HepVOŽ Running Adaptor 32mm - BV3 - 242909WT A HepVo Running Adaptor 32mm. HepVo is a self sealing valve designed to close the waste connection below a sanitary appliance to prevent the escape of foul sewer air into the dwelling. HepVo actively eliminates negative pressure within the waste system by opening and allowing in fresh air until a state of equilibrium with atmosphere is reached. This means that venting of the waste system, or the inclusion of air admittance valves in the waste system is no longer necessary. The HepVo valve means enhanced plumbing design and system efficiency, without compromising performance or risking the escape of foul air into the living space from the drain or sewer. Code: BV3