Heat exchanger inspections have almost become a science unto themselves. Imho way to much attention is given to furnace hxs. Conventional furnace heat exchangers that leak excessive amounts of flue gases into the circulating air stream can pose a safety problem when coupled, in turn, with poor burner operation that results in a high concentration of deadly carbon monoxide in the flue gases. 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. Heat exchanger cracks and carbon monoxide myths by reuben saltzman in carbon monoxide alarms, cracked heat exchanger, hvac, new on december 2, 2014 i recently had a reader email this question. A cracked heat exchanger might allow products of combustion to enter the air stream. In some rare cases, it can cause flame impingement when air from the blower enters the heat exchanger. The salt test a salt solution is sprayed into the combustion chamber. 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 it. So what is your procedure of checking heat exchangers on 90%. One of the oldest ways to check for heat exchanger cracks is to simply observe the flame when the blower starts. Its the best way to examine your heat exchanger for cracks. 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.
Easytesters heat exchanger testing and crack testing haccp. 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. Test readings provide documentation that a furnace with a cracked heat exchanger is not safe. Proper diagnosis of a failed or cracked heat exchanger.
There are a variety of methods of inspecting or testing heat exchangers. Combustion analyzer readings are light years ahead of visual inspection results. Avoid these 4 common furnace repair scams oconomowoc. Its not unlike a doctor telling you about the c word. A cracked heat exchanger is pretty serious, as far as safety for your home goes. How do you detect a crack heat exchanger in a furnace answers. If you turn the heat on and the flames flicker and seem devilish, this could be a clue that circulated air from the furnace is getting into the combustion area and you should h. Be on the watch for symptoms of a cracked heat exchanger like. This contractortalk forum entry is a compilation of a number of heat exchanger tests that can be used to identify a cracked fire box or if a heat exchanger has holes. The wintergreen test oil of wintergreen is sprayed into the combustion chamber. If your repairman claims to have found a crack in your heat exchanger, insist on seeing the crack for yourselfparticularly if it took very little time for the repair technician to make the. Dec 03, 2018 any change is an indication of a heat exchanger leak. Using a combustion analyzer to test for cracks in a heat exchanger also has limitations. Nowadays, checking for a cracked heat exchanger is way more scientific.
When you do find a cracked exchanger it should be quoted for repair and the furnace turned off. Id also like to hear about a cracked hx in a gas pack causing co poisoning if its ever happened. If you are not sure if you fall in our service area, check out our service. However, professional hvac technicians always check heat exchangers for damage during their preseason maintenance inspection. Dec 02, 2015 proper diagnosis of a failed or cracked heat exchanger. We are inventors and developers of unique haccp testing equipment specifically designed to prevent the hazard in liquid food processing, we do not use gases or chemicals but moreover develop systems that are completely environmental friendly and reducing or eliminating down time for the processors, preventing contaminants from making contact with the product. The cause of cracked heat exchangers avoid this common scam. I normally pulled blower motor to check, snake camera or let unit ran to check on roll out flame and check co level in the house while let unit running. With a severe crack, the combustiongases oxygen level rises considerably while the blower fan is running. Furnace heat exchanger leak standards allowable amounts of gas leakage from a residential heating furnace heat exchanger. I had a hvac tech tell me my boiler heat exchanger is cracked. So what to do if your expecting a crack, or you have evidence that there is a crack in the heat exchanger.
Avoid these 4 common furnace repair scams oconomowoc boiler. Co is produced as a result of incomplete combustion. Furnace heatexchanger crack signs your furnace has one. Cracked heat exchanger issues will affect how your heating system performs. Induceddraft furnace heat exchanger inspection procedure. This trips a safety switch and shuts down the furnace. The first step is simply to look where most homeowners cant. Serious cracks were found at tubetotubesheet welds during the start up operation of a cracked gassteam heat exchanger in a gas plant. Post a question or comment about the allowable leakage from a furnace heat exchanger, how the leak rate is calculated, how carbon monoxide hazard dangers are calculated inside a building. In many organizations, finding a cracked heat exchanger constitutes a really good day, and sometimes a boost to the wallet. 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.
This heat exchangers quiz module covers basics, selection, application and calculations with respect to heat exchangers. Every cracked heat exchanger needs to be replaced, either by replacing the heat exchanger itself or by replacing the entire furnace. Signs and symptoms of a cracked gas furnace heat exchanger. How to check a heat exchanger for a leak diy furnace. Combustible gas increases in temperature and collects in the heat exchanger, allowing it to increase the temperature of the air. 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. A damaged heat exchanger in a gas furnace is potentially dangerous to a homes occupants and should not be ignored. It describes most of the available tests and has images of some of the testing tools and methods of how to check for a cracked heat exchanger. At its outset, a cracked heat exchanger is a problem that will go unnoticed by most homeowners. Cracked heat exchanger furnace trouble shooting help. The company i working for deal with a lot of insurance customer, so we got quite a few calls as second opinions about cracked heat exchanger. 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. How do you detect a crack heat exchanger in a furnace. The american gas association has even put this in writing they say any visible crack or hole is reason.
We use it to check co levels given in parts per million, or ppm and determine for sure whether theres a crack in. 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. In a normal gas furnace, the flame will usually appear blue. A combustion analyzer provides accurate co readings. Dec 23, 2019 in a home heater, the heat exchanger heats up the air that travels through the ventilation system. Test your knowledge on heat exchangers online quiz. Searching documents and internet sources the following is what i found on heat exchanger inspection methods and sources. Read our blog to learn what to do if this happens to you. Diagnosis of a heat exchanger crack typically starts with a no heat service call. The gases will continue to seep into your homes air. Dec 12, 2016 we are familiar with the article heat exchanger applications in chemical industry.
In addition to a visual inspection to identify a crack, there are a few warnings of a potential complication with your heat exchanger that you may observe. Carbon monoxide and heat exchangers service experts heating. Checking for cracked heat exchangers a smoke bomb test a smoke generator is placed in the heat exchanger. You know its serious and you know you need to do something about it. Has a cracked heat exchanger on an induced draft furnace ever caused a co poisoning. Introduce a chemical that can be detected inside the heat exchanger, then use an instrument that can sense that chemical in the supply air stream. Dec 16, 2012 heat exchanger can crack for various reasons and should be checked every time furnace is repaired or maintained. The cause of the failure has been analyzed, and the. Older furnaces can develop major issues, such as a cracked heat exchanger. Combustion check to confirm cracked heat exchanger youtube. Simple furnace heat exchanger test hvac learning solutions.
A cracked heat exchanger allows air from the furnace blower to interfere with the flame causing it to flutter or even roll out. Any change is an indication of a heat exchanger leak. Jan, 2020 having a cracked heat exchanger can have a very adverse effect on the overall performance of your home heating equipment. Apr 17, 2006 this may be limited by the shape of the heat exchanger and by visual obstructions, such as an evaporator coil. Mar 11, 20 as a homeowner, getting the news that your heat exchanger is cracked is a bit of a harsh blow. Inspect for common heat exchanger leak, crack, or rust points. What to do about a cracked heat exchanger ballard natural. A combustion analyzer gives us co and oxygen readings. To determine if you have a cracked heat exchanger, an hvac contractor should use a combustion analyzer to check for co.
The test mostoften used to determine if theres a problem with the clamshell or sectional heat exchanger is called a candle test. He based this on performing a carbon monoxide test over 10 ppm detected near the boiler hood and evidence of acidic condensate dustsootwhatever on the top of the boiler by the hood. 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. Now its time to test out knowledge on heat exchangers through this online test. Many companies, upon finding a cracked heat exchanger, will shut your furnace down so you cannot run it.
This gives the tech more confidence the heat exchanger is cracked. The your heat exchanger is cracked so your furnace must be replaced scam duration. Though it is unlikely for an induceddraft furnace to leak flue products from the heat exchanger to the circulated airstream, a new test procedure has been developed that. If theres a crack in this component, the gases being burned off, such as carbon monoxide, sulfur dioxide, and nitrous oxide, could leak into your home, causing illness or, in extreme cases, death. A cracked heat exchanger in a gas furnace is a serious safety issue. This test should be performed by a trained hvac technician. Signs the heat exchanger in your home furnace is cracked. Pdf repair of tubetubesheet weld cracks in a cracked. In some cases, an oldfashioned visual inspection makes the most sense, either by removing the blower or the high limit or both and using a mirror or borescope to inspect. Some people choose to live in denial of the seriousness of a cracked heat exchanger.
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