The air-duct housings are uniquely design to  be use it with the photoelectric detector. Detector sensitivity can be check it by viewing the multicolor LED on the detector, or viewed from the control panel. The multi-color LED on the detector flashes green to indicate the detector has passed its self test and is within its proper sensitivity range. Yellow indicates either a Trouble condition or an Out of Sensitivity condition. Basically red indicates an Alarm state. he detector unit employs a cross-sectional sampling principle of operation. Inlet sampling tubes are available in four (4) lengths. he detector unit employs a cross-sectional sampling principle of operation. In addition, the unique design of the sampling chamber insures uniform sensitivity in air velocities, ranging from a low of 100-feet-per-minute to as high as 4,000 feet per-minute. Each housing comes with three (3) wiring entry ports:

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