The HTP 7500P-002 Thermodisc Flue Eco is a flue temperature safety control designed for compatible HTP heating equipment. It monitors flue gas temperature and responds to excessive heat conditions by helping regulate or interrupt system operation, protecting the appliance and venting components. This thermodisc is commonly used in boilers, water heaters, and other compatible gas-fired... https://www.partshnc.com/htp-7500p-002-thermodisc-flue-eco-190-f