Performed 3 system heating maintenance Main floor: 2014 Lennox 98% efficient modulating natural gas furnace Honeywell popup 2400 air filter is clean Blower wheel is clean Humidifier has wrong size water panel installed, recommend using aprilaire #35 water panel. Pulled and cleaned the flame sensor Cleared debris from the intake pipe Cleared debris from the inducer outlet drain tubing Lennox does not recommend adjustments to the modulating gas control valve Bonus room: 2000 Lennox 90% efficient single stage furnace Honeywell popup 2200 is clean Blower wheel is OK No humidifier installed Pulled and cleaned flame sensor Condensate lines are clear Intake clear Run tested furnace while running combustion analysis Gas pressure 3.8"wc with reference to the sealed burner box Combustion results are very healthy Temperature rise 50⁰ (spec 30-60) Despite age, this furnace is running well within manufacturer's specs Second floor: 2018 Trane 96% two stage Popup 2200 filter is good Blower wh