How to Clean a Dirty Furnace Flame Sensor

furnace flame sensor, flame sensorWith summer just about over and the arrival of fall around the corner, you need to be sure your furnace is in working order. When the furnace switches on, you may find that it only runs for a few seconds before shutting off. One possible cause may be a dirty furnace flame sensor.

What Is a Furnace Flame Sensor?

The flame sensor is a thin metallic rod located on the burner assembly and in front of the pilot flame. The furnace flame sensor determines whether a flame is present when the gas is on. Without the sensor, the pilot light could go out, and the furnace could emit harmful gas.

The sensor acts as a safety device. When it detects that the flame isn’t on, it shuts down the entire unit to prevent dangerous gas emissions.

Signs of a Dirty Flame Sensor

The flame sensor can become corroded due to carbon buildup from the flame. This can cause the sensor to fail. If the burner light goes out within seconds of switching on the unit, this is a telltale sign of a dirty sensor. If you see soot clearly covering the sensor, then it’s time for a cleaning.

Cleaning the Sensor

Unless you are completely comfortable tinkering with a furnace, we suggest leaving the cleaning to a professional HVAC maintenance crew.

If you have enough know-how, then begin by shutting off the furnace. Flip the toggle switch, or shut it off via the home’s breaker box. Next, remove the sensor by unscrewing the attached hex-head screw. Remove the soot by gently scrubbing the surface with sandpaper or a wire brush.

We Restore the Furnace Flame Sensor

We maintain heating and air conditioning units. If your furnace is acting up, give All Points Heating a call. A problem could lie in the sensor or it might be elsewhere. We will clean the furnace flame sensor if it’s due for maintenance.

Residential Furnace Maintenance

Serving customers from Arlington to Renton and Bellevue to Shoreline, including Seattle, Redmond, Bothell, Edmonds, Lynnwood, Everett, Marysville, Mill Creek, Woodinville, Kirkland, Mercer Island and the surrounding area.