Arrived to do a performance maintenance. Set up for combustion analysis temperature split and static pressure tests. Verified operation of all mechanical and electronic components of the furnace. Checked blower for cleanliness and to see if there is any play in the bearings. Found it coated in dust debris. Checked systems heat exchanger to ensure proper venting of flue gas. Found bacterial growth present on the evaporator’s condensation pan. Found that the home is sitting at 23% humidity. Performed an electronic gas leak search. Spoke with homeowner about the system. Furnace is operational at this time.