The Flamefast Auto-reset Thermal Fusible Link is to be installed directly above boiler plant and are designed to detect excessive heat, and when interfaced with a Flamefast BoilerGuard (or third party safety circuit) can be used to isolate the fuel supply to the plant.
 
With an activation point of 70°C, they will automatically reset once they drop below 55°C. This allows for functionality testing that is not available with traditional links.