For the best Gemaire experience, please update your web browser.

System Sensor D4120 - Duct Smoke Detector - Photoelectric 4-Wire

Item: D4120
MFR: D4120
What’s the price?
Sign in or register for pricing.

Your Order Templates
Save products for later, or create order templates to quickly re-buy items for routine jobs.

Add To Order Template

Inventory At Nearby Branches



The Innovair Flex D4120 Duct Smoke Detectors provide superb immunity to false alarms and easy, labor saving installation options. Its flexible configurations allow an easy replacement to any model, and its 2 to 1 sensor to power board offers cost savings where both supply and return installation is required.

The InnovairFlex D4120 4-wire photoelectric duct smoke detector features a pivoting housing that fits both square and rectangular footprints and mounts to round or rectangular ductwork. This unit senses smoke in the most challenging conditions. An improved cover design isolates the sensor head from the low-flow feature for simple maintenance. With its 2:1 sensor-to-power capability, the power board of the D4120 may be used to monitor a second sensor, D4S, simultaneously (i.e., supply and return side). As many as 50 InnovairFlex detectors can be interconnected. When one unit senses smoke, all interconnected detectors will switch their relays; only the detector sensing smoke will go into alarm, thus pinpointing the fire source. An easy-access Test/Reset button makes it possible to test the unit with the cover on. Three DIP switches can be used to configure field selectable settings: cover tamper delay, number of sensors to be controlled, and shut down on trouble option. Each power board has two LEDs that can be used to indicate the status of connected sensors, and a quick reference imprinted on the cover explains the LED status indications (Standby, Maintenance, Trouble, and Alarm). The InnovairFlex duct smoke detector can be customized to meet local codes and specifications without additional wiring.

Versatile mounting options: square or rectangular configuration

Air velocity rating from 100 ft./min to 4,000 ft./min (0.5 m/s to 20.32
  • m/sec)

    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

    Plug-in sensor offers superb false alarm immunity and the latest sensor technology

    Increased wiring space with a newly added 3/4 in. 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

    24VAC, 24VDC or 120VAC

    Backward compatibility with existing Innovair products, including remote accessories


NameSystem Sensor D4120 - Duct Smoke Detector - Photoelectric 4-Wire
BrandSystem Sensor
Gemaire Item NumberD4120
Manufacturer Product NumberD4120
SKU - PIM Number1368704705711
ERP Number242432
Unit of MeasureEA
Weight3.5 Pounds (Lb)
Length15.3 Inches (In)
Width5.5 Inches (In)
Height4.1 Inches (In)
Hazardous MaterialNo
EPA Cert RequiredNo
Country of OriginMEX
GEM - Case Quantity

Parts List