Top 10 Tips For Measuring HVAC Coils

1. When measuring HVAC coils, performance has very little to do with accurately measuring for replacement coils. Fitting the coil in the existing space with the least amount of labor has everything to do with measuring a coil.  If you duplicate the coil in almost every respect, the performance will match and take care of itself.  New is always more efficient than old.

2.  If you’re ever in doubt about a dimension, smaller is always better than bigger. You can always “safe off” around any coil as long as you can fit it in the space.  If a coil is too big, it makes a really ugly coffee table in your shop.  Too big is the enemy of measuring coils.

Chilled Water Coil

3.  The fin height and fin length are not the determining factors in measuring a coil. The overall casing dimensions are the most important, and you work backwards to determine fin dimensions.

4.  The depth of any coil is the total casing depth in the direction of airflow. The height is the number of tubes high in any row.  Depth is a function of rows deep and height is a function of tubes in a row.

5.  Overall length (OAL) is not the fin length and it’s not the casing length. It is the length from the return bends to include the headers that are inside the unit.  Again, it is necessary to work backwards to get the other dimensions once you know this critical dimension.

6.  Circuiting is the number of tubes connected to the supply header. Generally, you just want to count the number of tubes connected to the header and that will tell you whether it’s full, half, or even a double circuit.  It does not matter how the return bends are configured.  Your goal is to count the number of supply tubes and all performance is based on that.

7.  Fins are measured in fins per inch. Hold a tape measure up to the coils and count the number of fins in one inch.  If you can’t get in to take the measurement, a safe rule of thumb is 10-12 fins/inch.  That will work on almost every coil.  The exception to that rule is a condenser coil.  14-16 fins/inch on a condenser coil is usually pretty safe.

8.  Connection locations are difficult only if you are using the existing piping in the system (which are welded). Copper piping is brazed and can be changed easily.  If a system is old and the piping is being replaced as well as the coil, the connection location is not a major deal.  It’s very easy to match up!

9.  With replacement coils, the concept of “left hand vs. right hand” doesn’t actually exist. Connections are “top left-bottom right” or vice versa.  Ideally, all coils should be counter-flow which means that the water and air flow in opposite directions.  The air hits row one first and the water is piped into row eight first.  However, there are lots of installations that are piped backwards, and they work just fine.  Just match them up, and the coil’s performance will be equal to the old coil.

10.  Connections are not measured from the top of the header! They are measured from the top of the casing to the centerline of the connection.  Or the bottom of the casing to the centerline.  You need a point of reference, and the header height can be anything just as long as it doesn’t stick above or below the casing height.

 

All of the above “suggestions” or “secrets” are in no particular order.  They are just things that you should know to ensure that you are selecting the correct replacement coil. While most seem like common sense, your best bet is to talk with the sales team at Capital Coil & Air, who can walk your through the entire process and help you to fill out coil drawings when trying to measure the dimensions.

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Why are HVAC Coils Copper Tube and Aluminum Fin

HVAC CoilsIt’s really not a coincidence why HVAC coils use copper tubes and aluminum fins. Copper is great for heat transfer, and aluminum – while still very effective -is simply not as good. The first goal of any HVAC coil is to cool or heat. Heat transfer is always the first consideration. Cost is the second. Copper works well for the tubes, but would be prohibitive for the fins. You would need a compelling reason for the fins to be copper, and sometimes there are reasons to do just that. However, the vast majority of HVAC coils that you see are built with copper tubes and aluminum fins. That combination offers the most effective heat transfer at the most efficient cost. 

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. Fins are known as secondary surface, while tubes are referred to as primary surface. While this may seem counterintuitive, the secondary surface is responsible for twice the amount of heat transfer as the primary surface.

The tubes are expanded into the fins, and for that reason, the fins become secondary. As mentioned above, the fins are responsible for 65% – 70% of all heat transfer that takes place in the HVAC coil.  When you think about it logically, it really makes sense. At 8 fins/inch or 10 fins/inch, and with fins that run the height and depth of the coil, there is much more fin surface than tube surface. However, it also points out how good the fin/tube bond must be in the expansion process. Without that bond, the fins cannot perform their job.

Understanding the role and importance of the materials used in HVAC coils cannot be overstated. There is a distinct reason why the vast majority of coils are constructed using these materials. While coils can be built with other tube materials, such as steel, 304/316 stainless steel, 90/10 cupro-nickel, as well as various different fin materials, none of these are as efficient or economical as copper/aluminum.

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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Guidelines For Air Velocities

The height, length and resulting air velocities greatly figure in everything in determining the size and performance of a coil. Step # 1 in determining the size and performance of a coil is dependent upon understanding face & air velocities of air across the coil. Whether you use CCA’s coil selection program to help size the coil, or you are replacing an existing coil; the height, length and resulting velocity determine everything.

Hot Water Booster Coils

air velocities

Every coil has a specific, optimum velocity, so you want to make sure you are within 30% (+ or -) of that number. For example, booster coils have an optimum velocity of 800 ft/minute. That means that you can drop your velocity to 600 ft/minute, or conversely, increase the velocity to 1,000 ft/minute. The duct velocities are almost always higher, which means that you will need to transition to a larger coil. Try to get to as close to 800 ft/minute as possible, while sizing your coil to make the transition as easy as possible. Everything with coils is a balancing act.

Hot Water & Steam Coils

Like booster coils, hot water and steam coils should also have face velocities at approximately 800 ft./minute. Both steam & hot water coils have only sensible heating, which is why their face velocities can be the same. Face velocities ultimately control the coil’s cost, so 800 ft./minute really is a heating coil’s “sweet spot”.

If you are purchasing an air handler unit, oftentimes the heating coil is smaller than the cooling coil because the face velocities on heating coils can exceed those of cooling coils. Due to water carry-over, cooling coils cannot exceed 550 ft/minute, while heating coils only deal with sensible heat.

Chilled Water & DX Coils

Due to the limited face velocities of cooling coils, your choices are more limited. With cooling coils, your face velocity must be somewhere between 500 ft./minute-550 ft./minute. Remember that when dealing with cooling coils, you are dealing with both sensible and latent cooling, so the coil is wet. When you exceed 550 ft./minute, water carry-over occurs past the drain pans.

If you are purchasing an air handler unit, you probably will not have worry about the coil’s face velocity as most coils come pre-sized at the acceptable face velocities. Fan coils also come pre-sized with the correct CFM’s. However, if you are replacing an existing cooling coil, the face velocity must remain at or below 550 ft/minute!!

 Air Stratification Across The Coil

Air does not travel equally across the face of a coil. If you were to divide a coil into (9) equal sections, like a tic-tac-toe board, you would see a high percentage of air travelling through the center square, rather than the corner squares. In a perfect air flow scheme, 11% of the air would travel through each of the 9 squares, but that is not what happens. Because more air travels through the center of the coil, you want to avoid putting a fan too near the coil. Due to central air flows, most systems are draw-thru, rather than blow-thru. This is also why you want to avoid installing your coil near any 90 degree angles/turns in the ductwork. Avoid any situations that contribute more than the “natural” air stratification to help ensure your coil is at maximum efficiency.

In some situations involving cooling coils, you will have water carry-over even when the coil is sized correctly. How can this happen? Think about the tic-tac-toe board again. Air velocities are exceeding 700 ft./minute in the coil’s center, while the corners are around 300 ft./minute. This cannot and will not work.

Coils do not have any moving parts. They simply react to the air across the outside of the coil and whatever is running through the inside of the coil. Coils are 100% a function of your entire system, as well as the installation in general.

Capital Coil & Air is here to help with any coil selections that will help avoid costly missteps that lead to wasted time and money. Call us on your next project, we greatly look forward to working with you!

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OEM Replacement Coils: Repair or Replace

When considering OEM replacement coils, there are multiple reasons why coils can fail prematurely. Sometimes, OEM Coils 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 ongoing maintenance, air quality, and water/steam quality all have an effect on a coil’s lifespan.

OEM Replacement 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…which then necessitates the need for a reliable manufacturer for OEM replacement coils.

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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How to make your HVAC OEM Replacement Coil Buying Process Easier??

Roughly 100% of HVAC OEM 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 even before the pandemic struck, the trucking industry in general had been 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 (5-7).
  • 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 OEM replacement coil 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 replacement coil 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.OEM Replacement Coil
  • 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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Steam Distributing Coils (Non-Freeze)

Steam Distributing CoilsWere you aware that Steam Distributing coils or “Non-Freeze” steam coils were essentially discovered by accident? First, it must be mentioned that there is no such thing as a 100% “Non-Freeze” steam coil because under the right conditions, any coil can freeze. As such, Capital Coil tries to steer clear of the term “Non-Freeze” because it is a mischaracterization. Steam Distributing Coils is the correct terminology that Capital Coil uses when speaking about steam coils that see entering air temperatures under 32* F. Trapped condensate in the tubes and/or headers, coupled with entering air temperatures below 32*F over the face of the coil, creates a situation with a near-100% certainty that your steam coil will freeze. Because of this, there is no magical solution to fully eliminate freezing your coil, which again is why Capital Coil does not use the term “Non-Freeze”.

Steam turns to condensate little by little as it travels through the coil. Lower pressure steam turns to condensate faster than higher pressure steam!! The longer the tube length in the coil, the earlier the condensate is formed, and the longer it has to travel through the tubes. One very important fact to always remember is that too much condensate in a steam coil IS NEVER A GOOD THING…under any circumstances! Because of this requirement, everything is designed to ensure the removal of all condensate from the coil. Systems are heavily designed with float & thermostatic traps, vacuum breakers, and placement of piping to help get rid of any remaining condensate.

Another headache that occurs when condensate freezes is that it creates a “water-hammer”. A “water-hammer” can best be described as a loud banging noise as the steam is coming into contact with the condensate in the coil. It does not allow the steam to be evenly distributed across the face of the coil…again not a good thing!

At the inception of the HVAC industry, steam coils were originally designed to be shorter in length because there was not a good way to evacuate condensate. In an effort to make steam coils longer in length, the concept of a steam coil containing a tube within a tube was invented. The steam feeds only the inner tubes, which travels the entire of the length of the outer-tube. Holes are placed every 12” with the inner tube releasing condensate to the outer-tube. The idea is that the condensate is slowly and evenly “distributed” across the entire length of the coil. Heating is also evenly applied across the coil’s face, and if the casing is pitched at a downward angle, condensate cannot remain trapped. It was later discovered as an added bonus that under most circumstances these coils will not freeze. So while the concept was never designed or intended to become known as “Non-Freeze”, they are now used in almost all projects dealing with air temperatures below 32*F. Please keep in mind that you will still need all of the other steam protective devices in the system, including the freeze-stat, but all in all, it is much more difficult to freeze coils today than it was 30-40 years ago. Necessity may be “the mother of invention” but this great concept was discovered accidently.

Capital Coil is available for all of your coil-related trivia needs, so please don’t hesitate to reach out whenever we can be of assistance.

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How Should Steam Coils Be Designed??

Steam coils

Of all of  the various types of coils, steam coils operate in the most complicated ways. They are, in effect, a product of the system and controls around the coil. If not installed correctly, steam coils simply won’t work properly.

Overview:

The object of any steam coil is to have steam enter the coil as steam and exit as condensate. In a perfect scenario, the BTU load on the coil turns steam into condensate just before it’s ready to exit the coil. Under real world conditions however, condensate usually begins to form inside the tubes almost immediately. Especially when dealing with low-pressure systems, you have to find a way to evacuate the condensate from the steam coil.

Coil Pitch: 

A good coil manufacturer will internally pitch the steam coil within the coil casing to force the condensate toward the outlet connection. This pitch is usually 1/8 “ per lineal foot of coil.

Coil Length: 

If you require steam to travel 144” and make multiple passes through the coil, then, simply put, your system will not work properly. Condensate forms too early, and it cannot escape the coil. Because of this, coils cannot be too long. A better strategy is to break one long coil into two smaller coils side by side, while feeding from both sides.

Tube Diameter:

Steam Distributing coils often have to be 1  1/8 ” diameter tubes. If the BTU load on a coil is really large, then as a result, you will generate many more Lbs./hour of condensate. If the tube diameter is too small, then the condensate, which needs to evacuate, has no place to go.

Traps:

Traps are required on steam coil systems. The traps should be “float & thermostatic” type traps and be located 18 “ below the condensate connection on the steam coil. Without this, the condensate just sits in the system without any place to go.

Vacuum Breakers: 

Vacuum Breakers are often installed in coil systems to remove any excess condensate that may remain within the coil.

Insulated Piping:

There is no such thing as a “Condensate” Heating coil, built as a steam coil. IT DOESN’T WORK.  However, and this happens an astounding amount of times, due to the long distances the steam has to travel from the boiler to the coil, many times, the steam will enter the coil as condensate due to the piping not being insulated.

Anything that makes condensate lay in a coil is harmful to both the steam coil and the system. You will get a “water hammer” when the system is turned on and the incoming steam just blasts against the condensate. Worse than the loud and annoying sound that produces is the fact that it just destroys the steam coil. The brazing was never designed for “water hammer”.  Also, the coils do not heat properly. Have you ever seen a long coil and run your hand down its length only to feel that the entering steam end of the coil is hot but the far end is cold? More times than not, this means that condensate is laying in the coil and not allowing the steam to properly travel the length of the coil.

Steam Coils require a real expertise to design & build. We at Capital Coil have a long history in solving coil problems and building steam coils so that they work correctly the first time. Give us a call for your next job – you’ll be pleasantly surprised!

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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 hammers, 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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What Is Meant By A “Bank” Of Chilled Water Coils

For those that work with HVAC installations on a regular basis, you have run across the problem of needing to install new chilled water coils in very tight, confined areas. The coil is too big to fit in the Chilled Water Coilselevator, and/or the HVAC room is so small that you are likely to damage the coil simply by moving it. As a solution to this challenge, chilled water coils are often installed in “banks” of coils. You are most likely to see this configuration in Air Handler Units, as well as “built-up” systems. Due to face velocity limitations across the coil, you will need larger coils in order to meet your required face area. With this in mind, there are a few specific reasons why you want to avoid having a single, large coil in one of your units.  Starting with the obvious: larger coils are much more difficult to transfer and install. This is especially true for older buildings, where the rooms were essentially built around the HVAC system.

As you’ve probably experienced, some of these areas can barely fit a single person, so installation – if even possible – is a logistical nightmare. Also, the larger the coil, the easier it is to damage during transport to the jobsite. To avoid these issues, simply break down the single, larger coil into smaller coils. When piped together, those smaller coils are stacked into “banks” of coils in the system. If installed correctly, this “bank” should have the same performance as the larger, single coil.

Casing

There are many different casing options available, but “stackable” flanges are required for heavy chilled water coils that are “banked”. The flanges are often inverted inward and down to give added strength to the casing, which is needed due to the fact that another coil of equal weight will be stacked on top of it. When ordering coils in a “bank” configuration, be sure to let the manufacturer know that they will be “stacked”.

Many engineers also use stainless steel casings on chilled water coils. While more expensive than traditional galvanized steel, stainless steel protects against excessively wet coils and/or corrosive elements in the airstream. Keep in mind that the majority of coils fail because of old age and its casing, as opposed to failure with the coil’s core. With that in mind, doesn’t it make sense to select heavy-duty stainless steel casings that are more durable and meant for stackable installations?

Drain Pans & Water Carryover

Water Coils

All chilled water coils must be sized so that the face velocity across the coil does not exceed 550 ft/minute. Water on the outside of the coil is carried away from the coil’s leaving air side in an arc, while water in the highest point of the coil is carried further down the unit or ductwork. “Stackable” coils often require intermediate drain pans under each coil to catch the excess water carryover. Each coil in a bank requires its own drain pan, as a single, large pan under the bottom coil is not enough.

Circuiting/GPM

If all of the coils in a “bank” are of equal size and handling the same CFM, then the GPM of each coil will also be the same.

Always feed the bottom connection on the supply header on the leaving air side of the coil. This ensures counter air and water flow. This also prevents the coil from short circuiting because the header fills first and circuits all of the tubes equally.

Designing Banks Of Coils

Almost all coil “banks” perform more efficiently if you design something more square in shape, as opposed to long and/or high. In a “bank” of coils, you may find that one coil has points of 300 ft/minute, with other points at 800 ft/minute. Scenarios such as this will cause water-carryover! You generally want to be as close to 550 ft/minute as possible in order to allow equal airflow distribution across the face area of the coil.

Anytime you are designing and/or building coils, work closely with the manufacturer as an added resource to ensure that you are getting the ideal solution for your HVAC system. Capital Coil & Air works on similar jobs such as these daily, and we welcome the opportunity to work with you in whatever capacity is needed.

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Case Study: We Need These Coils on a (5) Day Quick-ship

In late June, Capital Coil received a call from a Trane office in Ohio regarding quick-ship availability. One of Trane’s top customers had an urgent need for (12) large chilled water coils with stainless steel casing. The problem/hurdle that they were encountering was that they needed all (12) coils to be built and ship out of the factory in (5) business days. Completion of the whole project was 100% contingent on them receiving the coils in their specified time-frame. An additional complication was the fact that July 4th was the following week, and they needed to have the coils ship prior to the holiday.

Trane shopped the project around to different manufacturers, but not one could guarantee to ship in (5) days. Some manufacturers waffled and claimed that they could have them built in (6) or (7) days, but not one could guarantee to ship in (5) days. A sales rep in that same Trane office, who had worked with Capital Coil previously, suggested that his co-worker reach out to us to see what we could do. After speaking with Trane’s project manager, we immediately contacted our head of production to make sure that we had the capacity to complete all (12) coils in the required (5) days. She assured us that we had the materials and manpower on-hand to get them all built and ship on time. We agreed to accept the project and began work on the coils immediately.

Due to the size of the project, as well as it’s time-sensitivity, we had multiple calls daily with our factory to ensure that everything was proceeding on schedule. We then gave Trane daily status updates, so they were constantly informed of everything from the brazing of the coils to entering the final testing phase. Chilled Water Coil

As promised, all (12) coils were built correctly and shipped out in the required (5) days. Our logistics team was then in constant communication with the freight company to make sure that the delivery was on schedule. And just like during the production phase, we passed daily tracking updates along to Trane, so they knew where their coils were at all times and when they could expect delivery. All (12) chilled water coils arrived on July 3rd with zero freight damage, and the project was completed on time!

A company as large and influential as Trane can have their coils built by anyone, but Capital Coil was the only manufacturer that could guarantee to have their coils built and shipped by a required date. Additionally, in working so closely with Trane throughout the whole process, they were kept up-to-date in real time from the start of production to final delivery.

Capital Coil offers a level of service that you won’t get with other manufacturers. When we guarantee to ship by a certain date, we stand by that guarantee, or you do not pay!

 

Trane’s project manager’s comments to Capital Coil upon completion/delivery:

“This will help us get a jump on this project prior to the big event taking place next week! 

I will make sure to share your information with others across our great lakes region about our experience with your company, so that they know we have THIS option to go to for our coil needs. THANK YOU ALL!!”