How Does a Furnace Work?

February 13, 2020

If you have ever been cold, you know the value your furnace brings. When it fails to produce the heat you expect, you begin paying attention to how it works and what might be wrong. The process a furnace uses to heat your space is quite simple. Taking the time to gain a basic understanding helps you keep it working well and find issues when a problem occurs.

4-Step Furnace Process

Most modern furnaces use a process called forced air. They operate on the following four basic principles.

  • Step 1: Produce the heat. A furnace produces heat by burning a fuel in the combustion chamber located at the bottom of the furnace. This starts when the thermostat sends a signal to the furnace to turn on.
  • Step 2: Transfer the heat to the air. As the burners generate heat, it ascends to the heat exchanger. The purpose of the exchanger is to transfer the heat from the furnace to the air that circulates through the house. This exchanger warms up and then signals the circulating fan to start.
  • Step 3: Force warm air into the house. The circulating fan forces air through the heat exchanger and then out through the ductwork. This forced air movement is what gives these furnaces their name.
  • Step 4: Continue circular air motion. As the circulating fan pushes warm air out, it is also drawing cooler air in through the return duct. The cycle continues until the thermostat senses the air has reached the desired temperature, which shuts the system down.

Common Furnace Problems

Common problems with a furnace include not enough airflow coming out of the ducts, the air not being warm or the entire system failing to start.

First, check the filters to ensure they are not clogged. Then check the thermostat batteries are good. These are quick, easy and inexpensive maintenance items.

If both of these seem to be okay, it is best to call a trained professional. Most other components in a furnace can quickly become dangerous if attempted by someone without the proper training.

Schedule Your Consultation With McKinney Heating & Air Conditioning Today

McKinney Heating & Air Conditioning has been serving southwestern Virginia since 1972, with service locations based in Martinsville, Rocky Mountain, Danville, and Stuart. Our team is experienced in servicing and installing heating systems, air conditioners, tankless water heaters, generators, and gas fireplaces. Our team can also help you improve the air quality of your home using humidity control and air purification solutions. Call McKinney Heating & Air Conditioning to schedule your consultation.

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