the furnace door. Wife comes running into the garage yelling - What did you do? There's dirt blowing out of all the vents for chrissakes!. Sure enough, the fan is return restricted and my opening the door dislodged thousands of dust bunnies.
Got to looking at the return - 2 12x16 floor level filter grilles in the hallway. Filters are clean, spotless really. Can't really feel any air moving at the grille faces. I'm thinking this is odd, so where is the restriction? Wen't back out to the garage and had the owner hold me by the back of my pants as I crawled under the furnace and looked up into the framing . . . Where the return air goes in the filter and up the wall, over the closet and down to the return box - was full of owens corning pink insulation!
I turned to the owner and pointed him at his drywall saw and told him - if any of your neighbors have problems with their a/c, have them call me.