How Do Furnaces Work?

April 10, 2019

Even with warmer temperatures on the horizon, it’s still a good idea to know a thing or two about your furnace. At Brennan Heating & Air Conditioning in Seattle, we believe that understanding how your furnace operates will not only help you to troubleshoot problems but potentially help you to avoid emergency services calls or even furnace replacement. Let’s start with the basics.

What Is a Furnace?

Although there are newer models, the most common type of furnace is a gas-powered system, which heats air in one area of your home and then distributes it evenly throughout your home via ductwork and vents. This type of system is also known as a forced warm-air distribution system.

The main parts in your furnace’s control system are the gas valve, heat exchanger, blower, and burner ventilation system. When your furnace is in use, any combustion gases are vented out of your home via a flue pipe, if you have a gas system.

How Do Home Furnaces Work?

Although different models will heat and distribute air differently, the overall premise is relatively the same. When the temperature inside your house drops below the setting on the thermostat, the thermostat sends two signals, one to the furnace to begin the heating cycle and another to the blower motor, which activates the fan.

The heating elements then receive the signal and activate. In oil or gas furnaces, fuel is then released through the valves to produce open flames. If you have an electric furnace, then it’s powered by electricity, similar to the elements found in electric space heaters.

In gas or oil furnaces, the flames warm the heat exchanger and the air around it. In electric systems, it’s just a matter of exposing the heating elements to the air. In all types of HVAC heating systems, the blower motor or fan pushes warm air through the ductwork and vents. Once the ideal temperature is reached in the home, the thermostat sends signals to shut off both the furnace and blower motor.

Whether you need routine HVAC maintenance or would like to know more about how furnaces work, contact Brennan Heating & Air Conditioning in Seattle, WA, today. We can also assist with cooling repair, installation, and maintenance, diagnostics, water heaters, heat pump installation, and more.

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