How must recirculation pumps and on‑demand systems be controlled and limited?

Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:

• § 501.2.2 High relevance — show source text

  Exception: Vertical supports, and horizontal and vertical anchors shall be installed on the pipe inside the pipe insulation.

  L 501.2.2 Building Cavities. Building cavities used for hot water supply and return piping shall be large enough to accommodate the combined diameter of the pipe plus the insulation, plus any other objects in the cavity that the piping must cross. L 501.3 Recirculation Systems. Recirculation systems shall comply with Section L 501.3.1 and Section L 501.3.2.

  L 501.3.1 For Low-Rise Residential Buildings. Circulating hot water systems shall be arranged so that the circulating pump(s) are capable of being turned off (automatically or manually) where the hot water system is not in operation. [ASHRAE 90.2-2007:7.2] L 501.3.2 For Pumps Between Boilers and Stor- age Tanks. Where used to maintain storage tank water temperature, recirculating pumps shall be equipped with controls limiting operation to a period from the start of the heating cycle to a maximum of 5 minutes after the end of the heating cycle. [ASHRAE 90.1:7.4.4.4] L 501.4 Recirculation Pump Controls. Pump controls shall include on-demand activation or time clocks combined with temperature sensing. Time clock controls for pumps shall not let the pump operate more than 15 minutes every hour. Temperature sensors shall stop circulation where the temperature set point is reached and shall be located on the circulation loop at or near the last fixture. The pump, pump controls, and temperature sensors shall be accessible. Pump operation shall be limited to the building’s hours of operation. L 501.4.1 Hot Water On-Demand Pumping Sys- tems. Hot water on-demand pumping systems manually actuated or automatically activated hot water pumping systems shall comply with IAPMO PS 115. L 501.5 Temperature Maintenance Controls. Systems designed to maintain usage temperatures in hot-water pipes, such as recirculating hot water systems or heat trace, shall be equipped with automatic time switches or other controls that are capable of being set to switch off the usage temperature maintenance system during extended periods where hot water is not required. [ASHRAE 90.1:7.4.4.2] L 501.6 System Balancing. Systems with multiple recirculation zones shall be balanced to distribute hot water uniformly, or they shall be operated with a pump for each zone. The circulation pump controls shall comply with the provisions of Section L 501.4.

  L 501.7 Flow Balancing Valves. Flow balancing valves shall be a factory preset automatic flow control valve, a flow regulating valve, or a balancing valve with memory stop.

  L 501.8 Air Elimination. Provision shall be made for the elimination of air from the return system. L 501.9 Gravity or Thermosyphon Systems. Gravity or thermosyphon systems are prohibited.

  L 502.0 Service Hot Water – Low-Rise Residential Buildings. L 502.1 General. The service water heating system for single-family houses, multi-family structures of three stories or fewer above grade, and modular houses shall comply with Section L 502.2 through Section L 502.7.3. The service water heating system of all other buildings shall comply with Section L 503.0.

• § 501.2 High relevance — show source text

  L 501.2 Insulation. Hot water supply and return piping shall be thermally insulated. The wall thickness of the insulation shall be equal to the nominal diameter of the pipe up to 2 inches (50 mm). The wall thickness shall be not less than 2 inches (51 mm) for nominal pipe diameters exceeding 2 inches (50 mm). The conductivity of the insulation [k-factor (Btu•in/(h•ft [2] - °F))], measured radially, shall not be more than 0.28 [Btu•in/(h•ft [2] - °F)] [0.04 W/(m•K)]. Hot water piping to be insulated shall be installed such that insulation is continuous. Pipe insulation shall be installed to within [1] ⁄ 4 of an inch (6.4 mm) of appliances, appurtenances, fixtures, structural members, or a wall where the pipe passes through to connect to a fixture within 24 inches (610 mm).

  2025 CALIFORNIA PLUMBING CODE 507

  ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

  APPENDIX L

  Exceptions:

  (1) Where the hot water pipe is installed in a wall that is not of a width to accommodate the pipe and insulation, the insulation thickness shall be permitted to have the maximum thickness that the wall is capable of accommodating and not less than [1] ⁄ 2 of an inch (12.7 mm) thick.

  (2) Hot water supply piping exposed under sinks, lavatories, and similar fixtures.

  L 501.2.1 Pipe Supports. Pipe supports shall be installed on the outside of the pipe insulation.

  Exception: Vertical supports, and horizontal and vertical anchors shall be installed on the pipe inside the pipe insulation.

  L 501.2.2 Building Cavities. Building cavities used for hot water supply and return piping shall be large enough to accommodate the combined diameter of the pipe plus the insulation, plus any other objects in the cavity that the piping must cross. L 501.3 Recirculation Systems. Recirculation systems shall comply with Section L 501.3.1 and Section L 501.3.2.

  L 501.3.1 For Low-Rise Residential Buildings. Circulating hot water systems shall be arranged so that the circulating pump(s) are capable of being turned off (automatically or manually) where the hot water system is not in operation. [ASHRAE 90.2-2007:7.2] L 501.3.2 For Pumps Between Boilers and Stor- age Tanks. Where used to maintain storage tank water temperature, recirculating pumps shall be equipped with controls limiting operation to a period from the start of the heating cycle to a maximum of 5 minutes after the end of the heating cycle. [ASHRAE 90.1:7.4.4.4] L 501.4 Recirculation Pump Controls. Pump controls shall include on-demand activation or time clocks combined with temperature sensing. Time clock controls for pumps shall not let the pump operate more than 15 minutes every hour. Temperature sensors shall stop circulation where the temperature set point is reached and shall be located on the circulation loop at or near the last fixture. The pump, pump controls, and temperature sensors shall be accessible. Pump operation shall be limited to the building’s hours of operation.

• § 140.4 High relevance — show source text

  Exception 1 to Section 140.4(k)4: Hydronic systems that use variable flow to reduce pumping energy in accordance with 140.4(k)1.

  Exception 2 to Section 140.4(k)4: Systems serving healthcare facilities. 5. Water-cooled air conditioner and hydronic heat pump systems. Water circulation systems serving water-cooled air conditioners, hydronic heat pumps, or both that have total pump system power exceeding 5 hp shall have flow controls that meet the requirements of Section 140.4(k)6. Each such air conditioner or heat pump shall have a two-position automatic valve interlocked to shut off water flow when the compressor is off.

  6. Variable flow controls.

  A. Variable speed drives. Individual pumps serving variable flow systems and having a motor horsepower exceeding 5 hp shall have controls or devices (such as variable speed control) that will result in pump motor demand of no more than 30 percent of design wattage at 50 percent of design water flow. The pumps shall be controlled as a function of required differential pressure. B. Pressure sensor location and setpoint. i. For systems without direct digital control of individual coils reporting to the central control panel, differential pressure shall be measured at the most remote heat exchanger or the heat exchanger requiring the greatest differential pressure. ii. For systems with direct digital control of individual coils with a central control panel, the static pressure setpoint shall be reset based on the valve requiring the most pressure, and the setpoint shall be no less than 80 percent open. Pressure sensors may be mounted anywhere.

  Exception 1 to Section 140.4(k)6: Heating hot water systems.

  Exception 2 to Section 140.4(k)6: Condenser water systems serving only water-cooled chillers.

  2025 CALIFORNIA ENERGY CODE 125

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES—PERFORMANCE AND PRESCRIPTIVE

  COMPLIANCE APPROACHES FOR ACHIEVING ENERGY EFFICIENCY

  7. Hydronic heat pump (WLHP) controls. Hydronic heat pumps connected to a common heat pump water loop with central devices for heat rejection and heat addition shall have controls that are capable of providing a heat pump water supply temperature dead band of at least 20°F between initiation of heat rejection and heat addition by the central devices.

  Exception to Section 140.4(k)7: Where a system loop temperature optimization controller is used to determine the most efficient operating temperature based on real-time conditions of demand and capacity, dead bands of less than 20°F shall be allowed. 8. High capacity space heating gas boiler systems. In Climate Zones 1 through 6, 9 through 14, and 16, gas hot water boiler systems for space heating with a total system input of at least 1 MMBtu/h but no more than 10 MMBtu/h shall meet all of the following requirements. A. Boiler system efficiency. Gas hot water boilers shall have a minimum thermal efficiency of 90 percent. Systems with multiple boilers can meet this requirement if the space-heating input provided by equipment with thermal efficiencies above and below 90 percent has an input capacity-weighted average thermal efficiency of at least 90 percent. For boilers federally regulated by combustion efficiency, the calculation for the input capacity-weighted average thermal efficiency shall use the combustion efficiency value. B. **Hot water distribution design.

• § 501.4.1 High relevance — show source text

  L 501.4.1 Hot Water On-Demand Pumping Sys- tems. Hot water on-demand pumping systems manually actuated or automatically activated hot water pumping systems shall comply with IAPMO PS 115. L 501.5 Temperature Maintenance Controls. Systems designed to maintain usage temperatures in hot-water pipes, such as recirculating hot water systems or heat trace, shall be equipped with automatic time switches or other controls that are capable of being set to switch off the usage temperature maintenance system during extended periods where hot water is not required. [ASHRAE 90.1:7.4.4.2] L 501.6 System Balancing. Systems with multiple recirculation zones shall be balanced to distribute hot water uniformly, or they shall be operated with a pump for each zone. The circulation pump controls shall comply with the provisions of Section L 501.4.

  L 501.7 Flow Balancing Valves. Flow balancing valves shall be a factory preset automatic flow control valve, a flow regulating valve, or a balancing valve with memory stop.

  L 501.8 Air Elimination. Provision shall be made for the elimination of air from the return system. L 501.9 Gravity or Thermosyphon Systems. Gravity or thermosyphon systems are prohibited.

  L 502.0 Service Hot Water – Low-Rise Residential Buildings. L 502.1 General. The service water heating system for single-family houses, multi-family structures of three stories or fewer above grade, and modular houses shall comply with Section L 502.2 through Section L 502.7.3. The service water heating system of all other buildings shall comply with Section L 503.0.

  L 502.2 Water Heaters and Storage Tanks. Residentialtype water heaters, pool heaters, and unfired water heater storage tanks shall comply with the minimum performance requirements specified by federal law. Unfired storage water heating equipment shall have a heat loss through the tank surface area of less than 6.5 British thermal units per square foot hour [Btu/(ft [2] - h)] (20.5 W/m [2] ).

  [ASHRAE 90.2-2007:7.1] L 502.3 Recirculation Systems. Recirculation systems shall comply with the provisions of Section L 501.3. L 502.4 Central Water Heating Equipment. Service water heating equipment (central systems) that do not fall under the requirements for residential-type service water heating equipment addressed in Section L 502.2 shall comply with the applicable requirements for service water-heating equipment found in Section L 503.0. [ASHRAE 90.2-2007:7.3] L 502.5 Insulation. Insulation for hot water and return piping shall comply with the provisions of Section L 501.2. L 502.6 Hard Water. Where water has hardness equal to or exceeding 9 grains per gallon (gr/gal) (154 mg/L) measured as total calcium carbonate equivalents, the water supply line to water heating equipment in new one- and two-family dwellings shall be roughed-in to allow for the installation of water treatment equipment. L 502.7 Maximum Volume and Length of Hot Water. The maximum volume of water contained in a hot water

  branch shall be in accordance with Section L 502.7.1. The maximum length per volume of piping shall comply with Section L 502.7.2.

• § 120.2 High relevance — show source text

  1. All zones are also served by an interior cooling system; and
  2. The perimeter system is designed solely to offset envelope heat losses or gains; and
  3. The perimeter system has at least one thermostatic control for each building orientation of 50 feet or more; and
  4. The perimeter system is controlled by at least one thermostat located in one of the zones served by the system.

  (b) Criteria for zonal thermostatic controls. The individual thermostatic controls required by Section 120.2(a) shall meet the following requirements as applicable:

  1. Where used to control comfort heating, the thermostatic controls shall be capable of being set, locally or remotely, down to 55°F or lower.

  2. Where used to control comfort cooling, the thermostatic controls shall be capable of being set, locally or remotely, up to 85°F or higher.

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum.

  72 2025 CALIFORNIA ENERGY CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS

  Exception 1 to Section 120.2(b)3: Systems with thermostats that require manual changeover between heating and cooling modes. Exception 2 to Section 120.2(b)3: Systems serving healthcare facilities. 4. Thermostatic controls for all single zone, air conditioners and heat pumps shall comply with the requirements of Sections 110.2(c) and 110.12(a) and, if equipped with DDC to the Zone level, with the Automatic Demand Shed Controls of Section 110.12(b). Exception 1 to Section 120.2(b)4: Systems serving non-covered process loads that must have constant temperatures to prevent degradation of materials, a process, plants or animals. Exception 2 to Section 120.2(b)4: Package terminal air conditioners, package terminal heat pumps, room air conditioners and room air conditioner heat pumps. Exception 3 to Section 120.2(b)4: Systems serving healthcare facilities.

  (c) Hotel/motel guest room thermostats.

  1. Hotel/motel guest room thermostats shall: A. Have numeric temperature setpoints in °F and °C; and B. Have setpoint stops, which are accessible only to authorized personnel, such that guest room occupants cannot adjust the setpoint more than ±5°F (±3°C); and C. Meet the requirements of Section 110.2(c).

  Exception to Section 120.2(c)1: Thermostats that are integrated into the room heating and cooling equipment.

  (d) Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section 110.2(b).

  (e) Shut-off and reset controls for space-conditioning systems. Each space-conditioning system shall be installed with controls that comply with the following:

  1. The control shall be capable of automatically shutting off the system during periods of nonuse and shall have: A. An automatic time switch control device complying with Section 110.9 with an accessible manual override that allows operation of the system for up to 4 hours; or

  B. An occupancy sensor; or C. A 4-hour timer that can be manually operated.

• § 180.2 High relevance — show source text

  2(c)2, 4, 180.2(b)2A Tower 110.2(e), 120.5(a)16, 120.6(a)4, 8, 120.6(b)1, 120.6(b)5, Table 130.5B, 140.4(b)3, 140.4(h), 160.3(d)1P, 170.2(c)2C, 170.2(c)4F

  2025 CALIFORNIA ENERGY CODE 303

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  INDEX

  Daylit Zone 130.1(d), 130.1(f), 140.3(c)1A, 140.6(a)2, 140.6(a)3, Table 140.6-A, 160.5(b)4D, F, 170.2(e)2B, Table 170.2-L DDC Applications and Qualifications Table 120.2-A, Table 160.3-C Dead Band 120.2(b)3, 140.4(k)7 Dead Band Flow Rate 140.4(d) Decibel Level 110.9(b)6 Decorative Gas Appliance 110.2(c), 140.6(b)4, 150.0(e), 160.1(f) Dedicated Electrical Receptacle 150.0(n)1A, 160.4 Dedicated Outdoor Air Systems (DOAS) 140.4(p), 170.2(c)4N Dedicated Raceway 150.0(s) Default Fenestration

  Product U-Factors Table 110.6-A

  Default Solar Heat Gain Coefficient (SHGC) Table 110.6-B, 10-111(a)1B, 110.6(a)3 Default U-Factor 10-111(a)1B, 10-111(b)1B, 10-112(a), 110.6(a)2 Default Values 10-112(a), Table 140.4-D, 150.1(c)3, 170.2(a)3A, Table 170.2-E Default Values for Fan KWdesign Based on Motor Nameplate HP Table 140.4-D, Table 170.2-E-1 Dehumidification Table 110.2-K, 120.6(h), 140.4(b)2A, 140.4(e)1, 141.1(c)1, 170.2(c)2B, 170.2(c)4C Demand Control ventilation (DCV) 120.1(d), 120.5(a)5, 160.2(c)5, 160.3(d)1 Demand-controlled local ventilation exhaust airflow rates and capture efficiency Table 150.0-E, Table 160.2-E

  Demand-controlled mechanical exhaust 150.0(o), 160.2(b)2A Flexibility 150.1(b)1 Management 110.12 Recirculation 150.1(c)8, 150.2(b)1H, 170.2(d), 180.2(b)3B Response signal 110.10(b)1A, 110.10(b)1B, 110.12(a-e), 140.6(a)2, 170.2(e)2B Responsive controls 110.10(b)1A,

• § 207.1.3 High relevance — show source text

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum. Exception: Systems with thermostats that require manual changeover between heating and cooling modes.
  4. Thermostatic controls for all unitary single zone, air conditioners, heat pumps and furnaces, shall comply with the setback thermostat requirements of Section A6.207.1.3 or, if equipped with DDC to the Zone level, with the Automatic Demand Shed Controls of Section A6.207.5.5.

  Exception: Systems serving zones that must have constant temperatures to prevent degradation of materials, a process, plants or animals.

  A6.207.5.3 Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section A6.207.1.2.

  A6.207.5.4 Dampers for air supply and exhaust equipment. Outdoor air supply and exhaust equipment shall be installed with dampers that automatically close upon fan shutdown.

  Exceptions:

  1. Where it can be demonstrated to the satisfaction of the enforcing agency that the equipment serves an area that must operate continuously.

  2. Gravity and other nonelectrical equipment that has readily accessible manual damper controls.

  3. At combustion air intakes and shaft vents.

  4. Where prohibited by other provisions of law.

  A6.207.5.5 Automatic demand shed controls. HVAC systems with DDC to the Zone level shall be programmed to allow centralized demand shed for noncritical zones as follows:

  1. The controls shall have a capability to remotely setup the operating cooling temperature set points by 4 degrees or more in all noncritical zones on signal from a centralized contact or software point within an Energy Management Control System (EMCS).
  2. The controls shall remotely set down the operating heating temperature set points by 4 degrees or more in all noncritical zones on signal from a centralized contact or software point within an EMCS.
  3. The controls shall have capabilities to remotely reset the temperatures in all noncritical zones to original operating levels on signal from a centralized contact or software point within an EMCS.
  4. The controls shall be programmed to provide an adjustable rate of change for the temperature setup and reset.

  A6.207.6 Pipe insulation. The piping for all space- conditioning and service water-heating systems with fluid temperatures listed in Table A6.207.6-A shall have the amount of insulation specified in Subsection A6.207.6.1 or A6.207.6.2. Insulation conductivity shall be determined in accordance with ASTM C335 at the mean temperature listed in Table A6.207.6-A and shall be rounded to the nearest 1 / 100 Btu-inch per hour per square foot per °F.

  Insulation shall be protected from damage, including that due to sunlight, moisture, equipment maintenance and wind, including but not limited to, the following:

  Insulation exposed to weather shall be suitable for outdoor service, e.g., protected by aluminum, sheet metal, painted canvas or plastic cover. Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation that can cause degradation of the material.

  Insulation covering chilled water piping and refrigerant suction piping located outside the conditioned space shall include a vapor retardant located outside the insulation (unless the insulation is inherently vapor retardant), all penetrations and joints of which shall be sealed.

• § 3106B.3 High relevance — show source text

  3106B.3 The recirculation system shall be in operation at all times that the spray ground is open for use and shall have a minimum of four turnover cycles prior to opening for proper disinfection and filtration.

  3106B.4 There shall be no standing water within the splash zone.

  3106B.5 Nozzles that spray from the ground level shall be flush with the ground with openings no greater than [1] / 2 inch. Spray ground water features that extend above the ground must be clearly visible.

  3106B.6 The splash zone shall be sloped so that only water from the spray ground water feature flows back to the surge basin. Areas adjacent to the splash zone shall be sloped away from the spray ground to deck drains or other surface water disposal systems.

  3106B.7 All foggers and misters that produce finely atomized mists shall be supplied directly from a potable water source and not from the surge basin.

  3106B.8 When multiple pumps are used the control systems for the spray ground water feature pump and recirculation system pump shall be electrically interconnected so that when the recirculation pump is off the spray ground water feature pump also is off.

  3106B.9 The spray ground shall have a surge basin or treatment tank constructed of materials which are inert, corrosion resistant, nontoxic and watertight including materials such as concrete, fiberglass, high density polyethylene, stainless steel or other materials as approved by the enforcing agent which can withstand all anticipated loadings under full and empty conditions as determined by an engineer or architect who has experience working on public pools.

  3106B.10 The total volume of the surge basin shall be at least 4,000 gallons or a minimum of three times the gallons per minute flow rate of all the spray ground pumps and the recirculation pump combined, whichever is higher.

  3106B.11 The turnover time shall be one-half hour or less.

  3106B.12 The suction intake for the spray ground or water feature pump in the surge basin shall be located adjacent to the recirculation return line.

  3106B.13 When separate pumps are used, the suction intake for the recirculation pump shall be located in the lowest portion of the surge basin and on the opposite side from the suction intake for the spray ground pump.

  2025 CALIFORNIA BUILDING CODE 31B-5

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  PUBLIC POOLS

  3106B.14 The surge basin shall be designed to have easy access for cleaning and inspection. The basin shall have at least one ladder access and shall have at least one 3-foot by 3-foot access opening. Lids shall be locked or require a tool to open.

  3106B.15 The surge basin shall be equipped with an automatic make up water fill device through an air gap or be protected by an approved backflow prevention device in accordance with Chapter 6 of the California Plumbing Code.

• § 110.3 High relevance — show source text

  1. Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature. Exception to Section 110.3(c)1: Systems covered by California Plumbing Code Section 613.0 shall instead follow the requirements of that section.
  2. Controls for hot water distribution systems. Service hot water systems with circulating pumps or with electrical heat trace systems shall be capable of automatically turning off the system. Exception to Section 110.3(c)2: Systems serving healthcare facilities.
  3. Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have: A. External insulation with an installed R -value of at least R-3.5; or

  B. Internal and external insulation with a combined R -value of at least R-16; or

  C. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot. 4. Water heating recirculation loops serving multiple dwelling units, high-rise residential, hotel/motel, and nonresiden- tial occupancies. A water heating recirculation loop is a type of hot water distribution system that reduces the time needed to deliver hot water to fixtures that are distant from the water heater, boiler or other water heating equipment. The recirculation loop is comprised of a supply portion, connected to branches that serve multiple dwelling units, guest rooms, or fixtures and a return portion that completes the loop back to the water heating equipment. A water heating recirculation loop shall meet the following requirements: A. Air release valve or vertical pump installation. An automatic air release valve shall be installed on the recirculation loop piping on the inlet side of the recirculation pump and no more than 4 feet from the pump. This valve shall be mounted on top of a vertical riser at least 12 inches in length and shall be accessible for replacement and repair. Alternatively, the pump shall be installed on a vertical section of the return line. B. Recirculation loop backflow prevention. A check valve or similar device shall be located between the recirculation pump and the water heating equipment to prevent water from flowing backwards though the recirculation loop. C. Equipment for pump priming. A hose bibb shall be installed between the pump and the water heating equipment. An isolation valve shall be installed between the hose bibb and the water heating equipment. This hose bibb is used for bleeding air out of the pump after pump replacement. D. Pump isolation valves. Isolation valves shall be installed on both sides of the pump. These valves may be part of the flange that attaches the pump to the pipe. One of the isolation valves may be the same isolation valve as in Item C. E. Cold water supply and recirculation loop connection to hot water storage tank. Storage water heaters and boilers shall be plumbed in accordance with the manufacturer’s specifications The cold water piping and the recirculation loop piping shall not be connected to the hot water storage tank drain port. F. Cold water supply backflow prevention. A check valve shall be installed on the cold water supply line between the hot water system and the next closest tee on the cold water supply line.

• § 803.2.1.3 High relevance — show source text

  The responsible person shall perform the field testing and verification work, and where this is the case, the responsible person shall complete and sign both the field technician’s signature block and the responsible person’s signature block on the certificate of acceptance form. The responsible person assumes responsibility for the acceptance testing work performed by the field technician agent or employee. E 803.2.1.3 Certificate of Acceptance. The certificate of acceptance shall be submitted to the Authority Having Jurisdiction in order to receive the final certificate of occupancy. The Authority Having Jurisdiction shall not release a final certificate of occupancy unless the submitted certificate of acceptance demonstrates that the specified systems and equipment have been shown to be performing in accordance with the applicable acceptance requirements. The Authority Having Jurisdiction has the authority to require the field technician and responsible person to demonstrate competence, to its satisfaction. Certificate of acceptance forms are located in Section E 806.0.

  E 804.0 Commissioning Tests. E 804.1 General. Functional tests shall be performed on new equipment and systems installed in either new construction or retrofit applications in accordance with this section. The appropriate certificate of acceptance form along with each specific test shall be completed and submitted to the Authority Having Jurisdiction before a final occupancy permit can be granted.

  E 804.2 Tests. Functional testing shall be performed on the devices and systems listed in this section. The functional test results are documented using the applicable certificate of acceptance forms shown in parenthesis and located in Section E 806.0. The functional tests shall be performed in accordance with Section E 805.0 using the following forms:

  (1) Minimum ventilation controls for constant and variable air volume systems (Form MECH-2A).

  (2) Zone temperature and scheduling controls for constant volume, single-zone, unitary air conditioner and heat pump systems (Form MECH-3A).

  (3) Duct leakage on a subset of small single-zone systems depending on the ductwork location (Form MECH-4A).

  (4) Air economizer controls for economizers that are not factory installed and tested (Form MECH-5A).

  (5) Demand-controlled ventilation control systems (Form MECH-6A).

  (6) Supply fan variable flow controls (Form MECH-7A).

  (7) Valve leakage for hydronic variable flow systems and isolation valves on chillers and boilers in plants with more than one chiller or boiler being served by the same primary pumps through a common header (Form MECH8A).

  (8) Supply water temperature reset control strategies programmed into the building automation system for water systems (e.g., chilled, hot, or condenser water) (Form MECH-9A).

  (9) Hydronic variable flow controls on a water system where the pumps are controlled by variable frequency drives (e.g., chilled and hot water systems; water-loop heat pump systems) (Form MECH-10A).

  (10)Automatic demand shed control (Form MECH-11A).

  (11)Fault detection and diagnostic for DX units (Form MECH-12A).

  (12)Automatic fault detection and diagnostic systems (AFDD) (Form MECH-13A).

  (13)Distributed energy storage DEC/DX AC systems (Form MECH-14A).

  (14)Thermal energy storage (TES) systems (Form MECH15A). E 804.3 Acceptance Process. The functional testing process shall comply with Section E 804.3.1 through Section E 804.3.4.

• § 608.3. High relevance — show source text

  A water heating recirculation loop shall meet the following requirements: A. Air release valve or vertical pump installation. An automatic air release valve shall be installed on the recirculation loop piping on the inlet side of the recirculation pump and no more than 4 feet from the pump. This valve shall be mounted on top of a vertical riser at least 12 inches in length and shall be accessible for replacement and repair. Alternatively, the pump shall be installed on a vertical section of the return line. B. Recirculation loop backflow prevention. A check valve or similar device shall be located between the recirculation pump and the water heating equipment to prevent water from flowing backwards though the recirculation loop. C. Equipment for pump priming. A hose bibb shall be installed between the pump and the water heating equipment. An isolation valve shall be installed between the hose bibb and the water heating equipment. This hose bibb is used for bleeding air out of the pump after pump replacement. D. Pump isolation valves. Isolation valves shall be installed on both sides of the pump. These valves may be part of the flange that attaches the pump to the pipe. One of the isolation valves may be the same isolation valve as in Item C. E. Cold water supply and recirculation loop connection to hot water storage tank. Storage water heaters and boilers shall be plumbed in accordance with the manufacturer’s specifications The cold water piping and the recirculation loop piping shall not be connected to the hot water storage tank drain port. F. Cold water supply backflow prevention. A check valve shall be installed on the cold water supply line between the hot water system and the next closest tee on the cold water supply line. The system shall comply with the expansion tank requirements as described in the California Plumbing Code Section 608.3.

  52 2025 CALIFORNIA ENERGY CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS

  5. Service water heaters in state buildings. Any newly constructed building constructed by the State shall derive its service water heating from a system that provides at least 60 percent of the energy needed for service water heating from site solar energy or recovered energy, per the statutory requirement of California Public Resources Code Section 25498.

  Exception to Section 110.3(c)5: Buildings for which the state architect determines that service water heating from site solar energy or recovered energy is economically or physically infeasible. 6. Isolation valves. Instantaneous water heaters with an input rating greater than 6.8 kBTU/hr (2 kW) shall have isolation valves on both the cold water supply and the hot water pipe leaving the water heater, and hose bibbs or other fittings on each valve for flushing the water heater when the valves are closed. 7. Air-source heat pump water heaters (HPWH). HPWH shall meet the following requirements: A. Backup heat. Backup heat is required for systems where inlet air is unconditioned, unless the compressor cut-off temperature is below the Heating Winter Median of Extremes for the closest location listed in Table 2-3 from Reference Joint Appendix JA2. Backup heat may be internal or external to the HPWH. B. Ventilation. Consumer integrated HPWHs shall meet one of the ventilation requirements below.

• § 1-20 High relevance — show source text

  Exception: An independent perimeter heating or cooling system may serve more than one zone without individual thermostatic controls if:

  1. All zones are also served by an interior cooling system;
  2. The perimeter system is designed solely to offset envelope heat losses or gains;

  APPENDIX A6.1-20 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]

  3. The perimeter system has at least one thermostatic control for each building orientation of 50 feet or more; and
  4. The perimeter system is controlled by at least one thermostat located in one of the zones served by the system.

  A6.207.5.2 Criteria for zonal thermostatic controls. The individual thermostatic controls required by Section A6.207.5.1 shall meet the following requirements as applicable:

  1. Where used to control comfort heating, the thermostatic controls shall be capable of being set, locally or remotely, down to 55°F or lower.

  2. Where used to control comfort cooling, the thermostatic controls shall be capable of being set, locally or remotely, up to 85°F or higher.

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum. Exception: Systems with thermostats that require manual changeover between heating and cooling modes.

  4. Thermostatic controls for all unitary single zone, air conditioners, heat pumps and furnaces, shall comply with the setback thermostat requirements of Section A6.207.1.3 or, if equipped with DDC to the Zone level, with the Automatic Demand Shed Controls of Section A6.207.5.5.

  Exception: Systems serving zones that must have constant temperatures to prevent degradation of materials, a process, plants or animals.

  A6.207.5.3 Heat pump controls. All heat pumps with supplementary electric resistance heaters shall be installed with controls that comply with Section A6.207.1.2.

  A6.207.5.4 Dampers for air supply and exhaust equipment. Outdoor air supply and exhaust equipment shall be installed with dampers that automatically close upon fan shutdown.

  Exceptions:

  1. Where it can be demonstrated to the satisfaction of the enforcing agency that the equipment serves an area that must operate continuously.

  2. Gravity and other nonelectrical equipment that has readily accessible manual damper controls.

  3. At combustion air intakes and shaft vents.

  4. Where prohibited by other provisions of law.

  A6.207.5.5 Automatic demand shed controls. HVAC systems with DDC to the Zone level shall be programmed to allow centralized demand shed for noncritical zones as follows: