How to prevent a heat exchanger crack in your furnace. 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. How to prevent a heat exchanger crack in your furnace hydes. This one is about a crack i found in a heat exchanger that caused no symptoms. Manual we wrote the book on heat exchanger repairs. Unless you are one of the top 3% of people who have all the money, replacing the furnace is going to hurt the pocket book if you have not planed for it, but it has to be done. I will start by saying that everything i write here is my own opinion and experience. Heat exchanger design handbook crc press book completely revised and updated to reflect current advances in heat exchanger technology, heat exchanger design handbook, second edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topicsall while keeping the qualities that made the first. R sekulib university of kentucky introduction a heat exchanger is a device that is used for transfer of thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a. This happens when combustion gases from the furnace burners enter the heat exchanger and heat up its. Heat exchanger design handbook by t kuppan free download. Have you heard this one recently, you have a cracked heat exchanger and your furnace has to be replaced, today. Its like the doctor that finds cancer it might not be good news, but it. Sekulic this book contains all basic and necessary information about heat exchanger design.
A cracked heat exchanger is a danger to your home and should be treated as one. Understanding cracked heat exchangers hamco heating. The heat exchanger is a key part of the furnace and is responsible for the actual heating of air. Heat exchanger design handbook mechanical engineering. This comprehensive reference covers all the important aspects of heat exchangers hestheir design and modes of operationand practical, largescale applications in process, power, petroleum, transport, air conditioning, refrigeration, cryogenics, heat recovery, energy, and other industries. If it is your heat exchanger, you cannot run your furnace, even if it. Heat exchanger experts training manual a roadmap to results.
Furnace heatexchanger crack signs your furnace has one. Completely revised and updated to reflect current advances in heat exchanger technology, heat exchanger design handbook, second edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topicsall while keeping the qualities that made the first edition a centerpiece of information for. Weve seen so much in fact, we wrote the book on heat exchanger repair. Searching documents and internet sources the following is what i found on heat exchanger inspection methods and sources. Furnace heat exchangers are used to transfer heat between the fuel being burned and the air in your home. Heat exchanging happens when the gas jets become cooler and the water becomes hotter. Compact heat exchangers is a compilation of experimental data on the basic heat transfer and flow friction characteristics of compact heat exchanger surfaces, i. Platefin heat exchangers have lots of thin metal plates or fins with a large surface area because that exchanges more heat more quickly. A salt solution is sprayed into the combustion chamber, a hole is drilled in the supply ducting, and a torch is held in the air blowing out of the hole to see if.
If not, they put it back, as it was, no harm, no foul, no charge. Due to high demand for nucalgon heat exchanger crack finder solution, heat exchanger inspection system, availability is subject to change without notice. This is dangerous, as one of the gases produced by the heat exchanger is carbon monoxide, a deadly. Completely revised and updated to reflect current advances in heat exchanger technology, heat exchanger design handbook, second edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topicsall while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians. 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 crack in your heat exchanger is no trivial matter. How to check a heat exchanger for a leak diy furnace. It is important that the heat exchanger is taken care of as hazards can build from a faulty exchanger. Heat exchanger experts training manual trutech tools, ltd. Bobs answer to whether or not a cracked heat exchanger can be dangerous is unambiguous.
Many companies, upon finding a cracked heat exchanger, will shut your furnace down so you cannot run it. As the part of the furnace that creates heat, the most common reason your heat exchanger cracks is normal wear and tear. Since fixing a cracked heat exchanger is a major repair, we recommend getting a second opinion to make sure there is in fact a crack in your heat exchanger. Cracked heat exchangers, causes and solutions what is a heat exchanger. Many heat exchangers crack simply because they are old. Essentially, an exchanger transfers heat between one fluid a liquid or a gas and another without the two mixing.
Because this is such a hot button topic dont take my word for. Heating and air conditioning contractors rarely find furnaces with cracked heat exchangers. The best way to locate cracks in heat exchanger is to visually locate a crack. Its why were known as a top rated national heat exchanger training company. Modern furnaces account for 80 percent to 90 percent of all forced air furnaces and a. When a gas furnace has a cracked heat exchanger you can sometimes become aware of it when you first fire it up. A look at a heat exchanger crack that cant be found youtube. 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. Other than this, there really isnt anything else that can definitively give you an answer.
Proper diagnosis of a failed or cracked heat exchanger. What are some tell tale signs of a cracked heat exchanger. The longer your system operates with a cracked heat exchanger, the worse the cracks will get. If youre experiencing any of these, were sorry, its time to say goodbye to your old furnace. Tubular heat exchangers the are in some cases used for pasteurization and uht treatment of dairy products. Youll be able to identify any issues in your clients heat exchanger and. Those who look for it everywhere and those who dismiss it and never look. I noticed the other day the my how water boiler had flames dancing around underneath the heat exchanger. On the other hand, if you are not experiencing any of these things and a technician still recommends you need a new system, here are some reasons why that might not be the case. If it cracks after the warranty is up, usually at least 20 years, consider replacing the entire furnace. A damaged heat exchanger in a gas furnace is potentially dangerous to a homes occupants and should not be ignored. A smoke generator is placed or blow into the heat exchanger, then the outside of the heat exchanger is visually accessed to watch for smoke passing through the crack.
There are two camps ive run into regarding cracked heat exchanger diagnosis. Signs and symptoms of a cracked gas furnace heat exchanger. The materials used in the construction of the heat exchanger will expand and contract numerous times over its lifespan. There is absolutely no known technique for finding a crack 100 percent of the time. 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. If you find that your furnace heat exchanger has trouble getting enough heat and power, then you may find that it has developed a crack or hole.
Combustion gases from the furnace burners enter the heat exchanger and heat up its. It can be difficult and expensive to find a matching heat exchanger for an older furnace. Every cracked heat exchanger needs to be replaced, either by replacing the heat exchanger itself or by replacing the entire furnace. In this way the technician can show the homeowner documented photos in the book, confirming that what the technician is showing them with the inspector camera is indeed failure. Second visual inspection, if you trust this company, good, agree to a new heat exchanger, new furnace contingent upon the fact that they can show you the crack once they remove the heat exchanger or replace the furnace. 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. So here are my suggestions on how to find cracked heat exchangers and other furnace safety issues. Highefficiency furnaces incorporate a secondary heat exchanger to increase efficiency by removing excess heat from the exhaust stream.
A heat exchanger can last 1518 years, but a lack of maintenance can. A consumers guide to water heater maintenance book, is a flip chart book your. Even though henry did not find a crack or breach of the heat exchanger, the flame rollout and the. When defect occur, they tend to crop up in the same areas on any given make or model of equipment. Its the most common cause of excess carbon monoxide in a home. He or she can use a combustion gas analyzer to determine if it is your heat exchanger or not. 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. Diagnosis of a heat exchanger crack typically starts with a noheat service call. However, using a combustion analyzer to test for cracks in a. These two words are nomenclature meaning the thin layer of metal that separates the good air that you breathe and the bad air comes from burning natural gas in a forced air heater or burning propane in a forced air heater. Cracked heat exchanger deciding to repair or replace depending on the age of your furnace, a cracked heat exchange probably means you need a new system. Through this crack, combustion fumes can escape from the exchanger, and can build up in the room. A practical guide for planning, selecting and designing of shell and tube exchangers takes users on a stepbystep guide to the design of heat exchangers in daily practice, showing how to determine the effective driving temperature difference for heat transfer.
Located in the center of the furnace, it is where fire, gas and heat connect. A heat exchanger crack is one of the biggest safety issues that your furnace can develop. If you do not locate a crack or perforation the heat exchanger seams may. This trips a safety switch and shuts down the furnace. How a cracked heat exchanger can endanger your family. There are a variety of methods of inspecting or testing heat exchangers.
Nucalgon heat exchanger crack finder solution, heat. The american gas association has even put this in writing they say any visible crack or hole is reason. The manufacturer of the unit in question says to use a bright flashlight to visually check the heat exchanger tubes and if any sign of the heat exchanger being compromised is found the technician should shut down and disable the unit. Few people in the hvac industry can make this claim, but we literally wrote the book on heat exchanger repair. Nowadays, checking for a cracked heat exchanger is way more scientific. In our many years of work with heat exchangers, weve seen nearly everything. In order to help you avoid these safety issues, today were going to talk about how a heat exchanger develops cracks and what you can do to prevent or identify the problem before its too late. The cause of cracked heat exchangers avoid this common scam. A documentation book of furnace heat exchanger failures 20072008 edition. Please read this article about why heat exchanger cracks do not allow carbon monoxide into the house.
Cracked heat exchanger deciding to repair or replace. For that reason it is very highly recommended that every technician use the documentation book of furnace heat exchanger failure as a third party authority. From what ive been told and read, it could mean that my heat exchanger is cracked. The gases will continue to seep into your homes air. The heating is to be accomplished by passing hot engine oil, which is available at. What is a heat exchanger and how do they break or crack. If you have a cracked heat exchanger, you need to replace it or replace the entire furnace. Inspect for common heat exchanger leak, crack, or rust points. This is because air is leaking through the crack in the heat exchanger into the combustion chamber.
This video is part of the heating and cooling series of training videos made to accompany my websites. Heat exchanger defects are usually caused by poor maintenance or operational issues. The author has been in the industry for years as a trainer for hvac technicians. Reflecting the authors extensive practical experienc. 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.
I sent a short answer, but thought this was deserving of a longer answer in the form of a blog post. You can do your part to prevent cracks from forming in your heat exchanger by understanding the root causes of these cracks. The extra air will cause the oxygen reading to change notably. In my view, the best books for heat exchanger design are these. With decades of experience in every page, our manual will make you feel like an expert. He has authored numerous research and educational archival journal articles, book chapters, and conference papers covering heat exchangers and related topics. Because the heat exchanger is the part of the furnace that creates your homes heat, the most likely reason for it to crack is simple wear and tear. A combustion analyzer gives us co and oxygen readings. So what to do if your expecting a crack, or you have evidence that there is a crack in the heat exchanger. But the decision to repair or replace a heating unit can be difficult. Beware of an unethical technician who finds a crack with a camera on a furnace that seems to be running just fine. A cracked heat exchanger allows air from the furnace blower to interfere with the flame causing it to flutter or even roll out.