Trane SEN1789 Smoke Sensor L99H008 indicating the SPDT contacts have

indicating the SPDT contacts have switched state

You must use a Lennox-specific conversion kit if your application requires propane

Durable Construction: Built to withstand standard operating temperatures in high-demand environments

The B1256558 is built for longevity in high-cycle applications

Trane SEN1789 Smoke Sensor L99H008 indicating the SPDT contacts haveThe Trane SEN1789 Photoelectric Smoke Sensor is a critical safety component designed for precise duct smoke detection within commercial and residential HVAC systems. As an OEM replacement for models like the SEN01789 and SL 2000 P 3WTRA, this unit utilizes advanced photoelectric sensing technology to identify smoldering fires by monitoring light scattering patterns within the air handler. This high sensitivity approach ensures reliable HVAC system