The WATERPROOF HEAT OF RISE DETECTOR BS-661/A is a conventional heat detector which integrates the function of rate-of-rise heat detection.

The detector transitions to o alarm state when the temperature reaches 57 C.

Also, the detector o transitions to alarm state when the temperature rises suddenly by 32 C regardless of the initial temperature at the beginning of the sudden rise event.

The detector have a visible led and a remote led driver which are light up constantly in case of detection of fire, till cancelled from the panel.

They are turned off only when a reset command is given from the panel. The indicator led blinks every 7 sec indicating the normal function.