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Preventing Cracked Heat Exchanger

Sep 17, 2015

Heating & Cooling
Exterior view of a modern home in a community on a summer day during sunset being heated by a Lennox furnace.


A number of things can go wrong in a furnace, but of all those things, a cracked heat exchanger is one of the most severe problems. This is due to the fact that a cracked heat exchanger not only spoils the performance of your furnace, but it will also create a safety threat to you and your loved ones. Although we can’t completely prevent cracked heat exchangers, there are a few steps you can take to prevent them from cracking.

Why is a cracked heat exchanger a safety issue?

When the burners of your furnace produce hot combustion gases, those gases are sent to the heat exchanger. While inside, the heat of those gases gets transferred to the metal walls of the heat exchanger. Your furnace blows air over the outer walls of the heat exchanger so that it can safely pick up the heat from the walls of the heat exchanger, without coming in contact with the gases inside. If your heat exchanger is cracked, carbon monoxide can leak out of it and get inside the airflow of your home, which is a severe safety concern.

How do heat exchangers crack?

Some of the most common causes of cracked heat exchangers are as follows:

  • Dirt buildup on heat exchanger: If the outer walls of your heat exchanger are covered in dirt, there will be an obstruction between the heat exchanger and the air that blows over it. This makes heat transfer difficult which again causes the heat exchanger to overheat and crack.
  • Closed or blocked air vents: If there is any furniture in the vicinity of the air vents which blocks them or you close the vents in some of your rooms, your furnace will receive a sufficient amount of airflow. This will lead to the same issues that are caused due to dirty filter as it will again cause your heat exchanger to overheat.
  • Dirty air filter: In normal conditions when the airflow of your furnace is normal, the air that flows through your furnace will blow over the heat exchanger and absorb heat from its outer walls. But, when your air filter gets dirty, it restricts the flow of air through your furnace. This can be responsible for overheating and cracking the heat exchanger as less air would be available to absorb heat from its walls.

Tips to prevent a cracked heat exchanger

  • Keep all the vents present in your home open and clear of hurdles
  • Don’t forget to change your air filter in order to maintain a proper air flow
  • Schedule regular tune-ups so that Romaniuk can check heat exchanger of your furnace for cracks, clean your system and repair any issues that could lead to cracks.

If you have any questions related to residential or commercial furnace repair, feel free to drop us a line.