Apollo Heat Detector, 17 → 28V dc

Rate of Rise Heat detector is designed to detect a fire as the temperature increases, but they also have a fixed upper limit at which the detector will go into alarm if the rate of temperature increase has been too slow to trigger the detector earlier.

Apollo Smoke - Fire Detectors

Series 65 conventional detectors which are designed to be aesthetically similar, and are moulded from a white polycarbonate case. The packaging is such that the lid can be used as a dust cover until the commissioning of the system. The detectors have an externally visible LED which lights up when the detector changes to alarm state.