DEMCO Air Duct Smoke Detector Housing D-501 is compact and comes with a clear cover for ease of monitoring the presence of smoke in heating, ventilation, and air-conditioning (HVAC) systems. This versatile unit can be mounted both vertically or horizontally onto a round or rectangular duct. It can be used with either photoelectric detector head or ionization detector head. The unit operates best at air velocities of 0.5 to 20.32 metre per second (100 to 4,000 feet per minute), temperatures of -20°C to 70°C (-4°F to 158°F), and a humidity range of 0 to 95 percent (non-condensing).
The D-501 housing completed with a detector head will sample air passing through a duct and detect potentially hazardous conditions. When sufficient smoke is sensed, the detector sends an alarm signal to the control panel which then shuts off fans and blowers or to switch to other air handling systems.