DNR Duct Detector: Features, Specifications & Replacement Guide
The DNR duct detector is an intelligent, non-relay photoelectric housing that samples air moving through HVAC ductwork and reports smoke to an addressable fire alarm control panel. If you are specifying a unit, replacing one, or wondering why a quote lists a housing and a separate sensor head, this guide explains how the product works, what to verify before ordering, how installation and testing are handled, and which parts to identify when something fails. What Is a DNR Duct Detector? The DNR is a duct smoke detector housing from System Sensor's InnovairFlex line. The same platform is offered under several fire alarm brands, including Notifier, Fire-Lite and Silent Knight, which is one reason part numbers can look confusing. The housing does not sense smoke by itself. It holds an addressable photoelectric sensor head that is sold separately, and the two together form the complete DNR duct smoke detector that connects to the panel. The "non-relay" description m...
