How HVAC Coil Corrosion Happens And What To Do

HVAC coil corrosion can lead to the destruction of your HVAC system. Before that happens, it can destroy the coils, or cause reduced efficiency over time.

Read along with H&S as we find out how HVAC coil corrosion happens and what you can do about it.

How HVAC Coil Corrosion Happens

Inside the air handler, airflow passing through the evaporator coil carries trace amounts of chemicals. If your HVAC system is outside your home, there will be different mix of chemicals naturally and not-naturally occurring in the air compared to inside your home.

Generally speaking, the chemicals which can cause HVAC coil corrosion include fluoride, chloride, acetic acid, and formic acid.

Fluoride typically is found in municipal water supplies, while chloride can come from salt used for melting ice, detergents and other cleaners, carpet, and fabrics. Acetic and formic acids can come from adhesives, paints, plywood, and cleaners.

When these chemicals are in a high enough concentration in the air inside or outside, they can cause coil corrosion over time. Fluoride and chloride ions form pits and pinholes in the metal coil, while the acids create tunnels and pinholes in the HVAC coils, both of which can lead to refrigerant leaks.

How To Prevent HVAC Coil Corrosion

These days, most coil manufacturers apply a coating to the coil prior to production. Along with this early protection, it’s important to schedule annual service with an HVAC contractor like H&S. We can observe the coils annually, looking for the black or blue deposits of the acids or the pits of the fluoride and chloride to identify problems before they get too big.

Additionally, we can clean the coils with an alkaline or PH-balanced cleaner to counteract acids.