Chapter 9 — INSTALLATION OF SPECIFIC APPLIANCES
903.2 Gas-Fired Air Conditioners and Heat Pumps — 2025 California Mechanical Code
California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-10-19 · 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) § 903.2 · Effective January 1, 2026 · Official source: Building Standards Commission
Gas-fired air conditioners shall comply with Section 903.2.1 through Section 903.2.7.
903.2.1 Application. Gas-fired air conditioners and heat pumps shall be listed in accordance with ANSI Z21.40.1/CGA 2.91 or ANSI Z21.40.2/CGA 2.92.
[NFPA 54:10.2.1]
903.2.2 Independent Gas Piping. Gas piping serving heating appliances shall be permitted to also serve cooling appliances where heating and cooling appliances cannot be operated simultaneously. [NFPA 54:10.2.2] 903.2.3 Connection of Gas Engine-Powered Air Conditioners. Gas engines shall not be rigidly connected to the gas supply piping. [NFPA 54:10.2.3]
903.2.4 Clearances for Indoor Installation. The installation of air-conditioning appliances shall comply with the following requirements:
(1) Air-conditioning appliances shall be installed with clearances in accordance with the terms of their listing and the manufacturer’s instructions. {NFPA 54:10.2.4(1)}
(2) Air-conditioning appliances shall be permitted to be installed with reduced clearances to combustible material, provided that the combustible material or appliance is protected as described in Table 303.10.1 and such reduction is allowed by the manufacturer’s installation instructions. [NFPA 54:10.2.4(2)]
(3) Where the furnace plenum is adjacent to plaster on metal lath or noncombustible material attached to
combustible material, the clearance shall be measured to the surface of the plaster or other noncombustible finish where the clearance specified is 2 inches (51 mm) or less. [NFPA 54:10.2.4(3)]
(4) Air-conditioning appliances shall have the clearance from supply ducts within 3 feet (914 mm) of the furnace plenum be not less than that specified from the furnace plenum. No clearance is necessary beyond this distance. [NFPA 54:10.2.4(4)]
903.2.5 Assembly and Installation. Unless the airconditioning appliance is listed for installation on a combustible surface, or unless the surface is protected in an approved manner, it shall be installed on a surface of noncombustible construction with noncombustible mate rial and surface finish and with no combustible material against the underside thereof. [NFPA 54:10.2.5]
903.2.6 Refrigeration Coils. The installation of refrigeration coils shall be in accordance with Section 904.8 and Section 904.9. [NFPA 54:10.2.7]
903.2.7 Switches in Electrical Supply Line. Means for interrupting the electrical supply to the air-conditioning appliance and to its associated cooling tower shall be in accordance with NFPA 70. [NFPA 54:10.2.8]
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