Tag Archive for "Commercial Coils"

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.
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!

Quick-Ship Fan/Coils & Light Duty Air Handlers

Quick, Reliable & Uncommonly Fast

Top 10 Tips to Measuring Coils

Steam Distributing Coils (Non-Freeze)

Frozen Steam Coils: How Do You Prevent This?

Commercial Steam Coils: Lengths & Controls

Steam Distributing Coils

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.

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!

Heating Season Will Soon Be Upon Us

Commercial Steam Coils; Lengths & Controls

Types of Steam Coils

Cooling Coils & Moisture Carryover

Moisture carryover is present on cooling 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.

Capital Coil does not typically build chilled water or DX (Evaporator) Coils over 50” in height. For example, with applications that call for a 96” high coil, we will build (2) 48” high coils and stack them with an intermediate drain pain. We do this for a couple reasons: first, the shipping & handling is far easier and there’s less chance for damage before the coil even gets to the job-site. Second, the drain pan in the bottom of the unit for a 96” high coil would be enormous, and it would be practically “raining” off the top of a coil 96” high.

Air velocity for cooling coils should never be higher than 550 feet/min!!! Anything higher and you are asking for complications. You’d be surprised how many manufacturers do not know that and/or won’t tell you that to keep you out of trouble.

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.
-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 of 550 ft/minute, which 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!

10 Things You Need to Know About Chilled Water Coils

Top 10 Chilled Water Coil Facts

Chilled Water Coil Circuiting Made Easy

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 elevator, 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

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.

Top 5 Reasons HVAC Coils Prematurely Fail

Coils and Counter-flow: 5 Common Questions

Chilled Water Coil Circuiting Made Easy

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.

4. 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!

Top 10 Chilled Water Coil Facts

Light-Duty Commercial Belt Drive Air Handlers

Top 10 Questions You SHOULD Be Asking Your Coil Supplier

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?

You’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 approximately 5% of the output. So if your coils are piped incorrectly, don’t expect to get the full performance, but they will still be more effective than whatever you’re replacing. Steam and hot water coils are 1 or 2 rows deep, so again, counter-flow is pretty much irrelevant. However, it can make a 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!

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!

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.

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!

Top 5 Reasons HVAC Coils Prematurely Fail

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

Repair or Replacement HVAC Coils?

Coils and Counter-flow: 5 Common Questions

1) Coils and counter-flow?

The first thing to remember about coils and counter-flow is that chilled water coils are always built to be piped in counter-flow. This means that the air flows in the opposite direction as the water. For example, with counter-flow, the air flows through rows 1-8, while the water runs through rows 8-1. Water always travels through the coil in the opposite direction of the air; hence the term “counter-flow.” Direct Expansion Coils (Evaporator Coils) are also piped in the same manner.

With that said, what happens when you do not pipe cooling coils counter-flow? Almost all coil selection programs you will see or use will be based on counter-flow conditions. If you opt to not counter-flow a chilled water coil, you’ll have to reduce the coil’s overall performance by a certain percentage. That percentage reduction varies based on each coil’s unique dimensions, but a reliable estimate is a loss of 8-12%. Simply piping the coils in the correct manner from the beginning would seem to be the easiest and most cost-effective solution.

2) Why do you feed from the bottom of the coil?

You always want to feed a water coil from the bottom connection so that the header fills from the bottom on up and feeds every tube connection evenly. All tubes must be fed evenly with the same amount of water. If you try to feed the header from the top, you greatly increase the risk of “short circuiting” the coil and having a higher water flow through the top tubes in the coil.

3) What is a Water Hammer in a Steam Coil?

On a long Steam Coil, you will be hard pressed to get the steam through the length of the coil. Slowly but surely, that steam converts into condensate, which is pretty much the worst thing that can happen to any system. If not evacuated, the condensate just lays in the coil when the system is shut off. This problem comes into play when the steam is turned back on and meets the condensate laying inside the coil. In addition to the noise, the steam and condensate cause huge amounts of additional stress on the coil’s joints. As a result, over time, your coil will inevitably fail.

4) What else happens if you do not evacuate condensate?

When you cannot or do not evacuate the condensate on long steam coils, the condensate ends up blocking the steam. A steam coil should never feel cool to the touch, but when condensate blocks steam, one part of the coil will be warm while the other will be cool. Again, that should not happen. Steam coils are interesting in that they are more dependent upon the system and installation than any other type of coil. A steam coil must be pitched to the return end of the coil. Obviously, steam is not water. Traps, vacuum breakers and other steam accessories must be installed and located properly for the system to function.

5) Is it necessary to pipe steam and/or hot water coils in counter-flow?

Simply put – no! Circuiting a coil is only necessary to ensure the connections are on the side of the coil that you want. The rows and tubes in the coil dictate how and where you feed, but the steam supply always needs to be the high connection. This method ensures that the leaving condensate is on the bottom of the coil and below the lowest tube within the coil. Whatever else you do, know that the condensate must leave the coil!

If you have any questions or need assistance with ordering and/or installation, please contact a sales engineer at Capital Coil & Air. We will walk with you step-by-step through your entire project should you require any assistance. CALL OR E-MAIL US! We look forward to the opportunity to work with you on your future projects.

Tips on Hand Designation & Counter-flow

Chilled Water Coils & Moisture Carryover

Chilled Water Coil Circuiting Made Easy

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.

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.

Stock Hot Water Coils – Quick Buyers Guide

Your Goals as a Buyer of Commercial HVAC Replacement Coils

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

Quick Ship Program

Coil Selection Software

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Casing

Drain Pans & Water Carryover

Circuiting/GPM

Designing Banks Of Coils

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1) Coils and counter-flow?

2) Why do you feed from the bottom of the coil?

3) What is a Water Hammer in a Steam Coil?

4) What else happens if you do not evacuate condensate?

5) Is it necessary to pipe steam and/or hot water coils in counter-flow?

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Hot Water Coils

Booster Coils

Steam Coils

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