Conventional Duct Detectors

Watertight 4-Wire Duct Detector

Product Overview

D4120W watertight 4-wire Photoelectric + relay Duct Smoke Detector is listed as a watertight enclosure providing protection against falling dirt, rain, windblown dust, splashing and hose directed water. D4120W duct smoke detector features a pivoting housing that fits various applications: both square and rectangular footprints mount to round or rectangular ductwork.

This unit senses smoke in the most challenging conditions, operating in airflow speeds of 0.5 m/s to 20.32 m/sec, temperatures of –20 °C to 70 °C and a humidity range of 0 to 95 % (non condensing).


  • NEMA Type 4 UL listed for non-hazardous indoor and outdoor applications
  • UV Resistant, UL listed housing and cover material
  • Photoelectric, integrated low-flow technology
  • Air velocity rating from 100 ft/min to 4,000 ft/min (0.5 m/s to 20.32 m/sec)
  • Versatile mounting options: square or rectangular configuration
  • Plug-in sensor offers superb false alarm immunity and the latest sensor technology
  • Broad ranges for operating temperature (–4°F to 158°F) and humidity (0% to 95% non-condensing)
  • Patented sampling tube installs from front or back of the detector with no tools required
  • Increased wiring space with a newly added ¾-inch conduit knockout
  • One easy-access Test/Reset button and improved LED status
  • Patented interconnect feature for multi-fan shutdown
  • New high contrast terminal designations
  • Built-in short circuit protection from operator wiring errors
  • Field selectable settings for configuring the detector
  • Two DPDT Form-C relay contacts
  • 24 Vac/dc or 120 Vac
  • Backward compatible with existing Innovair products, including remote accessories

Click here to download the white paper: Duct Application Smoke Detectors

Ordering Information

Product code
Conv 4 Wire Photo Duct Detector. 24VAC/DC & 120VAC w/relay No Tube Waterproof