Abstract: A manually resettable valve comprises a valve body having a cylindrical portion with a wetted enclosure defined by an internal coaxial aperture within which a magnetically attractable plunger is slidable between two terminal positions establishing the states of the valve. A spring urges the plunger toward a first terminal position; and an electromagnet mounted on the body and responsive to an electrical signal when the plunger is in its first terminal position magnetically attracts the plunger and moves it to a second position against the action of the spring. Finally, a permanent magnet in a magnetic circuit, whose elements include the cylindrical portion of the body and the plunger, holds the plunger independently of the electromagnet in its second terminal position thereby holding the valve in its "latched" state.