How To Spot A Cracked Heat Exchanger, And Why It’s ImportantA cracked heat exchanger in your furnace can mean you need to buy a new furnace. The heat exchanger is a single piece located deep inside the system. There’s no safe way to repair it if it cracks, and the labor needed to take apart the entire unit and rebuild it usually exceeds the value of the furnace. 

Meanwhile, it’s a safety hazard because that’s the chamber where combustion occurs. When gas or another resource burns to create heat, it also produces carbon monoxide. 

Today, we know carbon monoxide, or CO, as a deadly gas that’s also odorless and colorless. In other words, it’s impossible to know it’s there unless you have a CO detector. 

When everything’s working right, the carbon monoxide escapes through the exhaust and never gets into your home. But, if the heat exchanger’s cracked, it can build up and cause CO poisoning. If you don’t know it’s there, you’ll become nauseous and pass out. Eventually, you’ll stop breathing, and the result can be fatal. 

However, you’ll have plenty of warning before things get that severe — especially if you have a CO detector near your HVAC system. If you know the warning signs of a cracked heat exchanger, you can head things off soon. And, if you know how to prevent it from happening, you can save yourself a lot of time and money. 

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In this article, we’ll cover: 

  1. Three Signs Of A Cracked Heat Exchanger
  2. What To Do If You Find Out Your Heat Exchanger Is Cracked
  3. How To Prevent A Cracked Heat Exchanger

We’ll get into the specifics below. But for now: If the carbon monoxide detector near your furnace keeps beeping after you’ve opened the windows, leave the house and call the fire department. Then contact your HVAC contractor. If you live in South Central PA, call us here at Air Comfort Technologies. We’ll help you determine if it’s safe to run your furnace and if you’ll need a new one. 

Three Signs Of A Cracked Heat Exchanger

It’s important to understand that, technically, you can only know for sure if the heat exchanger is cracked once you have it inspected. You can’t see it without taking apart the furnace. But, you can watch for these three signs: 

  1. Your Carbon Monoxide Detector Keeps Going Off
  2. Your HVAC Tech Tested Your System’s CO Output
  3. Your Heater Turns On And Off Every Few Minutes

Your Carbon Monoxide Detector Keeps Going Off

if Your Carbon Monoxide Detector Is Going Off there Is A ProblemThe CO detector near your unit goes off if and when the gas starts building up inside your home. It’s usually a sign the heat exchanger is cracked — that’s where it’s coming from. 

If it goes off only once, open the windows and call your HVAC contractor for service. With any luck, something with an easy fix caused it. But, if it keeps going off, leave the house and call the fire department. 

Your HVAC Tech Tested Your System’s CO Output

An HVAC tech can test your exhaust levels to see if any of that gas is escaping the unit. This process is how most cracked heat exchangers get found. Unfortunately, it’s also an opportunity for scammers. 

Since you can’t see the part yourself, you have to take tech’s word for it. But, we’ll go through some ways to avoid a scam a little later in this article. 

Your Heater Turns On And Off Every Few Minutes

“Short-cycling” is when your heater turns on and off every few minutes. It should run for 10 to fifteen minutes at a time. But, if the system is overheated, it will turn itself off before it gets damaged. 

But, the problem is that it also blows cold air to control the temperature. And, it will keep turning on every few minutes, then overheat, then turn off again. Those drastic temperature swings will stress the parts inside the furnace. Eventually, something will break. 

Now, while short-cycling is always a problem, it doesn’t always mean the heat exchanger is damaged. But, a crack is likely to occur if you don’t have a professional get to the root of the problem. 

Why Does My Heater Keep Turning On And Off?

What To Do If You Find Out Your Heat Exchanger Is Cracked

Unfortunately, cracked heat exchangers are a common target for scammers. Since you can’t see the part yourself, and since it’s considered a safety issue, a dishonest tech or contractor can put you in a bind. They’ll shut off your furnace and say you can’t turn it back on unless the problem gets fixed (which means installing a new furnace). 

However, you can take a few steps to ensure you’re not getting cheated. We go into more detail in our article here

But, the bottom line is that if you have a trustworthy contractor, keep up on maintenance, and address problems right away, you’ll be able to avoid this scam. 

To that point, don’t trust an HVAC company that cold-calls you in the winter and offers you a free inspection or service. This is a common fly-by-night scam: Get in the door, red-flag the furnace, and make money on an install. 

Instead, always use a contractor with a longstanding presence in your community, a record of positive reviews, and an A+ BBB rating. 

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How To Prevent A Cracked Heat Exchanger

So how do you prevent this problem from happening in the first place? There are really only two ways to do it: 

  1. Have Your Furnace Serviced Annually 
  2. Watch For These Common Problems

Have Your Furnace Serviced Annually 

An annual tune-up heads off all sorts of heating problems — including the big ones. It’s when your HVAC tech inspects dozens of items, including electrical connections, exhaust, the motor, and other parts. They’ll replace anything that’s broken, clean out the system, and ensure it’s optimized for the cold weather ahead. 

This way, you avoid the clogs, short-cycling, and other problems that can stress the exchanger and cause it to crack. You’ll also enjoy better comfort with a system in great shape. That means lower energy bills all winter, too. 

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Watch For These Common Problems

We mentioned these two items before, but they’re worth going over again: 

  1. Furnace Is Short-Cycling
  2. Cold Air When The Heat Is On

The problems, especially when they happen together, can put a whole lot of extra stress on your system. And, one of the typical results is a cracked heat exchanger. 

If you live in Manchester, Camp Hill, York, PA, or anywhere in South Central Pennsylvania, you can call us here at Air Comfort Technologies for service or any HVAC questions. We have a longstanding, positive reputation, and we’re here for all your service, repairs, or installation needs.

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