The LF-HD-4212 Conventional type heat detector identifies fire with both rapidly rising and gradually increasing temperature. It has three levels of fixed temperature settings to adapt itself to the local temperature of the area being protected. The detector utilizes a modern, accurate, state of the art negative temperature coefficient (NTC) thermistor that senses thermal changes in the protected area. And combined with the data stored in its non-volatile memory, the detector sends out alarm information to the Fire alarm control unit during rapid rise of heat or upon reaching its pre-set temperature rating.