O’Hara Heating Repair Question: What Causes Cracks in a Heat Exchanger?

Furnaces are designed so that the heat – and the combustion byproduct produced inside – doesn’t interact directly with the outside air. This design is to ensure you have a safer furnace in your O’Hara home that won’t inadvertently affect your family’s health.

The metal piece that separates the furnace heat from the outside air stream is called the heat exchanger. The heat exchanger performs a very important function, and if it is broken or cracked, it can’t work properly.

A cracked heat exchanger is very common problem with heating systems, as well as one that should be repaired as soon as possible. But what causes a heat exchanger to crack? Here are some of the most common reasons:

• A long period of normal use. A furnace heat exchanger naturally expands and contracts with the heat of the furnace, over and over again as the furnace is turned off and on to heat the home. Over several years, this stress can crack the metal.
• Poor air flow, often caused by dirty or obstructed vents, can result in poor air flow through the furnace. This overworks the furnace, which can crack the heat exchanger prematurely.
• Poor, incomplete or improper combustion can also cause a heat exchanger to crack. When the combustion process is less efficient – which can also be a result of poor air flow — your furnace’s burners have to run hotter and longer to heat your home, which means extra stress on the heat exchanger.

Essentially, if a furnace is running at less than optimal efficiency for an extended period of time, the heat exchanger is put under additional stress beyond the usual and can crack prematurely. Therefore, the best way to prevent a cracked heat exchanger is proper maintenance, particularly keeping all vents clean and unobstructed and getting an annual maintenance inspection.

If your heat exchanger does crack, do not hesitate to call an O’Hara professional and get it repaired. The crack can allow potentially dangerous combustion gases to seep into your home, which can have a negative impact on your family’s health.