The InnovairFlex D4240 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 operates in airflow speeds of 100 to 4,000 feet
per minute, temperatures of –4°F to 158°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