Ashcroft B420S Differential Pressure Switch

The Ashcroft B420S Differential Pressure Switch is a rugged, industrial-grade sensor in Ashcroft’s B-Series line that converts a sensed pressure difference between two ports into a discrete electrical output for control, shutdown, or alarm purposes. Designed for industrial environments, it supports diaphragm-based sensing and a configurable switch element to suit media compatibility and temperature requirements, making it suitable for monitoring differential pressure across filters, pumps, valves, or process vessels. As part of the B-Series family, the B420S leverages Ashcroft’s proven approach to differential pressure switching, offering solid reliability, repeatable setpoints, and stable operation over long service life. Typical applications include filtration-differential monitoring in HVAC and cleanroom systems, pump suction/discharge differential checks, and general process control where maintaining or detecting a pressure difference is critical. The model is intended for field installation on standard process connections and interfaces with conventional control circuits or alarm panels, delivering a clear, binary signal when the differential threshold is reached. Materials and diaphragm options follow the B-Series framework to accommodate a range of media and mounting environments, with Buna-N diameters among the common configurations, and additional wetted-material choices available across the broader Ashcroft lineup. In short, the B420S provides a dependable differential pressure monitoring solution that helps protect equipment, ensure process integrity, and support automatic responses in industrial systems.