Coating the coils of an HVAC unit is a known to extend the unit’s life. However, the performance of an HVAC unit is about more than just the coil. HVAC units are constructed from a variety of metals. These dissimilar metals react to environmental conditions in a variety of ways. Depending on the metal used and its application, it is not unusual to see an HVAC unit fail, not because the coil failed, but because the rest of the unit was not coated.
At Heresite, we often see extensive corrosion on copper pipes, particularly surrounding the copper joints (unions, elbows, etc.). Copper pipe protective coating is important to ensure that the entire unit is protected from harsh environmental conditions, such as in wastewater treatment plants, food plants, commercial buildings near coastlines and other harsh environments where corrosion can begin in just a few months. The photo below is a perfect example. The coils have been protected with a coating and are in good condition, but the copper pipes in front of the coil are corroded because a protective coating was not applied to the copper pipe.
Corrosion can also be the result of the assembly process. In the case of a coated coil, if care is not take to protect the coating during assembly, the coating can be heated above the upper temparature limit, which essentially damages the coating in that localized area. After assembly, the final connection points should be coated as well.
The easiest way to protect copper pipes is to simply coat the entire unit. Dissimilar metal connections are a weak point for corrosion protection and contribute to the inability of a unit to maximize its lifespan. While it might seem like overkill to coat an entire HVAC unit, coating the entire unit is much less expensive than replacing it when it fails prematurely. At Heresite, we are able to coat units ranging in size from a toaster up to units that fill a flatbed semi-truck. Your HVAC units are an investment. If coating the entire unit is not practical, ensure the unit resists environmental damage by applying a copper pipe protective coating. It will help the entire unit perform at its maximum ability much longer.