One major furnace component is the heat exchanger which is where much of the heat for the home is created. The heat exchanger can, at times, develop cracks and other problems resulting in furnace failure and even carbon monoxide poisoning. Air Supply Air Conditioning & Heating will cover how the heat exchanger works and some of its most common repair needs.
Heat Exchanger Definition
In every gas fueled furnace there is a heat exchanger which is the primary component for creating the heat for the home. To create the heat, the furnace needs to combust the fuel such as gas with a sealed chamber. It is this combustion process that creates heat. In an electrical furnace they will use electric coils to create heat. In a gas fueled furnace the gas and combustion fumes, which is called flue gas, is toxic and should never be breathed in. This is where the exchanger plays a major role. The heat exchanger is a thin metal shield that fits between the combustion chamber and the blower. As the combustion chamber creates the heat, the exchanger takes the heat and sends it through the blower to be distributed throughout the home. To ensure the heat makes it through the blower, and to ensure the household’s safety, the heat exchanger must be sealed.
How to Identify a Cracked Heat Exchanger
As a furnace heat exchanger is made with metal, which is fairly durable, even over time heat can weaken and impact the metal. Since the heat exchanger will undergo rapid heating, this will cause the metal to expand. Once the furnace ends a heating cycle, the metal will cool and contract back to its original shape. Even though the metal used for the heat exchanger is durable and can thrive even with rapid heating and cooling, over time this process has its effects. Given enough time, due to the intense heating and eventual cooling, the heat exchanger can crack and snap. Once the heat exchanger cracks the heat system is compromised, and worse, the home is now exposed to harmful gases. The heat exchanger houses the flue gas that is created during the heating cycle. If the heat exchanger is cracked, it will release the gases. The flue gas which is carbon monoxide gas is odorless, sightless, and tasteless which makes it impossible to detect. The only clue that this gas is present is that a household member will begin to get sick. One sign however that there could be a possible cracked or damaged heat exchanger is lack of heat in the home. If the furnace runs and the fan is blowing cold air instead of warm air, then the heat is being lost, most likely due to a cracked heat exchanger. When the furnace is running and you only feel cold air coming from the vents, turn off the furnace immediately. Have the furnace inspected by a professional HVAC technician to determine the problem and see if the heat exchanger is to blame.