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AAction Air Conditioning & Heating Co. Blog

How Does My Gas Furnace Work?

The furnace may be the most common heating system used in the country, but that doesn’t mean homeowners are familiar with its operation. Furnaces are a mystery to many (especially in our area, where warmer weather calls for infrequent use). And due to the complexity of these systems, you should only allow a professional to service your gas furnace whenever you need repairs or a replacement.

But if you’re curious, we can help you to understand the basics of your gas furnace. Here, we list some of the essential steps of a furnace’s operation.

  • The thermostat on the wall detects low temperatures and sends a signal to the gas furnace.
  • The gas valve opens up and sends gas to the burner assembly.
  • The pilot flame ignites the gas, but this may not work in the way you’d expect. Today, a standing pilot that’s on all the time is no longer the way furnaces are manufactured. Here are the two most common ignition systems used today.
    • Hot surface ignition – Silicon carbide gets very hot as electricity passes through.
    • Direct spark intermittent pilot – A high-voltage spark ignites the gas.
  • Flue gases vent out of one end of the heat exchanger and to the flue vent to move safely outdoors.
  • The fan limit switch activates the blower fan once the air plenum reaches the proper temperature.
  • The blower fan pulls in air from your home, which moves into the air plenum and is heated by the heat exchanger.
  • As it heats, the air moves back through the supply ducts in order to heat your home.
  • Once the air in the home reaches a certain temperature, the thermostat signals the furnace to shut off.

AAction Air Conditioning & Heating Co. Inc. does quality work at a fair price, every time. Call us today to schedule furnace installation or service in Savannah or a surrounding area.

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