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Bosch D273THES

Bosch D273 Smoke Detector - 4 Wire smoke detector with therm istor, EOL relay/sounder

The D273 Series Detector models use an infrared (IR) LED light source and a silicon photodiode to measure light in a chamber. A fine screen covers the chamber to deter insects and reduce dust accumulation and nuisance alarms. During a fire, smoke particles reflect light onto the photodiode. When the photodiode measurements exceed the alarm threshold, the detector signals an alarm condition. After the alarm condition clears, interrupt power at the control panel to reset the detector. When a D132B Reversing Relay Module is used, the LED does not latch on alarm.

General Information

  • Product Type: Smoke Heat Detector
  • Product Series: D273
  • Brand Name: Bosch
  • Manufacturer: The Bosch Group
  • Product Model: D273THES
  • Product Name: D273THES Smoke Heat Detector

Technical Information

  • Detectable Medium: Fire
  • Sensing Technology: Photoelectric

Physical Characteristics

  • Height: 2"


  • Compatibility: D132B Reversing relay module
  • Package Contents:
    • 1 x D273THES Smoke Heat Detector
    • 1 x Literature Pack
    • 1 x D273THES Smoke Heat Detector
    • 1 x Literature Pack
  • Additional Information:
    • Designed for commercial or residential use
    • Four-wire application
    • Removable terminal block to simplify wiring connections
    • UL Listed
    • MSFM
    • NYC-MEA
    • CSFM

Power Description

  • Input Voltage Range: 10 V DC to 30 V DC


  • Status Indicators: LED - Status of the Chamber, Power, and Alarm

Full specifications (PDF)