Tips and Information

Steam Coils

There are 2 kinds of steam coils:

Standard steam coils are used for entering air temperatures above 40 degrees. They look like a hot water coil and are typically one or two rows. Supply and return connections can be on the same end of the coil or on opposite ends. They are available in 5/8” tubes. If this type of coil is exposed to temperatures below 40 degrees, it will freeze immediately. A steam distributing coil should be used for these applications.

Steam distributing coils are used for entering air temperatures below 40 degrees. Each tube, whether it is 1” or 5/8”, has another tube inside it to distribute the steam. The condensate leaves the coil in the outer tube. Likewise, the steam header has a header within it for the removal of the condensate. The premise behind this design is that the steam inside the inner tubes prevents the condensate in the outer tubes from freezing. For this reason, these coils are sometimes called non-freeze coils, although if not properly maintained, freeze-ups will occur. These coils are also typically one or two rows deep.

All steam coils require controls, such as traps and vacuum breakers which, when maintained properly, will increase the performance and the life of the coil.

Reason for coil failures, repairs/replacements

With time, erosion takes place inside the coil at joints, manifolds, and tubes. This erosion happens to all coils but steam is more erosive than water, so eventually you will need to purchase replacement steam coils. This corrosion decreases the effectiveness of the coils because the fins will become loose. Another factor to consider when thinking about replacement steam coils is, the filters should be changed properly, and the maintenance should be done regularly. Several things can cause coils to fail prematurely that makes it essential to obtain replacement steam coils from time to time.

Steam is different from hot water; hence, replacement steam coils are not the same as hot water coils. Even low-pressure steam needs to be handled in a different way than hot water. The construction of replacement steam coils should be considered as you have a number of different options. Steam systems involve sets of controls and valves that are not present with hot water systems. Depending on efficiency of design and control of these valves decides both the life expectancy and the performance of the steam system. This will determine the replacement time of the steam coils. Steam coil systems are more likely to fail more often than other types of coil systems because they are more complicated and function in a more hostile environment. Maiocco & Associates has specialized in replacement steam coils for over 20 years.

Consider if the system would benefit from an upgrade to heavier wall tubes, thicker fins or different materials designed to extend the life of the coil and to optimize performance of the HVAC or industrial process application. We use many types of materials – copper, cupro-nickel, aluminum, stainless steel, carbon steel, and admiralty brass, to produce a coil that best fits your requirement.

We can help you with the replacement of existing coils, or with the design of a coil for a new application. Call us to help with evaluation and recommendations for your coil needs for the winter months.