What is the function of a dielectric union in plumbing systems?

The function of a dielectric union in plumbing systems is fundamentally to prevent galvanic corrosion by connecting dissimilar metals. When two different metals are joined together in plumbing systems—like copper and galvanized steel—there’s a risk of galvanic corrosion occurring due to the electrochemical reactions that can happen when water is present. This type of corrosion can lead to the deterioration of one of the metals, which can cause leaks or failures in the system over time.

A dielectric union incorporates a non-conductive material, usually plastic or rubber, which separates the metals from direct contact. This barrier prevents the flow of electrical current that would otherwise result in galvanic action, thus prolonging the life of the piping system and maintaining its integrity.

The other options refer to functions that do not align with what a dielectric union is specifically designed to do. Connecting different types of water heaters, increasing water pressure, or acting as a vent for sewer gases are tasks handled by other components in plumbing systems, each serving a distinct purpose not related to the focus of a dielectric union.