Model D-103-3
 
Demco Heat Detectors D-103 employ the principle of electro thermodynamics, the science of relation between heat and electro-mechanical 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 Heat Detectors meet the requirement of UL521.