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

The ZoneFirst PIRR is a 24Vac 4PDT Plug-In Relay engineered as a direct high-performance replacement for RR and RMABS relays

The robust design includes a stainless steel bellows assembly and a 16 bar maximum working pressure rating

638-inch ID

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

Siemens Industrial Controls 3RH2921-1DA11 Switch R-410A making it the reliable choiceThe 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