DEMCO Heat Detectors D-103 employ the principle of electrother- modynamics, the science of relation between heat and electromechanical works. They are professionally designed to work reliably with most fire detection system with central control equipment.
These units feature a double stage fire detection by employing two distinct methods: Rate-of-Rise and Fixed Temperature, both of which are open circuits designs designed to close an electrical circuit upon activation. The DEMCO D-103 Heat Detectors meet the require- ment of UL521.