The flame sensor in a furnace ensures that the gas ignites and that there is no leakage of gas. Thus, the flame sensor is a very important safety measure, and it must be maintained properly. After using for a long time, the flame sensor might become dirty, and if the flame sensor does not function properly, the furnace will not work. Cleaning the sensor is not a difficult job and can be done easily.
Step 1 - Remove the Flame Sensor
First, turn off the furnace, and then use the screwdriver to open the furnace door. The furnace door can be opened easily, and once opened, you can access the internal part of the furnace. The flame sensor is a thin metallic rod attached with a single screw below the burner. Remove this using the screwdriver.
Step 2 - Clean the Sensor
The sensor might have dirt and soot deposits on its body, and it might have turned greenish. Use the sand paper to clean the sensor properly.
Step 3 - Reinstall and Check
Reinstall the sensor and the door of the furnace, and then turn on the power to check if the sensor is working or not.