Rinnai is introducing its new dedicated return valve (DRV) which makes installation a snap on any plumbing system with a dedicated recirculation line. The DRV is a two-piece fitting with ¾” FNPT connections. It contains an internal spring check valve to prevent backflow of the cold-water supply line into the dedicated return line. The DRV has ball valves and drain ports on both on the cold water inlet and the return line, so that you can isolate and purge either section of the plumbing system.