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A heat exchanger is a vital part of any HVAC system. It;’s the component that is responsible for transferring heat from one fluid to the next. You will find heat exchangers in furnaces, air conditioning units, and space heaters. They also appear in other systems unrelated to the heating or cooling of a home, such as refrigerators or automotive engines. Because the heat exchanger is so important in HVAC systems, though, the issue of a cracked heat exchanger tends to be one of the bigger question marks for consumers struggling with their heating or cooling systems.

Heat Exchangers, Cracks, and What You Need to Know

Cracked Heat ExchangerIt should go without saying that a crack or hole in your heat exchanger is a problem. Suffice to say that these devices do not have cracks in them when they are manufactured. Just like you would want to investigate further if you spotted a crack in your car’s radiator or exhaust pipe, you should be eager to get to the bottom of what happened with your heat exchanger.

First off, it’s important to note that heat exchanger cracks in furnaces are different from cracks in air conditioning exchangers. Furnaces use gas, which means there is a risk of carbon monoxide poisoning with any holes or cracks in the system. Air conditioners don’t utilize gas, which means the risks aren’t the same. This article, therefore, will focus specifically on furnaces and their heat exchangers.  

Industry standards for furnaces dictate that you should replace heat exchangers when they start to crack. If you call a technician to consult about a cracked heat exchanger, there is a good chance that he or she will instruct you to replace the system ASAP. The relevant standard comes from the American Gas Association (AGA) and states that “any visible crack or hole” should be seen as a reason to replace to the heat exchanger.

Why is this industry standard in place? Because cracked heat exchangers can be dangerous, depending on how severe they are. If a crack in your heat exchanger becomes wide enough, there’s a chance that it can start leaking exhaust gas from your furnace. This gas can lead to carbon monoxide poisoning, which can, of course, be lethal.

The interesting wrinkle here is that most heat exchanger cracks are very, very small. Following AGA protocol, these exchangers should be replaced right away. In most cases, though, the cracks aren’t big enough to allow exhaust gas to leak out and contaminate the air in your home. They might be so slight and insubstantial that you could fill the heat exchanger with water and see no evidence of leaking through the crack. In other words, the crack in your heat exchange might not be dangerous at all.

Bottom Line: What to Do about a Cracked Heat Exchanger

So, what should you do about that crack in your heat exchanger? Obviously, there is a sizable dilemma here. Either you pay to replace your furnace, or you take the risk that your damaged system might be leaking carbon monoxide into the house. Neither of these options is ideal.

If you want to find out a little bit more, you should call a furnace maintenance technician to come and take a look at your heat exchanger. Your technician will be able to give you a little more guidance about how big the crack is and whether it’s a real risk.

In most cases, though, your best bet is to replace the heat exchanger in question, which might mean replacing the entire furnace. This answer probably isn’t the one that most people want to hear, but it’s the most sensible answer there is. Carbon monoxide is not something you want to mess around with, especially when the health and safety of you, your family, your pets, and anyone who visits your home is at stake. It’s worth replacing the damaged unit to protect your family and get some peace of mind.

That’s the answer to the “should I replace my cracked heat exchanger?” question. The answer to the question posed by the title of this article, though—about whether cracks in a heat exchanger matter—is considerably more difficult to answer. On the one hand, heat exchanger cracks might not be big enough to be a cause for concern. On the other hand, a cracked heat exchanger is a sign that your furnace is damaged. Those cracks should not be there, which means something happened to cause them.

Usually, the issue with your heat exchanger isn’t that it’s faulty or poorly made. Consider a furnace in the wintertime. How many times does the heat exchanger have to heat up and then cool back down in an average day to maintain the home’s thermostat temperature? Over time, those repeated temperature changes tend to take their toll. This demanding function, combined with the onslaught of time, means that most heat exchangers tend to fail after 15 years or so. Furnace maintenance can add extra years to the lifespan of the exchanger, along with other components.  

Ultimately, heat exchange cracks probably aren’t as dangerous as most people tend to think they are. However, to keep your furnace running well and avoid any potential dangers, it’s smart to replace any heat exchanger with visible holes or cracks. In other words, yes, a cracked heat exchanger does matter.

Valley Comfort conducts furnace repair services in the following communities: Santa Rosa, Napa, Rohnert Park, Healdsburg, St Helena, Calistoga and Windsor

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