The flame sensor is an important part of gas furnaces. As the name suggests, it’s designed to detect or “sense” a flame. All gas furnaces produce a flame when running, which is how they create hot air. The flame sensor is a rod-shaped component within gas furnaces that checks to make sure a flame is present while the gas valve is open. If there’s no flame present, the flame sensor will shut down the furnace and close the gas valve. Here are five signs your furnace’s flame sensor needs replacing.
#1) Corrosion
Is there are corrosion on your furnace’s flame sensor? If so, you may need to replace it. Most flame sensors are made of metal. Metal, of course, can rust and corrode when exposed to moisture. Depending on how much corrosion has built up on your furnace’s flame sensor, it may no longer be able to detect a flame.
#2) Burners Don’t Stay Lit
Burners that fail to stay lit is a potential sign of flame sensor failure. Burners are hollowed passages in gas furnaces where combustion takes place. Most gas furnaces have multiple burners. Within these burners, gas and air is mixed together and burned to generate heat. A bad flame sensor, however, can prevent the burners from staying lit. They may initially light, only to burn out just a few minutes later.
#3) Physical Damage
Physical damage is a sign that your furnace’s flame sensor needs replacing. Flame sensors aren’t immune to damage. Like all other parts of your furnace, they can sustain damage – even from regular usage. Cracking, for instance, is a common form of damage sustained by flame sensors. The porcelain shell of a flame sensor may crack, in which case it may no longer function as intended.
#4) Poor Heating
Of course, poor heating can be a sign that your furnace’s flame sensor is bad. If the flame sensor is bad, your furnace may turn off prematurely. Your furnace won’t heat your home when it’s off. Therefore, you should beware of poor heating when investing problems with your furnace’s flame sensor.
#5) It’s Loose
If your furnace’s flame sensor is loose, you may need to replace it. This component should fit snug within your furnace. You can try pulling it out and reconnecting it. If the flame sensor is still loose, however, replacing it might be the best option.