Based on advanced thermistor technology, the Edwards SC20 Series heat detectors provide a reliable response to fires in areas where environmental conditions prohibit the use a smoke detection. The SC20FTU-3 is a fixed temperature unit, with an alarm threshold, operating at 135?F (58?C). It is intended for applications where flucuations of ambient temperature may be expected such as overmachinery in laundries, or factory locations where industrial processes may cause sharp temperature increases.The SC20RRU-3 has an alarm threshold of 135?F (58?C) and operates on the rate of rise of 15? or greater per minute. To increase response time, without compromising reliability, a rate compensation element enables the detector to become more sensitive to higher rates of temperature rise. Applications include general use in areas where smoke detection would be likely to produce false alarms such as in kitchens or shower rooms.A high intensity, red LED indicator situated on the detector moldingprovides clear indication when the unit is in alarm. For ease of removal, these detectors plug into the CSBU-1 base unit by a simple twist and lock action. In order to prevent unauthorized removal, a site selectable option is provided to lock the detector into its base. Once applied, the unit can only be removed by means of a special tool (Cat. No. EC-PST). See specifications for mounting box options and terminal sizes. All detectors are monitored for detector removal.