Heat exchanger inspections have almost become a science unto themselves. This problem is often avoidable with regular and diligent heater maintenance. A heat exchanger is made of thin metal, and as it heats up from the combustion of the furnace, it transfers the heat to the air being distributed through the house by the blower 3. However, the current mind set in the industry is that every heat exchanger crack is dangerous. Heat exchanger testers, plate heat exchanger crack testing and spray dryer crack testing equipment. This will be detected with a combustion gasses tester. For a good example of a hazardous heat exchanger, check out the photo below showing a large rust hole in the heat exchanger of this highefficiency furnace that was only ten years old. Other than this, there really isnt anything else that can definitively give you an answer. Its the best way to examine your heat exchanger for cracks. Dec 02, 2014 i recently had a reader email this question. In addition to spotting the actual crack, there are other visual clues to a cracked heat exchanger such as. Searching documents and internet sources the following is what i found on heat exchanger inspection methods and sources. Dec 02, 2015 if the heat exchanger is compromised by a crack or rust, flue gases and carbon monoxide will leak into the home resulting in illness and possibly death of the occupants.
A cracked heat exchanger in a gas furnace is a serious safety issue. One of the oldest ways to check for heat exchanger cracks is to simply observe the flame when the blower starts. When these components wear down, the pressure changes to a level that the heat exchanger cannot handle. Read our blog to learn what to do if this happens to you. I sent a short answer, but thought this was deserving of a longer answer in the form of a blog post.
Find them too often, and your company could get a rep for using scare tactics. A gas furnaces heat exchanger is the furnace component that actually heats the air. There are older, traditional ways for finding cracked heat exchangers, such as smoke bomb methods, which contractors have relied on for years. I show how a furnace reacts when there is a crack in the heat exchanger. Heat exchanger leak test, plate heat exchanger crack. When a heat exchanger becomes damaged and the combustion fumes and gases mix with the clean air, serious consequences can result.
The american gas association has even put this in writing they say any visible crack or hole is reason. Any visible crack or hole discovered in this step is reason for requiring. Looking for nucalgon heat exchanger crack finder solution, heat exchanger inspection system 20hy29. Checking for cracked heat exchangers a smoke bomb test a smoke generator is placed in the heat exchanger. Heat exchanger leak detection plate dyetesting wcr. Since access for visual inspection of the heat exchanger is frequently limited by evaporator coils and the like, a removable inspection plate, access panel or heat register on the plenum is helpful in viewing the heat exchanger from the circulating air side. A damaged heat exchanger in a gas furnace is potentially dangerous to a homes occupants and should not be ignored. There are many areas on a heat exchanger that you can not get to for visual inspections while the heat exchanger is in the furnace. I hear you can do a combustion c02 test, fill it up with water and see if it leaks on the edges around the chamber or smoke bomb it.
If a heatexchanger is cracked, air forced into the combustionchamber will cause the oxygen reading in the furnaces exhaust to rise to abnormal levels. If your heat exchanger is most likely the issue, its time to call in a professional. The combustion analyzer also helps us gauge the overall performance of your furnace. The prevailing viewpoint is that any hole or or heat exchanger crack can and. If theres a possibility of your heat exchanger being cracked, dont ignore it. Most furnaces will have a blower delay to get the furnace up to temperature before moving air over the exchanger. There are other test gases that have been or continue to be used to test furnace heat exchangers for leaks. Hunker may earn compensation through affiliate links in this story. The author has been in the industry for years as a trainer for hvac technicians. A cracked heat exchanger allows air from the furnace blower to interfere with the flame causing it to flutter or even roll out. Please read this article about why heat exchanger cracks do not allow carbon monoxide into the house.
Signs and symptoms of a cracked gas furnace heat exchanger. Broken and leaking heat exchangers are responsible for about 1,500 deaths per year in the united states, and many more people are poisoned by exposure to toxic gasses that go unfiltered by defective heat exchangers. A combustion analyzer gives us co and oxygen readings. With slight increases a more thorough examination of the heat exchanger may be required. Visually check heat exchanger for cracks you will find most cracks form near the back and where the heat exchanger metal bends, since this is where it will be weakest due manufacturer weakening the metal by bending. Easytesters heat exchanger testing and crack testing haccp. Cracks or corrosion on other parts of your furnace. Furnace heatexchanger crack signs your furnace has one.
Would the size of my heat exchanger affect test sensitivity. With proprietary red dyepenetrant saturating the plate surface, and white developer solution covering the reverse side, wcr is capable of detecting even miniscule imperfections. How do you detect a crack heat exchanger in a furnace answers. Dec 12, 2016 we are familiar with the article heat exchanger applications in chemical industry. Nucalgon heat exchanger crack finder solution, heat. Aga and gama insist that even a hairline crack in a heat exchanger constitutes a defect and requires replacement. The following are various procedures and test methods to tell how to identify a cracked furnace heat exchanger. To determine if you have a cracked heat exchanger, an hvac contractor should use a combustion analyzer to check for co. This trips a safety switch and shuts down the furnace. A pencil size hole or hairline crack in a heat exchanger does not, in my opinion, justify shutting off the heat on someone in the middle of winter. The most comon way to detect a crack in a heat exchanger is with a visual inspection, removal of the burner assembly and the use of a mirror and flash light. This procedure is as simple as watching the flame and observing if it the flame moves or changes when the blower starts. Nov 05, 2019 one way to tell if you have a cracked heat exchanger is if you can actually see a crack it in. The wintergreen test oil of wintergreen is sprayed into the combustion chamber.
This heat exchangers quiz module covers basics, selection, application and calculations with respect to heat exchangers. Thanks for watching guy browns youtube channel was. Its not that youre questioning their credibility, youre just wanted to see for yourself. Furnace with a cracked heat exchanger and flame rollout. A cracked heat exchanger is pretty serious, as far as safety for your home goes. Older furnaces can develop major issues, such as a cracked heat exchanger. Diagnosis of a heat exchanger crack typically starts with a no heat service call. Located in the center of the furnace, it is where fire, gas and heat connect. Overheating causes nearly all premature heat exchanger cracks. Residential gas furnace heat exchanger testing douglas dewerth, p. Guide to furnace heat exchanger inspection, testing, leaks how to inspect and test furnace heat exchangers for leaks photographs show clues indicating leaky, dangerous furnace heat exchangers furnace heat exchanger leak testing, a complete list of methods used to find or test for leaks in a furnace heat exchange what is the allowable amount of gas fired heat exchanger leakage. If a crack has developed, air from the house will be forced into the combustion chamber when the blower turns on, causing some visible disturbance of the flame, he says.
A look at a heat exchanger crack that cant be found youtube. With hexteq, the size of the heat exchanger is not a factor for this methodology as the sensors are searching for defect size and leakage volume in microlitres. The shape of the coils depends on the type or model of your furnace. Cracked heat exchanger furnace trouble shooting help. The problem with finding a crack in a furnace heat exchanger is that you can see very little of the heat exchanger without disassembling the furnace. Dec 23, 2019 when internal temperature increases, there is a high likelihood that the heat exchanger will crack. A furnace with a cracked heat exchanger is usually an exception, because of the cost of the repair. If they say its not a visible crack, but they have a co detection device that found a crack, ask them to show you.
Heat exchanger leak test, plate heat exchanger crack testing. The american gas association has even put this in writing they say any visible crack or hole is reason for requiring replacement of the heat exchanger or furnace. In many organizations, finding a cracked heat exchanger constitutes a really good day, and sometimes a boost to the wallet. Overheating is the most common cause of a cracked heat exchanger. If it is your heat exchanger, you cannot run your furnace, even if it. Diagnosis of a heat exchanger crack typically starts with a noheat service call. This one is about a crack i found in a heat exchanger that caused no. Now its time to test out knowledge on heat exchangers through this online test. If high readings are obtained, there is no doubt that the heat exchanger has a crack or fault. So what to do if your expecting a crack, or you have evidence that there is a crack in the heat exchanger. We use it to check co levels given in parts per million, or ppm and determine for sure whether theres a crack in. A correctly operating furnace has a clear, steady blue flame. Test your knowledge on heat exchangers online quiz. Mar 19, 2007 the pressure test all openings in the heat exchanger are sealed, the blower energized, and a pressure sensor or draft gauge is inserted inside the heat exchanger to see if a crack is allowing distribution air to blow into the heat exchanger through a crack or hole.
The heat exchanger is a key part of the furnace and is responsible for the actual heating of air. Its comprised of a set of tubes or coils that repeatedly loops through the airflow inside the furnace to heat the air. Cracked heat exchanger issues also occur due to worn out control valves. Does the o2 change on a combustion test when the blower comes on. We use it to check co levels given in parts per million, or ppm and determine for sure whether theres a crack in your heat exchanger. In years past, with older furnaces, a heat exchanger crack or small slit could turn into a big, gaping split once the heat exchanger warmed up. All traditional methods are volume dependent and the larger the heat exchanger, the less sensitive the test will be. Dec 16, 2012 heat exchanger can crack for various reasons and should be checked every time furnace is repaired or maintained. The salt test a salt solution is sprayed into the combustion chamber. Easytesters heat exchanger testing and crack testing. Dec 03, 2018 testing combustion wont necessarily tell you if you have an exchanger leak but it will tell you if you have a high co which can help you prevent a dangerous situation for your customers if there is an exchanger crack. Third party inspection for shell and tube heat exchanger article provides you a procedural content for heat exchanger inspection. Nowadays, checking for a cracked heat exchanger is way more scientific. One test procedure used by some practitioners is to release a small amount of carbon monoxide co in the hot heat exchanger and then check for high concentrations of co in the circulating air stream.
Using a combustion analyzer to test for cracks in a heat exchanger also has limitations. Proper diagnosis of a failed or cracked heat exchanger. I open up the plenum and show the crack from the top. If you are not sure if you fall in our service area, check out our service. Heat exchanger leak detection plate dyetesting wcr 100% dyetesting is our standard for locating cracks, pinholes, or failures. Review following standard inspection and test plan for shell and tube heat exchanger. He or she can use a combustion gas analyzer to determine if it is your heat exchanger or not. How do you detect a crack heat exchanger in a furnace. Simple furnace heat exchanger test hvac learning solutions. The cause of cracked heat exchangers avoid this common scam.
If the heat exchanger is cracked, the meter will show us. There are a variety of methods of inspecting or testing heat exchangers. Its like the doctor that finds cancer it might not be good news, but it. It is important that the heat exchanger is taken care of as hazards can build from a faulty exchanger. Inspect for common heat exchanger leak, crack, or rust points. Mar 11, 20 our recommendation on finding a crack in a heat exchanger will always be to replace the heat exchanger or the furnace it is in because your familys health and safety is far too important to make guesses and assumptions about how dangerous this crack may or may not be.
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