Performed heating maintenance on a Carrier two stage 96% efficient gas furnace. Changed 20x25x1 Filter Humidifier pad is still in good shape Pulled and cleaned flame sensor Pulled and flushed condensate trap Tested furnace in high fire and low fire with the humidifier bypass damper open. Temperature rise within factory spec Gas pressures 3.2 and 1.7 Ran combustion test, heat exchanger pass.