Light-Duty Commercial Belt Drive Air Handler Units

There are lots of jobs that require large custom built Air Handler Units, as well as jobs that require Central Station Air Handler Units that are semi-custom built units. There are also plenty of jobs that Belt Driverequire neither of the above products. This application only requires that a light-duty standard unit be built that will match the duty and requirements of the job.

 Examples

  • Strip Malls/Shopping Centers
  • Dormitories and other college campus buildings
  • Military installations
  • Office areas in factories or other industrial settings
  • Condominiums

These examples do not need large heavy-duty units that are expensive and custom built. Instead, most of these units require standard light-duty construction that can provide 800-12,000 CFM. These units come with various options and choices, and are well-built with the highest quality components available. However, the units are not designed for overkill.

Capital Coil manufactures “Belt Drive” units that operate from 800 CFM (2 Tons) – 12,000 CFM (30 Tons). They are available in both horizontal and vertical airflow styles. Included are blowers, coils, drives, filters as well as additional accessories if required. Additionally, they are available in Chilled Water Coils, DX Coils, Hot Water Coils, and electric heat if needed.

So, why would you want to use these units in lieu of a heavy-duty air handler? Cost, cost, and cost again are the primary reasons. In addition, the light-duty units weigh less, they are more economical to install, and long-term maintenance is much easier. The overall cost of a Custom-Built Unit or a Semi-Custom Station Unit is dramatically higher and not needed in most installations. Please visit Capital Coil’s Belt Drive Product Page for additional descriptions of our units.

Shipping Schedules

  • Standard lead time: (6) weeks
  • (4) week quick-ship: 30% adder
  • (2) day quick-ship: 40% adder

Capital Coil is 100% transparent on all prices and pricing options. Each option is clearly listed on all quotes to help make your buying experience that much easier.

The Air Handler industry is pretty easy to understand when boiled down. If your job allows you to stay within “Production” type units that are built to normal standards without any customizations, you can save a lot on your price. The proper units for your project are still of the highest-grade quality, but they are much more of a fit for commercial, light-duty jobs.

Capital Coil & Air looks forward to working with you on all of your future Air Handler projects. You’ll be glad you did.

RELATED TOPICS


Chilled Water, DX (Evaporator) Coils & Moisture Carryover

Moisture carryover is present on DX (Evaporator) Coils or Chilled Water coils where dehumidification happens.  Many people do not think it’s a problem…until you have moisture running down ductwork or spewing all over the inside of an air handler. If you’ve ever experienced that then you probably know all of these rules regarding moisture carryover.

  • Entering air temperatures of 80/67 of return air in the Northeast carry far less moisture than an outside 95/78 entering air temperature in Florida. Outside air always has more moisture. Chilled Water Coil

    Your location plays a part as well. The drain pans will absolutely have be sized differently. Florida’s will be much larger in size.

  • Fin design is irrelevant when it comes to moisture carryover. Whether you have copper corrugated fins, or aluminum flat fins, plate fins or even the old fashioned spiral fins, none of it has any effect on moisture carryover.
  • Lastly, be careful when installing a new chilled water or DX (Evaporator) Coils in a system. Many end users like to increase the airflow on older coils because those old coils can act like filters, the fins are covered in dirt/dust and you’re not getting the same airflow through the coil. This dirt on the coil also semi-prevents moisture carryover. When that brand new chilled water coil is installed, the airflow might be higher than that 550 ft/minute and that, of course, will cause moisture carryover problems. 

Please give us a call with any questions about your coil, your system or its design. Capital Coil is here to help you avoid situations like the one described in this post, and we would love for the chance to work with you!

 

RELATED POSTS

10 Things You Need to Know About Chilled Water Coils

Top 10 Chilled Water Coil Facts

Chilled Water Coil Circuiting Made Easy


Why are HVAC Coils Copper Tube and Aluminum Fin?

Chilled Water 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.

RELATED POSTS

Why Is Fin Design On HVAC Coils Important?

Top 10 Tips to Measuring Coils

Did You Know? Facts about Commercial HVAC Coils


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.

RELATED POSTS

Is Your Quick-ship Shut Down When Needed Most??

Four Things That You Need When Buying Replacement Coils

Replacement HVAC Coils: 10 Common Ordering Mistakes

Top 5 Reasons HVAC Coils Prematurely Fail


Is Your Quick-ship Shut Down When Needed Most??

Why are quick-ships so important??

With winter already well upon us with various “polar-vortexes” swarming over most of the country, time is not on your side if your current supplier isn’t able to meet your needs. Generally speaking, most jobs require some form of “quick-ship“.

Approximately 70% of all Capital Coil’s orders over the last (3) months have involved some sort of quick-ship. Quick-ships are an integral part of Capital Coil’s overall business structure, and for that specific reason, unlike other manufacturers, Capital Coil & Air NEVER shuts down its quick-ships!!! Quick-ship

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%. Through the last 3 months of 2019, approximately 75% of all orders were 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!

 

RELATED POSTS

Uncertain About Recent Changes In The HVAC Industry?

Repair or Replace Your HVAC Coils?

10 Things You Need to Know to Buy Replacement Coils Effectively

 


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

With replacement coils, as a customer, you have more choices than ever. But don’t you ever get tired of dealing with largely nameless corporations with high staff turn-over? As you’ve probably Replacement coilsexperienced first-hand, there are plenty of companies in the HVAC industry that fit this description. You are simply a number or a project instead of a customer/partner with a name and face. If given the alternative, would you rather deal with a company who knows you and is interested in your success, or a company who’s sole interest is finding out when your check is in the mail? Don’t you want somebody that values your business, regardless of the $ amount, and will go the “extra mile” for you when you need it? Capital Coil & Air places a great emphasis on those attributes in our business relationships, and common sense tells us that you probably do as well.

Capital Coil & Air was created as a family-owned business, with Matt and Dan Jacobs as joint owners and partners. What differentiates Capital Coil & Air from our competition is that we are big enough to handle all of your coil requirements, but still small enough to know who our customers are and what they need. We have decades worth of knowledge and expertise, and because of that, we have learned to not try to be all things to all customers. Capital Coil’s knowledge and experience is in the replacement and design/build market, and we are very disciplined at “staying in our lane”. Additionally, we’d much prefer to have customers and relationships that last years instead of one-off transactions. Working with Capital Coil is as simple and easy as it gets, and here are some examples:

  • When requesting a quote, we almost always respond within the same hour, or within 24 hours at the latest.  We recognize that there is an urgency to almost every coil order, and your time is valuable. In the end, a 3 day delay for a quote and/or revisions to said quote, is the same as if the manufacturer shipped your coil 3 days late.
  • When you place an order with us, we’ll send you an order acknowledgment within 24 hours detailing what you ordered, overall costs, and when it is going to ship.
  • We understand the value and necessity of clear communication. To minimize mistakes, we attach submittal drawings for every quote and order. We want to communicate with you throughout the entire buying process to make sure we are building exactly what you need.  More communication leads to less mistakes and wasted time.
  • We follow up on our shipments very carefully. We’ll work with both you and the carrier to help track your shipments to ensure your order gets to you the fastest way possible.
  • We will not ignore you simply because a sale is complete. Before, during and/or after installation, we’re here to answer your questions and help in any way possible.
  • If you need some help on pricing, we’ll do our best to work with you. While every job is unique, we want to work with you for the next 20 years, rather that a one and done purchase.

You now have some insight into our values and who we are at Capital Coil & Air. Please contact us for any future coil requirements. We greatly value your business and look forward to be your coil replacement partners on your next project!

RELATED POSTS

Top 10 Questions You SHOULD Be Asking Your Coil Supplier

Your Commercial HVAC Replacement Experts-Why Work With US?

Customers are a business’ top priority. So why is customer service such a challenge?

Quick, Reliable & Uncommonly Fast

 


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!

RELATED POSTS

Chilled Water, DX (Expansion) Coils & Moisture Carryover

Tips on Hand Designation & Counter-flow

Coils and Counter-flow: 5 Common Questions


How Did The HVAC Commercial Coil Replacement Market Originate???

How in the world did the commercial coil replacement market start? This specific newsletter is more of a story than anything technical that we have covered in most of our previous emails or blogs. Rather, this is the story of how one manufacturer’s representative, Robert Jacobs, almost by accident, stumbled upon the concept of the coil replacement market back at a time when the only way one could get a replacement coil was to go through the original equipment manufacturer – (OEM). In full disclosure, Bob Jacobs is the VP of Business Development with Capital Coil & Air.

Way back in the day – (1970’s) – HVAC coils were not stand-alone pieces of equipment as they are considered by some now. Coils were nothing more than a single part in an Air Handling Unit (AHU) or a bank of coils. Like a bearing, a drive, or fan wheel, coils were simply part #’s that one needed to reference with the OEM in order to get a replacement built. This situation was a very good deal for the OEM’s because much like car parts, they could charge upwards of 3x’s the original cost of the coil or “part”. And, it was built according to their schedule/timeline, not yours’.

In the 1970’s, Bob Jacobs was a manufacturer’s rep in the Philadelphia-area, and his main line of equipment was Bohn Aluminum & Brass. Bohn was a division of Gulf & Western and competed against many of the top manufacturers, such as Trane & Carrier. For comparison-sake, Bohn was very similar to what Dunham-Bush is today.Commercial Coil Replacement

During this period, Bob Jacobs was asked by numerous local contractors to replace old and/or broken coils. Due to the lack of a quality alternative, he initially used Bohn for coil replacement projects, but replacing coils was not exactly Bohn’s “sweet spot”. It should be mentioned that during this period, replacement coils were not really on any manufacturer’s radar as a separate product – hence the point of this story. Regardless of the OEM, standard lead-times were upwards of (12) – (14) weeks, and those “replacement parts” were very expensive. It was during this period that he realized that there was serious potential for some kind of HVAC coil replacement market. To test this theory, he initially spent $75.00 on an ad deep within the classified section of “Air Conditioning & Refrigeration News”. It was the old type where one had to “circle the bingo card” to request additional information, and this single ad received over 525 inquiries from across the country!! This eye-opening initial response to his idea made him realize that he had come across something good, but now the challenge was how to satisfy this new market. Bob Jacobs initially contacted Bohn to see if there was any interest in building replacement coils, as well as marketing the idea across the United States. Bohn essentially laughed at the idea and countered that he’d be violating his sales rep agreement by going into the territories of other reps. This was very flawed reasoning as none of the other reps were engineering or selling replacement coils in the first place! Within a week, he had canceled his agreement with Bohn and was looking for alternative vendors. He also decided to run a second ad that received another 450 inquiries; furthering his idea of the need for a coil replacement market.

The next step was to reach out to Singer Coils (yes, like the sewing machine), who was located in North Carolina. Because they had built coils for other manufacturers, he pitched his idea to them along with the request that they build his special or “custom” coils. While initially skeptical of the concept, the doubters were proved wrong as his firm gave Singer over $3,500,000 in business in that first year alone. Admittedly, that $ amount in the first year in a brand new market is impressive whether it’s 1971 or 2021!!

One must also remember that these were the days before fax machines and most certainly before email and the internet. Quote requests for coils were received via USPS and were hand-drawn sketches written on things, such as legal pads, envelopes and pretty much every way imaginable compared with today. Because everything was starting from scratch at this time, there were no coil model libraries or other materials to cross-reference, so going through a random building trying to locate the correct coil to replace could be torturous. However, over the next 6-8 years, his business grew quite rapidly, and he was able to collect and build a substantial reference library of coil drawings and other relevant information. The experiences of the prior 8 years, coupled with his firm’s knowledge of commercial coils, eventually allowed his company to begin building their own replacement coils for the 1st time, rather than relying on a 3rd party manufacturer.

Bob Jacobs’ original coil replacement company developed relationships with literally thousands of customers and laid out the initial blueprint for success in the coil replacement business. Due to that success, you now have approximately (10) alternatives that have attempted to copy his model as it’s become obvious that this is a lucrative market. Even OEM’s have recognized that they need to have a piece of the replacement market. But an important point to remember is that just because a company says or even advertises that they are in the coil replacement business does not mean that they are any good or even fully understand how the replacement market operates. For example, most coil manufacturers today are still more interested in the production of larger quantities, so replacement coils are “special” to them. In other words, sometimes these manufacturers want to be in the coil replacement business, and other times, without telling you, they do not. And not knowing where a company’s focus or priorities lie makes it extremely difficult to work with them under emergency conditions.

Bob Jacobs was there at the beginning and is still quite active within Capital Coil. Having daily access to a resource that literally invented the coil replacement market is what separates Capital Coil from all other competitors. Capital Coil will continue to be your coil replacement experts, and we greatly look forward to the chance to work with you on future projects.

RELATED POSTS

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

How to Identify Different Types of Coil Manufacturers

Does Your HVAC Coil Selection Program Leave You With More Questions Than Answers?


Tips on Hand Designation & “Counter-flow”

Are your chilled water coils right hand or left hand?  Are you looking into the face of the coil with the air hitting you in the back of the head?  What exactly is counter-flow and why is it important?  Are you completely confused by why right hand vs. left hand even exists?  Most manufacturers probably do not know or understand the technical reasons themselves.

First, let’s figure out what coils even need a hand determination.  Chilled Water Coils, Direct Expansion (Evaporator) Coils, and Condenser Coils are the only coils that need this figured on almost every job.  Hot Water Coils, Booster Coils, and Steam Coils rarely need this determination!  The reason for this is when the coils are only 1 or 2 rows deep, they can be flipped over.  When a chilled water coil is 3+ rows deep, hand determination is much more important because it needs to be counter-flow.  With most suppliers determining hand designation with the air hitting you in the back of the head….do you want the connections on the right or left?

Chilled Water CoilsYou’ve probably heard the term “counter-flow” countless times, but here’s the simplest explanation.  For peak performance, you want the air and the fluid traveling in opposite directions through the coil.  Is it the end of the world if your coils are not counter-flow?  The short answer is no, but you will lose anywhere from 12-15% of the output.  So if your coils are piped incorrectly, don’t expect to get the full performance.  Steam and hot water coils are 1 or 2 rows deep, so again, counter-flow is pretty much irrelevant.  However, it can make a BIG difference with any chilled water or direct expansion coils (3-12) rows deep.

We also get asked many times “what is the proper way to pipe coils?”  Put simply, steam coils should always be fed on the highest connection and the return on the lowest connection.  Water coils should always be fed on the lowest connection and returned on the top connection to ensure that all of the tubes are are fed the same volume of fluid. 

Hand designation and counter-flow are two pretty simple concepts when they are properly explained.  When dealing with a HVAC coil manufacturer, 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 in handling pretty much any scenario that you may come across, so we want to be your coil resource for any and all projects. Please give us a try on your next job!

RELATED POSTS

Why are HVAC Coils Copper Tube and Aluminum Fin?

Did You Know? Facts about Commercial HVAC Coils

You should never have to worry about performance on replacement coils…Well, almost never!

 


Top 5 Reasons Commercial HVAC Coils Prematurely Fail

Capital Coil & Air has come across virtually every scenario over the years in which a commercial HVAC coil had to be prematurely replaced, and we have since created an easy guide targeting the main reasons HVAC Coils prematurely fail.

  • Coil 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!

RELATED POSTS

Four Things That You Need When Buying Replacement Coils

Replacement HVAC Coils: 10 Common Ordering Mistakes

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