Fusible Link Heat Detector 

Thermal link for increased longevity and reliability.

The thermal link is designed for use in boiler house applications.

Inside the thermal link there is a fuse which is designed to melt at 72 Degrees C, when positioned above a boiler, in the event of a fire the thermal link can break a contact to the Merlin gas safety system causing the gas solenoid to close and prevent any more gas entering the boiler room.