1715.4 DX System Testing — 2025 California Mechanical Code

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

CBSC: official editions, supplements and errata

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) § 1715.4 · Effective January 1, 2026 · Official source: Building Standards Commission

For direct exchange (DX) systems, each refrigerant u-bend shall be tested and proved tight with an inert gas at not less than 315 psi (2172 kPa) and maintained for 15 minutes without pressure drop. The pressure reading after tremie grouting of the boreholes shall be maintained in the ground-heat exchanger for not less than 2 hours, in accordance with ANSI/ CSA/IGSHPA C448.

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

California Mechanical Code (Title 24, Part 4)

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