The last I heard, Josh did get a good look at the unit above the Wood Shop ceiling. It needs a thorough cleaning. He does not have gage set to check refrigerant levels. So, the recommendation was to pay someone to do a professional cleaning and inspection.
I, personally, wonder if there is any way we could deflect or screen some of the combination of roof debris, metal dust, wood dust, (and pink powder coating), so that the dust layer takes longer to accumulate. I also wonder if the filter that is in the return at the ceiling is being leaked around.
Mike B