The NAVIEN 30024183A Water Adjustment Valve helps regulate water flow for consistent and efficient system performance. This replacement valve is designed for compatible Navien tankless water heaters and boiler systems, controlling the flow of water to maintain proper operating conditions. It works by adjusting water passage based on system requirements, supporting stable performance a... https://www.partshnc.com/30024183a-navien-tankless-water-heaters-water-adjustment-valve