Water Heaters

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

• CPC § 505.0 High relevance — show source text

  505.0 Oil-Burning and Other Water Heaters. 505.1 Water Heaters. Water heaters deriving heat from fuels or types of energy other than gas shall comply with the standards referenced in Table 501.1(1), Section 505.3, or Section 505.4. Vents or chimneys for such appliances shall be of approved types. An adequate supply of air for combustion and for adequate ventilation of heater rooms or compartments shall be provided. Each such appliance shall be installed in a

  location approved by the Authority Having Jurisdiction and local and state fire-prevention agencies. 505.2 Safety Devices. Storage-type water heaters and hot water boilers deriving heat from fuels or types of energy other than gas, shall be provided with, in addition to the primary temperature controls, an over-temperature safety protection device that complies with and is installed in accordance with nationally recognized applicable standards for such devices and a combination temperature and pressure-relief valve.

  505.3 Oil-Fired Water Heaters. Oil-fired water heaters

  shall be installed in accordance with NFPA 31.

  505.4 Indirect-Fired Water Heaters. Indirect-fired water heaters shall be in accordance with the applicable sections of the ASME Boiler and Pressure Vessel Code or shall comply with one of the other applicable standards shown in Table 501.1(1). Each water heater shall bear a label in accordance with ASME requirements, or an approved testing agency, certifying and attesting that such an appliance has been tested, inspected and meets the requirements of the applicable standards or code. 505.4.1 Single-Wall Heat Exchanger. An indirectfired water heater that incorporates a single-wall heat exchanger shall be in accordance with the following requirements:

  (1) The heat transfer medium shall be either potable water or contain fluids recognized as safe by the Food and Drug Administration (FDA) as food grade.

  (2) Bear a label with the word “Caution,” followed by the following statements:

  (a) The heat-transfer medium shall be potable water or other nontoxic fluid recognized as safe by the FDA.

  (b) The maximum operating pressure of the heat exchanger shall not exceed the maximum operating pressure of the potable water supply.

  (3) The word “Caution” and the statements in letters shall have an uppercase height of not less than 0.120 of an inch (3.048 mm). The vertical spacing between lines of type shall be not less than 0.046 of an inch (1.168 mm). Lowercase letters shall be compatible with the uppercase letter size specification.

  506.0 Air for Combustion and Ventilation.

  506.1 General. Air for combustion, ventilation, and dilution of flue gases for appliances installed in buildings shall be obtained by application of one of the methods covered in Section 506.2 through Section 506.7.3. Where the requirements of Section 506.2 are not met, outdoor air shall be introduced in accordance with methods covered in Section 506.4 through Section 506.7.3.

  Exception: This provision shall not apply to direct vent appliances. {NFPA 54:9.3.1.1} 506.1.1 Other Types of Appliances. Appliances of other than natural draft design, appliances not designated as Category I vented appliances, and appliances equipped with power burners shall be provided with combustion, ventilation, and dilution air in accordance with the appliance manufacturer’s instructions. [NFPA 54:9.3.1.2]

• CPC § 507.2 Medium relevance — show source text

  2_
  507.2|||X|X|X|||X|||||||||||||||||

  This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

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  CHAPTER 5

  WATER HEATERS

  501.0 General.

  501.1 Applicability. The regulations of this chapter shall govern the construction, location, and installation of fuel-burning and other types of water heaters heating potable water, together with chimneys, vents, and their connectors. The minimum capacity for storage water heaters shall be in accordance with the first-hour rating listed in Table 501.1(2). A list of accepted water heater appliance standards is referenced in Table 501.1(1). Listed appliances shall be installed in accordance with the manufacturer’s installation instructions. Unlisted water heaters shall be permitted in accordance with Section 504.3.2.

  Water heaters shall be installed in accordance with the

  manufacturer’s installation instructions. The final installation shall be approved by the Authority Having Jurisdiction.

  TABLE 501.1(1)

  WATER HEATERS

  TYPE*	STANDARD
  Electric, Household Storage	UL 174
  Oil-Fired Storage Tank	UL 732
  Gas-Fired, 75 000 Btu/h or less, Storage	CSA/ANSI Z21.10.1/CSA 4.1
  Gas-Fired, Above 75 000 Btu/h, Storage and Instantaneous	CSA/ANSI Z21.10.3/CSA 4.3
  Electric, Commercial Storage	UL 1453
  Solid Fuel-Fired	UL 2523
  Electric Instantaneous	UL 499

  For SI units: 1000 British thermal units per hour = 0.293 kW

  • Dual purpose water heaters shall be installed in accordance with this code and the manufacturer’s installation instructions.

  501.2 California Energy Code Water Heating System Requirements. [CEC] See California Energy Code Section 110.3 for additional mandatory requirements for all service water heating systems, and 150.0(n) for additional mandatory requirements for residential service water heating systems.

  502.0 Permits.

  502.1 General. It shall be unlawful for a person to install, remove, or replace or cause to be installed, removed, or replaced a water heater without first obtaining a permit from the Authority Having Jurisdiction to do so.

  TABLE 501.1(1)

  WATER HEATERS

  For SI units: 1000 British thermal units per hour = 0.293 kW

  • Dual purpose water heaters shall be installed in accordance with this code and the manufacturer’s installation instructions.

  503.0 Inspection.

• CPC § 507.2 Medium relevance — show source text

  2_
  507.2|||X|X|X|||X||||||||||||||||| |Adopting Agency
  Adopt Entire Chapter
  Adopt Entire Chapter as
  amended (amended
  sections listed below)
  Adopt only those sections
  that are listed below
  Chapter/Section
  501.2
  507.2|||||||||||||||||||||X|||| |Adopting Agency
  Adopt Entire Chapter
  Adopt Entire Chapter as
  amended (amended
  sections listed below)
  Adopt only those sections
  that are listed below
  Chapter/Section
  501.2
  507.2||||||||||||||||||||||||| |Adopting Agency
  Adopt Entire Chapter
  Adopt Entire Chapter as
  amended (amended
  sections listed below)
  Adopt only those sections
  that are listed below
  Chapter/Section
  501.2
  507.2|||||||||||||||||||||X|||| |Adopting Agency
  Adopt Entire Chapter
  Adopt Entire Chapter as
  amended (amended
  sections listed below)
  Adopt only those sections
  that are listed below
  Chapter/Section
  501.2
  507.2|||X|X|X|||X|||||||||||||||||

  This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

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  CHAPTER 5

  WATER HEATERS

  501.0 General.

  501.1 Applicability. The regulations of this chapter shall govern the construction, location, and installation of fuel-burning and other types of water heaters heating potable water, together with chimneys, vents, and their connectors. The minimum capacity for storage water heaters shall be in accordance with the first-hour rating listed in Table 501.1(2). A list of accepted water heater appliance standards is referenced in Table 501.1(1). Listed appliances shall be installed in accordance with the manufacturer’s installation instructions. Unlisted water heaters shall be permitted in accordance with Section 504.3.2.

  Water heaters shall be installed in accordance with the

  manufacturer’s installation instructions. The final installation shall be approved by the Authority Having Jurisdiction.

  TABLE 501.1(1)

  WATER HEATERS

• CPC § 501.1 Medium relevance — show source text

  Table 501.1(1) Water Heaters . . . . . . . . . . . . . . . .83

  501.2 California Energy Code Water Heating System Requirements . . . . . . . . . . . . . . . . .83

  502.0 Permits . . . . . . . . . . . . . . . . . . . . . .83

  502.1 General . . . . . . . . . . . . . . . . . . . . . .83

  503.0 Inspection . . . . . . . . . . . . . . . . . . . .83

  503.1 Inspection of Chimneys or Vents . . .83

  503.2 Final Water Heater Inspection . . . .83

  504.0 Water Heater Requirements . . . . . .83

  504.1 Location . . . . . . . . . . . . . . . . . . . . .83

  Table 501.1(2) First Hour Rating . . . . . . . . . . . . . .83

  504.2 Vent . . . . . . . . . . . . . . . . . . . . . . . .84

  504.3 Clearance . . . . . . . . . . . . . . . . . . . .84

  504.4 Pressure-Limiting Devices . . . . . . .84

  504.5 Temperature-Limiting Devices . . . .84

  504.6 Temperature, Pressure, and Vacuum Relief Devices . . . . . . . . .84

  504.7 Lead Content . . . . . . . . . . . . . . . . .84

  505.0 Oil-Burning and Other Water Heaters . . . . . . . . . . . . . . . . . . . . . .84

  505.1 Water Heaters . . . . . . . . . . . . . . . .84

  505.2 Safety Devices . . . . . . . . . . . . . . . .84

  505.3 Oil-Fired Water Heaters . . . . . . . . .84

  505.4 Indirect-Fired Water Heaters . . . . .84

  506.0 Air for Combustion and

  Ventilation . . . . . . . . . . . . . . . . . . . .84

  506.1 General . . . . . . . . . . . . . . . . . . . . . .84

  506.2 Indoor Combustion Air . . . . . . . . . .85

  506.3 Indoor Opening Size and Location . . . . . . . . . . . . . . . . . . . . .85

  506.4 Outdoor Combustion Air . . . . . . . . .85

  506.5 Combination Indoor and

  Outdoor Combustion Air . . . . . . . . .87

  506.6 Engineered Installations . . . . . . . . .87

  506.7 Mechanical Combustion Air Supply . . . . . . . . . . . . . . . . . . . . . . .87

  506.8 Louvers, Grilles, and Screens . . . .87

  506.9 Combustion Air Ducts . . . . . . . . . . .87

  507.0 Appliance and Equipment Installation Requirements . . . . . . . .88

  507.1 Dielectric Insulator . . . . . . . . . . . . .88

• CPC § 90.1 Medium relevance — show source text

  [ASHRAE 90.1: TABLE 7.8]

  EQUIPMENT TYPE	SIZE CATEGORY (INPUT)	SUBCATEGORY OR RATING CONDITION	PERFORMANCE REQUIRED1	TEST PROCEDURE2,3
  Electric table-top water heaters	≤12 kW	<4000 (Btu/h)/gal ≥20 gal and≤120 gal	For applications outside U.S., see footnote (8). For U.S. appli- cations, see footnote (7).	Appendix E of 10 CFR 430
  Electric storage water heaters	≤12 kW	<4000 (Btu/h)/gal ≥20 gal and≤55 gal	For applications outside U.S., see footnote (8). For U.S. applications, see footnote (7).	Appendix E of 10 CFR 430
  Electric storage water heaters	≤12 kW	<4000 (Btu/h)/gal >55 gal and≤120 gal	For applications outside U.S., see footnote (8). For U.S. applications, see footnote (7).	Appendix E of 10 CFR 430
  Electric storage water heaters	>12 kW5	<4000 (Btu/h)/gal	SL≤ 0.3 + 27/Vm%/h	10 CFR 431.106
  Electric instantaneous water heaters	≤12 kW	≥4000 (Btu/h)/gal <2 gal	For applications outside U.S., see footnote (8). For U.S. applications, see footnote (7).	Appendix E of 10 CFR 430
  Electric instantaneous water heaters	>12 kW and ≤58.6 kW3	≥4000 (Btu/h)/gal ≤2 gal ≤180°F	Very Small DP: UEF = 0.80 Low DP: UEF = 0.80 Medium DP: UEF = 0.80 High DP: UEF = 0.80	Appendix E of 10 CFR 430
  Electric instantaneous water heaters	≤58.6 kW3	≥4000 (Btu/h)/gal <10 gal	No requirement	No requirement
  Electric instantaneous water heaters	≤58.6 kW3	≥4000 (Btu/h)/gal ≥10 gal	No requirement	No requirement
  Gas storage water heaters	≤75 000 Btu/h	<4000 (Btu/h)/gal ≥20 gal and≤55 gal	For applications outside U.S., see footnote (8). For U.S. applications, see footnote (7).	Appendix E of 10 CFR 430
  Gas storage water heaters	≤75 000 Btu/h	<4000 (Btu/h)/gal >55 gal and≤100 gal	For applications outside U.S., see footnote (8).

• CPC § 608.3 Medium relevance — show source text

  The expansion tank shall be properly sized, securely fastened to the structure, and installed in accordance with the manufacturer’s installation instructions and listing. Systems designed by a licensed plumbing contractor or registered design professionals shall be permitted to use approved pressure relief valves in lieu of expansion tanks provided such relief valves have a maximum pressure relief setting of 100 psi (689 kPa) or less. 608.3 Expansion Tanks, and Combination Tempera- ture and Pressure-Relief Valves. A water system provided with a check valve, backflow preventer, or other normally closed device that prevents dissipation of building pressure back into the water main, independent of the type of water heater used, shall be provided with an approved, listed, and adequately sized expansion tank or other approved device having a similar function to control thermal expansion. Prepressurized water expansion tanks shall comply with IAPMO/ANSI Z1088. Such expansion tank or other approved device shall be installed on the building side of the check valve, backflow preventer, or other device and shall be sized, securely fastened to the structure, and installed in accordance with the manufacturer’s installation instructions.

  A water system containing storage water heating equipment shall be provided with an approved, listed, adequately sized combination temperature and pressure-relief valve, except for listed nonstorage instantaneous heaters having an inside diameter of not more than 3 inches (80 mm). Each such approved combination temperature and pressure-relief valve shall be installed on the water-heating device in an approved location based on its listing requirements and the manufacturer’s installation instructions. Each such combination temperature and pressure-relief valve shall be provided with a drain in accordance with Section 608.5.

  Exception: An expansion tank shall not be required for an instantaneous non-storage water heater. 608.4 Pressure Relief Valves. Each pressure relief valve shall be an approved automatic type with drain, and each such relief valve shall be set at a pressure of not more than 150 psi (1034 kPa). No shutoff valve shall be installed between the relief valve and the system. 608.5 Discharge Piping. The discharge piping serving a temperature relief valve, pressure relief valve, or combination of both shall have no valves, obstructions, or means of isolation and be provided with the following:

  (1) Not less than the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down.

  (2) Materials shall be rated at not less than the operating temperature of the system and approved for such use or shall comply with ASME A112.4.1.

  (3) Discharge pipe shall discharge independently by gravity through an air gap into the drainage system or outside of the building with the end of the pipe not exceeding 2 feet

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  WATER SUPPLY AND DISTRIBUTION

  (610 mm) and not less than 6 inches (152 mm) above the ground and pointing downwards.

  (4) Discharge in such a manner that does not cause personal injury or structural damage. (5) No part of such discharge pipe shall be trapped or subject to freezing. (6) The terminal end of the pipe shall not be threaded. (7) Discharge from a relief valve into a water heater pan shall be prohibited. (8) The discharge termination point shall be readily observable.

• CPC § 150.1 Medium relevance — show source text

  Exception 1 to Section 150.1(c)7A: Packaged systems for which the manufacturer has verified correct system refrigerant charge prior to shipment from the factory are not required to have refrigerant charge confirmed through field verification and diagnostic testing. The installer of these packaged systems shall certify on the Certificate of Installation that the packaged system was pre-charged at the factory and has not been altered in a way that would affect the charge. Ducted systems shall comply with minimum system airflow rate requirements in Section 150.1(c)7Aib, provided that the system is of a type that can be verified using the procedure specified in Section RA3.3 or an approved alternative in Section RA1.

  8. Domestic water-heating systems. Water-heating systems shall meet the requirements of A, B or C, or shall meet the performance compliance requirements of Section 150.1(b)1. For recirculation distribution systems, only demand recirculation systems with manual on/off control as specified in the Reference Appendix RA4.4.9 shall be used: A. A single 240 volt heat pump water heater (HPWH). The storage tank shall be located in the garage or conditioned space. In addition, meet the following: i. A compact hot water distribution system that is field verified as specified in the Reference Appendix RA4.4.6 in Climate Zones 1 and 16; and

  ii. A drain water heat recovery system that is field verified as specified in the Reference Appendix RA3.6.9 in Climate Zone 16.

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  SINGLE-FAMILY RESIDENTIAL BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

  B. A single 240 volt HPWH that meets the requirements of NEEA Advanced Water Heater Specification Tier 3 or higher. In addition, for Climate Zone 16, a drain water heat recovery system that is field verified as specified in Reference Appendix RA3.6.9 and the storage tank shall be located in the garage or conditioned space. C. A solar water-heating system with electric backup meeting the installation criteria specified in Reference Residential Appendix RA4 and with a minimum annual solar savings fraction of 0.7. Exception 1 to Section 150.1(c)8: An electric water heater with point of use distribution as specified in RA4.4.5 may be installed for new dwelling units with a conditioned floor area of 500 square feet or less. Exception 2 to Section 150.1(c)8A and B: A 120V HPWH may be installed in place of a 240V HPWH for new dwelling unit with one bedroom or fewer.

  9. Space-conditioning distribution systems. All space-conditioning systems shall meet all applicable requirements of A or B below:

  A. High performance attics. Air handlers or ducts are allowed to be in ventilated attic spaces when the roof and ceiling insulation level meet Option B in Table 150.1-A. Duct insulation levels shall meet the requirements in Table 150.1-A. B. Duct systems and air handlers of HVAC systems shall be located entirely in conditioned space and confirmed through field verification and diagnostic testing to meet the criterion of Reference Residential Appendix Section RA3.1.4.3.8. Duct insulation levels shall meet the requirements in Table 150.1-A. For dwelling units with attics, the duct system and air handlers of HVAC systems shall be located below the ceiling separating the occupiable space from the attic.

• CPC § 507.5 Medium relevance — show source text

  507.5 Drainage Pan. Where a water heater is located in an attic, in or on an attic ceiling assembly, floor-ceiling assembly, floor-subfloor assembly or where damage results from a leaking water heater, a watertight pan of corrosion-resistant materials shall be installed beneath the water heater in accordance with the following: (1) The drainage pan shall be provided with not less than [3] ⁄ 4 of an inch (20 mm) diameter drain to an approved location. The terminating end of the drainpipe shall be readily visible. (2) The drainage pan shall be not less than 1 [1] ⁄ 2 inches (38 mm) in depth. (3) Where a drainage pan pipe is installed, the material of the piping shall be rated for the temperature rating of the water heater and shall be approved for use with the liquid being discharged. (4) Discharge from a relief valve into a drainage pan shall be prohibited. 507.6 Added or Converted Equipment or Appliances. When additional or replacement appliances or equipment is installed or an appliance is converted to gas from another fuel, the location in which the appliances or equipment is to be operated shall be checked to verify the following: (1) Air for combustion and ventilation is provided where required, in accordance with the provisions of Section 506.0. Where existing facilities are not adequate, they shall be upgraded to meet Section 506.0 specifications. (2) The installation components and appliances meet the clearances to combustible material provisions of Section 507.26. It shall be determined that the installation and operation of the additional or replacement appliances do not render the remaining appliances unsafe for continued operation. (3) The venting system is constructed and sized in accordance with the provisions of Section 509.0. Where the existing venting system is not adequate, it shall be upgraded to comply with Section 509.0. [NFPA 54:9.1.2] 507.7 Type of Gas(es). The appliance shall be connected to the fuel gas for which it was designed. No attempt shall be made to convert the appliance from the gas specified on the rating plate for use with a different gas without consulting the installation instructions, the serving gas supplier, or the appliance manufacturer for complete instructions. Listed appliances shall

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  WATER HEATERS

  not be converted unless permitted by and in accordance with the manufacturer’s installation instructions. [NFPA 54:9.1.3] 507.8 Safety Shutoff Devices for Unlisted LP-Gas Appliance Used Indoors. Unlisted appliances for use with undiluted LP-Gases and installed indoors, except attended laboratory equipment, shall be equipped with safety shutoff devices of the complete shutoff type. [NFPA 54:9.1.4] 507.9 Use of Air or Oxygen Under Pressure. Where air or oxygen under pressure is used in connection with the gas supply, effective means such as a backpressure regulator and relief valve shall be provided to prevent air or oxygen from passing back into the gas piping. Where oxygen is used, installation shall be in accordance with NFPA 51. [NFPA 54:9.1.5]

• CPC § 170.1. Medium relevance — show source text

  MULTIFAMILY BUILDINGS—PERFORMANCE AND PRESCRIPTIVE COMPLIANCE APPROACHES

  (d) Domestic hot water systems. Water-heating systems shall meet the applicable requirements of 1 or 2 below:

  1. Individual systems. For systems serving individual dwelling units, the water-heating system shall meet the requirement of either A or B, or shall meet the performance compliance requirements of Section 170.1. For recirculation distribution systems serving individual dwelling units, only demand recirculation systems with manual on/off control as specified in the Reference Appendix RA4.4.9 shall be used. A. A single 240 volt heat pump water heater. In addition, meet the following: i. A compact hot water distribution system as specified in Reference Appendix RA4.4.6 in Climate Zones 1 and 16; and

  ii. A drain water heat recovery system that is field verified as specified in the Reference Appendix RA3.6.9 in Climate Zone 16.

  B. A single heat pump water heater that meets the requirements of NEEA Advanced Water Heater Specification Tier 3 or higher. In addition, for Climate Zone 16, a drain water heat recovery system that is field verified as specified in Reference Appendix RA3.6.9. Exception 1 to Section 170.2(d)1: Multifamily buildings four habitable stories or greater may install a gas or propane instantaneous water heater with an input of 200,000 Btu per hour or less and no storage tank. Exception 2 to Section 170.2(d)1: A 120V HPWH may be installed in place of a 240V HPWH for new dwelling units with one bedroom or less.

  2. Central systems. For systems serving multiple dwelling units, the water-heating system shall meet the applicable requirement of A through F, or shall meet the performance compliance requirements of Section 170.1: A. For heat pump water-heating systems serving multiple dwelling units, the water-heating system shall be installed according to the manufacturer’s design and installation guidelines and meet the following requirements, or meet the requirements of NEEA Advanced Water Heater Specification for commercial heat pump water heater Tier 2 or higher: i. The primary heat pump water heater shall be a single-pass heat pump water heater. ii. The hot water return from the recirculation loop shall connect to a recirculation loop tank and shall not directly connect to the primary heat pump water heater inlet or the primary thermal storage tanks. iii. The fuel source for the recirculation loop tank shall be electricity. iv. The primary storage tank temperature setpoint shall be at least 135°F. v. The recirculation loop tank temperature setpoint shall be at least 10°F lower than the primary thermal storage tank temperature setpoint. vi. The minimum heat pump water heater compressor cut-off temperature shall be equal to or lower than 40°F ambient air temperature. vii. Design documentation shall be provided in accordance with JA14.4. B. For gas or propane systems serving multiple dwelling units, the water-heating system that includes the following components shall be installed: i. For Climate Zones 1 through 9, gas service water-heating systems with a total installed gas water-heating input capacity of 1 MMBtu/h or greater shall have gas service water-heating equipment with a minimum thermal efficiency of 90 percent. Multiple units are allowed to meet this requirement with an input capacity-weighted average of at least 90 percent.
• CPC § 3.785 Medium relevance — show source text

  For SI units: 1 gallon = 3.785 L

  Notes: 1 The first-hour rating is found on the “Energy Guide” label. 2 Solar water heaters shall be sized to meet the appropriate first-hour rating as shown in the table.

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  WATER HEATERS

  Exception: Where acceptable to the Authority Having Jurisdiction, gasketing of non-combustible or limitedcombustible material shall be permitted to be applied to the frame, provided closing and latching of the door are not inhibited.

  504.2 Vent. Water heaters of other than the direct-vent type shall be located as close as practical to the chimney or gas vent. 504.3 Clearance. The clearance requirements for water heaters shall comply with Section 504.3.1 or Section 504.3.2.

  504.3.1 Listed Water Heaters. The clearances shall not be such as to interfere with combustion air, draft hood clearance and relief, and accessibility for servicing. Listed water heaters shall be installed in accordance with their listings and the manufacturer’s installation instructions. 504.3.2 Unlisted Water Heaters. Except as otherwise permitted in this code, unlisted water heaters shall be approved by the Authority Having Jurisdiction prior to being installed. Clearance for unlisted water heaters shall be not less than 12 inches (305 mm) on all sides. Combustible floors under unlisted water heaters shall be protected in an approved manner. {NFPA 54-2018:10.27.2.2} 504.4 Pressure-Limiting Devices. A water heater installation shall be provided with overpressure protection using an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. Pressure relief devices shall have a pressure setting greater than the water service pressure and not exceed 150 psi (1034 kPa) as required in Section 608.4. 504.5 Temperature Limiting Devices. A water heater installation or a hot water storage vessel installation shall be provided with overtemperature protection by means of an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. {NFPA 54:10.26.5} 504.6 Temperature, Pressure, and Vacuum Relief Devices. Temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices shall be installed in accordance with the terms of their listings and the manufacturer’s installation instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly British thermal units (Btu) (kW•h) discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. {NFPA 54:10.26.6} Discharge piping shall be installed in accordance with Section 608.5.

  504.7 Lead Content. Water heaters shall comply with the lead content requirements of Section 604.2.

• CPC § 608.3. Medium 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.

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  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.

• CPC § 101.0 Medium relevance — show source text

  2025 CALIFORNIA PLUMBING CODE 487

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

  488 2025 CALIFORNIA PLUMBING CODE

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

  APPENDIX J

  COMBINATION OF INDOOR AND OUTDOOR COMBUSTION AND

  VENTILATION OPENING DESIGN

  The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.

  J 101.0 General.

  J 101.1 Applicability. This appendix provides general guidelines for the sizing of combination indoor and outdoor combustion and ventilation air openings. J 101.2 Example of Combination Indoor and Outdoor Combustion Air Opening Design. Determine the required combination of indoor and outdoor combustion air opening sizes for the following appliance installation example.

  Example Installation: A fan-assisted furnace and a drafthood-equipped water heater with the following inputs are located in a 15 foot by 30 foot (4572 mm by 9144 mm) basement with an 8 foot (2438 mm) ceiling. No additional indoor spaces can be used to help meet the appliance combustion air needs.

  Fan-Assisted Furnace Input: 100 000 British thermal units per hour (Btu/h) (29 kW)

  Draft Hood-Equipped Water Heater Input: 40 000 Btu/h (11.7 kW)

  Solution:

  (1) Determine the total available room volume. Appliance room volume:

  15 feet by 30 feet (4572 mm by 9144 mm) with an 8 foot (2438 mm) ceiling = 3600 cubic feet (101.94 m [3] )

  (2) Determine the total required volume. The standard method to determine combustion air is used to calculate the required volume. The combined input for the appliances located in the basement is calculated as follows:

  100 000 Btu/h (29 kW) + 40 000 Btu/h (11.7 kW) = 140 000 Btu/h (41 kW)

  The standard method requires that the required volume be determined based on 50 cubic feet per 1000 Btu/h (4.83 m [3] /kW). Using Table J 101.2, the required volume for a 140 000 Btu/h (41 kW) combined input is 7000 cubic feet (198.22 m [3] ).

  Conclusion: The indoor volume is insufficient to supply combustion air since the total of 3600 cubic feet (101.94 m [3] ) does not meet the required volume of 7000 cubic feet (198.22 m [3] ). Therefore, additional combustion air shall be provided from the outdoors.

  (3) Determine ratio of the available volume to the required

  volume:	Col2
  3600 cubic feet	= 0.51
  7000 cubic feet	7000 cubic feet

  (4) Determine the reduction factor to be used to reduce the full outdoor air opening size to the minimum required based on the ratio of indoor spaces:

  1.00 – 0.51 (from Step 3) = 0.49

  (5) Determine the single outdoor combustion air opening size as though all combustion air is to come from outdoors. In this example, the combustion air opening directly communicates with the outdoors: