Why Is A Failing Heat Exchanger So Dangerous?

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Why Is A Failing Heat Exchanger So Dangerous?

Have you ever had an HVAC professional tell you it's time to get a new furnace? A common reason why they might have told you that is because your heat exchanger could've been failing. If that's the case, it's very important that you get the problem addressed before it becomes hazardous to your safety. In this blog post, we'll talk about what a heat exchanger is, why it's so dangerous when it fails, and what you can do to prevent it from happening. 

What Exactly Is A Heat Exchanger?

The Heat Exchanger is the part of a furnace that transfers heat from burning fuel within the system into the air from your home. The fuel can be gas, liquid, or a combination of both. Some examples of heat exchangers are steam condensers, radiators, and air conditioner evaporator coils. 

Heat exchanger diagram

Heat Exchanger Failures and Risks

Over time, your heat exchanger is exposed to vigorous expansion and contraction, which causes cracks, holes, split seams, disconnected parts, or severe deterioration. These conditions are all considered unsafe and potentially life-threatening system failures.

The primary risk associated with heat exchanger failure is leakage of Carbon Monoxide (CO), which is created during the fuel combustion process. CO is an odorless, colorless, and extremely hazardous gas produced when fuel is burned, such as during the combustion process inside your heating system. When there is failure in the heat exchanger, there is a possibility that the CO created within the system may escape and leak into your home.

The presence of a failure in a heat exchanger does not necessarily mean that there is already CO leaking into your home. A failure simply means there is a risk of of a leak occurring. 

CO Poisoning 

When CO begins to leak into your home, you are at risk for CO poisoning. Symptoms of CO poisoning may include:

  • Headache
  • Dizziness
  • Weakness
  • Nausea and/or Vomiting
  • Sleepiness
  • Confusion

Do not ignore these symptoms, particularly if more than one person is feeling them. If you suspect CO poisoning, get outside to fresh air immediately and then call 911.

CO poisoning graph

Ways To Prevent and Fix Heat Exchanger Failure

Detecting CO Leaks

To help avoid the danger of undetected failures, we strongly recommend installing professional-grade low level CO detectors in your home. A healthy home should be monitored for CO levels starting as low as 10 PPM (parts per million). Most CO detectors sold at retail only go into alert starting at 70 PPM, which is why we recommend upgrading to level detector. Give us a call at (715) 564-4328 to set up your free estimate for a new CO detector!

Moving Forward After Detecting A Failed System

A system with a failed heat exchanger is considered to be a failed system, even if carbon monoxide is not currently present. When a heat exchanger failure is discovered, the service technician is required by state building code to shut off the service switch to the system, close the fuel supply valve, and mark the system unfit for use until the heat or exchanger or the full heating system is replaced. The best replacement option will vary depending on the age of your system, the condition of other components in the system, and the underlying cause of failure. 

We strongly urge you not to turn back on your system until it has been repaired or replaced, even though you are legally allowed to. HVAC technicians are required to shut down systems with heat exchanger failures because they are considered unsafe for operation. It's a technician's job to help protect you and your family, and code requires a technician to shut off a system with a failed heat exchanger. Heeding this professional recommendation is encouraged by the American Gas Association (AGA).

Click here for an informational video on Heat Exchangers!