The AquaMotion ODR Valve is a small, quiet, lead free stainless/brass hot water recirculation valve for single pipe systems. It installs at the fixture furthest from the tankless hot water heater. It acts in conjunction with a circulator to supply hot water ON DEMAND or Built-in Timer on pump. The ODR Valve mounts below the fixture between hot and cold supply lines. When hot water is called for using an On-Call control or Built-in Timer, the circulator forces the cooled hot water in the hot water line into the cold supply line which returns it to the hot water heater. As hotter water reaches the ODR Valve it closes until a 95°F temperature is reached at which point the valve automatically adjusts to maintain this temperature. A Hot Water Circulator must be installed at the tankless.