Performed two system heating maintenance Attic furnace 2018 tempstar 80% two stage natural gas furnace Pulled flame sensor and cleaned with steel wool Replaced 20x25x4 filter Blower is clean Checked inducer pressure switch port for blockage Run tested furnace High fire gas pressure set to 3.2" Low fire gas pressure set to 1.4" Inducer motor amps in spec No concerns found for attic system Basement furnace American standard 90% efficient single stage natural gas furnace Pulled and cleaned flame sensor with steel wool Pulled condensate trap and flushed with water Replaced popup 2200 filter Blower in OK condition Replaced aprilaire #80 steam cannister and verified correct operation Replaced aprilaire #35 water panel and verified correct operation Gas pressure adjustment screw cap is stuck, so setting cannot be adjusted. Furnace is over 20 years old and it is showing Replacement will be needed soon