Performed heating maintenance on a Trane S9V2 furnace Incorrect filter size installed (20x25x5) Correct filter size is 21x27x5 Having the wrong size filter in place allows unfiltered, dirty air to bypass the filter and allow the system to get plugged with dirt. Humidifier bypass damper open to winter position Humidifier water panel used is aprilaire #10 Pulled and cleaned flame sensor with steel wool Blew out Condensate trap Wired furnace for proper two stage heating control at the thermostat Pulled burners and inspected for rust buildup Run tested furnace while running combustion analyzer High fire gas pressure set to 3.5" Temperature rise 59⁰ Low fire gas pressure set to 1.7" Temperature rise 47⁰ Combustion test results were perfect Furnace is operating within factory specifications at this time.
