Potter's CoilKeeper Supervisory Switch is designed to supervise the position of a coil on a solenoid for a preaction/deluge system as required by NFPA 13 (8.3.1.2.1). The unit monitors the coil electronically and determines if the coil is installed on the valve stem. If a technician removes the actuator from the stem, the CoilKeeper will activate a normally open set of dry contacts that can be wired to a supervisory circuit of the releasing control panel.