Preventative maintenence inspection on Carrier high efficiency furnace. 20x25x1 air filter in good condition. Left two new filters near other new filters. Cleaned flame sensor and checked ignitor. Visual inspection of burners. Flush condensation trap and drain lines. Run test unit in heating mode. Air temperature rise is within specifications. Blower and inducer motors are operating properly. Humidifier pad in good condition, damper opened, test ran during heating test and set to 45%. 2" pvc flue in good condition and no sign of leaks. 0 PPM CO detected during testing. Furnace is operating properly, efficiently and ready for Winter.