Cracked Heat Exchanger? This Might Be The Cause


Your heat exchanger is the warm, beating heart of your furnace. This vital component is used to exchange heat between the combustion chamber and the environment while also keeping dangerous exhaust gases out of your home. Cracks are the most common mode of failure for heat exchangers. Once cracks develop, there is a risk of exhaust gases leaking into your home. Even worse, a weakened heat exchanger will likely continue to fail, allowing small cracks to develop into significant problems later on.

If an HVAC technician has just informed you that your heat exchanger requires replacement, then you're probably wondering how you ended up with such an expensive repair on your hands. Although heat exchangers can fail for a variety of reasons, these three issues are the most common.


It can seem counterintuitive, but your furnace can overheat. The internal components in your furnace are designed to operate with specific maximum temperatures, and damage can occur if these temperatures are exceeded. When your heat exchanger gets too hot, the metal will expand and become stressed. As it cools, the metal contracts and cracks can form in vulnerable areas. These cracks may not cause leaks immediately, but they are guaranteed to grow over time. A heat exchanger that has begun to crack from overheating always requires replacement.

The Causes of Overheating

In most cases, overheating is the result of airflow restrictions in your HVAC system. When operating normally, your furnace transfers heat to the air in your house through the heat exchanger and a blower moves that air away from the furnace. When there is a restriction in the system, warm air will build up in the furnace and near the heat exchanger. A build-up of heat over a short time may not cause damage, but long-term exposure to excessive temperatures will quickly lead to cracks as the metal expands and then later contracts during cooling.

Airflow restrictions of this type have two common causes: dirty filters and ductwork issues. When your furnace filter becomes too clogged, it can prevent the blower from moving enough air away from the furnace. Not only does this threaten your heat exchanger, but it can also cause the blower motor to overheat. Regular filter changes will prevent this condition from occurring and help your heating system to last much longer.

Ductwork issues are more serious. Restrictions in your ductwork can occur due to installation faults or damage incurred later. Rodents or other pests that make their way into the ductwork can create sharp bends or leave debris that stops airflow. Restrictions of this type will cause other symptoms as well, such as warm and cool spots or reduced air flow from your vents.

Dealing with a Cracked Heat Exchanger

Since your heat exchanger is responsible for keeping dangerous combustion gases out of your home, a crack should never be ignored. The best way to ensure that your heat exchanger is in good shape is to schedule regular furnace inspections and, if a problem is discovered, have the damaged part replaced immediately. For more information, contact a furnace repair service in your area.


12 November 2019

furnace repairs - do it yourself?

Can furnace repairs be made by the average DIYer? If you know a little about what you are doing, is it possible to avoid the expense of having a professional come out to take care of any problems that you are having? My blog is all about furnace safety and repair. You will learn a few things that you can do on your own and advice for when to call in the professional repair technician to assist with the repairs. By the time you reach the end, you will have a better understanding of what you can and should not do on your own.