System Sensor D4120W


Watertight Duct Smoke Detector, 4-Wire, Photoelectric Type

Availability: In Stock

Condition: New
Brand: System Sensor
Status: Active
SKU: 31607
Manufacturer Part #: D4120W


The InnovairFlex D4120W watertight 4-wire photoelectric duct smoke detector is UL 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 100 to 4,000 feet per minute, temperatures of -4ºF to 158ºF, and a humidity range of 0 to 95 percent (noncondensing). A plug-in sensor head offers superior false alarm immunity. These features, plus a NEMA 4 rating, allow operators to mount the detector to rooftop HVAC equipment or use the detector in other harsh environments.

The new design provides the same form, fit, and wiring terminations as the standard InnovairFlex unit. Superior test and operational features added to the standard model are also available in this watertight unit. As the only watertight duct smoke detector on the market, D4120W provides unsurpassed environmental protection while simplifying installation, testing, and maintenance.

This InnovairFlex duct smoke detector can be customized to meet local codes and specifications without additional wiring. The new InnovairFlex product line is compatible with all previous Innovair models, including remote test accessories.

Additional information

Weight 2.5 lbs
Dimensions 2.50 × 5.00 × 14.38 in



Indoor, Outdoor

Material Qualities

UV Resistant, Watertight

Detection Method






Production Status



  • NEMA Type 4 UL listed for non-hazardous indoor and outdoor applications
  • 4-Wire Photoelectric, integrated low-flow technology
  • UV Resistant, UL listed housing and cover materia



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