Best Carbon Monoxide Analyzer for Cracked Heat Exchanger (2024 update)

Carbon Monoxide Detector, CO Alarm, CO Detector -

Best Carbon Monoxide Analyzer for Cracked Heat Exchanger (2024 update)

Carbon monoxide analyzers are a must have for the professinoal HVAC or plumber that is used to identify carbon monoxide gas leaks. Home inspectors, in particular, can greatly benefit from using a carbon monoxide analyzer when assessing homes for potential hazards. These analyzers can detect CO leaks caused by cracked or compromised heat exchangers in furnaces, alerting homeowners to the potential dangers. By implementing reliable CO gas detection during home inspections, professionals can help prevent tragic incidents and protect the health and safety of residents. Regular use of carbon monoxide analyzers is crucial for identifying and mitigating the risks associated with this silent killer.



  • A cracked heat exchanger in a furnace is dangerous and can cause carbon monoxide poisoning.
  • Carbon monoxide analyzers are accurate and precise, providing a good measurement of the amount of carbon monoxide gas present.
  • Carbon monoxide analyzers can identify the location of a furnace CO leak.
  • Carbon monoxide analyzers can have a high upfront cost.
  • Carbon monoxide analyzers may need to be charged frequently.
  • Carbon monoxide analyzers are affected by moisture and humidity which may cause them to give an incorrect reading.
  • CO Analyzers need periodic calibration.

carbon monoxide detector

Best Carbon Monoxide Detector for Inspectors?

Forensics Detectors has designed a carbon monoxide analyzer specifically for the home inspectors and to detector carbon monoxide coming from cracked heat exchangers. The unit can quickly identify carbon monoxide in air streams. Like heated air coming our of vents / registers from a HVAC system. CO in a heater air stream may indicate a cracked heat exchanger that would warrant further investigation for maximum occupant safety. The unit comes with a 4 ft probe so sampling air at high vents / registers is easy.


What is a Heat Exchanger and Why is it Important?

The heat exchanger in a furnace is a metal component that transmits heat from the fuel being burned while preventing your home's air from mingling with the furnace exhaust. The heat exchanger might fail for a variety of reasons, including cracks caused by the metal's constant expansion and contraction as it heats and cools, or rust. When a heat exchanger fails, the exhaust gases, including carbon monoxide, might mix with the air in the house under certain situations. A properly operating furnace should not produce substantial amounts of carbon monoxide, but a damaged or leaking heat exchanger might be dangerous.

Is Carbon Monoxide Dangerous from a Cracked Heat Exchanger?

In terms of house safety, a damaged heat exchanger is a major concern. The chemicals being burned off, including as carbon monoxide, sulfur dioxide, and nitrous oxide, could escape into your home if this component cracks, causing disease or, in extreme situations, death.

Carbon monoxide is a dangerous gas that is even fatal in some cases. Statistically, more than 400 Americans die from carbon monoxide poisoning that is not caused by the presence of fires per year. More than 4,000 are hospitalized from carbon monoxide poisoning each year. Infants, the elderly, and those suffering from conditions such as chronic heart disease, anemia, and more are particularly vulnerable.

    What Is a Carbon Monoxide Analyzer?

    A carbon monoxide analyzer is a gas detection tool used to measure the concentration of carbon monoxide gas present in a given environment. Analyzers are useful for both point probe sampling and continuous monitoring. They are particularly useful for finding carbon monoxide leaks, making them ideal for inspectors evaluating heaters for cracked heat exchangers.

    medidor analizador detector de monóxido de carbono carbon monoxide

    How Do Carbon Monoxide Analyzers Work?

    Carbon monoxide analyzers function by monitoring the presence of carbon monoxide in the air. Most units are made using electrochemical sensors that are robust and allow analyzers to be sold less than $500. When the sensors react with carbon monoxide, their output potential voltage increases as a linear function of carbon monoxide concentration and hence a quantitative carbon monoxide part per million representation can be displayed. The relationship between the voltage and the ppm CO reading is accomplished via "calibration" where a known value of CO ppm gas is exposed to the sensor and transposed to its representative output voltage.

    How Expensive are Carbon Monoxide Analyzers?

    Carbon monoxide analyzers can be expensive. Many range from $200-700.

    How Long Do Carbon Monoxide Analyzers Last?

    Most analyzers are made using electrochemical sensor cells which last from 2 to 3 years. 

    How Accurate are Carbon Monoxide Analyzers?

    Accuracy of a carbon monoxide analyzer is mostly dependent on calibration. If the analyzer was recently calibrated and correctly calibrated, it should read within a few ppm of the actual "real" carbon monoxide concentration. If the analyzer was not calibrated (say for over 12 months), then the sensor would drift due to sensor degradation and a error of up to 5% of the Full Scale (F.S.) may be produced. So for example, if the carbon monoxide analyzer has a full scale reading of 0 to 1000ppm, then a 5% F.S. error would mean a 50ppm error.

    cracked heater exchanger

    How to Identify a Cracked Heat Exchanger?

    Carbon Monoxide Testing

    Testing using a carbon monoxide analyzer and probe. While the heater is operating, go around to all of the registers / vents and put the probe as close as possible to the register and take a reading. A reading above zero is concerning that warrants further investigation and further probing. A home should have zero ppm of carbon monoxide, otherwise it indicates a source of carbon monoxide emissions such as a cracked heat exchanger.

    Visual Inspection

    Using a flashlight with high intensity, such as the Forensics Detectors Flashlight, visually inspect the burner chamber region and the exterior of the heat exchanger.

    Make use of a wide range of mirrors. Most welding supply stores have small round and oval mirrors with a lengthy telescopic reach. Sears also has a huge round mirror with a long reach available.

    UV Inspection Testing

    Fluorescent Dye with UV light inspection system. This is a specialized method that requires some skills. UV is often used for defect analysis and can be a useful tool in this case when it comes to heater exchanges.

    Smoke Bomb Testing

    A Smoke bomb is placed inside burner chamber and lit. Evidence of smoke on the exterior of the heat exchanger indicates leakage. Sometimes small amounts of smoke is visually hard to detect, so this method is not the preferred "go to".

    heat exchanger crack leak

    How Do You Use a Carbon Monoxide Analyzer to Detect a Heat Exchanger Crack or Leak?

    • The first step to using a carbon monoxide analyzer is to ensure all necessary components are present.
    • Ensure it is calibrated. Bump test before using to ensure operation.
    • After this, assuming the analyzer was pre-calibrated, it should be tested
    • Turn ON and start sampling. Most units, have a 1 minute warm up, and then from that point show the instantaneous CO ppm reading.
    • Turn on the heater and ensure it is operating.
    • Take samples. Do not rush. For each HVAC register, take about 30 to 60 seconds so any readings have a chance to react with your carbon monoxide analyzer. 

    How Do You Calibrate a Carbon Monoxide Analyzer?

    Nearly all carbon monoxide analyzers arrive pre-calibrated. 

    If an individual does not wish to calibrate their device on their own, they can often send it to a company to calibrate for them. Forensics Detectors is one example of a company that offers calibration service.

    What is a Normal Reading on a Carbon Monoxide Analyzer for Heat Exchanger Inspection?

    The normal reading on a carbon monoxide analyzer should be zero when testing a vent to determine if a heater exchange is cracked. If it displays more than this, 2, 5 or 10ppm, then one can confidently assume the heater exchange is compromised and should be further visually inspected to then be replaced.

    Can Carbon Monoxide Analyzers Give False Readings?


    While carbon monoxide detectors may be more likely to give off a false reading since they tend to be mounted for continuous detection while carbon monoxide analyzers are only used during certain situations, analyzers may give false reading.

    • Hydrogen Gas: Most carbon monoxide detector are sensitive to hydrogen gas as well, so they may alarm in the presence of hydrogen gas.
    • High Humidity: The presence of high humidity and moisture in the air can cause detectors to falsely go off and alarm the user.

    Who Should use a Carbon Monoxide Analyzer?

    Home Inspectors, Plumbers, HVAC Technicians

    Detecting and locating potential leaks in heating systems. 

    Home Owners for Carbon Monoxide

    Some home owners may be interested in carbon monoxide analyzers to track the safety of their indoor air quality.

    Will my Home Carbon Monoxide Alarm trigger if there is a Cracked Heat Exchanger?

    No it will not. 

    Your home CO detector alarms at 70 ppm after 60 minutes. Carbon monoxide can be harmful at much lower levels than 70ppm, therefore waiting for a home CO detector to alarm to confirm a heat exchange crack is a terrible idea.

    Carbon monoxide analyzers detect down below 10ppm and are much more sensitive to provide early warning and detection. 

    Why Do Home Inspectors Check for Carbon  Monoxide?

    Home inspectors check for carbon monoxide to ensure that homes are safe for the people living within them. They use their own devices for this to ensure that home owners are not using faulty carbon monoxide detection equipment. Inspectors check for potential buildup of carbon monoxide gas that may result in safety concerns. They also check for potential leaks in appliances such as heaters that may allow carbon monoxide to be introduced to the home.

    cracked heat exchange carbon monoxide

    Is It Dangerous if a Home's Heater Exchange is Compromised?


    If a home's heater exchange is compromised, it may release carbon monoxide gas into the home and potentially expose those to carbon monoxide.

    There is much argument about the level of "acceptable" CO in the output of heater air coming out of a register. However, in our opinion, any amount greater than zero is too much in a home situation. The leak can increase at any time. Running this risk is simply a foolish game of "chicken".

    What Happens if I have a Cracked Heat Exchanger?

    If the heater exchange is cracked, carbon monoxide gas may be introduced to the rest of the home. This could lead to carbon monoxide poisoning, even at very low levels. Most often, the heater unit or heater exchanger will be replaced if one find a cracked heat exchanger.

    Final Words

    Carbon monoxide (CO), a dangerous and potentially lethal gas, can pose significant risks in residential settings. Home inspectors play a crucial role in detecting CO leaks and protecting homeowners from this silent killer. By using carbon monoxide analyzers during inspections, professionals can identify potential leaks caused by cracked heat exchangers in furnaces or compromised heaters. These gas detection devices are essential tools for home inspectors, enabling them to alert homeowners to the presence of CO and prevent tragic incidents. Regular use of carbon monoxide analyzers during home inspections is a critical safety measure that helps ensure the health and well-being of residents by identifying and mitigating the risks associated with this hazardous gas.

      About the Author

      Dr. Kos Galatsis ("Dr.Koz") is the President of FORENSICS DETECTORS, where the company operates from the scenic Palos Verdes Peninsula in Los Angeles, California. He is a subject matter expert on gas sensor technology, gas detectors, gas meters, and gas analyzers. He has been designing, building, manufacturing and testing toxic gas detection systems for over 20 years.

      gas detector expert

      Every day is a blessing for Dr. Koz. He loves to help customers solve their unique problems. Dr. Koz also loves spending time with his wife and his three children going to the beach, grilling burgers, and enjoying the outdoors.

      Read more about Forensics Detectors here.

      Phone: +1 424-341-3886