A gas furnace has a lot of components. There are those that actually combust fuel and create heat, like the ignition assembly (or pilot light, in older furnaces) and the burner. There are those that get that hot air distributed, like the blower fan and its motor. But there’s something else as well: components whose job is to keep you safe!
There’s a flame sensor to make sure gas won’t be released if there’s no flame to burn it. There’s a limit switch that will shut down the system if it starts to overheat. There’s also something called a heat exchanger. It’s absolutely critical to both the functionality and the safety of your furnace! Here’s why.