The Navien Tankless Water Heaters 30025036A Thermal Fuse is a replacement safety component designed for compatible NPE-2 and NCB-H tankless water heaters. It works by monitoring temperature and interrupting the electrical circuit if excessive heat is detected, helping prevent overheating and potential equipment damage. This thermal fuse provides an important layer of protection for th... https://www.partshnc.com/30025036a-navien-tankless-water-heaters-thermal-fuse-npe-2-ncb-h