The 12-inch probe is optimized for commercial-grade air handlers and large ducting

making it the reliable choice for maintaining water-source heat pump integrity in commercial or residential geothermal applications

High-Durability Construction: Materials selected for resistance to corrosion and structural fatigue in outdoor refrigeration systems

or overheating the valve body during the brazing process

638-inch ID

Siemens Industrial Controls 3RH2921-1DA11 Switch R-410A The 12-inch probe is optimizedThe Siemens 3RH2921 1DA11 is a high performance lateral auxiliary switch block specifically engineered for the expansion of control circuit contacts. Designed for veterans in the field, this Sirius auxiliary contact features a robust 1NO + 1NC (1 Normally Open and 1 Normally Closed) configuration, providing essential feedback for motor control logic. Its side mount architecture allows for a space efficient 10mm profile, attaching seamlessly via snap