You and Your AC against the Sea: Fighting Seawater-Borne Rust and Corrosion

Living near the ocean may have its perks, but it also comes with a few downsides. One such downside is rust and corrosion caused by salt-laden air and sea water. In this environment, your AC system won't stand a chance unless it's adequately protected against exposure to salt and other corrosive chemicals. Here is how rust and corrosion can affect your AC system and ways you can effectively deal with it.

The Ravages of Rust in a Salty Environment

If you live in coastal region, then you may have noticed a good amount of rust on cars, equipment, and practically anything else metal (aside from galvanized or stainless steel). That's because the air itself often contains corrosive salts that, when mixed with a little moisture and plenty of oxygen, do quite a number on exposed metals.

These salts often come from seawater that's been aerosolized after breaking on shore or in open water. The fine mist of seawater evaporates quickly, leaving a very small amount of salt that can be carried by the wind. Eventually these salt deposits have to settle somewhere, and oftentimes that "somewhere" happens to be on a metal surface. Add high humidity levels and you'll start to see rust form on unprotected portions of these surfaces.

While it's not out of the ordinary to see a small amount of rust on an AC unit, the salt-laden environment of a coastal area can easily exacerbate overall rust and corrosion. Once salt makes its way into an AC system, it can cause various components, such as the condenser fan, compressor, and refrigerant lines, to rust. Aluminum condenser coils and fins can also disintegrate as they corrode, resulting in potential refrigerant leaks and poor cooling performance.

Removing Rust and Corrosion

The best and most efficient way of removing existing rust and corrosion is to replace the rusted component with new, rust-free components. This is often the best route to go for dealing with compressors and metal fittings that can seize or otherwise malfunction due to excess rust. Other components, such as the protective cabinet covers, can be sanded down and repainted to eliminate rust.

Condenser coils and their aluminum fins should be carefully inspected for signs of corrosion or damage due to rust. A trained air conditioning service employee should conduct a leak test to check for any refrigerant losses. If the coils are corroded or otherwise damaged, they should be replaced as soon as possible.

When dealing with extreme cases of rust and corrosion, the entire outdoor condenser unit may have to be replaced. Keep in mind that the working life of a typical AC unit under coastal conditions could be as short as 3 to 5 years without proper care.

Preventive Steps to Consider

If you've recently replaced rusted or corroded AC components or installed a brand-new AC unit, there are several ways you can protect and extend the working life of your investment:

  • Rust inhibitors can help slow down or even prevent rust from forming on critical AC components. Most inhibitors work by creating a barrier between bare metal surfaces and corrosive salt.
  • Installing a sacrificial anode on your AC unit can also help prevent rust and corrosion formation. These highly active metals are designed to attract corrosion, thereby sacrificing themselves to protect other metals.
  • If you live near the coastline, you can also keep your AC unit out of the line of fire by placing a physical barrier between it and the sea spray. Just keep in mind the minimum clearances needed for your AC system to operate effectively.
  • If you're in the market for a new AC unit, you may want to consider purchasing a coastal air conditioning unit. These units often feature stainless steel cabinets with covered copper and aluminum connections and a condenser coil specifically designed for duty in coastal environments.

Although taking a proactive role in rust prevention is beneficial in its own right, it may be necessary if you want to keep your factory warranty valid. In some cases, AC manufacturers may not honor their factory warranties unless homeowners have taken steps to safeguard their systems against seawater-borne rust and corrosion.


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