Different Types of Steam Coils?

There are two types of steam coils:  standard steam coils, which are used in most reheat applications, and steam distributing coils, which are used in applications where the entering air temperature is below 40 F degrees.  Many times, this type of coil is also known as a “non-freeze” coil, but that name is misleading because in reality, there is no such thing as “non-freeze”. 

Standard Steam

Standard steam coils operate a lot like hot water coils, but the construction is very different even if the coils appear to be constructed the same.  The supply and return connections are often on the same end like a hot water coil.  But, steam is very different than hot water, and the coil must be built for and circuited for steam.  Keep in mind that steam is always more erosive than hot water.  The brazing and tube wall thickness must account for steam. ALWAYS remember that even low pressure steam is more erosive than hot water, and a steam coil needs to be built accordingly.

Steam Distributing (Non-Freeze)

Steam distributing coils are a completely different type of coil because they are constructed as a tube within a tube. Every place that you see an outside tube or header, there is an inside tube and header that you can’t see. The steam on the inner tube keeps the condensate in the outer tube from freezing.  The purpose of the Steam Coiloriginal coil design was to distribute the steam evenly along the length of the coil and to eliminate any dead spots on the coil.  A byproduct of this coil was also found.  The coils didn’t freeze nearly as easily as the standard steam coil, so the coils became known as “non-freeze”, which as mentioned, is not completely accurate.  Any coil can freeze under the right conditions, but, this design is what needs to be used when the entering air is under 40F degrees!!! 

Steam Coil Design

Steam coil designs can be very tricky.  Steam coils are totally a function of the system and installation, while other coils operate more independently of the system.  There needs to be correctly designed traps, and they need to be installed in the correct place and depth in the system.  Often, vacuum breakers are also needed in the system.  The piping must also be installed correctly to make sure the steam is entering the coil and not the condensate.  Even with all of those factors, you’ll need a correctly designed steam coil that matches the steam pressure, length of the coil, and the entering air temperature.  Coils can freeze easily.  Coils can be too long in length and the steam cannot travel the length of the coil and distribute evenly.  Condensate can easily be trapped somewhere in the coil, and the result is water hammer. 

Capital Coil & Air has years of experience designing steam coils, and is here to answer any questions and help to design the right coil for your project! 

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IN NEED OF A COIL YESTERDAY??

Why are quick-ships so important??

With winter approaching and various “polar-vortexes” on the immediate horizon, 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!!! Steam Coil

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!

 

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Quick, Reliable & Uncommonly Fast

 Quick, Reliable & Uncommonly Fast

You have many choices when buying replacement coils and choosing a coil supplier. You could decide to diversify and work with numerous suppliers, based on a particular need. However, Capital Coil & Air can make your buying decisions a lot easier. We have been in the coil business for many years, and in this industry, we recognize what is important vs. what is irrelevant. That translates into us having good insight on what you need and how best to support you as a customer.

Quick

Coils today typically do not have much “preventative” maintenance done on them. Most everybody just waits until a coil fails and then worries about the problem at that time. And when coils inevitably fail, they fail during the times when you need them most; i.e. cooling coils failing in the summer and hot water coils breaking down in the winter. As a result, there is usually an urgency attached to most HVAC projects. Generally speaking, most jobs require some form of “quick-ship”. Capital Coil & Air gives you (4) different shipping options for all replacement coils. Our standard ship time is 3 – 4 weeks, but if you need your order faster, Capital Coil will accommodate that need. We do not want to have a “one and done” transaction. Capital Coil’s goal as a business is to have a customer base that we work with for 20 years, not 20 minutes. While we will do our best to give you the fairest price possible, you have to recognize that there is an additional premium associated with quick-shipments on replacement coils. However, you will never pay that premium if Capital Coil is late on manufacturing your order. We’ve built our business on quick-ships, and we hit 99% of all deadlines on orders the last two years. In other words, we rarely miss! We give you options, and you only pay for what you really need.

Reliability

Reliability encompasses so many things in the coil industry. For example, if you need a price today, and the sales rep takes (2) days to get back to you, that’s unacceptable and unreliable. If you require a drawing to help you design a job, and you are waiting for a week to have it returned? Again, not what Capital Coil considers reliable. If a coil supplier promises you a ship date and ships (2) weeks late? Once again, not reliable. Do any of the above issues sound familiar? It is easy to make extravagant promises, and companies do it all of the time. However, Capital Coil’s success rate on meeting and exceeding shipping schedules says more than any promise we can make. We believe in under-promising and over-delivering, not the reverse!

  • Capital Coil responds quickly to all inquiries for pricing, general information, and engineering assistance
  • Capital Coil manufactures high quality equipment in the U.S.A. and is AHRI Certified
  • Capital Coil’s years of experience will help you quickly pick the correct product for the correct application
  • Capital Coil provides accurate shipping dates, real-time tracking and common carrier information after your order has left our factory

We do all of the above to make everything in your life easier. Capital Coil holds itself to the highest standards for both reliability and customer service. In short, we want your experience with us to be professional and simple. Please call or email our sales department for any job – no matter how large or small. We greatly look forward to the opportunity to work with you on your next project.

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Frozen Steam Coils: How Do You Prevent This?

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

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

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

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

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

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

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

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