Bosch D273THR Four‑Wire Smoke/Heat Detector with Trouble Relay

Bosch D273THR Four‑Wire Smoke/Heat Detector with Trouble Relay

These 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.

Key Features:

• 12 VDC or 24 VDC input
• Designed for commercial or residential use
• Four-wire application
• Light-emitting diodes (LEDs) indicate the status of the chamber, power, and alarm
• Removable terminal block to simplify wiring connections