The Hydrolevel 48-3204SF HydroStat is a 24V boiler control designed for Slant/Fin Sentinel SE-70 and Sentry S-60 hot water boilers. It regulates boiler water temperature, manages heating cycles, and provides low-water cut-off protection when installed with the required Electro-Well. This control helps maintain consistent indoor comfort, improve energy efficiency, and protect the boile... https://www.partshnc.com/48-3204sf-hydrolevel-hydrostat