The Lochinvar & A.O. Smith 100166256 SPDT Pressure Switch is a dependable safety and control component designed for use in commercial and residential heating systems. This single-pole double-throw (SPDT) pressure switch accurately monitors system pressure and activates or deactivates circuits to help ensure safe, efficient operation. Commonly used in boilers and water heaters, it help... https://www.partshnc.com/spdt-pressure-switch-11