utilizing the slave module expansion is recommended to maintain response times

it must be manually depressed to close the circuit again

Universal Lennox Compatibility: Integrated into a wide range of Lennox Elite and Merit series furnaces and air handlers

25-150 Amp sensing range

System Sensor D4S Detector Sensor 30067439-890 utilizing the slave module expansionThe System Sensor D4S is a 4 wire photoelectric duct smoke detector sensor component designed specifically for integration with the D4120 duct smoke detector housing. Engineered for high performance HVAC smoke detection, this replacement sensor head utilizes an advanced optical sensing chamber to detect combustion particles across a wide range of airflow speeds. It is optimized for low flow duct smoke detection, maintaining reliable operation in