How A 2 Way Normally Open Solenoid Valve Operates

A 2-way, normally open, solenoid valve has 2 pipe connections, an inlet called the cavity port and an outlet called the stop port.
In its natural de-energized state the stop port is open and media flows into the cavity port and out of the stop port.
When the valve is energized the plunger seals the orifice, stopping flow through the valve.