Posted on: 22 October 2020Share
If you have a gas furnace, you have to deal with the byproducts of combustion, such as soot. Soot needs to be removed from your furnace regularly or else your furnace might malfunction. Soot is like dust, except it clings to parts in the combustion area, so it often has to be scrubbed off. If soot builds up, the flame sensor can be affected, and then you may need to call a heating repair service. Here's why the proper operation of the flame sensor is critical to your furnace and what repairs it could need.
The Flame Sensor Connects To The Control Board
The flame sensor sends signals to the control board of the furnace, which controls the heating cycle and operates the safety shutdown mechanisms. The control board waits for a signal from the sensor that the pilot light has ignited the burner. If the sensor can't detect the flame because of a malfunction, no signal is sent and the control board shuts down the furnace so gas doesn't accumulate.
The burners may actually be burning, but if the sensor is broken, the sensor can't detect the flames, so the furnace goes into safety mode. In this way, the flame sensor protects you from a gas leak, and your furnace won't operate unless the flame sensor is working properly.
The Sensor Can Malfunction Due To Damage Or Soot
A flame sensor has a metal end and a porcelain end. The metal end can become so coated with soot that it can't detect the flame. The metal part might also rust and stop working. The porcelain part might crack or even chip off. Since the sensor connects to the control board, a short in the wiring could also cause a malfunction.
A Bad Sensor Can Be Replaced Or Cleaned
If the sensor has a buildup of soot, the heating repair technician can scrub it with an emery board to clean it. If the soot can be removed, the repairs might be finished.
In some cases, the repair technician may recommend replacing the sensor instead. A flame sensor is one of the more affordable furnace parts, so it's often best to simply replace it so it is in good shape and ready to last a long time. If the porcelain is cracked or the metal is rusted, then replacing the sensor is probably necessary.
Since the flame sensor is tucked away inside your furnace, you may not be able to tell its condition. If you can see the flame and the flame is yellow, that's an indication the combustion and ignition areas are dirty and the sensor may be dirty too. Normally, the flame should be blue. If your furnace kicks on and then kicks back off quickly, that's another sign of a bad flame sensor, and you may want to call a heating repair service right away before your house gets too cold.
Visit a website like https://www.imsheatingandair.com to learn more.