Heat Exchanger Cracking? Some Possible Causes And What To Do

A heat exchanger is an essential part of your furnace, and unfortunately, a cracked heat exchanger not only can spell doom for your furnace; it can also lead to potentially lethal carbon monoxide leaks in your home. This is why it’s so important to recognize the three most common causes of cracks in the furnace’s heat exchanger and what you should do when they occur.

The most common cause of heat exchanger cracks is improper airflow that leads to overheating. Excessive heat leads to constant expansion and contraction of the surrounding metal, which results in cracks in weakened areas. Factors that impede airflow include poor furnace maintenance, dirty air filters, closed-off vents, blocked return vents, and using an oversized furnace. A furnace that’s too big for your living spaces will cycle on and off frequently, adding stress to metal parts in the furnace.

Another common cause of heat exchanger cracks is burner problems. If your furnace burners do not fire properly, they will run hotter and at a lower efficiency. Burner problems often occur when the airflow is inadequate because they must work harder to heat the air.

The final common cause of cracking is condensation. If your furnace hasn’t been running for a long time, condensation may naturally accumulate throughout the whole system. This increases the odds of rust that will weaken the system and make it prone to cracking.
In most cases, a cracked heat exchanger is discovered because the furnace is no longer able to adequately heat your home or breaks down completely. Effectively repairing these types of cracks is rarely possible. Depending on your furnace’s age and whether it’s under warranty, you may want to consider replacing the entire furnace because the primary cause of the cracking may not be resolved.

To learn more about the causes of heat exchanger cracks and what your options are, please contact us at Marsh Heating & Air Conditioning. We have been reliably serving the Twin Cities area since 1974.

Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems).  For more information about cracked heat exchangers and other HVAC topics, download our free Home Comfort Resource guide.

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