Preventative maintenence inspection on Trane S9V2 high efficiency furnace running in great condition. Two 20x25x4 air filters are in good condition. Check again in 1-2 months. Clean flame sensor and check ignitor. Visual inspection of burners. Flush condensation trap and drain lines. Humidifier pad in good condition, damper is already open. Test operation of humidifier. No issues. Tes run gas heating. Temperature rise is within specs. Blower and inducer motors tested good. Pvc flue vents in good condition and no sign of leaks. 0PPM CO detected during testing. System is operating properly, efficiently and ready for Winter Mike mentioned that the humidifier seems to run constantly or for extended periods of time. Due to both the lower temperatures and flonger furnace operation times causing lower humidity, the Humidifier will undoubtedly run longer to compensate. Indoor humidity during inspection was 43%. If the humidifier is struggling to keep up at approximately 30-35% then ther may