Tenuta Tech

Corrosion problems that occur within several inches of the tube to header joints or in the return bends are usually velocity-related. These areas are subject to increased turbulence and failures normally show up as pinhole leaks on the outer tube surfaces. The figure above shows how the inner tube s…

FROZEN STEAM COILS: HOW DO YOU PREVENT THIS? Even if you have steam coils or steam distributing (non-freeze) coil, you can still freeze the coil. When freezing occurs, everyone immediately looks to the steam coil as the cause. When in fact, there are numerous reasons that must be looked at well befo…

This tech brief is on coil failure analysis. This is an important topic for those responsible for replacing coils that have failed prematurely. Obviously, when coils need to be replaced, the designer or buyer has an opportunity to modify or upgrade new coils so that they will last longer and provide…

The operating temperature, either by the fluid flowing thru the tubes or the gas flowing over the fins, is a critical consideration in coil design. Failure to adequately address the impact of temperature may cause premature coil failure or personnel injury Therefore, it is very important that both t…

In this tech brief we will limit discussion to those factors that primarily influence the selection of a coil type. Performance related considerations such as surface requirements, fluid velocities, temperatures, pressure drop, etc., will be addressed in future Tenuta Tech briefs. Material selection…

In this tech brief we will try to identify the attributes of the various fin designs and point out limitations that should be considered. The selection of fin design is one of the most important criteria in coil construction. A poor choice could result in a loss of thermal performance or unmanageabl…

Installations of large multi- sectional central station air handling units rarely take into consideration that the units someday may need to be replaced. For every unit that sits next to a very accessible space within a building there may be ten more that have virtually no access and half the mechan…

What makes an “industrial coil” different than a “standard HVAC coil”? The answer is pretty straight forward. Standard HVAC coils are copper tube/ aluminum fin and with galvanized steel casing construction. But, HVAC coils are built to handle standard water/steam and air conditions. When you change t…

The selection of coils initially by designers of a project can cause real problems down the road when these coils actually try to function in a HVAC system. Many times, the true aspects of the HVAC system are not known until well after the coils have been installed for a few years. Modern Day CoilCo…

There are many types and coils in the field. To replace one, the type and arrangement are very important. If you see a coil with return bends at the back end and two side by side headers on the connection end, this is known as a standard steam coil. Standard steam is used for aboveContinue reading

The term “Fan Coil Unit “has a very general meaning in our industry and many do not truly understand the operational aspects of these units. They have a very limited range for air flow and conditioning and deviations from this range can cause problems in the system and facility. Selection A fan coil…

As a precautionary measure, owners/contractors test their heating systems periodically to find out if everything still works. Because of the erosive nature of steam, it’s not uncommon to have to regularly replace steam coils. This newsletter will be devoted to things that will help you understand ho…

What is it? Why is it necessary? Are there limits? Coil circuiting clearly explained. At every sales meeting or training session, there always seems to be a lot of confusion over the circuiting of coils. Circuiting is not really as mysterious as everyone makes it out to be. This Tenuta Tech will tr…

This Tenuta Tech will be very “old fashioned”and very technical. This one is for all you closet engineers out there who actually want to know how coils are selected, and the factors that go into picking a coil. If you really are interested in how all this information is developed and the inter-relat…

There are ways to eliminate replacing steam coils, but it requires a little preventative maintenance, a little design engineering, and an understanding of how steam coils work. So, that’s what this Tenuta Tech will be devoted to. We’re going to give you as much good information on steam coils as we …

Hot water coils and chilled water coils are often thought of, and designated by the HVAC industry, as though they were completely different. The truth is that a water coil is equally capable of handling hot water or chilled water, and the construction for either is exactly the same. Let’s first defin…

Coils, like any other mechanical function, are not fail-proof. This issue of Tenuta Tech will identify some of the most important reasons why coils will fail, as well as give some advice on how to prevent it. Coils invariably fail for one of three different reasons: Coils die of “old age”. This is, …

There are two major fin designs that are commonly used on HVAC coils. The most common is the “plate fin” design which most of the big coil companies use to build their coils. The other type of fin design that you sometimes see in the replacement market is the “spiral fin” which was used by … Continu…

When you sit down to design any type of coil, replacement or new, it’s important to remember what costs money and what doesn’t. There are many design changes that you can make to a coil that are free and there are others that increase the cost of the coil dramatically. Let’s go over all the … Contin…

There is no such thing as a “Non-freeze” steam coil. Under the right circumstances any steam coil can freeze, including those labeled “Non-freeze”! The proper nomenclature to use when describing a steam coil is “Steam Distributing”. The whole idea behind this type of coil is to insert an inner tube …

We all use computer programs to select coils today, and it is certainly quicker and more accurate to use these programs than to do it long-hand. The problem is, however, that many of us do not know how we arrived at these selections. Yes, there really are formulas and methods and limitations built i…

Condenser coils hardly ever freeze, so usually they fail because they have “died of old age” or they have suffered severe corrosion. Condenser coils often appear very easy to replace. They don’t look terribly complicated to build and they are out in the open where you generally can see most of the c…

HVAC and mechanical contractors buy coils for many different types of applications and jobs. Depending on the duty, coils can be complicated and rather expensive or simple and straight forward. At one time or another, just about every contractor buys hot water duct coils. It’s pretty hard to be in t…

This week’s Tenuta Tech will focus on the ten things your coil vendor never told you when purchasing new or replacement coils. It’s important to keep these in mind whenever you are buying new or replacement coils to make sure that you are informed and educated going any coil discussion. We can help …

This week’s Tenuta Tech will provide you with ten interesting things that may help you become more knowledgeable about coils. If you built a coil with only tubes and eliminated the fins entirely, you would only get about 30% of the performance compared to the same coil with fins. It’s hard to believ…

Fins are responsible for up to 70% of the heat transfer process on any coil, so as you can imagine, manufacturing fins is critical. Most companies have several fin dies that cut the fins to the proper height, and depth, based on the fin height and row depth. This Tenuta Tech will explore the things …

In this Tenuta Tech we will be discussing UV-C light solutions and how they can be a great solution for school systems. UV-C light keeps coils free of mold, while APCO technology neutralizes odors & toxic VOCs. For more information on how UV light might help you please contact Tenuta & Co! Introduct…

This week’s Tenuta Tech will be dedicated to discussing UV disinfection and its advantages for any application. Reduce Energy Consumption According to the 2012 ASHRAE Handbook, through the use of UV-C, heat transfer and airflow are restored which results in energy savings, with the possibility of pa…

For over a century scientists have known that certain frequencies of light have a devastating effect on microbial life. We now know that exposure to ultraviolet light in the range of 254 NM (UV-C band) disrupts the DNA of micro-organisms thus preventing them from reproducing, thereby effectively kil…