A furnace heat exchanger is a metal compartment that serves as a barrier between the warming flame and the fumes it generates and the air in your home.

The heat exchanger is heated by the flame, which in turn warms the air that enters your home. This system keeps combustion fumes contained, directing them to the flue to be carried away safely through the chimney.

A cracked heat exchanger can allow dangerous fumes to leak, such as carbon monoxide, and can create other hazards, such as poor combustion, soot buildup and flame roll out.

What causes a cracked heat exchanger?

Metal expands and contracts during temperature changes, so the repetitive cycle of heating and cooling stresses the heat exchanger, eventually causing deterioration. In a properly installed and well-maintained furnace, the heat exchanger should last approximately 15 to 20 years. However, insufficient airflow, due to dirty filters, poor maintenance or improperly sized ductwork can cause excessive heat in the furnace, leading to stress cracks in the heat exchanger, or moisture problems can promote rust, causing premature failure.

Diagnosing a dangerous heat exchanger

Your heat exchanger should be inspected for damage by a reputable HVAC professional at least once a year. Many heat exchangers develop hairline cracks that aren’t necessarily dangerous, but will require monitoring. If cracks are severe enough that you can see light shining through upon evaluation, they definitely need immediate attention.

Your heat exchanger should be inspected for damage by a reputable HVAC professional at least once a year. Typically, a crack will cause problems with furnace operation, making burner flames dance or roll out of the combustion chamber.

If you’ve been informed that your furnace needs replacement due to a cracked heat exchanger, feel free to contact us for a second opinion. Family owned and operated, Apollo Home Heating, Cooling and Plumbing has been a trusted source in home mechanical repair in the greater Cincinnati area since 1910.

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