Understanding the parts of your furnace is the first step toward a worry-free winter. The flame sensor plays a very important role in the functioning of your furnace and in keeping you safe.
After your system kicks on, the igniter gets the flames going. Gas will then move across your heat exchangers, which in turn begin emitting larger flames that warm your house. The flame sensor is located right next to your heat exchangers to make sure that the flames are actually kicking on. That’s because you don’t want to have a bunch of gas pumping in your system with no flame. This could be very detrimental to your safety. The flame sensor looks like a little hook that is positioned over one of the heat exchangers to feel the flame.
This sensor can wear out over time since it is constantly hit by flames. It can generally be salvaged and just needs to be cleaned up, but after a certain amount of time it may need to be replaced.