How to Clean Furnace Flame Sensors
- 1). Disconnect the power and gas valve to your furnace.
- 2). Detach the combustion chamber door from the front of the furnace by loosening screws with a screwdriver, lifting up on the door and pulling it toward you. Locate the flame sensor inside the furnace. It consists of a long wire attached to a metal rod that usually has a white ceramic base.
- 3). Unscrew the nut beneath the bracket holding the flame sensor in place.
- 4). Pull the flame sensor out of its bracket. It should lift out from above.
- 5). Sand the flame sensor gently with a clean emery cloth. This will remove built-up residue preventing the furnace flame sensor from properly working.
- 6). Replace the flame sensor into the bracket and tighten the bolt that will hold it in place. Affix the combustion chamber door back onto the front of the furnace.
- 7). Restore power to your furnace.
Source...