A furnace heat exchanger is a barrier that prevents toxic fumes generated by the burner from contaminating the warm air that circulates into the living area of your home. Rather than warming the air directly, the flame heats the metal surface of the heat exchanger, which then radiates that warmth to the air above it while keeping hazardous fumes contained below to be vented out through the chimney. If that barrier is compromised by significant cracks, operating the furnace can be very hazardous.
Potential heat exchanger problems
Since metal expands and contracts with temperature changes, the heat exchanger in your furnace is subjected to stress every time it heats and cools, a process that occurs in a constant cycle throughout the heating season. Of course, the engineers that design furnace parts are aware of that stress and build them accordingly. In properly installed and maintained units, heat exchangers will hold up to that stress for 15 to 20 years.
However, heat exchangers can be damaged under certain circumstances, so it is essential that they are inspected every year by a qualified HVAC professional. Poor airflow is the most common source of premature problems, allowing excessive heat to build up beneath heat exchangers, causing stress cracks. Typically, restricted airflow is caused by poor maintenance, such as dirty air filters, or ductwork that hasn’t been sized properly for the system.
Cracks that penetrate all the way through the metal can allow hazardous fumes, like carbon monoxide, to leak into the household air. They can also cause burners to operate poorly, making flames dance on the burners, roll out of the combustion chamber or fail to burn fuel completely, generating more fumes than normal. Superficial cracks that do not extend all the way through the heat exchanger are typically not an immediate danger, but will need to be monitored by your HVAC service professional.
In addition to scheduling regular maintenance visits from an HVAC technician, it is also important to install and maintain carbon monoxide detectors in your home. They can warn you and your family if a problem with your furnace develops.
For more information on cracked heat exchangers or any other home comfort concerns, please contact Around the Clock Heating & Air Conditioning. We’ve been providing fast and reliable service to our valued customers in the Los Angeles area since 1967.
Our goal is to help educate our customers in Los Angeles, North Hollywood and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about heat exchangers and other HVAC topics, download our free Home Comfort Resource guide.
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