Preventative maintenence inspection on Carrier high efficiency furnace running in great condition. Air filter and humidifier pad in good condition. Clean flame sensor and check ignitor ohms. Visual inspection of burners. Flush condensation trap and drain lines. Run test unit in heating mode. 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. Humidifier tested during heating mode test. Systems are operating properly, efficiently and ready for Winter.