Hot Water Coils

Steam Distributing Coil

There are many terms used in the HVAC Industry. One that is often misunderstood is heat transfer. Wikipedia’s definition states that heat transfer is a thermal engineering discipline that concerns the generation, use, conversion, and exchange of thermal energy between physical systems. It affects the measurement of heat.   The various heat transfer types are thermal conduction, thermal convection, thermal radiation, and the transfer of energy...

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Steam Distributing

The “holiday season” may be over, but the “coil replacement season” is in full swing in many areas of the country. Particular attention must be paid to the condition of your heating and cooling coils. Heating coils that aren’t providing the needed BTUH capacity can become a huge problem in the dead of winter, while cooling coils and condenser coils must be ordered and replaced...

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Hot Water Coil

The HVAC industry has many manufacturers of units that all have heating and/or cooling coils as an integral part of their package. There are also many free-standing coils in large built up systems and some are mounted in duct runs from a central station unit. What they all have in common is the presumption that all the coils will meet the designated performance. They do...

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Condenser

  Almost all packaged A/C or split system units do not have a service factor for extra capacity. Even when new, these units may not yield the cooling BTUH capacity specified due to improper installation and/or incorrect load calculations at the inception of installation and startup. Consequently, as the system gets older and parts become less efficient, the system may lower its capacity to the point...

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Sentry Guard

Operating water coils that are prone to air temperatures below freezing normally need the use of anti-freeze. The most common is glycol. This has been used for over 40 years, and there are two common types, ethylene and propylene. Anti-freeze provides a safeguard if there are mechanical or electrical breakdowns that may cause fluid to sit in a coil with below freezing air going across...

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Dirty Coil

Finned tube coils are meant to have contact with the air flow, as more contact creates more heat transfer. Heat transfer is nothing more than heat exchanged from one medium to another, and the goal is to create maximum heat transfer efficiency. The downside to this process is the coil’s susceptibility to foreign materials becoming lodged in them. The following explores this problem in a...

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Outside Air Loads

HVAC and process heating/cooling must deal with the added tonnage created by using fresh air from outside. Most times, the requirement for fresh air is mandatory and can go from 10% all the way to 100 % of the system air flow. There are numerous rules and regulations written to eliminate air flow quality problems, including bacteria and other micro-organisms, that can cause health problems....

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Corrosion in Tube

There are many reasons why hot water coils in your system can under-perform. Some reasons are from the time of the design, and many other instances can also occur after the coils have been installed. Here are 10 common reasons why hot water heating coils can fail:   Air stratification issues - The air flow across the surface of the coil is not being evenly...

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Hot Water Coil

Water Cooling and Heating Coils   Water is the most widely used heat transfer medium because it’s readily available and low in cost. Water can be used as a heat transfer medium if the temperature range is between 15 degrees Fahrenheit (when mixed with glycol) when cooling and a high of 210 degrees Fahrenheit when heating.   Chilled Water Coils   When maintaining an acceptable living or working condition in...

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Replacement Coils

Coil replacement has been a part of the HVAC aftermarket for as long as finned tube coils have been used to create heat transfer. The coils installed in the 50’s and 60’s were heavier duty than today’s coils and were almost always spiral fin type with a tension wound fin onto copper tubes.  The plate fin didn’t become prevalent until the mid-60’s. By the end...

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