CHUBB EDWARDS 521NC SMOKE DETECT PHOTO ELEC2W 24VDC CLEAN ME

Edwards 500 Series two-wire conventional photoelectric smoke detectors work on a light-scattering principle. A pulsed infrared light-emitting diode serves as the light source and a high-speed photo diode as the sensing element. This design protects against nuisance alarms caused by dust, insects, RF interference and ambient light. Built-in drift compensation allows the detector to automatically adjust its sensitivity over time as it becomes dirty. The 500 Series optical chamber is field replaceable. In the event of a confirmed alarm the LED will light continuously. The unit indicates trouble by flashing the LED every second. This meets the NFPA 72 field sensitivity testing requirements.