Simple Strategies For Your Replacement Coil Buying Process

Roughly 100% of HVAC replacement coil shipments use some kind of trucking company or common carrier. There are occasions when the shipment is small enough to use UPS or FedEx, but the vast majority of HVAC shipments are sent by way of truck. Anyone who has frequently used freight companies has experienced damaged shipments and/or late arrivals. In our industry, these annoyances and inconveniences are typically written off as “the cost of doing business”. Think of the airline industry as an example. Our expectations have been reduced to point where we expect something to go wrong and are pleasantly surprised when the trip is smooth from start to finish.

Many folks might not know this, but the trucking industry in general is experiencing a gross shortage of drivers throughout the country. Some estimates have put this shortage of drivers as high as 50,000 throughout the country.

So what does this shortage mean for the HVAC industry? Put simply, it translates into complications and confusion for all involved.

  • Longer delivery times. For example, a delivery that used to take (3) days is now (5).
  • One major reason for the longer delivery times is that trucks now have many more stops than in years past. There are also many instances of more trips through connecting terminals as well.
  • More time on the truck usually equates to both “visible” and “hidden” freight damage.
  • The shipments become harder to track, and with fewer people at the trucking companies doing more work, shipments can and will get lost entirely.

Because the freight process is at the very end of the buying cycle, Capital Coil & Air has developed some simple strategies for the entire buying process that should help in avoiding many of the annoyances listed above. We’ve also added a very useful “hint” to counter longer freight delivery times.

  • Getting a price, delivery & accurate proposal from your vendor: Capital Coil responds to every quote request quicker than any of our competitors, and we are always willing to put that claim to the test. A (2) day delay in receiving your quote is the same as a (2) day freight delay on the back end.
  • Receiving your submittal drawings in a timely fashion: You need to approve these drawings, so once again, how is a (2) day delay in receiving approval drawings any different than receiving your order (2) days late?
  • Quick-Ships: As you’ve probably experienced numerous times in the past and/or present, other coil manufacturers seem to be consistently shutting down their quick-ship programs with little to zero notice for the customer. Why is this? Many manufacturers take on a glut of OEM business, or other large projects with small profit margins. In many cases they do this simply to keep the factory running during the slower periods of the year. This has the effect of delaying standard lead times, and in many cases, cancelling quick-ships altogether. It is very hard to do business with companies that make themselves unavailable when you need them the most.

Capital Coil NEVER shuts down our quick-ship programs, and we emphasize NEVER! Over the last (2) years, CCA has hit approximately 99% of all quick-ship orders.

  • Crating equipment to minimize freight damage.Steam Coils
  • Shipping on time: Simply put, we consistently ship when we say we’re going to ship.
  • Select a freight carrier that delivers to your area without interlining or stopping at several terminals: This is when freight damage is most likely to occur!
  • Pay the carrier fee for a guaranteed delivery date: Although seemingly not well-known, most carriers offer a guaranteed delivery date for a fee of $50-$100. Paying the fee will ensure that your order is now a “priority”, and most freight companies schedule deliveries based on these “priorities” first. If both your order and delivery are critical and time-sensitive, Capital Coil can help you with exploring these delivery options.

Capital Coil & Air will work with you throughout the entire buying and shipping process because you as the customer, deserve to work with a hands on manufacturer that will not turn its back on you once the order has been placed. Please give Capital Coil a try on your next project!

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In Need Of A Reliable Steam Coil Manufacturer?

With winter rapidly approaching, time is not on your side if your current supplier isn’t able to meet your needs. Winter will not wait for you to receive those Steam CoilsSteam Coil and/or Hot Water coils that HAVE to be installed before temperatures begin to plummet.

You can call the OEM, but more times than not, they are not flexible or nimble enough to handle your emergency within an acceptable time-frame. Whether you need a coil in (3) weeks, or (5) days, Capital Coil has got you covered.

Quick-ships are generally based on emergency conditions, and that is precisely the worst time to discover that your regular supplier has suspended their quick-ships. When we call Capital Coil reliable and dependable, one of the main reasons is because of our ability to keep our quick-ship program open 12 months/year. Capital Coil does not try to be all things to all customers, but quick-ships are an integral part of our business. Keeping our quick-ship program available all year is a top priority, and this has allowed us to hit 99.9% of our quick-ship requests over the last (3) years – an unfortunate forklift mistake makes up the other .1%. 5.5 months into 2019, approximately 75% of all orders have been quick-ships, and they have either all been completed on time, or are 100% on schedule.

So why do so many manufacturers seem to get so overwhelmed at some point every year? Many manufacturers take on a glut of OEM business, or other large projects with small profit margins. In many cases they do this simply to keep the factory running during the slower periods of the year. This has the effect of delaying standard lead times, and in many cases, cancelling quick-ships altogether. It is very hard to do business with companies that make themselves unavailable when you need them the most.

An RFQ that sits on a desk unanswered is useless to everyone involved. If you need a quote, you’ll have your price and any required submittals that same day. It really is that simple and easy! Working with Capital Coil removes many of the annoying and unannounced shut-downs that come with other manufacturers, so please let us help you when you need it the most!


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Frozen Steam Coils: How Do You Prevent This?

Regardless if you have steam coils or steam distributing (non-freeze) coil, you can freeze ANY coil.  When freezes happen, everyone immediately looks to the steam coil as the cause.  When in fact, there are numerous reasons that must be looked at well before the coil.

Freezes generally happen in older systems, however if your new system is not maintained properly or correctly installed, your steam coil can and will freeze.  For instance, you’d be surprised at how many times dampers are left open, controls fail, freezestats don’t work, etc.Steam Coils

In a Standard Steam or Steam Distributing Coil, a freeze-up can occur when condensate freezes within the tubes of the steam coil.  The two most common reasons for freezing steam coils are the steam trap and the vacuum breaker.  The function of steam trap is to remove the condensate as soon as it forms.  Condensate usually collects in the lowest part of the coil.  If your steam trap isn’t installed properly, that condensate will lay in the coil and it will inevitably freeze as soon as it sees outside air.  The vacuum breaker also helps clear the condensate, minimizes water hammer, and helps with uneven temperatures. This must be installed on the control valve and always above the steam trap.

Unfortunately, there are no ways to determine exactly where your steam coil will freeze.  And a common misnomer is that the condensate turns to ice and the expansion is what causes the tubes of the coil to pop.  In reality, it’s the pressure that builds up between freeze points.

Here’s couple tips in your coil design that can help prevent your standard steam and steam distributing coils from freezing:

  • Standard steam coils should NEVER see any outside air below 40 degrees.  If it does, steam distributing is the only way to go!
  • 5/8” OD Steam distributing coils over 72” long are recommended to have a dual supply
  • 1” OD Steam distributing coils over 120” long are recommended to have a dual supply
  • Make sure your steam coil is pitched if possible.  This slopes the condensate to the return connection making it easier to remove the condensate

Give Capital Coil & Air a try on your next project. Our engineering, pricing and service is the best in the industry!

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Repair or Replace Your HVAC Coils?

Regarding replacement hvac coils, there are multiple reasons why coils can fail prematurely. Sometimes, they simply freeze and can never be repaired. Other times, the coil was selected incorrectly, which in turn, made the coil significantly underperform. Many times, there is substantial corrosion or something else in the system that causes the coil to fail. However, most coils, when selected correctly, and in systems that are properly maintained, can last anywhere from 10-30 years!  10-30 years is also a pretty wide range, and there are many variables in how long you can expect a coil to perform. Factors, such as on-going maintenance, air quality, and water/steam quality all have an effect on a coil’s lifespan.


Steam Coils

Reasons Why Coils Fail Of Old Age

  • While the coil’s tubes are considered the primary surface, 70% of all coil performance is performed by the finned area on a coil, which is known as the secondary surface. The fin/tube bond is easily the most important manufacturing feature in any coil. Without the bond between the tubes and fins, the coil could never properly function. Like all things however, over time the fin/tube bond becomes less efficient with constant expansion and contraction. While the construction of the coil, as well as the fin collars, does not allow the fins on the coil to move, that fin/tube bond naturally weakens a coil’s life over time after installation. Because of this, it is not a stretch to say that a coil is easily 30% less efficient after (20) years.
  • Cleaning coils often pushes dirt to the center of the coil, and this occurs even more so on wet cooling coils. Just remember that coils can become great air filters if not properly maintained. The BTU output of any coil is in direct proportion to the amount of air going through the coil. If you decrease the CFM by 20%, you are also decrease the BTU’s by 20%!
  • Cleaning agents often corrode aluminum fins. Since every square inch of fin surface matters in performance, corrosion of the fin surface is always detrimental to the coil’s performance.
  • Many times, there are coil leaks simply because of old age. No coils are immune to erosion. You might find the brazing in the tubes, as well as the brazing in the header/tube connections failing over time. Steam can be both erosive and corrosive under higher pressures. Water travels through the coil at 2 – 5 ft/second, so erosion is an enormous part of coil failure, regardless of how well-maintained. Erosion is always there, whether you realize it or not.
  • Water/steam treatment and the corrosive effects of bad steam/water can all be causes of coil failure.

So What Is The Solution?

Some coils can last 5 years, and some coils can last 30 years. As you have read, there are numerous factors that contribute to a coil’s life. In the end, there will most likely have been multiple attempts to repair that coil to make it last as long as possible. The depressing news is that most of these “Band-Aid” attempts do not work well. The most likely outcome is that you are buying a new coil anyway, so why waste the time and money on a temporary solution?

Coil failure is a “pressure event”, which is a fancy way of saying that a coil is leaking. We’ve listed some of the most common repair methods that you are likely to come across:

  • Drop leaking tubes from the circuit: Keep in mind however that every dropped tube reduces the coil’s performance by triple the surface area of the tube that is dropped. Again, while ok in the short-term, this is simply another “Band-Aid” fix. Over time, your energy costs will rise exponentially, and you will probably end up buying a new coil anyway.
  • Braze over the existing braze: As mentioned above, erosion has caused the original braze to fail, so all that you are really doing is pushing the pressure to another braze, which will then begin to fail as well.
  • High Pressure Cleaning: This method bends the fins, further restricts the airflow, and pushes dirt more to the center of the coil, which can never be adequately cleaned.

The real reason why coils need to be replaced rather than repaired is due to energy costs. If your coil is not operating near desired levels, you’ll need to increase the energy to make it work at its peak performance. Energy increases might be slight at first, but they are guaranteed to continue to rise over time. For example:

  • Somebody adjusts the fan drive for higher speeds, higher CFM’s and higher BTU’s.
  • Someone adjusts the boiler; the water and steam temperatures are higher.
  • Someone adjusts the chiller (1) degree higher for colder water to the chilled water coil.

Whichever method is used, performance begins to suffer and adjustments to the system occur. These adjustments cost energy efficiency and ultimately, money!

If you have ever experienced repairing a coil, then you know it is labor intensive and typically will not work as a permanent solution. With very few exceptions, repairs should be seen as nothing more than temporary until you’re able to replace that coil!

Capital Coil & Air has seen every “repair” method used, as well its inevitable outcome, so instead of putting yourself through that, call Capital Coil and allow us to be your coil replacement experts.

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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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Top 5 Reasons Commercial HVAC Coils Prematurely Fail

  • Commercial HVAC CoilsCoil Plugging: If you are not changing filters and/or your commercial HVAC coils are not properly cleaned in a timely manner, your coil will actually begin to act as a filter. When dirt builds up on the coil, that blockage prevents heat transfer and can cause an approximate 20% to 40% drop in performance. Dirt adds to the coil resistance and can be a primary cause for your coil to fail prematurely.
  • Vibration: When your HVAC coils are installed near a moving piece of equipment, vibration can occur and cause leaks. You can tell if vibration is the main cause if leaks are near the tube sheet and look like they are slicing through the tube. If/when that happens, the coils should be isolated from the rest of the system to prevent vibration from causing damage. One way to combat this is by oversizing the tubesheet holes, but many manufacturers will not do this. Condenser Coils are usually the most common victims of vibration.
  • Corrosive Environment: This applies to both the air in the environment and inside the tubes. For instance, if there is a corrosive element in the air, it will eat away at the copper tubes; whether you have 0.020” wall or 0.049” wall. This is very common in coastal areas where there may be salt in the air. To keep the costs down from going to a stainless steel or cupro-nickel coil, we usually suggest coating the HVAC coils. Coatings are almost always within your budget, and its application will only add about a week to the overall lead time. Steam condensate and untreated water can cause corrosion within the tubes of HVAC coils as well. If you have a steam coil that has failed before the one year warranty, there’s a great chance that corrosive agents are in the steam, and it’s eating away at the copper tubes.
  • Freeze-Ups: Most people think that when HVAC coils freeze, the water or condensate laying in the coil freezes into ice and it expands causing the tubes to bulge and eventually spring leaks. What really happens is that the coil will freeze in multiple areas simultaneously, and it’s the pressure between these areas that cause the tubes to swell and eventually burst. These are very easy to spot as the leaks will run the length of the tube rather than around the tube.  ALSO be very careful when considering “freeze-proof” coils!  If you remove 5-6 inches from the fin length to make the “freeze-proof” application fit, your coil’s performance will suffer considerably. 
  • System Design: You would be amazed to learn how many HVAC coils were never designed properly for their systems. If there is a design problem, replacing the coil will only waste time and money; while you have done nothing other than duplicate the previous problem. A little known fact in the replacement market is that a high percentage of all our projects are because the coils were built incorrectly or were never designed correctly in the first place. In some cases, owners attempt to improve the coil’s performance by adding additional rows. Most however do this without taking into account the air pressure drop or fluid pressure drop that comes with it.

When dealing with an HVAC coil manufacturer, try to partner up with one who will walk you through the engineering and explain it along the way. Capital Coil & Air has well over a decade of experience and can help you diagnose whatever problem that you are experiencing correctly the first time. We look forward to working with you on your next project!

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Why Is Fin Design On HVAC Coils Important?

HVAC Coils

At first glance, fin designs on HVAC coils seem about as exciting as watching grass grow. “Why would I ever care about fin design on any coil” was probably your initial response to our question. Nevertheless, we would not dedicate a newsletter to this subject if fins were not important.

One of the primary reasons fins are so important is that you want to keep your coil as clean and maintained as possible. In order to properly maintain your coil, you need to have an understanding as to how HVAC coils are constructed. While fins do not look like much, they are MUCH more complicated than what you can observe at the entering or leaving airside of the coil.

To begin, fins are responsible for a surprising 65% – 70% of the heat transfer on any coil, while tubes are responsible for the remaining 30% – 35%. Additionally, in order for your coil to work at optimum performance, you need to have a terrific fin/tube bond, (which we will discuss below).

  1. Fins are known as secondary surface, while tubes are referred to as primary surface. While this may seem counter-intuitive, the secondary surface is responsible for twice the amount of heat transfer as the primary surface.
  2. There are special dies (see picture) that stamp out aluminum or copper fins with the correct thickness, height, and depth to make the coil the correct size. For example, a coil might be 36” (height) x 96” (length) x (8) rows deep x 8 fins/inch.
    1. Fin Height: 36”
    2. Fin Depth: 12”, (8) rows deep
    3. # of fins in the coil: 768 (8 fins x 96”)
  3. Each fin has 192 holes stamped in the fin for 5/8” OD tubes (8 Rows x 24 Tubes), and each fin is identical.
  4. Each hole has extruded metal, which is more commonly referred to as the fin collar. The collars are sized to self-space the fins and allow for later expansion of the tube into the fin collar. This practice is also known as “bonding” and is essential to having your coil run efficiently/correctly.
  5. Each fin is rippled at the entering and leaving edge of the fin to help create air turbulence.
  6. Each fin is corrugated in the direction of airflow to allow for greater air turbulence. This is important to remember because turbulence creates heat transfer.

So again, what is the point of understanding the importance of fins in HVAC coils? While coils can be built with flat fins for various reasons, the vast majority of coils are built with enhanced fins. Enhanced fins help to ensure that the airflow is not running straight through the coil.

Regardless of fin type, keep in mind that HVAC coils can and will act as great “filters”. The tubes are staggered and not in-line; while the fins are designed to help break up the airflow and not facilitate an easy, straight-through air path. Dirt and/or other particles in the air get caught easily, which again, is why coils can act as great filters. Additionally, coils with more rows will usually get dirtier than coils with less rows. Lastly, chilled water or DX coils are typically wet coils, which results in them catching virtually everything in the air.

The amount of BTU’s through any coil is in direct proportion to the amount of air through the coil. For example, if you are only getting 90% of the design air through the coil, then you are only getting 90% of the BTU’s.

Coils require good filtration and periodic maintenance. If not done correctly, you’ll pay the price of higher energy costs on an inefficient coil.

By now, you have hopefully come to the realization that HVAC coils are much more complicated than they appear, and that fins are an integral part of the coil as a whole. Again, while admittedly not the most exciting topic, understanding the role and importance of fins in HVAC coils cannot be overstated. Capital Coil & Air is here to help you with any and all coil selections, and we look forward to working with you on your next project.

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