Performed the level 2 furnace and modine cleanings. Furnace: Burners and flame sensor are clean. Heat exchanger looks good. Combustion readings were normal. No CO detected in the air. Drain is clear. High limit passed the safety check. Heat rise was 38°. Unit is heating properly. Modine: I wiped away dust on both the interior and exterior of the unit. Cleaned the burners and flame sensor. No CO detected in the air. Exhaust readings were normal. Unit is heating properly. We will call to schedule the AC cleaning in the spring.