If your house doesn’t have a connection to the municipal natural gas supply, you probably use electricity to power most appliances, including the heater. The most common type of electric central heating system is the electric furnace, which works on the basic principle of electrical resistance heating. Electrical current flows through wires in the heating elements, causing the elements to heat up. The air sent through the furnace picks up heat from the surface of the elements and then continues into the ventilation system to the rest of the house.
It’s easy to explain—not much different from how a toaster works—but there are special components involved that allow an electric furnace to work reliably and provide precision home heating. We’re going to focus on one of them in this post: the sequencer.