[Video] The Furnace Sequence

By: Brian Schutt  |  February 15, 2022
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Here at Homesense, we started as homeowners first. That’s why we’re all about reducing confusion and simplifying the complicated parts of HVAC. We try to put everything we do into language that we could have understood as homeowners. One of the things we’ve noticed is that a lot of people don’t know how the heat from your furnace actually happens. What’s the sequence of events that gets heat into your home?

When you click up on your thermostat and decide you want more heat in your home, this is what happens:

  1. Your thermostat sends a signal to the control board in your furnace.
  2. The control board tells your inducer motor to turn on, which creates a vacuum to remove exhaust air from the home.
  3. Next up, the gas valve opens and clicks on the igniter, which in turns start the process of flames kicking on.
  4. The flames will turn on across the heat exchangers and the flame sensor will ensure that there are in fact flames and not just gas.
  5. Once the control board gets the signal from the flame sensor that all is well, it then turns on the blower motor.
  6. The blower motor pushes air across the hot heat exchangers, sending warm air through your vents and into your home.

As a very detailed mechanical system, it’s important to make sure your furnace gets consistent maintenance. We recommend having a tune-up once a year, around fall, to ensure it’s ready for winter.

To learn more about some of these constituent furnace parts and see other helpful content, follow us on Instagram and our YouTube channel.

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