Top 10 Hints for Replacing Tube Bundles in U-Tube Exchangers

There are basically three kinds of shell and tube heat exchangers:

  • “U” Tube heat exchangers where it is possible to remove the entire bundle
  • Fixed tube heat exchangers where the tube sheet are welded to the shell and stationary and the bundle is not removable
  • Floating tube heat exchangers where one tube sheet is fixed and the other floats axially.  This tube bundle is also removable.
  1. The shell for this type of shell & tube exchanger can/will last just about forever. However, the copper tube bundles located inside will often need to be replaced. The idea here is to slide the old bundle out and replace it with a new bundle, using the least amount of labor possible.
  2. One very important question to ask is which types of tube bundles are replaceable? “U” tube bundles and straight tube bundles with “floating tube sheets” can be replaced, while fixed tube sheet bundles must be re-tubed rather than replaced.
  3. Replacing a bundle is pretty straightforward and easy. Simply slide the bundle out and measure the overall length (including the tubesheet). Keep in mind that the bundle’s OAL will always be several inches shorter than the shell’s OAL. Tube Bundles
  4. The next step is to determine the size of the tubes in the bundle. While the vast majority of bundles have ¾” OD tubes, it is possible to have ½” OD, 5/8” OD, or 1” OD.
  5. Next, decide on the tube thickness that you need. Thicker tubes will last longer, but will obviously be more expensive. Typically ¾” tubes will have a .049” wall thickness, but you can easily upgrade if needed.
  6. Including tube supports or baffles, the number of tubes in the bundle should always be the maximum number that you can fit inside the shell. If you are not sure of the # of tubes, contact us, and Capital Coil can tell you the maximum number.
  7. You also want to make sure to count the tube supports or baffles on the length of the shell. While tube supports only serve to keep the bundle together, baffles actually direct the fluid on the shell side to go back & forth across the bundle. If you are unsure which is which, tube supports run the complete circumference of the bundle, while baffles are generally staggered and look to cover only a portion of the tubes.
  8. The only real way to not get the bundle correct is if the tubesheet is not duplicated correctly. First, measure the thickness of the tubesheet. ¾”, 1”, 1 ½” are examples that you’re likely to see.
  9. Next, you want to determine the number of bolt holes, as well as the center to center distance of the bolt holes. Doing this basically determines the bolt hole pattern. The bolts are responsible for connecting the head and the tube bundle to the shell, so they all must match up exactly! But, please also keep in mind that it is possible to have no bolts in the tubesheet as the bolts then bypass around the tubesheet.
  10. Lastly, every bundle has a number of passes that create fluid which runs through the tubes. That fluid will ultimately end up back at the same end. (2) pass, (4) pass, or (6) pass are among the most common. Gasketing and head design determine the number of passes.

 

Replacing a bundle is pretty easy, and it should take you approximately 15 minutes to gather all of the necessary information. But if you happen to run into any difficulties, please call us here at Capital Coil & Air, and we’ll help walk you through everything. We have the capability to build almost any kind of bundle of various construction types and different tube materials. Please give us a try on your next project as we want to be your go-to resource for all bundle replacements.

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Replacing a Shell and Tube Heat Exchanger? And Have the Model Number?

Replacing a Shell and Tube Heat Exchanger? Whether you’re dealing with an old TACO or Bell & Gossett unit, give us the model number and serial number to your heat exchanger and 9/10 times we can replace it!  If you’ve dealt with Shell & Tube Heat Exchangers in the past, you know that the shell portion of the Heat Exchanger can last 40+ years. You are also aware that the tubes and bundles usually cannot. When these bundles fail, the typical customer cannot wait 8-10 weeks for the OEM to get the requisite part manufactured and sent back. Capital Coil understands that quick turn-around time is essential, so we offer both 10 & 5 day shipments 12 months/year.Shell and Tube Heat Exchanger

There are 3 main types of shell & tube heat exchangers:

  • “U” Tube heat exchangers where it is possible to remove the entire bundle
  • Fixed tube heat exchangers where the tube sheet are welded to the shell and stationary and the bundle is not removable
  • Floating tube heat exchangers where one tube sheet is fixed and the other floats axially.  This tube bundle is also removable.

So what information do we require to get started on your replacement Heat Exchanger or Tubes & Bundles? As mentioned, if you have the model #, in most cases, we should be able to cross-reference that unit from our product library. Send that information to our sales department, and a member of our team will get back to you with a quote – simple as that.  In the rare cases when we cannot cross-reference your model number, we can provide blank drawings that specify what measurements we need and where they’re located on the unit.  Please see our product pages on REPLACEMENT TUBE BUNDLES and SHELL & TUBE HEAT EXCHANGERS for product specifications and blank product drawings.

Capital Coil has extensive expertise at replacing bundles and heat exchangers for emergency situations. We can easily get you information on performance, design and cost. Please give us a call for your next job. We look forward to working with on your next opportunity.

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Coil Costs: What Will Make Your HVAC Coils More Expensive?

We get questions all the time about how we build our HVAC coils, and what will add costs and what will not. This post will address the many inaccuracies other “mass production” manufacturers Hot Water Coilshave put out there. It’s very simple. There are only three areas on a coil that will add costs: the casing, the tubing, and the fins. Now we’ll deal with the many inaccuracies that most manufacturers try and “upsell” to you.

  • Connection sizes: There should be no additional cost switching from a 2” MPT connection to a 3” MPT connection. Only on rare cases with a 4” or 5” connection, should you ever see an adder in price.
  • Pitching the casing in a steam coil: All steam coils should be pitched. There is not some mysterious adder you need to pay to have you coil built the right way.
  • Casing depth and dimensions: Whether you want your coil 4” deep or 8“ deep, or want a 2” flange instead of a 1” flange, there should be no cost associated with simply more sheet metal.
  • Distributors on a DX Coil. This is our favorite. We actually had a call from a contractor who asked how much extra it was to get a distributor on his DX Coil. Distributors come standard with DX coils!
  • Flanges for “stackable” coils. This is just standard practice to meet the needs of your customer.

Coil Casing Adders: Most HVAC coils we manufacture are built with 16 ga. galvanized steel casing. We offer 3 other options that are slightly more expensive, but it all depends on your application if any of them are actually needed. Stainless steel casings are used in a corrosive atmosphere and are the most expensive option (even then, it’s only 10-15% more). 14 ga. galvanized steel casings are used primarily in coil banks where you might have between 2-4 coils stacked on one another. This adder for 14 ga. casing is only roughly 2-3% per coil.

Tubing Adders: There are many materials options in tubing and we offer all of them. Whether you need stainless steel, carbon steel, cupro-nickel, or standard copper tubes, we can build exactly what you need. Like any product, the more unusual the material, the more expensive the cost is. For most jobs with just copper tubes, adding a thicker tube wall will add only 10-15% in cost to the job and could double the life of your coil. For just a couple hundred dollars, that coil that would last 10 years could last 20. Some applications, like high pressure steam coils, require a thicker tube wall or more durable material or the life span of that coil will be extremely short. You’d be surprised at how many other manufacturers’ coils we’re asked to rebuild with the correct materials.

Fin Adders: Most coils are offered with aluminum fins with a thickness of .006”. The adders to go up in fin thickness are not much, but always remember, the thicker the fin, the more air pressure drop it’s going to add to your coil. The most costly adder you can do to a coil is adding copper fins. It will double the cost of your coil, and in some cases, be 2.5 to 3 times more expensive. This wasn’t the case 20 years ago, but the price of copper has risen over the last few years. We usually recommend coating your coils instead. It’s far more economical and only adds a week to the lead time.

Capital Coil & Air understands that people do business with you like and who you trust. Coil manufacturers should be an open book with this information. Unfortunately, most try and prey on what you don’t know. Hopefully, this helps with any confusion. Capital Coil & Air looks forward to working with you!

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Quick, Reliable & Uncommonly Fast

 Quick, Reliable & Uncommonly Fast

You have many choices when buying replacement coils and choosing a coil supplier. You could decide to diversify and work with numerous suppliers, based on a particular need. However, Capital Coil & Air can make your buying decisions a lot easier. We have been in the coil business for many years, and in this industry, we recognize what is important vs. what is irrelevant. That translates into us having good insight on what you need and how best to support you as a customer.

Quick

Coils today typically do not have much “preventative” maintenance done on them. Most everybody just waits until a coil fails and then worries about the problem at that time. And when coils inevitably fail, they fail during the times when you need them most; i.e. cooling coils failing in the summer and hot water coils breaking down in the winter. As a result, there is usually an urgency attached to most HVAC projects. Generally speaking, most jobs require some form of “quick-ship”. Capital Coil & Air gives you (4) different shipping options for all replacement coils. Our standard ship time is 3 – 4 weeks, but if you need your order faster, Capital Coil will accommodate that need. We do not want to have a “one and done” transaction. Capital Coil’s goal as a business is to have a customer base that we work with for 20 years, not 20 minutes. While we will do our best to give you the fairest price possible, you have to recognize that there is an additional premium associated with quick-shipments on replacement coils. However, you will never pay that premium if Capital Coil is late on manufacturing your order. We’ve built our business on quick-ships, and we hit 99% of all deadlines on orders the last two years. In other words, we rarely miss! We give you options, and you only pay for what you really need.

Reliability

Reliability encompasses so many things in the coil industry. For example, if you need a price today, and the sales rep takes (2) days to get back to you, that’s unacceptable and unreliable. If you require a drawing to help you design a job, and you are waiting for a week to have it returned? Again, not what Capital Coil considers reliable. If a coil supplier promises you a ship date and ships (2) weeks late? Once again, not reliable. Do any of the above issues sound familiar? It is easy to make extravagant promises, and companies do it all of the time. However, Capital Coil’s success rate on meeting and exceeding shipping schedules says more than any promise we can make. We believe in under-promising and over-delivering, not the reverse!

  • Capital Coil responds quickly to all inquiries for pricing, general information, and engineering assistance
  • Capital Coil manufactures high quality equipment in the U.S.A. and is AHRI Certified
  • Capital Coil’s years of experience will help you quickly pick the correct product for the correct application
  • Capital Coil provides accurate shipping dates, real-time tracking and common carrier information after your order has left our factory

We do all of the above to make everything in your life easier. Capital Coil holds itself to the highest standards for both reliability and customer service. In short, we want your experience with us to be professional and simple. Please call or email our sales department for any job – no matter how large or small. We greatly look forward to the opportunity to work with you on your next project.

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Large enough to service all of your replacement coil needs, but small enough to care about what you think