Understanding What Your Furnace's Heat Exchanger Is | HB Home Service
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Your furnace is a complex system that helps to keep your family and home safe during the colder winter months. If you’re like most homeowners, you don’t quite understand how the internal components of your furnace work. Fortunately, we’re going to take a few minutes and dive into explaining what your furnace’s heat exchanger is and how it works.

What Does a Heat Exchanger Look Like?
Before you can really understand the job of a heat exchanger and how it works as part of your furnace, you need to understand what it looks like. A heat exchanger is comprised of a series of metal tubes that run through thin metal shielding. Each furnace’s heat exchanger is going to vary from the next slightly.

Defining the Job of a Heat Exchanger
The largest component of your furnace, the heat exchanger, is responsible for safely transferring heat. However, its job doesn’t stop there. It’s also in charge of making sure that all the flue gases make their way safely out of your home.

You’ll only find heat exchangers on furnaces that burn gas or oil. As your furnace combusts your fuel of choice, it generates heat and combustion fumes, also known as flue gases. These flue gases, like carbon monoxide, are not safe for you to breathe. Your exchanger is in charge of properly diverting those flue gases to your furnace’s exhaust outlet.

As the flue gases travel through the inside of the heat exchanger, their high temperature heats up a thin metal shield. Air from your fan blower will be blown across this thin metal shield in the direction of your ducting. The now heated air will proceed to travel through your ducting and deliver that warm air to your entire home.

Most Common Heat Exchanger Problems
Ask any furnace technician what their most common furnace repairs entail, and most will reveal that they deal with an abundance of cracked heat exchangers. It’s vital to remember that your heat exchanger is made out of metal. As it heats up, the metal will expand. As it cools down, the metal will contract.

This can wreak a lot of havoc on your heat exchanger over many years. Eventually, the metal will become brittle and more prone to snapping and cracking. When the metal cracks, it’s no longer safely sealing in those harmful flue gases. This is why it’s so important to have your furnace evaluated each year and to have well-placed carbon monoxide detectors throughout your home.

Signs of a Cracked Heat Exchanger

Heat exchangers take many years to develop cracks, which can put them at the back of your mind. However, there are some signs that should always be on your radar when you’re evaluating your furnace. First is the existence of soot buildup on your heat exchanger. If you notice an area or multiple areas where the soot has buildup on the metal, it’s an indication that there is damage where the soot is at.

Another common sign of a cracked heat exchanger is unusual noises when you turn your furnace on. You may hear rattling, banging, or popping noises as the metal expands where the cracks are located at. When you look at your heat exchanger, it may also be overly obvious that there are physical cracks near connections.

How Long Do Heat Exchangers Last?
A factory heat exchanger should last a good 15 to 20 years. Obviously, with annual maintenance, your heat exchanger will last closer to the 20-year mark. However, it will eventually crack at some point due to its metal makeup and constant expansion and contraction.

When a heat exchanger goes out, it can be costly to replace. In most cases, homeowners will opt for replacing their entire furnace when the heat exchanger goes out, as the rest of the furnace components will be nearing the end of their lifespan. However, in the odd instance that your heat exchanger develops a problem while your furnace is still under warranty, getting only the heat exchanger replaced is ideal. Most warranty coverage will cover all or mostly all of the cost of the replacement.

Reliable Heating Service
HB Home Service Team is your reliable heating professional in the Harrisburg, PA area. We’re also here for all of your cooling, plumbing, oil, propane, electrical, indoor air quality, and safety needs. Contact our office today to get the help that you need.

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