Patterson-Kelley 23-0000-0230 Thermostat Hi Limit is a temperature safety control designed for compatible commercial boilers and hydronic heating equipment. It monitors system temperature and interrupts the heating circuit when the temperature reaches the selected high-limit setting, helping prevent overheating and potential equipment damage. Adjustable from 100°F to 240°F, it provide... https://www.partshnc.com/23-0000-0230-patterson-kelley-high-limit-thermostat-100-f-240-f