The basic valve can be operated manually through the use of a 3-way selector. Selector options and their functions include:

(C) CLOSED
Upstream pressure or pressure from an external source is applied to the control chamber. Initiated by the spring, the diaphragm is pressed down to close the valve drip-tight.

(O) OPEN
Relieving the water or air pressure to the atmosphere from the control chamber causes the valve to open.

(A) AUTOMATIC
The automatic port of the 3-way selector is connected to a solenoid, hydraulic relay or pilot, which controls the valve. The common port of the 3-way selector connects the control chamber to either A, O, or C, depending on the direction the selector is pointed.