Navien 30008247A Water Adjustment Valve is a precision control component designed to regulate water flow within compatible tankless water heater systems. It works by adjusting the volume of water passing through the unit, helping maintain accurate temperature control and efficient heat transfer during operation. This valve is commonly used in Navien tankless water heaters and hydronic... https://www.partshnc.com/30008247a-navien-tankless-water-heaters-water-adjust-valve-t405-180r