The CoilKeeper Supervisory Switch (CSS) is designed to supervise the position of a coil on a solenoid for a preaction / deluge system as required by NFPA 13. The unit monitors the coil electronically and determines if the coil is installed on the valve stem. If a technician removes the coil 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. Local LEDs at the CoilKeeper shows when the coil is in a normal state on the valve body, when the coil is removed from the valve body in a maintenance state, when the releasing circuit is energized and if the coil is open or shorted. The releasing circuit energized LED allows the technician to locally see the state of the circuit, preventing accidental release by re-installing an energized coil.