Now Offering R-454B Refrigerant for All DX Coils

In keeping with most of the OEM’s in 2024, Capital Coil is helping everyone transition from R-410A over to R-454B refrigerant in their DX Coils. Whether you are designing a new system, or retrofitting an existing one with a condensing system, Capital Coil can help in making the switch in refrigerants.DX Coils

If you are not yet aware, the EPA is working hand in hand with many of the major OEM’s to help reduce commercial HVAC’s carbon footprint. One of the major ways in which HVAC manufacturers are helping and complying with the new industry standards is the gradual change in refrigerants from R-410A to R-454B. Beginning in January of 2025, no new system is allowed to be built or imported using the older refrigerants. Without going into a deep dive on the differences, R-454B offers a lower GWP (global warming potential) alternative to R-410A. Hence the mandate to change to that refrigerant type. 

However, Capital Coil will still offer R-22 and R-410A for DX Coils in older systems that might not be compatible with R-454B. In other words, Capital Coil has been, and will remain, the most reliable source for all commercial and OEM replacement coils. Our #1 job is to make to your job easier, so please reach out. You will be glad you did.

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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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TOP 10 FAN COIL FAQ’S

1. A fan coil is among the easiest units to understand in the HVAC industry.  Basically, there is a small forward curved fan, a coil, and sometimes a filter.  They are all direct drive units. Click HERE to see Capital Coil’s full Fan Coil Product Lineup.

2.  Fan coils run from 200 CFM to 2200 CFM, which is 0.5 ton through 5.5 tons.  Anything larger than these sizes requires a belt drive unit…which is really a full fledged air handler.

3.  The thing that differentiates fan coil units is where and how they are going to be installed.  Is the unit going to be hidden above the ceiling or maybe in a closet?  Or is it going to be exposed so that everyone can see it?  Will it be ducted or will it just pull air from the space where it’s located?  These are things that determine the configuration of the unit and which style of unit to choose.  But, every unit has 3 things in common:  fan, coil, and sometimes a filter.

Fan Coils4.  Some units have (2) coils.  One for heating and one for cooling.  Obviously, there is a separate supply and return connection for each coil and these units are known as 4 pipe fan coils.  Many units only use the same coil for both heating and cooling and these units are 2 pipe fan coils.

5.  Units are either horizontal or vertical depending on the orientation and flow of the air.  A typical fan coil in a hotel room is a vertical unit with a mixture of air coming from outside and the air recirculating in the room.  The air enters at the bottom of the unit and is drawn upward through the fan.  This makes the unit a vertical style.  Many units are horizontal with the air entering at the back of the unit and traveling horizontally through the unit.

6.  Almost all fan coils are 3 speed or infinite speed settings based on the controls.  The high speed gives you more BTU’s, but more noise too.  Because the unit is direct drive, when you dial down the speed, you also dial down the performance.

7.  Coils in the units tend to be 3 or 4 row deep coils.  3 row is typically used the most, but if you need the extra performance, 4 row is the way to go.  Performance is always governed by the cooling aspect.

8.  Fan coils sometimes have short runs of duct work and there is static pressure on the unit.  Static pressure reduces the amount of CFM and BTU’s that the fan coil can give you.  This is true of both horizontal and vertical units.  Most performances listed on charts that you will see are static free performances.

9.  The control systems for fan coils are often more complicated and more expensive than the units themselves.  There are balancing valves, isolation valves, unions, y-strainers, p/t plugs, air vents, ball valves, thermostats, condensate float switches, and disconnects.  Capital Coil & Air can do this at the plant, but it is much cheaper and easier to do it at the installation. 

10.  Just describe your installation requirements to a sales engineer at Capital Coil & Air and they will guide you to the right design and configuration of the unit for you.  It requires only a phone call or e-mail! We look forward to working with you!

 

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Condenser Coils Failing? Here’s probably why….

Did you recently turn on your DX systems only to find your Condenser Coils are not working?  Simple fix right?  Unfortunately, no.  If you get lucky, you can send us the model number of the unit, and there’s a great chance we’ve already built it.  In the case that we do not have that model number on file, you have two options.  You can go back to the OEM, wait (5) months for a part and pay through the roof.  Or you call Capital Coil, and we’ll walk you through the engineering it takes to replace a condenser coil.                                                                      Condenser Coils

Very rarely do condenser coils ever freeze so the first thing you’re going to want to know is if your coil died of corrosion, old age, or possibly vibration.  Old age is obviously preferable because with a few easy dimensions, we’ll have enough to price up your duplicate coil.  Condenser coils are usually outside and are easily accessible for measurements and digital pictures.  With just the size, the rows, and fins/inch, you can get a price.  And digital pictures of the headers and return bends will give us a good idea of the circuiting and sub-cooler circuits. 

If the coil has been eaten away by corrosion, it was an improper design to begin with.  Most people don’t know that salt in the air will ruin aluminum fins within a year or two.  There are two ways to combat this.  The first option is to make the switch to copper fins and stainless steel casings.  While this will extend the life of your coil considerably, most people are not too happy about the additional cost over aluminum fins.  The second option is to use a coating.  Coatings are the much more popular choice.  They are a fraction of the cost as copper fins and only add (1 – 2) weeks to your lead time. 

When your HVAC coils are installed near a moving piece of equipment, vibration can occur and cause leaks.  The area where these leaks occur is very important and will clue you in to if the problem is vibration.  If they are near the tube sheet and look like they are slicing through the tube, 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.

The last concern is with cleaning condenser coils.  Since condenser coils see outside air almost exclusively, they need to be cleaned more than other coils.  The reason for this is most condenser coils have fin spacing of 12-20 fins/inch.  With fins that tight together, the coil can and will act like a filter.  And when the coil is clogged up, the performance suffers greatly.  Recently, we’ve been getting more and more calls about using a heavier fin thickness.  This is to help with high pressure cleaning and corrosive cleaning agents. 

When dealing with an 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 and has seen every issue to make sure your everything from the quote to the installation go smoothly! Give us a try on your next project!

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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!!”

How to Make Sense of Heating Coils

Various winter storms have already ripped through multiple parts of the country necessitating the obvious need for working heating coils!!  With conditions such as these, emergencies with your HVAC systems are almost inevitable. THIS is precisely when you need your coil supplier to have the speed and flexibility to be able to tackle whatever emergencies arise.Steam Coil

Of all the types of HVAC coils available, heating coils are probably the easiest to select and understand. Capital Coil has listed the three most common types of heating coils that you are likely to come across.

Hot Water Coils

When looking at a water coil, the first thing to remember is that it is in effect “dumb”. In other words, water coils do not know the temperature of the water moving through it. While standard HVAC water coils are mostly constructed in the same design, the number of rows contained within the coil is a key differentiator in determining if the coil is hot water or chilled water. 99% of all hot water coils are (1) or (2) rows based on performance requirements. The “Delta T” between the entering air temperature and the hot water temperature is very large. As a result, you only need a coil with (1) or (2) rows to do the job. Face velocities across the coil can be anywhere from 600 to 1,200 FPM (feet/minute), while water velocities are usually 2-4 FPS (feet/second). As a result, you will always end up with a (1) or (2) row coil with somewhere between 8-14 fins/inch.

Booster Coils

Hot water booster coils are just another variation of the standard HVAC hot water coil.  They are always (1) or (2) rows as well, but the casing is designed for duct work installation. This basically means there is usually a 1” or 1.5” casing on all four sides of the coil. You select the proper size of the coil to make sure the air velocity across the coil is correct and simply transition the duct work to make the casing size around the coil.  Generally speaking, the size of the coil face is larger than the duct size, so you must transition the duct to make it larger. Just remember, a booster coil is nothing more than a standard hot water coil that is used for duct work installation.

There can also be a casing variation called “slip & drive”, where the coil is installed in the duct work. The coil does not have the standard casing on all four sides like a flanged coil. Capital Coil’s selection program allows you to pick either option.

Steam Coils

The real secret to any steam coil installation is to know that steam coils are much more of a product of the entire system than any other coil; meaning that other coil types are much more independent of the system.  Steam coils require numerous considerations, such as traps, pitched casing, piping flexibility, and vacuum breakers.  Steam coils are also built according to steam pressure through the tubes and headers.  2 – 50 psig is considered “low pressure” steam for coils, while 50-100 psig is considered “medium pressure”. Anything over 100 psig is considered “high pressure” steam.  An important fact to remember is that each of these categories requires a separate kind of construction with different brazing and different materials.  Additionally, almost all steam coils are (1) or (2) rows deep. Steam coils are known either as “standard” steam or “steam distributing”, but the differences are very easy to understand.  Outside air temperatures below 40˚F require that you have a “non-freeze” steam distributing coil.

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5 Work Day Quick-Ships on HVAC Coils – Why Capital Coil does it right

Day 1 – 38% of all orders sent to Capital Coil are on some kind of quick-ship, whether it be on a (5 day, 10 day, or 15 day). We enter the order immediately so that all departments in the plant have the project in their systems and are ready to move on it right away. The coil isQuick-Ships engineered, routing sheets are sent to the shop floor, and everybody now knows what needs to be built. 

Day 2 – Sheet metal casings are cut and sized, headers and connections are fabricated, while tube sheets are fabricated.

Day 3 – All tubing and fins are cut, stamped and assembly begins. You can see what the coil will look like upon final assembly at this point. Coils can be seen sitting on assembly tables.

Day 4 – Tubes are then expanded into the fins, and keep in mind that this is not a short process. Headers are then brazed to the tubes, and if there are return bends, they are connected. The coil is completely assembled and moved to the testing tank. The coil is tested under water for 20 minutes at 550 PSI. About 3% of coils have small leaks someplace in the brazing and are sent back to braze again.

Day 5 – The coil is crated and sent to shipping for routing to the customer. Then most importantly, your coil will be shipping in the guaranteed (5) days.

As you can see by this description, with quick-ships, there is not a lot of room for error in the timing and shipping with OEM HVAC replacement coils. We’ve been doing this for a while now, and we’ve had an approximately (97%) success rate fulfilling all quick-ship requests. We offer quick shipments 365 days per year, with both (10) day shipments & (15) day shipments also available for lower premiums.

diagram 

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Fan/Coil Units Without the Mysteries

Lots of companies in the HVAC business attempt to keep their products as complicated as possible in order to lend a certain “mystery” to the industry, which has never made sense to us at Capital Coil. We have all been in this information age for quite some time with more information/data available to more people than ever before. We feel that by removing some of the “secrecies” surrounding fan/coil units, our customers will be able to better understand the products as we do.

Most of our potential customers know Capital Coil strictly for our HVAC coils, which makes sense because the word “coil” is in our company’s name. But some people may not be aware that we do in fact offer multiple fan/coil models with various quick-ship options, or that fan/coils comprise a significant portion of Capital Coil’s overall business.

With that said – what are fan/coil units (FCU’s) exactly?fan/coil units

  • Fan/coils are easy to understand when you remove a lot of the complex terminology. Our definition of a FCU unit is one that is direct drive and not belt driven…easy enough to understand, right? There is a fan, a coil, and sometimes a filter. Capital Coil offers numerous model types, but the only thing that really differentiates the various models from each other is the casing on the outside of the unit. And the casing is typically based on how and where you want to install the unit.
  • The fan is directly mounted on the motor, and the maximum CFM that can be used in these units is typically 1,200 FT/min. However, Capital Coil does offer some units that can have a CFM as high as 3,000 FT/min, or (7.5) tons.
  • FCU’s can be divided into two groups based on airflow – Horizontal and Vertical. Think of fan/coils installed in a hotel or classroom. These are typically vertical units because the air goes from the bottom of the unit to the top discharge airflow.  Horizontal units have horizontal airflow with inlet and discharge both horizontal as well.
  • As mentioned, fan/coil casings are determined based on how and where you want to install the unit. But figuring that out involves asking some additional questions, such as is the unit hidden above the ceiling or is it exposed? Is the unit horizontal or vertical? Does the unit need a filter?
  • Like most any product, there are several “packages” that you can select, such as certain valves, that will make the unit more expensive and complex. But once you strip away the complex terminology and are able to understand the basic design and concept of FCU’s, they are pretty easy to work with.

Now you know that Capital Coil is very much in the fan/coil business, and when you are looking for something fast, Capital Coil should be your first call or email!

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