New Look (Coming Soon) Same Company! We Do It Right or It's Free! Read More

Skip navigation

Serving North Georgia Since 1999


Furnace Repair Needs: The Danger of a Cracked Heat Exchanger


If your home is like most throughout the Roswell area and beyond, then you use a furnace for your heating needs. Given that gas is so widely available, it’s very likely this heating system is gas-powered. A gas furnace produces a large amount of heat, and it does so at less expense than using an electric furnace, since natural gas costs less than electricity per unit.

However, there’s a potential hazard with using a gas furnace. We aren’t saying that to scare you—gas furnaces are not inherently dangerous, after all—especially with all the safety features built into today’s models. But older furnaces or furnaces that haven’t been well cared for over the years have one specific danger that needs to be watched for—a cracked heat exchanger.

What’s a Heat Exchanger?

This is essentially what enables a furnace to heat up the air that travels through the ventilation system. When the burners of the furnace come up, they generate hot combustion gas, which is collected inside the heat exchanger—a metal chamber or series of chambers.

The hot combustion gas in the heat exchanger heats up the metal walls, and the blower fan of your furnace comes on and sends air around the exchanger, where it picks up the heat from the furnace wall and continues into the ductwork. In this way, the combustion gas heats the air without the gas ever needing to come in contact with it.

Once this heating process is finished, the combustion byproducts in the heat exchanger are vented out of the system through a flue, to release the gas harmlessly into the air.

When a Heat Exchanger Is Damaged

Since the metal of a heat exchanger expands and contracts as it heats and cools, and also since furnaces can accumulate a lot of wear and tear over the years from natural causes, the strain eventually can cause a crack to form on the heat exchanger. Corrosion, due to the reaction between the combustion gas and the metal, can also weaken the metal to the point that it cracks. This is often due to improper venting, which is one of the many problems that is checked for during furnace maintenance.

The cracks might be very small, but since the exchanger expands with the heat, the cracks open enough to allow some of the combustion gasses to escape and enter your airflow. The gas you should be concerned with is carbon monoxide—it is tasteless and odorless, and in severe cases even deadly.

How to Tell If You Have a Cracked Heat Exchanger

First, we can’t stress enough how important it is to have a carbon monoxide (CO) detector in your home. So that if a cracked heat exchanger does allow this harmful gas in, you’ll be alerted to it right away. CO occurs naturally in our environment, but when it’s leaking into your sealed up home, it becomes a health and safety hazard.

Aside from ensuring the proper precautions are in place, you should also listen for a clicking soon after the blower shuts off. This is a sign of a CO leak and cracked heat exchanger. Even if you only suspect there may be a problem, it’s always best to call in a pro to investigate.

When you need quality furnace repair in Roswell, GA, contact DC Cheek Heating, Cooling & Plumbing—Fixed, at the Speed of Life!

Comments are closed.