Recirculating Pump Hot Water Tankless By-Pass Valve kit for recirculation systems without a dedicated return line. Kit includes a lead-free Stainless/Brass Crossover Valve, Brass Tees and 2 ft. Flex Hose for Reliance Water Heaters Premium and Standard condensing gas tankless water heater models. It works by bypassing the hot water tank, allowing hot water to be delivered to the tap faster and more efficiently. This can save energy and water, as well as reduce the amount of time you spend waiting for hot water. The Recirculating Pump Hot Water Tankless By-Pass TBPV is easy to install and maintain. It is also very durable, so you can be sure that it will last for years to come. If you are looking for a way to improve the efficiency of your tankless water heater, then the Recirculating Pump Hot Water Tankless By-Pass TBPV is the perfect solution.