Do You Need to worry about performance on replacement HVAC coils?

With replacement HVAC coils, performance is almost never the issue. This is a common mistake that a lot of folks make. When duplicating a coil, your efforts need to be directed towards making sure the coil fits correctly, as that’s usually the main issue. While you may be thinking that doesn’t make a whole lot of sense, here are the main reasons:

  • Coils were never intended to be filters, but that’s exactly what they become over time. For those that routinely work with coils, you know its design is tailor-made for the collection of dirt and Chilled Water Coilother air particles The tubes are staggered, which means that dirt can not get through. The fins are rippled and corrugated, which typically leads to the same result. Wet coils tend to collect more dirt than dry coils. The process of cleaning coils is very difficult, and the deeper the coil, the more difficult it is to clean. The end result, depending on the age, maintenance and operation, means that your coils operate anywhere from 50%-70% of their maximum efficiency.
  • Fins do approximately 70% of the work in a coil, with the tubes making up the remaining 30% (generally). When manufactured, the tubes are expanded into the fin collars. But, over time, the fins tend to loosen a little. While not sliding back and forth, the fins lose efficiency and their performance is lessened.
  • So what’s your typical solution after 5, 10 or 15 years? You’d probably raise or lower the water temp on you coil. You might also speed up the drive to get more CFM across the coil. You’ll try most anything to make up for the loss of the coil’s efficiency. Everybody does.

But when you replace the coil, it’s new and clean. Additionally, with a new fin/tube bond, your new coil is operating at 100% efficiency, while the old coil was working at 60% – 70% efficiency…maybe. With this automatic increase in efficiency means that performance is not really the issue. Your main concern should be that the coil fits in the space available. Otherwise, your new coil is nothing more than an ugly, metallic coffee table.

Your main goal is to replace your coils with as little trouble and cost as possible. While you may still have offsets in piping, as well as other small installation adjustments, performance should be the least of your worries. We’re here to help you meet your requirements quickly and easily.  CALL OR E-MAIL US!  We look forward to the opportunity to work with you on your future projects.

Chilled Water Coil

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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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Different Types of Steam Coils?

There are two types of steam coils:  standard steam coil, which is used in most reheat applications, and steam distributing coils, which are used in applications where the entering air temperature is below 40 F degrees.  Many times, this type of coil is known as a “non-freeze” coil, but that name is very misleading because there is no such thing as “non-freeze”. 

Standard Steam

Standard steam coils operate a lot like hot water coils, but the construction is very different even though the coils may appear to be constructed the same.  The supply and return connections are often on the same end like a hot water coil.  But, steam is very different than hot water and the coil must be built for steam and circuited for steam.  Steam is always more erosive than hot water.  The brazing and tube wall thickness must account for steam. ALWAYS remember that even low pressure steam is more erosive than hot water and a steam coil needs to be built accordingly.

Steam Distributing (Non-Freeze)

Steam distributing coils are a completely different coil because they are built with a tube within a tube construction. Every place that you see an outside tube or header, there is an inside tube and header that you can’t see. The steam on the inner tube keeps the condensate in the outer tube from freezing.  The purpose of the Steam Coiloriginal coil design was to distribute the steam evenly along the length of the coil and to eliminate and dead spots on the coil.  A byproduct of this coil was also found.  The coils didn’t freeze nearly as easily as the standard steam coil., so the coils became known as “non-freeze”, which as mentioned, is not totally correct.  Any coil can freeze under the right conditions.  But, this design is what needs to be used when the entering air is under 40F degrees. 

Steam Coil Design

Steam coil designs can be very tricky.  Steam coils are totally a function of the system and installation while other coils operate more independently of the system.  There needs correctly designed traps, and they need to be installed in the right place and depth in the system.  Often, vacuum breakers are also needed in the system.  The piping must be installed correctly to make sure the steam in entering the coil and not the condensate.  Even with all of those factors, you need a correctly designed steam coil that matches the steam pressure, length of the coil, and the entering air temperature.  Coils can freeze easily.  Coils can be too long in length and the steam cannot travel the length of the coil and distribute evenly.  Condensate can easily be trapped somewhere in the coil and the result is water hammer. 

Capital Coil & Air has years of experience designing steam coils, and is here to answer any questions and help to design the right coil for your project! 

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HEATING SEASON WILL SOON BE UPON US

 


HEATING SEASON WILL SOON BE UPON US

The real ability and competency in selecting hot water coils or any other heating coil is to know and understand the products that are available. Our goal here is to help simplify your selection process. Just as you’d spend time researching cars before a purchase, you want to be as educated of a buyer as possible!Hot Water Coil

HOT WATER COILS

The HVAC industry classifies coils as “Hot Water” if they are (1) or (2) rows deep, and “Chilled Water” if the coil is (3) to (10) rows deep. One important fact to remember is that whether the water is hot or cold, a water coil is still just a water coil. Just because you do not need as many rows for hot water applications, all water coils are built the same. Tubes can be 5/8 ” copper or 1/2 ” copper, and water can travel through the coil’s tubes at temperatures up to 200˚F. Capital Coil’s selection program is very user-friendly and can greatly assist in your selection process.

STANDARD STEAM COILS

While steam coils look very similar to water coils, the construction and circuiting of the coil are usually very different. Specifically, the brazing for the tubes and headers has a higher percentage of silver solder in the brazing. The tubes are generally thicker (.025”), and the circuiting of the coil minimizes the passes to allow for easy condensate removal. Unless you have (2) PSI or (5) PSI steam, hot water coils and steam coils are not interchangeable! Steam pressure is extremely important to take into account.

STEAM DISTRIBUTING COILS  “NON-FREEZE”

The construction of a “non-freeze” coil is completely different than that of a water coil or standard steam coil. Steam Distributing coils are manufactured as a tube within a tube. This application should always be used when the entering air temperature on a coil is 40˚F or below. There are (2) types of designs for steam distributing coils. They can be constructed with 5/8” (outer-tube) / 3/8” (inner-tube)  &  1” (outer-tube) / 5/8” (inner-tube).  A Capital Coil sales rep is always available to help with proper selections.

HOT WATER BOOSTER COILS

Hot water booster coils are primarily used in duct applications for reheat purposes. In addition to hot water, booster coils can also be used for low pressure steam. The best part is that Capital Coil has a standard (1) week lead time for booster coils. We value speed and quality as much as you.

Capital Coil manufactures all of the above for whatever heating application you may need. All coils are also available on our quick-ship program – if you need your coil built in 3, 5, or 10 days. Capital Coil & Air welcomes the chance to work with you, and be your source for quick answers and immediate service. Please give us a call on your next project!

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