Preventative maintenence inspection on high efficiency Carrier furnace running in great condition. 20x25x1 air filter in decent condition. Check again in 1-2 months. Clean flame sensor and check ignitor. Visual inspection of burners. Humidifier pad in good condition. Damper opened. Test run system in heating mode. Temperature rise is within specs for both stages. Blower and inducer motors tested good. Pvc flue vents in good condition and no sign of leaks. 0PPM CO detected during testing. Humidifier tested during heating mode test. Furnace and humidifier are operating properly, efficiently and ready for Winter. Due to some rooms in the house having different temperatures than others, the fan is recommended to be turned on to help with temperature differences between rooms. Performed air balance on a few vents. Confirmed both bedrooms that were cold had the vents open. Front office vent is closed. Basement vents other than basement bedroom is closed. Turned fan to on for constant circu