This steam is converted back to water in condensers and further cooled in heat exchangers. The development of fouling depends on a number of things, 5 and 16. A crack in your heat exchanger is no trivial matter. Cracked heat exchanger deciding to repair or replace.
Eventually, a leaking heat exchanger will cause an increase in operations costs. The result will be a buildup of soot around the crack site andor spots that are a darker color than the rest of the metal. Press this onto the furnace heat exchanger, and allow it. Here are the signs you need to call reimer for an inspection. Crack detection services the hawkeye 2000 and its variants use the principles of balance field electromagnetic technique bfet to detect surface and subsurface cracking in welds and base metal. As the combustion happens, the metal of the exchanger expands until it cools off again and contracts. Broken heat exchanger pacific coast heating and air. But the decision to repair or replace a heating unit can be difficult. The training course series on leak detection in heat exchangers and underground pipelines using radiotracers addresses the needs of the radiotracer groups and their end users.
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. Over time, this stress creates cracks in your heat exchanger. For a new heat exchanger the fouling factor is zero and it increases with time with increased fouling. For temperatures up to 1,022f 550c and pressures up to 2,175 psig 150 bar. All of the expanding and contracting stresses the metal and eventually leads to failure of the heat exchanger. Sometimes the heat exchanger fails, either from cracks produced by continual expansion and contraction due to heating and cooling of the metal, or from rust. Ripley this month we are going to focus on the importance of a company having a set procedure in. If you are inspecting your heat exchanger for cracks, check the bends or weld areas first. Theres a lot of good info on there, but some of it is misleading and there are a lot of straw man arguments made.
Since steam is used to produce energy, corrosion of the heat exchanger is a constant maintenance problem. Mar 19, 2007 the crack is open when the heat exchanger metal is at or close to room temperature. 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. Metallurgical heat exchanger failure analysis along with metal corrosion testing and investigation services provided by metallurgical technologies, inc. Platenwarmtewisselaar cp heat exchanger technologies. However, using a combustion analyzer to test for cracks in a heat.
But similar to other heat exchanger types, plate heat exchangers can become polluted over time, which significantly affects their cooling capacity. Metal heat exchanger installation process technology. A cracked heat exchanger might allow products of combustion to enter the air stream. Carbon monoxide and heat exchangers service experts. Heat exchanger leak detection plate dyetesting wcr 100% dyetesting is our standard for locating cracks, pinholes, or failures. For homeowners with newermodel furnaces, there may be a more favorable outcome in the event that a crack develops in their heat exchanger. In some rare cases, it can cause flame impingement when air from the blower enters the heat exchanger. How can leakage in tubes of heat exchangers can be found. Chart industries pioneered the use of bahx for cryogenic gas processing in the 1950s and weve produced over,000 units since. The plate heat exchanger phe of jpc has 56 special stainless steel plates astm a240 type.
In terms of eddy current testing of heat exchanger tubes, highquality. Carbon monoxide and heat exchangers service experts heating. A furnaces heat exchanger is a metal component that transfers heat from the fuel being burned while blocking the air in your home from mixing with the furnace exhaust. One of the best ways you can protect your home from the dangers of a cracked heat exchanger is to know how those cracks develop in the first place. The detection of circumferentially oriented cracks in heat exchanger tubing is difficult to detect with the usual bobbin probes for two reasons. When a heat exchanger becomes damaged and the combustion fumes and gases mix with the clean air.
Located in the center of the furnace, it is where fire, gas and heat connect. Metal heat exchanger installation hot water or cooling applications. 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. Its like the doctor that finds cancer it might not be good news, but it. Ultimately, surface array ect techniques work best for metal crack testing, heat damage testing, and thickness coating measurements, among many other nondestructive testing ndt strategies. The cause of cracked heat exchangers avoid this common scam.
Just because my test didnt allow any water to leak doesnt mean. Fill one side with dyed water, and see where color m. Some cracks have been known to only open when the unit is fired and the heat exchanger metal is hot. In fact, he adds, most heat exchangers have a longer warranty than most other parts of the furnaceoften 10 to 25. Cracked heat exchangerslegalities, methods of detection. If the heat exchanger develops cracks, the metal will get discolored with the. Leak detection in heat exchangers and underground pipelines. 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. Corrosion on the process side causes the heat exchanger tubing to mechanically fail, allowing process fluid to leak into the condensate return line. 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. Connection sizes up to 12 dn300 on the plate side and up to 28 dn700 on the shell side. The crack is open when the heat exchanger metal is at or close to room. Natural gas or propane is being burned and the byproduct of that process is energy in the form of heat, along with water vapor h2o, carbon dioxide co2, carbon monoxide co, carbon or soot. Plate heat exchanger cp heat exchanger technologies.
This heat exchanger is using for cooling of the hot transport water tw by cooling water. Eddy current testing is widely used in the aerospace automobile, power generation and in other manufacturing and service environments that require inspection of thin metal for potential safetyrelated or qualityrelated problems. Rft is ideal for ferromagnetic tubes, such as carbon steel, and ferritic stainless steel. Thats why if theres a risk of carbon monoxide leak, a one hour technician will always examine your heat exchanger for cracks using a infrared camera. A cracked heat exchanger is pretty serious, as far as safety for your home goes. Metal drums may be rolled over hardened mandrel to produce either exterior or interior forms. Often when cracks are present in a heat exchanger, soot from the combustion process will seep through and discolor the metal. In addition to crack detection in metal sheets and tubing, eddy current can be used for certain metal thickness measurements such as identifying corrosion under. The heat exchanger on a furnace is the section that keeps the combustion chamber and the breathing air separate 3. How do you detect a crack heat exchanger in a furnace. Our leak test procedures exceed the requirements of asme, asnt and other applicable codes. Uniform taper and smooth surface finish help to ensure positive sealing with minimum force required for. Its important to invest in highcaliber surfacearray technology that will fare well even in harsh testing environments.
Eddy current for crack detection entails a variety of methods, but surface array is one of the best techniques for metal sheets or irregular shapes such as tubing. The bobbin coil creates eddy currents in the tube wall which flow in the circumferential direction. Determination of mean metal temperature industrial. Circumferential cracking is very difficult to detect and characterize with standard eddy current. Besides training purposes, this material will assist radiotracer groups in establishing their quality control and accreditation systems. Heat exchanger leak detection heat exchanger leak detection download 42 kb. Heat exchangers are made of metal that expands and contracts every time your furnace turns on and off. Ive heard that when heat exchangers get very hot, the metal expands and the cracks open up, allowing air to leak in to or out of the heat exchanger.
The plate heat exchanger is a highly efficient and versatile heat exchanger design. Heat exchanger tubes are generally splined or fluted to increase surface enhancement or liquid surface tension reduction. With proprietary red dyepenetrant saturating the plate surface, and white developer solution covering the reverse side, wcr is capable of detecting even miniscule imperfections. 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. The use of highlow liquid level detectionalarm systems in conjunction with frequent coil and system inspections are. If a crack makes its way through the walls of your heat exchanger, dangerous carbon monoxide fumes can leak into your homes air. A co detector cannot tell you if a heat exchanger is good.
Extend the life of your heat exchanger by sealing the ends of leaking tubes with heat exchanger tube plugs. The new oilwater safety heat exchanger bamnzsc which, by means of a double tube, prevents the danger of mixing the cooling and the to be cooled medium. Look for contamination traces, say you fill one side with salt water, and look for tds increases from each tube. 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. The cracks will allow that deposit through, making the heat exchanger appear sooty, as discussed in the section above. Fire up a welder, and use the liquid metal to form a gluelike line around the edge of your sheet metal. Wherever there is steam, there is a process liquid to be cooled. 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.
Believe it or not, cracks can develop in most furnaces after years of normal use. Process line heat exchanger failures can be very costly or even catastrophic for a business. Overheating causes nearly all premature heat exchanger cracks. Although you should certainly not wait until your carbon monoxide.
How do you detect a crack heat exchanger in a furnace answers. The site of the crack should have a buildup as well, or there might be spots that are darker than the rest of the metal. A forcedair gas furnace upflow or horizontal is a metal cabinet that has. Therefore, it is necessary to monitor the condensate downstream of the heat exchanger and to dump the condensate as soon as it shows signs of contamination. If the heat exchanger develops cracks, the metal will get discolored with the soot that builds up on it. Eddy current techniques for crack detection in metal. A cracked heat exchanger is one of the waysif not the most common way your furnace leaks carbon monoxide.
These are the weak areas most likely to break first. Heat exchangers wa have an exceptionally reliable and versatile crack detection service, able to test the largest of plates and deliver the most accurate possible results. 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. It is possible in some cases to see a damaged heat exchanger by spotting cracks in the steel. It is important that the heat exchanger is taken care of as hazards can build from a faulty exchanger. Residential gas furnace heat exchanger testing douglas dewerth, p. Phe cracks can be dangerously costly to your business.
The flame generates enough co lack of oxygen, excess fuel, high temperature. While designing a sthe, bem type, with the following process data for normal operating case. Heat exchanger leak detection plate dyetesting wcr. If you have a steel exchanger, then cut down a piece of sheet metal to cover the crack, plus 2 inches all the way around. If you do not locate a crack or perforation the heat exchanger seams may be leaking and the cause for the flame deviation, or the metal may have. Its important to invest in highcaliber surfacearray technology that will fare well even in. Louisiana and texas heat exchanger leak detection services.
Determination of mean metal temperature posted in industrial professionals. Heat exchangers failure analysis metallurgical technologies. Home products leak detectors, lubricants, and sealants heat exchangers tube plugs. Furnace heat exchanger leak standards, hole sizes, permitted leakage allowances. What are the causes of a cracked heat exchanger in a gas. Best practices for eddy current testing of heat exchanger tubes. Eddy current techniques for crack detection in metal sheets. Inside of your furnace or boiler there is actually a fire burning. This is really what the heat exchanger inspection is all about to make sure that the furnace. The crack is open when the heat exchanger metal is at or close to room temperature. Enough exhaust gases are emitted from the heat exchanger crack or.
When a furnace cannot get enough airflow, the heat exchanger. Co is produced as a result of incomplete combustion. Manufacturers estimate the lifespan of their heat exchangers to be between 10 and 20 years. Why do all furnaces eventually develop these cracks. Its the most common cause of excess carbon monoxide in a home. A heat exchanger can be replaced without changing the entire furnace, says bob.
For heat exchanger tubing inspections, a probe that combines bobbin and array capabilities can offer additional flaw detection and shorter inspection times. 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 co detector can indicate a heat exchanger is cracked or perforated only if all of the following conditions occur simultaneously. The heat exchanger is a set of coils or tubes typically located above the blower and below the plenum, where the pilot light starts. The heat exchanger is a key part of the furnace and is responsible for the actual heating of air. One common example of a heat exchanger is the radiator in a car, in which a hot enginecooling fluid, like antifreeze, transfers heat to air flowing through the radiator. With maximum scanning speeds of one foot per second, the hawkeye 2000 is much faster than conventional ndt techniques such as dye penetration and. Heat exchangers plate heat exchanger crack detection test. The service technician has the time, experience, or even reason to suspect the exchanger is cracked. We are able to detect large and very small leaks in heat exchangers before the leaks become a liability.
Thanks to the large surface of their corrugated plates, plate heat exchangers have very good heat transfer efficiency. Since the metal heat exchanger expands and contracts with the temperature, over time it can crack. Charts brazed aluminum heat exchangers also known as a plate fin heat exchanger and cold boxes are at the heart of low temperature natural gas, air separation and petrochemical processes worldwide. 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. A cracked heat exchanger is not a problem that should be taken lightly. A furnace with a cracked heat exchanger will definitely produce carbon. Besides training purposes, this material will assist radiotracer groups in establishing their. A small crack in a heat exchanger can cause a smaller yet potent amount of carbon monoxide to enter your home. To my knowledge there is no single check available that will find a crack in a heat exchanger 100% percent of the time and cracked heat exchangers result in less than 1 percent of. The plate heat exchanger phe or plate and frame heat exchanger is a type of heat exchangers that comprises of the special metal plates and sealing polymeric gaskets. Although a poorly designed duct system can also contribute to your heat exchanger failure by not allowing proper air flow through the furnace heat exchanger the metal can heat up to temperatures it is not intended to operate at.