Comapnies 06 & 42 were originally dipatched to the area of Oak & Macdade Blvd for a smoke investigation. Fireboard was receiving numerous calls for smoke covering a large area of collingdale & darby township. 77-9 went on loc and req;d the BLDG assignment for Forman Mills after noticing the smoke condition was coming from the roof. Companies went in svc w/ aerial devices and ground ladders and found the source of the smoke to be coming from an air conditioning unit, there was no actual fire.