Furnace Not Working? Check Your Flame Sensor!

So, you come home from a long day at work and find that it feels a bit cold in your house. You head over to check the thermostat when you realize it's downright frigid in your home and your gas furnace isn't working. It's odd because you hear it trying to cycle on and off, but no warm air comes out of any of your vents. What could the problem be? Well, before you panic and assume you're going to need an expensive repair, consider the possibility of a dirty flame sensor.

What's a Flame Sensor?

A flame sensor is found on all gas furnaces and typically looks like a small, bent rod of metal. It's usually located near the furnace's flame stream and is responsible for making sure that a flame is indeed present when the gas valve is open. If the sensor doesn't detect a flame, it will typically shut the system off momentarily and try again a few times before shutting the system down entirely as a safety precaution. This is done to prevent the buildup of dangerous gas.

How to Clean a Flame Sensor

Over time, your flame sensor can get dirty--especially if your furnace air filter hasn't been changed in awhile. As dust, dirt, and other debris settle on the sensor, it's no longer able to detect the presence of a flame (even if it's there).

The good news is that, if this is the problem with your furnace, it's an extremely easy fix that doesn't take any special tools. All you'll need is a piece of fine sandpaper, a clean paper towel, and a wrench (to remove the sensor itself). 

Start by shutting the power off to the furnace completely. Then open it up and removing the flame sensor. Next, gently rub the metal part of the sensor across the fine sand paper; this will remove the dirt and debris. Use a clean paper towel to wipe off any excess before replacing the sensor. Close the door to the furnace unit, and turn the furnace back on. It may take a second for the system to kick back on, but once it does, your furnace should once again be spitting out warm air and heating your home efficiently.

If you run into any trouble along the way or are still experiencing problems after cleaning your flame sensor, be sure to contact a professional HVAC contractor.

For more information, contact a business such as Roode & Rose Plumbing & Heating Specialists Ltd.