How Does a Furnace Work?

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Most homeowners have a furnace inside of their homes, a heating system that often uses natural gas (although it may use electricity or oil) to heat up the air and send it throughout the home. But because the furnace itself tends to be out of your sight, you might not think much about how it operates. Curious about how a furnace keeps you warm? Get the basics below!
  • When the temperature drops below the settings on the thermostat, it calls for heat from the furnace.
  • Gas flows out of the valve.
  • An igniter lights the burner in the combustion chamber. The igniter is likely made of a substance like silicon nitride, which gets extremely hot as electricity flows to it. This part may need replacement every 3-5 years.
  • The heat heats up the heat exchanger. Combustion gases move out the other end of the heat exchanger and vent to the outdoors.
  • After the plenum warms up enough, the blower fan switches on.
  • The fan sucks in air from around your home through an air filter (which you should change every 1-3 months).
  • The fan pushes warm air through the ducts and to the various rooms of your home.
  • Once the temperature in the home is within the proper range, the gas valve closes and, after it cools, the fan shuts off as well.
These are just the basics of how your furnace operates. There are also a number of safety controls, some electrical wiring, motors, and other components helping to keep your furnace running smoothly and safely. When something goes wrong with your furnace, be sure to call in a professional to help and ensure the job is done right. Call Air Mechanical, Inc. today, your heating specialists in the Andover, MN area for decades. We offer professional furnace repairs, installation, and routine maintenance services.

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