Potter OSYSU-1 Outside Screw and Yoke Valve Supervisory Switch (Single Switch)

The Potter OSYSU-1 functions as a high-integrity, weather-resistant supervisory switch designed to monitor the open or closed state of OS&Y type gate valves within life-safety fire protection systems. Encased in a rugged NEMA 4X and NEMA 6P die-cast housing, the device features a single set of Single Pole Double Throw (SPDT) Form C dry microswitch contacts. It is designed to clamp onto the valve yoke bracket via adjustable mounting hardware, interfacing directly with the moving valve stem through a spring-loaded stainless steel trip rod. When the gate valve is fully open, the trip rod rests inside a user-filed notch on the valve stem. If the valve handwheel is turned toward the closed position, the stem moves, forcing the trip rod out of its groove within the first two revolutions and immediately dispatching a supervisory alert signal to the main fire alarm control panel. The OSYSU-1 incorporates unique three-position diagnostic logic that also trips the electrical contacts if the entire device is unbolted or physically removed from the valve, providing comprehensive tamper security.