229 Neb. Admin. Code, ch. 24, § 007
Each hot-water supply boiler or water heater supplying potable water shall have at least one (1) officially rated pressure-temperature relief valve of the automatic resealing type, set to relieve at or below the maximum allowable working pressure of the boiler. Hot water supply boilers supplying non-potable water shall have at least: one (1) officially rated pressure temperature relief valve of the automatic resealing type, set to relieve at or below the maximum allowable working pressure of the boiler; or one (1) officially rated pressure relief valve of the automatic resealing type, set to relieve at or below the maximum allowable working pressure of the boiler. These relief valves shall be identified by the ASME Certification Mark and "V" or "HV" designator.
229 Neb. Admin. Code, ch. 24, § 007