Performed heating maintenance on a 2011 Carrier Infinty 3 stage 97% efficient natural gas furnace Replaced humidifier water panel (aprilaire #10) 16x25x4 filter is still good Pulled flame sensor and cleaned Pulled condensate trap and flushed with water Blower wheel is clean Burners are in good shape Run tested furnace while performing combustion test and checking temperature rise High fire set to 3.7" Med fire set to 1.75" Low fire set to 0.65" No concerns found