• 4-Wire 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 deg F to 158 deg F) and humidity (0% to 95% non-condensing)
• Rotary address switches
• Patented sampling tube installs from front or back of the detector with no tools required
• Increased wiring space with a newly added 3/4-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 compatibility with existing Innovair products, including remote accessories

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, operating in airflow speeds of 100 to 4,000 feet per minute, temperatures of -4 deg F to 158 deg F and a humidity range of 0 to 95 percent (non-condensing). A plug-in sensor head offers improved false alarm immunity and simple installation, testing and maintenance. An improved cover design isolates the sensor head from the low-flow feature for simple maintenance. The InnovairFlex housing provides ample wiring space, a 3/4-inch conduit knockout and built-in short circuit protection to prevent damage to sensitive components during installation. High contrast terminal designations make wiring easy. 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.