A cracked heat exchanger allows air from the furnace blower to interfere with the flame causing it to flutter or even roll out. Expert express plumbing heating and air conditioning 31,231 views. Last season when i looked at the hole i saw that the jb weld must have fallen off or at least the majority of it, but i had no antifreeze leaks and the overheat light never. The cause of cracked heat exchangers avoid this common scam. Repair of tubetubesheet weld cracks in a cracked gas. The leak was on the side that is towards the center. We have a gas pack that has a heat exchanger with a spot that is rusting about the size of dime and at the center is a small pin tip area that looks about ready to give way. The alfa laval compabloc range provides compact and efficient heat transfer for a wide range of clean and dirty process duties. Fatigue crack initiated from the defects at the tubetotubesheet welded joint. If the heat exchanger is under warranty, this is a good way to. I am an experienced welder but recently ran onto a couple of new things to me.
Hi folks, there was a tiny little drip coming out a cast iron piece on the heat exchanger as the engine ran. Heat exchanger failure analysis of heat exchanger page. The heat exchanger has a warranty of 20 years, but shipping and installation will still be costly and a pain. What happens if a crack heat exchanger goes without attention. Put a healthy portion of jb weld over the hole and put radiator stop leak in the coolant jug. I bought a natural gas home leak pressure guage at a hardware store that has a 15 lb guage 34 outlet and a schrader valve to pressure up just plug off the other end of the cooler. If area appears slightly soft, use a nonflame heat source, such as a hair dryer, to speed cure time, or allow 24 hours before allowing high heat exposure. The repair included removal of all the flange bolt holes and welding the heads directly to the tubesheets. Weld the cast iron using low currents for minimum penetration make 1inch to 3inch welds to limit heat input. If your fan motor failed and you asked if you could put a hand crank on it. This one takes apart the ruudrheem heat exchanger to inspect the cracks. Dec 02, 2015 proper diagnosis of a failed or cracked heat exchanger. Its only going to get worse, not betterthe only question is when.
A combustion analyzer gives us co and oxygen readings. This is a requirement, is part of the fuel gas codes and is ultimately not negotiable. Combustion test to determine if the heat exchanger is cracked duration. The design of our plate heat exchanger permits an easy inspection and mechanical cleaning on both sides. Tubetubesheet joint on heat exchanger heat transfer. A cracked heat exchanger in a gas furnace is a serious safety issue. Now that you have fixed the heat exchanger, replace it in the furnace.
Welding heat exchanger revxp xs chassis performance. It really is not worth the time and effort to weld it, and of course there are liability issues as mentioned previously. Test cure by pressing fingernail or thumbnail into repair material. After cleaning the area down to bright shiny metal i applied the compound to the cracked area. I welded a cracked laser weld in a heat exchanger tube in a carrier gas package central unit about 4 years ago with a weld pak 100 mig welder. Heres why your furnace heat exchanger cracked in carbon monoxide testing, central heating and air conditioning. Pour a little bit of the chemical on the hole, and leave it to dry until it seals around the exchanger. This heat exchanger sees the thermal cycles 24 times a year. Opened up and it appears theres a crack there and not just a faulty seal, the piece is quite old and not sure it could be welded without further damage. Bad welding and unsuitable expansion gave rise to the formation of initial cracks. When we pointed it out to the powers that be the local building inspector, who also happens to be a local plumber, said he would just weld it shut. If you are inspecting your heat exchanger for cracks, check the bends or weld areas first.
Well had something come up and cracked the front heat exchanger on my 19 summit 154 took to dealer its been there 2 days keep telling me they are waiting for brp to get back to them on parts availability. Failure analysis cracked tube to tubesheet welds on. Many of the heat exchangers destined for harsh service are built in our sulphur facility, where we use customdesigned equipment for overlaying steel and welding high alloy heat exchanger components. Bobs answer to whether or not a cracked heat exchanger can be dangerous is unambiguous. A fixed tube sheet heat exchanger is the most common type of heat exchanger in all industries. This effect will get worst as the furnace heats up from expansion and the crack gets bigger.
Our special plate heat exchangers and quench columns are particularly well adapted to high temperature processes, up to c. Serious cracks were found at tubetotubesheet welds during the start up operation of a cracked gassteam heat exchanger in a gas plant. Repair of tubetubesheet weld cracks in a cracked gassteam. The your heat exchanger is cracked so your furnace must be. Short of seeing a visible crack, a combustiongases analysis is the surest way to determine if the heat exchanger is cracked. Welding castiron heatexchanger boiler body diynot forums. Proper diagnosis of a failed or cracked heat exchanger. Dec 04, 2017 jb weld extremeheat is not an adhesive like jb weld epoxy, meaning it is not designed to bond two parts together.
Immediately strike or peen the face of each weld with a small ballpeen hammer to relieve stresses in the weld. Jun 12, 2014 the casing housing was leaking straight antifreeze at an original weld seam at the top. Sep 18, 2009 heat exchangers on forced air furnaces are rarely, if ever, made from cast iron. A shelltube heat exchanger was found failed when it was used about 30 days after assembling. Signs and symptoms of a cracked gas furnace heat exchanger. If you have an iron heat exchanger, then you need to find an iron repair liquid, which uses chemical reactions to seal holes in iron. Page 1 of 2 welding heat exchanger posted in revxp xs chassis performance trail 120129 inch models. If the heat exchanger ends up becoming cracked or severely damaged, then major issues could arise. 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. Full and easy cleanability on both circuits makes it the most service friendly welded heat exchanger on the market. Finite element analysis was used to simulate the thermal and structural responses of the reactor tubes, tubesheets, perforated plate rim, and tubetotubesheet welds during the controlled heat up and cooldown process. The american gas association has even put this in writing they say any visible crack or hole is reason.
Many times a heat exchanger that has areas of concern or a crack will not emit co. 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 material specimen was removed from the location of the crack in heat exchanger th15 for metallographic. 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. One of the most common reasons a gas furnace can be taken out of service, is when the repair technician finds to a cracked heat exchanger. If a heat exchanger is cracked at one point it is certainly weakened at other points. Either the heat exchanger or furnace must be replaced your options if the heat exchanger has cracked.
Mostly used in higherpressure and higher temperature applications. It would cost more than a new unit or heat exchanger would cost. Will either have to get another heat exchanger or try to weld the crack. Fixed tube sheet heat exchangers are the one that are very much used in process chemical industries and refinery services, as there is absolutely no chance for intermixing of fluids. 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. Its the most common cause of excess carbon monoxide in a home. Depending on where the crack is, the supply fan creates a positive pressure on the outside of the heat exchanger that can blow air inside the heat exchanger and on to the flame.
It works well on steel, iron, copper, stainless steel, and most other metals that endure high heat. Tubetubesheet joint on heat exchanger acrylonitrile chemical 11 jun 07 08. Heating or cooling fluid is circulated through the coil by transferring the heat system trough halfpipe or seg pipe coil. I never thought it would last a few months, but it lasted this long. The heat exchanger is a set of coils or tubes typically located above the blower and below the plenum, where the pilot light starts. You might be able to weld it successfully now, but it will likely be cracked again in a different place soon. Bad news from a plumber who says that a leaking boiler is a cracked body heat exchanger. The furnace heat exchanger is the one of the main components inside the gas furnace and its used to transfer the heat from the gas burner to the warm air thats blown into your home. The exchanger is one of the nine identical shellandtube heat exchangers, fixed tube exchanger type 1 shell1 tube pass type, made by the.
There are only two options if a heat exchanger is bad. We were requested to perform a stress analysis on a proposed plan by nasa for repairing the inlet and outlet of the heat exchanger cracked tubesheets. Crack is underneath where it sits on top of hotwater contaiiner so cannot be seen. Jb weld extremeheat is the perfect repair solution. 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.
We can tell you its a failed part and needs to be replaced. Dozens of leak points were found near the tubetotubesheet welded joints of the shelltube heat exchanger. Analysis and repair of cracking in partition plate of rhr. Adhesives are a costeffective solution for sealing heat exchanger tubes onto endplates and are popular alternatives to welding or brazing. The welder had to grind to get the one exchanger off, repair it and weld it back to the base. However, according to the aga american gas association. Adhesives can also be used for bonding heat exchanger fins and rubber gaskets to flat plate heat exchangers. Clamshell heat exchangers are made up of two concave halves that, when joined either by welding or folding, form a passageway with an inlet and an outlet. In an attempt to sell new furnaces, numerous heating contractors will lie about cracked heat exchangers. The metal in the heat exchanger is usually too thin to weld and impossible to access with welding equipment even with removing the heat exchanger completely. Cracked heat exchanger deciding to repair or replace.
In this white paper, we show that fatigue problems can be. We find some cracked heat exchangers from the pilot lights that are blown out. 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. Anyone have any luck welding up an aluminum heat exchanger. A damaged heat exchanger in a gas furnace is potentially dangerous to a homes occupants and should not be ignored. How to minimize fatigue problems in plateandshell heat. My concern is the fact that mechanics walk past other potential carbon monoxide poisoning issues to get to heat exchanger inspection. That is most certainly not a final repair, not just because the heat exchangers normal operating temperature exceeds the epoxys 500 f rating, but because where theres one pinhole theres bound to be more.
I cleaned off the corrosion and found the extent of the crack which extended from the square mounting flange about an inch and a half longitudinally along the pipe. With that said, lets go into more details about what an exchanger is, why its important and how to tell whether or not you have a cracked heat exchanger. The goal was to let us keep the furnace running until we could schedule the replacement after the holidays. Opened up and it appears theres a crack there and not just a faulty seal, the piece is quite old and not sure it could be welded without further.
Any verifiable crack requires replacement of the heat exchanger or furnace. We use it to check co levels given in parts per million, or ppm and determine for sure whether theres a crack in. The cause of the failure has been analyzed, and the. Cracked heat exchanger revgen 4 summitfreeride 850. Jb weld extremeheat is perfect for making repairs on all manner of highheat parts, including exhaust manifolds, mufflers, catalytic converters, exhaust pipes, engine blocks, fireplaces, smokersfireboxes, and many more crackprone items. A work horse of industry, the heat exchanger is a reliable piece of equipment, however, they do wear out and often require more than routine maintenance. Fatigue failure of welded joints in a shelltube heat exchanger was analyzed. How to fix a cracked furnace heat exchanger step 1 check the furnace heat exchanger. If we do find a leak in the heat exchanger, and since its only 7 weeks old, i wonder if welding any leaks. We are working in a municipal building in ny where we found a cracked heat exchanger in one of the furnaces. A longterm repair for commercial heat exchangers is possible but not very practical. When the furnace was being installed, i did notice the sloppy welding on the heat exchanger seams, but i assumed it would be ok.
Its the best way to examine your heat exchanger for cracks. Waited longer than the listed 24 cure time, because without a fire the house doesnt get to 80 degrees. I ended up taking out the quad exchanger and am sitting at a weld shop waiting while they try to weld it up. A crack in your heat exchanger is no trivial matter. As described from other people on this thread, the weight of the gas tank added to the problem. Rarely is welding a cracked heat exchanger successful as they will usually crack again either through or right along the weld.
Furnace heatexchanger crack signs your furnace has one. Example number 1 your exhaust manifold has developed a stress crack near a bolt. Jan 25, 2011 page 1 of 2 welding heat exchanger posted in revxp xs chassis performance trail 120129 inch models. Jan 24, 2019 page 1 of 2 cracked heat exchanger posted in revgen 4 summitfreeride 850 turbo. The causes of cracking in the closing circumferential tubetubesheet welds of five cracked gassteam heat exchangers in a petrochemical plant were studied, in order to identify the mechanisms that caused the failures, to define responsibilities, and to evaluate possible corrective actions. Can you repair a cracked heat exchanger on a gas furnace. Dont know what to do,anybody have any luck welding or patching them dont want to lose the rest of the. Nowadays, checking for a cracked heat exchanger is way more scientific. This is especially the case with the heat exchanger. But the decision to repair or replace a heating unit can be difficult. Every ohmstede facility is selfsufficient with all the equipment required to produce complete heat exchangers and repair existing ones. This video is part of the heating and cooling series of training. After allowing to build temp and letting it cool, i checked the repair.
The metal of the heat exchanger is generally too thin to weld shut and nearly. So here are my suggestions on how to find cracked heat exchangers and other furnace safety issues. Fresno, california i try repairing cracks on an exhaust manifold with jb weld extreme heat. We have a gas pack that has a heat exchanger with a spot that is rusting about the size of dime and at the center. Welding furnace heat exchanger practical machinist. If the heat exchanger is under warranty, this option is a good way to go unless it is unavailable in the time frame needed, which can be immediate in cold weather. When a gas furnace heat exchanger fails, not only is it dangerous and can result in carbon monoxide poisoning, the heat exchanger replacement cost is usually on the high side of typical furnace repair costs. Failure analysis of tubetotubesheet welded joints in a. Dont know what to do,anybody have any luck welding or patching them dont want to lose. Even though your furnace may look and seem fine, dangerous gases could leak into your home and seriously affect, even kill, your family members. Page 1 of 2 cracked heat exchanger posted in revgen 4 summitfreeride 850 turbo. Keywords heat exchanger failures tubetotube joints.
If you have been told your furnaces heat exchanger is cracked, ask the tech to show you the exhausts oxygen readings when. Mostly they are aluminized sheet steel, aluminized to reduce rusting. These are the weak areas most likely to break first. Most clamshell heat exchangers have one thing in commonthey fail. The cause of the failure has been analyzed, and the exchanger is repaired. Fhr was first used for heat up and cooldown for both air and salt temperatures. Failure analysis of tubetubesheet welds in cracked gas heat. Heres why your furnace heat exchanger cracked heating.
I put a stud through my front heat exchanger on my srx a couple seasons back. This will be detected with a combustion gasses tester. A cracked heat exchanger is pretty serious, as far as safety for your home goes. If you have an iron heat exchanger, then you need to find an iron repair liquid, which uses chemical. Failure analysis of tubetotubesheet welded joints in a shelltube. Pdf repair of tubetubesheet weld cracks in a cracked gas. The exchanger is one of the nine identical shellandtube heat exchangers, fixedtube exchanger type 1 shell1 tube pass type, made by the. They are thin to promote heat transfer to the passing air stream. Pdf failure analysis of tubetubesheet welds in cracked gas heat. Leaking tubetotube sheet joints can cause cross contamination of fluids resulting in rejected product, increased utility and maintenance cost. If you have a heat exchanger crack, you need to replace the heat exchanger or the furnace. Heat exchangers on forced air furnaces are rarely, if ever, made from cast iron.
If someone informs you that your heat exchanger is cracked, call the tedder company, and one of our. Skip weld move around the cracked area do not keep heating the same area. Common myths regarding furnace heat exchangers youtube. How to minimize fatigue problems in plateandshell heat exchangers. Dont weld over the ribs grind them down flat clean with a stainless wire brush heat with a mapp gas torch for cleaning and heat soak. Diagnosis of a heat exchanger crack typically starts with a no heat service call. Heat exchanger pipe welding welding tips and tricks. Keywords heat exchanger failures tubetotube joints weld cracks background the object for repair in this study is a weldment tube tubesheet joints on a cracked gassteam heat exchanger in a. Just got a hole in the heat exchanger on my 600 etec. Plate type heat exchanger this is constructed by a series of corrugated parallel plates held firmly together between frames.
Bobs answer to whether or not a cracked heat exchanger can be dangerous is. Press this onto the furnace heat exchanger, and allow it to dry. If a heatexchanger is cracked, air forced into the combustionchamber will cause the oxygen reading in the furnaces exhaust to rise to abnormal levels. Pdf repair of tubetubesheet weld cracks in a cracked. For some serious positions, the tube ends were broken down from the tubesheet. This trips a safety switch and shuts down the furnace.
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