FireClass 601H-R Conventional Heat Detector

FireClass 601H-R Conventional Heat Detector, where two negative temperature coefficient thermistors are used, one is exposed to the air whilst, the other is thermally lagged inside the detector body. If the temperature of the air around the detector rises quickly a temperature difference will be established between the two thermistors. If a particular rate of change of temperature is sustained for sufficient time the detector will notify the alarm. If the rate of temperature increase is very slow, then the temperatures of the two thermistors will be more nearly equal. Under these conditions the detector will notify the alarm condition when the predetermined fixed temperature is reached.