I conducted a performance maintenance check, setting up for combustion analysis, temperature split, and static pressure tests. The furnace exhibited excessive static pressure due to undersized ductwork. All mechanical and electronic components were verified for proper operation. The blower was inspected for cleanliness and bearing play, revealing dust and debris coating. The heat exchanger was checked for proper flue gas venting, and significant debris was found in the evaporator coil. The furnace remains operational.