905.6 Circulating Air — 2025 California Mechanical Code

California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-10-19 · 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) § 905.6 · Effective January 1, 2026 · Official source: Building Standards Commission

Where a duct furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall also be handled by a duct(s) sealed to the furnace casing and terminating outside the space containing the furnace. The duct furnace shall be installed on the positive-pressure side of the circulating air blower. [NFPA 54:10.9.6]

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

California Mechanical Code (Title 24, Part 4)

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