1004.2 Open-Type Expansion Tanks — 2025 California Mechanical Code

California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-09-25 · California

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Italicized text is a California amendment to the model code, as printed in the official publication.

Cite as: 2025 California Mechanical Code (Title 24, Part 4) § 1004.2 · Effective January 1, 2026 · Official source: Building Standards Commission

Open type expansion tanks shall be located not less than 3 feet (914 mm) above the highest point of the system. Such tanks shall be sized based on the capacity of the system. An overflow with a diameter of not less than one-half the size of the supply or not less than 1 inch (25 mm) in diameter shall be installed at the top of the tank. The overflow shall discharge through an air gap into the drainage system.

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▸Contents — California Mechanical Code (Title 24, Part 4)

California Mechanical Code (Title 24, Part 4)

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