The NAVIEN 30012262B Control Board is a replacement PCB designed for the KDC-350M NCB series condensing gas combination boilers and tankless water heaters. It serves as the system’s electronic control center, coordinating temperature regulation, ignition operation, pump functions, sensors, and safety controls to support reliable heating and hot-water delivery. https://www.partshnc.com/30012262b-navien-tankless-water-heaters-control-board-bd-kdc-350m-ncb