Caleffi launched its new 304 Series Vacu-Stop Vacuum Relief Valve (VRV). Available in ½” and ¾” MNPT, the Vacu-Stop is suitable for use in water and low-pressure steam services. It is ideal for use in water heaters and supply tanks. The valve automatically allows air into the piping system to prevent a vacuum which could siphon water from the system and damage water heater/tank equipment.