Section 455C.234 - Lined potable water heaters: Relief valves1. A potable water heater must have at least one pressure and temperature relief valve that is:(a) Not smaller than three-fourths of an inch standard pipe size; and(b) Marked with the symbol V or HV to ensure compliance with the construction and rating requirements of the code.2. The pressure setting of the relief valve must be less than or equal to the maximum allowable working pressure of the potable water heater. The temperature setting of the relief valve must not exceed 210 degrees Fahrenheit. If any other components of the hot water supply system, such as a valve, pump, expansion or storage tank or piping, have a working pressure rating that is less than the potable water heater, the pressure setting for the relief valve must be based upon the component with the lowest maximum allowable working pressure rating. If there is more than one safety relief valve on a potable water heater, the pressure of the additional valve must not exceed the pressure of the first valve by more than 10 percent.3. The relieving capacity for the safety relief valve of an electrically powered potable water heater must be greater than 3,500 British thermal units per hour per kilowatt of input. The required relieving capacity for the safety relief valve on any other potable water heater must be in British thermal units per hour and must not be less than the maximum allowable input.4. A potable water heater must have a safety relief valve capacity such that when the fuel-burning equipment is installed and operated at maximum capacity, the pressure cannot rise more than 10 percent of maximum allowable working pressures.5. If operating conditions change or additional heating surface is installed, the capacity of the safety relief valve on a potable water heater must be increased to meet the requirements of this section. If any additional valves are required because of a change in operating conditions, the valves may be installed on the outlet piping if there is not an intervening valve.Nev. Admin. Code § 455C.234
Added to NAC by Div. of Industrial Relations by R101-02, eff. 12-15-2004; A by R045-20A, eff. 10/26/2020