Watts Regulator Co. offers the Series TWH Tankless Water Heater Valves for use with wall-hung tankless water heaters to simplify their installation, maintenance and operation. Series TWH replaces four unions, three tees, seven nipples, two ball valves, two boiler drains and two hose bib covers used in typical installations. Series TWH's full-port ball valve design has an integral purge and drain valve for simple water heater flushing.