Arrived to do a performance maintenance. Set up for combustion analysis temperature split and static pressure tests. Found that the system is operating with excessive static pressure. Tuned gas valve to bring oxygen content to manufacturers specifications. 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 that the fan for heating and cooling is coated in dust debris. Checked systems heat exchanger to ensure proper venting of flue gas. Found large hotspots on heat exchanger but no damage. Performed an electronic gas leak search. Verified operation of the humidifier. Found humidifier panel is coated in calcium buildup. Furnace and humidifier are operational at this time.