Galvanic Corrosion Explained for HVAC Professionals

As HVAC professionals, understanding the various types of corrosion that can affect system components is crucial for ensuring longevity and reliability. One of the most significant yet often overlooked types is galvanic corrosion.

What is Galvanic Corrosion?

In simple terms, galvanic corrosion occurs when two different metals are in electrical contact with each other while exposed to an electrolyte, such as moisture or condensation. This process can cause one metal to corrode at an accelerated rate compared to its normal corrosion rate, leading to premature failure of HVAC components.

How Does It Happen?

Galvanic corrosion is influenced by the electrochemical series, which ranks metals based on their electrochemical potential. When two dissimilar metals are connected, the less noble (more reactive) metal acts as an anode and corrodes faster, while the more noble (less reactive) metal acts as a cathode and is protected. For instance, if copper and aluminum are connected, the aluminum will corrode more rapidly due to its position in the electrochemical series.

Common HVAC Applications

This type of corrosion is particularly relevant in HVAC systems where different metals are often used in close proximity, such as:

• Pipe connections
• Fittings and brackets
• Metal ducts with varied coatings or materials

Each of these applications presents potential galvanic corrosion issues if not properly managed.

Preventing Galvanic Corrosion

To mitigate the risk of galvanic corrosion, HVAC professionals should consider the following strategies:

1. Material Selection: Whenever possible, use metals that are similar in the electrochemical series for components that will be in contact.
2. Insulation: Incorporate non-conductive insulating materials between dissimilar metals to interrupt the electrical contact.
3. Protective Coatings: Utilize protective coatings or galvanization to prevent direct contact and moisture exposure to the metals.
4. Regular Inspections: Conduct routine inspections to detect signs of corrosion early before it leads to significant damage.

Conclusion

Galvanic corrosion is a silent enemy in HVAC systems that can significantly impair performance and lead to costly repairs. By understanding the principles of galvanic corrosion and implementing preventive measures, HVAC professionals can enhance the lifespan and effectiveness of their systems. Stay informed and proactive to ensure optimal function and reliability in your installations.