Have you ever wondered how irrigation control valves work? In this short video, we’ll take you on a tour inside a Rain Bird valve to learn about the parts and technology that help keep water flowing exactly when and where you want it.Water naturally flows into the inlet side of the valve which is most often located on the side opposite the solenoid water fills the bonnet chamber above the diaphragm via the pilot flow filter and the force of this water pressing down on the diaphragm holds the diaphragm in place. Notice that the larger surface area of water on the top side of the diaphragm has more force pressing down to close the valve versus the force on the bottom of the diaphragm pushing up to open the valve.
The water continues to travel on through a port in the bonnet to the solenoid area. The solenoid has a light spring loaded metal piston that, when the valve is closed, covers the inlet port hole. The surface area that the water comes in contact with on top of the diaphragm is greater than the surface area on the bottom of the diaphragm, so the valve stays closed until the water in the upper chamber is released.
There is also a path for water to fill the solenoid the flow of water is stopped from flowing out the solenoid dump port by the solenoid plunger seal which is attached to the bottom end of the solenoid plunger when the irrigation controller sends electricity to the valve solenoid the solenoid coil becomes an electromagnet pulling the plunger up into the solenoid which allows the water in the solenoid and bonnet chamber to flow into the outlet of the valve.
This lower pressure above the diaphragm allows the high Inlet water pressure to push the diaphragm up which allows water to flow through the valve once the flow of electricity to the solenoid stops the plunger drops inside the solenoid and the water stops flowing in the solenoid dump port eventually the bonnet chamber water pressure becomes high enough to offset the water pressure below the diaphragm and the valve closes./RainBirdCorp