How Does an Electric Irrigation Valve Work?

Lower Chamber

• The lower chamber of an irrigation valve receives water through the valve inlet from the main irrigation pipeline. When the valve is closed, either manually or electronically, the water from the main irrigation line is held within the first chamber and blocked from entering the second chamber by the diaphragm that separates the two.

Diaphragm

• The valve's internal diaphragm prevents water from flowing through the upper chamber and through the irrigation valve outlet. The diaphragm pushes against the chamber opening with a spring, although the spring is not strong enough to seal the chambers off by itself. The diaphragm is held closed by two components: a small spring and compressed air.

Upper Chamber

• The upper chamber houses the diaphragm and contains air pressure needed to keep the diaphragm closed. A small opening that leads from the solenoid to the upper chamber allows air into the upper chamber to later become trapped. The trapped air further applies pressure against the diaphragm to cut off water flow from the lower chamber. The upper chamber is connected to the valve outlet, which is closed off, until the solenoid is activated.

Solenoid

• The solenoid plays a large part in the operation of the valve. The solenoid houses electrical components that allow it to be lifted or closed by signals from a connected irrigation control timer. The solenoid can also be operated manually. When the solenoid is closed, its internal plunger prevents air from escaping the valve and keeps the diaphragm pressed against the chamber opening, thus preventing water flow into the upper changer. When the solenoid opens, the plunger lifts and allows air pressure to drop in the upper chamber. With low air pressure in the upper chamber, the water pressure in the lower chamber is now greater than the force applied to the diaphragm. This enables the water from the lower chamber to rush past the diaphragm into the upper chamber and through the valve outlet to activate the sprinklers.