Performed preventative maintenance on Coleman Gas Furnace and Aprilaire Humidifier. Homeowner stated he had already replaced 16x25x1 air filter. Completed combustion analysis and CO PPM was 0. Cleaned and inspected burners, flame sensor and blower compartment along with verifying proper amperage on the motors. Cleaned and replaced water panel #35 for humidifier. Customer stated that he will not prepay for spring maintenance and that he will contact us to schedule if he wants appointment. Both systems are in good condition and ready for the season!