Bosch Security D340

Duct detector housing, 2-wire
Two-wire duct detector housing for the D285DH Duct smoke head. Use with compatible control panels.

  • Factory New
Brand: Bosch Security Part #: 50272 Categories: , Manufacturer Part #: D340


The D340 Two‐wire duct smoke housings mount on the ducts of heating, ventilation, and air conditioning (HVAC) systems. The housing works with the D285DH Duct smoke head. The D285DH detector in the housing monitors the presence of smoke in the conditioned air.

The efficient housing design samples the air passing through a duct and detects potentially hazardous conditions. When smoke is detected, the detector sends an alarm signal to the control panel or HVAC control equipment. The control panel or HVAC control equipment initiates the necessary action to control air handling systems.


Weight 4.23 lbs
Dimensions 4.30 × 6.50 × 15.50 in


Material Qualities

Fire Retardant, High Impact Resistance





Bosch Security

Production Status



  • For 1 ft. (30.5 cm) to 10 ft. (3 m) ducts with air velocity between 300 ft./min. to 4000 ft./min. (1.52 m/s to 20.3 m/s)
  • Easy duct tube installation through the housing cuts installation time
  • Detector test and reset without removing covers
  • Clear cover allows quick visual inspection
  • Tube filters, dust immune smoke detector, and easy disassembly for cleaning reduce maintenance time and cost


D340 Family two-wire duct smoke detector housings
Bosch Security – Data Sheet – 2019
Duct smoke housing, 2-wire; D340/D340P
Bosch Security – Installation Manual – 2017
Two-wire Smoke Detectors; D285 / D286 / D263 / D603 / D604 / D605 / D340
Bosch Security – Technical Service Note – 2017

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