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Serving the Greater New Braunfels, TX Area

Serving the Greater New Braunfels, TX Area


The Biggest Gas Furnace Worry: A Cracked Heat Exchanger


Gas furnaces are one of the best ways to provide comfort to a home during any winter season. They are reliable, work fast at delivering heat, and are powerful enough to help drafty and poorly insulated homes get through cold days.

Homeowners sometimes have worries about the safety of using a gas furnace. But if gas furnaces were inherently dangerous, they wouldn’t be permitted in homes at all—and they certainly wouldn’t be the number type of heating system in the country. The modern gas furnace is built with numerous safety precautions. If you make sure to keep up with regular maintenance and prompt furnace repair in San Antonio, TX when necessary, you shouldn’t have to worry about your gas furnace posing any hazards. 

However … we do need to talk about one concern: the cracked heat exchanger.

The Heat Exchanger, Explained

The heat exchanger is the component of a gas furnace that safely transfers the heat from the combustion gas created by the burners into the air that moves through the furnace and into the ventilation system. Obviously, this gas cannot come in contact with the air.

Instead, it gathers inside a metal chamber—the heat exchanger—and it raises the temperature of the metal walls. The air from the blower moves around the heat exchanger and picks up heat from its surface. When the heat exchanger cools down, the combustion gas byproducts are safely vented through a flue and out of the house.

A Crack in the Heat Exchanger

Reading how a heat exchanger works, you can probably guess why a crack would be bad news. Because the metal of the heat exchanger expands as it heats up, a crack can stretch apart wide enough to allow the harmful gases inside to escape and enter the airflow. The toxic gases can end up in the living spaces of the house. (This is why you must have carbon monoxide detectors in your home if you use natural gas.)

Cracks can form due to corrosion, which may affect an older furnace because of the years of exposure to vapor in the heat exchanger. Improper ventilation can also speed up the corrosion process. It’s most common in older heaters that should’ve been retired years earlier. If you notice any corrosion on your furnace, please call technicians to look into it and see if there’s any danger to the heat exchanger.

Avoiding the Cracked Heat Exchanger

Fortunately, you have an easy tool to use to catch problems with the heat exchanger before they become serious problems: regular annual inspections and tune-ups for your furnace.

This regular maintenance is critical for locating any issue with the furnace that might become hazardous. Our technicians carefully check the heat exchanger to see if there are any weak points, corrosion, or cracks starting to develop. A cracked heat exchanger can be replaced, although for an older furnace (more than 15 years), it’s often more cost-effective to have a new furnace put in.

At Thayer Air Conditioning, your comfort is our #1 priority! Call us for furnace repair—we’re already on our way!

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