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The Dangers of a Cracked Heat Exchanger in a Furnace

Are you one of the many people who use a natural gas furnace to provide heat for the winter? If so, then you probably understand why they’re so popular for home comfort: gas furnaces are dependable and provide a level of heating that few other systems can top—and that’s especially important in our part of the country, when it gets cold.

You need to take some special precautions with gas furnaces, however. They aren’t automatically dangerous—they’re built with safety uppermost in mind—but they may run into some troubles that might lead to carbon monoxide poisoning. (Always have CO detectors in your home if you use natural gas.) Perhaps the most worrying problem is a cracked heat exchanger, which we’re going to look at now.

Cracked Heat Exchangers

The heat exchanger is one of the essential parts of a gas furnace. It’s a metal container that traps the combustion gas from the burners. The heat from the combustion gas raises the temperature of the metal walls of the exchanger. The blower fan then sends air around the exchanger, and the air picks up the heat from the metal surface. This is how the air in a furnace is heated with combustion gas—without the combustion gas actually touching it.

But if the exchanger suffers from corrosion, it can leads to cracks opening up along it. These cracks are small, but the exchanger expands as it heats up, causing the cracks to widen. This will allow carbon monoxide, a byproduct of the combustion gas, to escape into the airflow—and into the house.

If you spot corrosion on your furnace, you should call for a technician right away to see if there are cracks on the exchanger. Clicking noises from the furnace after the blower turns off can also indicate cracking. And any furnace that’s more than 20 years old is at a heightened danger of heat exchanger cracks and probably should be replaced with a new system.

Red Rock Mechanical LLC serves the Plattsburgh, NY area. We offer complete furnace services.

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