Heating maintenance flowery branch. Completed 2 system maintenance. Main floor furnace is 12 years old and has good blower with new filter. Inducer motor is good. Cleaned inducer port. Flame sensor is good. Ignitor has silicon build up. Burners have slight rust inside and around openings. If rust gets bad enough it will make a hole and allow carbon monoxide slip into house. Systems are heating properly at this time.