Get to Know Your Electric Furnace: The Sequencer

stripping-electrical-wiresWe’d like to introduce you to your home’s electric furnace. Yes, you use it every winter for comfort, but how often do you think about it? Do you know how it works beyond “an electric thingy inside gets hot, air passes through it”?

You don’t have to know the details of the workings of an electric furnace—that’s the job of HVAC specialists. But knowing a bit more about such an important appliance can help you understand when it needs to be fixed and why. Plus, electric furnaces are more interesting devices than you might think.

Today we’re going to do an Electric Furnace 101 lesson on an important component, the sequencer.

The Sequencer: Stopping Electrical Overloads

Let’s start inside the electric furnace and the basic way it delivers warmth. The interior of an electric furnace contains a succession of heating elements, which are sets of electrical coils. When electric current runs through the coils, the coils turn hot and glow. You see this same effect in a standard toaster, and it’s known as electrical resistance heating.

When a thermostat makes a heating request to the furnace, the heating elements do not turn on all at the same time. Instead, the first element activates, and after a number of cycles (different for each furnace), the other elements start to turn on. If the elements turned on at once, the electrical power demand would cause an overload on the circuit for the furnace, tripping the breaker. With a tripped breaker, no power will go to the furnace at all—and that means a chilly house.

The job of the sequencer is to create the staggering of the activation of the heating elements, preventing an electrical mishap. Think of the sequencer as a timed switch to turn on each of the heating elements one by one. The way it works is that wires pass through a series of heat reactive circuits, which are usually made from copper. The circuits won’t permit the voltage to pass until the circuits reach a specific heat. When the circuit hits the heat threshold, the voltage moves onward and routes to the next heating element. This continues for the next circuit until all the heating elements are on. When the furnace shuts down, the sequencer staggers cutting off electricity to the heating elements.

The broken sequencer

One of the common electrical troubles in a furnace is a failed sequencer: broken wires, broken circuits, etc. A faulty sequencer can mean only one or two heating elements turn on, causing the furnace to lose heating power. A bad sequencer can also cause all the heating elements to activate simultaneously, overloading the circuit; or it may not turn on any heating elements. If you have an electric furnace that isn’t warming your house to the temperature you want, or isn’t warming anything at all, the sequencer might be the trouble.

Don’t try to fiddle with the wiring in the furnace when it isn’t working! When you need heating repair in Corvallis, OR or the surrounding areas, get in touch with our experts. They’ll have the sequencer replaced so you can return to relaxing in comfort.

Midway Mechanical Inc. has served the Willamette Valley for over 40 years. Call today and experience our company’s exceptional customer service!

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