Edwards Signaling SD-2W SD Series SuperDuct 2-Wire Duct Smoke Detector, Photoelectric, 16-30VDC Operating Voltage, 50-750 Ohm Alarm Impedance

Super Duct 2 wire detector features a unique design that speeds installation and simplifies maintenance. Removable dust filters, conformally coated circuit boards, and optional water-resistant gaskets keep contaminants away from components, ensuring years of trouble-free service.  When cleaning is required, the assemblies come apart easily and snap back together in seconds.

SuperDuct detectors use differential sensing to prevent small environmental changes from triggering false alarms. A rapid change in environmental conditions, such as smoke from a fire, causes the detector to automatically signal an alarm condition but dust and debris accumulated over time does not change alarm sensitivity.

The detector assembly cover provides easy access to the smoke sensor, its wiring connections, sample and exhaust tube fittings, and the smoke chamber itself. Air enters the detector’s sensing chamber through a sampling tube (ordered separately) that extends into the duct and is directed back into the ventilation system through an exhaust tube (included). The difference in air pressure between the two tubes pulls the sampled air through the sensing chamber. When a sufficient amount of smoke is detected in the sensing chamber, the detector initiates an alarm.