What You Need To Know About A Cracked Heat Exchanger In Your Home Furnace

image of blue furnace flames

According to HVAC experts, the best way to avoid problems like a cracked heat exchanger is by practicing good furnace maintenance. If your home furnace has a cracked heat exchanger, several signs will help you identify this issue. This article will help you find out what the heat exchanger in your furnace is and why this component is so important. Also, we’ll cover how to determine if your furnace is dealing with a heat exchanger that is cracked.

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What Your Furnace’s Heat Exchanger Does

The heat exchanger is the part of a furnace that transfers heat between fluids to either warm up the living space or cool it back down. In a residential furnace, the heat exchanger warms up the air that moves throughout the vents. Combustible gas grows warmer and then accumulates within the exchanger, thereby allowing it to raise the indoor air temperature. When the heat exchanger has a crack, this affects the overall performance of the furnace.

Tell-Tales Signs That The Heat Exchanger In Your Home Furnace Is Cracked

Be on the lookout for these tell-tale signs that your furnace has a cracked heat exchanger:

Changes In The Furnace Flame’s Appearance

When everything is functioning normally, the flame in your gas furnace should look blue. A blue flame means that the heater is working as it should. If this flame becomes yellowish, however, this may indicate that the burner needs cleaning or that your heat exchanger is cracked. A normal heating system will have a steadily burning flame. If this flame flickers, they may be a problem within the unit.

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image of soot

The Development Of Soot

Soot develops when carbon starts to build up at the furnace interior. This typically occurs when the unit is unable to cleanly and completely burn fuel as the result of a cracked heat exchanger or a burner that isn’t adjusted correctly.

Cracked Or Corroded Furnace Components

Take a look at the external components of your furnace to check for cracks and corrosion. If the external components are rusted or damaged, the interior components could also be damaged.

Strange Furnace Smells

When the heat exchanger is cracked, the furnace can start emanating a strange odor that smells quite a bit like formaldehyde. This smell can negatively impact human health, such as causing headaches. If this is something that you or anyone else in your household experiences, contact a reputable HVAC company to have your furnace checked right away.

image of woman covering nose from bad furnace odor

Health Troubles

Carbon monoxide from your furnace can cause frequent and potentially serious health problems, including eye and nose irritation, disorientation, sleepiness, nausea, and many other flu-like symptoms. These are problems that you can experience whenever you’re at home.


What Causes A Heat Exchanger To Crack?

Cracked heat exchangers are commonly caused by overheating. This is usually the result of insufficient airflow – which is an issue that crops up when routine maintenance isn’t performed. As the interior of the furnace accumulates lots of dust, dirt, and other debris, the filter gets blocked, and clogs develop throughout the blowers and coils. This, in turn, diminishes overall airflow. Air is essential for keeping temperatures within the system interior at a moderate level and for the absorption of extra heat. Whenever there’s a significant increase in internal temperatures, there is a high likelihood of having the heat exchanger crack.

A cracked heat exchanger can also be the result of a worn control valve. If these components break or wear down, pressure can fluctuate to a level that the heat exchanger is unable to tolerate. This makes it essential to have your furnace regularly inspected so that the potential for developing issues can be identified and dealt with.

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Why Is A Cracked Heat Exchanger Is So Problematic?

Experiencing the signs of a cracked heat exchanger is more than just a mere inconvenience. These are issues that may pose a serious threat to both your personal safety and your home. A lot of people use natural gas, fuel oil or propane to power their home heating systems. All of these fossil fuels create fumes when burned. These are fumes that may contain soot, water vapor, carbon monoxide, and carbon dioxide. If the levels of harmful gases become too high, serious health issues can develop across all building residents.

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How To Take Care Of A Cracked Heat Exchanger

You should never attempt to inspect or repair a cracked heat exchanger on your own. If the heat exchanger in your furnace has a crack, you will need to replace this part. It may even be necessary to pay for a full-on furnace replacement. In either case, there are several major considerations that you must make. Your heating system can be tested by a professional HVAC technician to determine the root source of the problem and to arrive at a reasonable solution. Your provider can also tell you how to take care of the problem and how to care for your furnace going forward.



When the heat exchanger has a crack this can lead to serious damages throughout the entire furnace. It can also cause health problems for those living in the building. Fortunately, all of these consequences are easily preventable. With regular maintenance and care, you’ll be able to get many years of service and reliable functioning from your heat exchanger. If you have concerns or questions about the condition of your heater, reach out to a local HVAC company to find the best solutions and preventative strategies. The more that you take care of your furnace now, the better this system will serve you in the long-run.

Reach Out To McAllister Energy For Your Home Furnace Needs

McAllister Energy

McAllister Energy offers top-notch heating and cooling solutions throughout the area. Our technicians are NATE-certified and capable of providing homeowners with HVAC system replacements, repairs, and tune-ups of the highest quality. They are ready to service your HVAC system properly.

Does your furnace need to be replaced or repaired? If so, not to worry. With McAllister Energy, you are always in trustworthy hands. We offer highly competitive furnace replacement and repair prices throughout the region. If your home heating system requires a replacement, we’ll be able to help you find the perfect option for your budget and for your home. As ever, comfort, energy-efficiency, good air quality, and many other factors remain among our top priorities. To schedule a consultation, call McAllister Energy now to get your free estimate.
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