Arrived to do a performance maintenance. Set up for combustion analysis temperature split and static pressure tests. Found that the furnace was overheating. Tuned the gas valve during the combustion analysis to bring the systems burn within spec. Found that the system was operating with failing static pressure. 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. Checked systems heat exchanger to ensure proper venting of flue gas. Performed an electronic gas leak search. Verified operation of the humidifier. Furnace and humidifier are operational at this time.