The solenoid valve opens, directs high-pressure fluid into the closing chamber, and results in an upward movement of the sliding piston.

The solenoid valve closes, reduces the water pressure to the paring chamber, and allows the spring force to move the sliding piston upward.

The solenoid valve closes, allows the water in the opening chamber to bleed off through "S", and the sliding piston moves upward due to the force developed in area "J".

The solenoid valve closes, allows the weight of the sliding piston to oppose the low water pressure, and moves it along the axis of the spindle.