The coil winding is not energized, the plunger tapered retaining spring, due to fluid pressure, pushes the sealing gasket onto the solenoid body seat ( hole ) and keeps it closed.
The exhaust is connected with the outlet, and they present a balanced pressure level.
When the coil winding is energized, the plunger is attracted by the fixed core, the main hole (DN) is opened and exhaust is simultaneously closed, and the fluid is free to pass directly from inlet to outlet.
EXHAUST STEP RESIDUAL PRESSURE
After the opening position, de-energizing the coil electrical winding , the plunger moves away from the fixed core, freeing the exhaust and returns to the orifice ( DN) load position.
The residual pressure into the plants downstream the system is discharged by the load position.