Heating / October 31, 2018

Your Furnace’s Heat Exchanger

The Role of the Heat Exchanger in Residential Furnaces

Gas furnaces are such an everyday part of people’s lives that it can be easy to overlook their innate complexity. In order for a furnace to function properly, it must successfully integrate a wide variety of key components. Should any of these components fail or cease to perform its function, you will no longer be able to enjoy the heat you want and need.

One of the most critical of all furnace components is known as the heat exchanger. Unfortunately, many people fail to understand the role the heat exchanger plays. If you would like to keep your furnace repair costs to a minimum by educating yourself about what’s inside your furnace, read on. This article will introduce you to the role played by the heat exchanger.

Heat Transfer
A gas furnace generates heat through the combustion of natural gas. The blower system then comes on and pushes this heat throughout your home by means of the duct system. While this explanation of a furnace’s operation may seem complete, it leaves out one key step, which is the transfer of heat from the inside the furnace to the outside.

What many people imagine is that the air inside of the furnace is the same air that is pushed out into the home. This air, however, contains large amounts of poisonous exhaust substances like carbon monoxide. For that reason, it must be safely sequestered from the air of your home while still allowing its heat to pass out to where it’s needed.

As its name would suggest, a heat exchanger acts to facilitate this transfer of heat from the inside of your furnace to the air of your home. The heat exchanger is made up of a series of thin-walled metal tubes. While the furnace air passes through the exchanger en route to the flue, air from your home swirls around its exterior, absorbing precious heat.

Potential Problems
Heat exchangers tend to be among the most problematic furnace components, thanks to the fact that they are regularly subjected to wild swings in temperature. As hot air flows through a heat exchanger, its metal sidewalls expand outward. When the furnace shuts off and the metal starts to cool, the heat exchanger undergoes contraction.

As time goes on, all of this expansion and contraction causes what is referred to as metal fatigue. This is essentially the same thing that happens when you bend a paperclip back and forth too many times. The metal grows thinner and more worn until, at last, it breaks. In the case of a heat exchanger, metal fatigue involves the formation of cracks, split seams, and other forms of structural damage.

Things only get worse when you consider the sorts of exhaust byproducts that flow through a heat exchanger. These substances tend to be highly acidic, meaning that they contribute to the formation of rust on the inside walls of the heat exchanger. Such corrosion only hastens the development of structural weakness and other problems.

Damage Dangers
A heat exchanger that has suffered structural damage resulting in holes or cracks is a highly dangerous thing. Those holes allow dangerous exhaust gases to leak out into the air that will move through your home. This puts you and your family at an elevated risk of poisoning. Fatalities may even occur if carbon monoxide levels grow high enough.

Be sure that your home contains multiple carbon monoxide detectors. Install one near your furnace, with others scattered around your house. These will help alert you to problems that may stem from a damaged heat exchanger. In addition, be proactive about having your furnace serviced regularly by a reputable HVAC company.

If you would like to learn more about what it means to keep a heat exchanger in good working condition, contact the HVAC experts at Mauzy Heating, Air & Solar.

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