The Bosch D273TH four-wire photoelectric smoke detector uses 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 to 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 D273TH signals an alarm condition. After the alarm condition clears, interrupt power at the control panel to reset the detector. The D273TH is equipped with a 135 degreesF (57 degreesC) heat sensor.
Also known as -D273TH Smoke Detector-Detection Systems/Bosch Sec 4 WIRE SMK DET W/ HEAT DET - DS-D273TH-Bosch D273TH Smoke Detector - Photoelectric