When To Use A DIY Coating?

Applying aftermarket protective coil coatings is critical to sustaining the full lifecycle of newly-installed HVAC equipment destined for corrosive environments, but many engineers and contractors don’t specify this important step.

Coastal areas are the most likely target markets for coil coatings. Salt spray from oceans can prematurely corrode outdoor HVAC coils in as little time as a year if not coated before use. Salt spray can travel as far inland as 10 miles, which creates a huge area of vulnerable equipment on North America’s seaboard.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans.

Protecting HVAC equipment with coil coatings isn’t a new concept. For many years, HVAC manufacturers have shipped newly-made coils directly to coating specialists as per the specification of engineers and contractors. Sensitive parts, such as electrical components, are masked-off, then coils are sprayed or electro-coated before the unit is shipped and installed in their corrosive environment destination.

What is new today are coatings that have been packaged in game-changing, convenient easy-to-use aerosol cans. Contractors can now coat coils in their shop or onsite before installation. This skips the past time and effort required to send a coil or the entire unit out for factory-applied coatings. Furthermore, contractors can create an entire do-it-yourself (DIY) coating niche that requires minimal experience or training.

3D Wood Color Coated Coils

Choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When selecting a coil coating it is important to make sure that the product has passed ASTM B117 test standards for salt spray. It also should have multiple marine and industrial ASTM test standard listings for resisting ultraviolet (UV) rays, acid rain, high concentrations of urban vehicle emission air pollutants and other outdoor contaminants. It’s also important to choose a brand that with a long history and reputation for providing OEM-approved, factory applied coil coatings.

When To Use A DIY Coating?

Deciding when to use a coating specialist versus a contractor with field-applied DIY aerosol applications, usually depends on the project scope. For example, it’s more economical to request the manufacturer ship 200 new split system condensers to a factory-coating specialist if the units are destined for a beachfront condo complex.

However, a contractor using DIY aerosol protective coatings for a beachfront home’s condenser(s) can be very economical and reduce the installation time versus shipping the product(s) to and from a coating specialist. As for unit size, typically any HVAC coil in a system 10-tons or smaller is perfect DIY coating application.

Aluminium Coils for Can-end & Tab Application

While coastal areas play a large part in coil corrosion, other potential areas where premature coil corrosion can occur are:

Urban areas, and particularly airports, which have heavy concentrations of airborne vehicle emissions;

Buildings near or located inside properties of waste water treatment plants;

Any heavy industrial area that emits airborne chemicals;

Restaurants where cooking grease particulates are exhausted in close proximity to the HVAC rooftop system.

Heat Transfer and Static Pressure Considerations

Many engineers and contractors have questions about how the coatings will effect a coil’s heat transfer performance. While some coating formulas might be borrowed from other industries, only coatings designed specifically for HVAC coils should be used, because they’re formulated for negligible heat transfer loss. These specialty coil coatings are typically only 1.4-ml thick or less, versus other thicker industrial coatings that can negatively affect heat transfer.

Static pressure is also a consideration, but coatings designed specifically for HVAC coils don’t increase the pressure drop through the coil. Instead, they may even lower the pressure drop versus an uncoated coil, because less static pressure-increasing contaminants will reside or adhere to the coil surfaces.

Of course, there’s more to consider about corrosion than its effect on static pressure. Corrosion, especially from salt, can create formicary and pitting processes that ultimately lead to leaks.