The ones on the left are valves...solenoid operated. You manually shut them off by turning the knob at the top, clockwise,
The two devices on the right...I don't think you turn them off. Look to be possibly combo filter and backflow preventer. Can't tell for sure in the photo.
The stem on the top of the valve is the manual flow control and shut off. It is easier to close the valve when the water is shut off, rather than "fight" the pressure of water flowing through the valve. The piece on the right is a filter, (you remove the cap and turn on the water to flush it out), the white thing to the right of the filter is a pressure regulator/volume control. However, if you have to manually shut it off, then there is a problem with the valve or the electronics that work it.
The knob is also used to throttle the flow. Based on the other components, and the tubing in the photo, I assume this is a drip system, so often you do need to throttle it back.
Failure to turn off is not usually the solenoid, as it is spring loaded to return to she closed position. If the solenoid plunger got rusty or dirty, it could stick,
Usually, replace the diaphragm in the valve
The solenoid valves in your photo looks like Richdale Lawn Genie Valves. I used to use them, and the cost of replacement parts was the same or more than a new valve. the most recent valves I bought were at HD and they cost about 14 bucks each for 1 inch ports with female pipe threads in each end. I think they were Toro brand. I said they looked like Lawn Genie beacause of what looks like those stainless steel semi circles under the assembly screws.Excellent! Where can I find a replacement diaphragm? What is the best way to match it?
HJ - I am in North Scottsdale and work at the airpark if anyone knows of a place where I can find this part?
Rain Drip has special inline pressure reducing valves in 15 psi and 25psi choices that connect to the 1/2 inch black poly tubing. I have used both, and still do, but when a dripper emitter wants to clog up, it just does, with or without the pressure regulator, but the lower pressure is much less likely to blow a joint or emitter apart. I have lots and lots of drip irrigation for my wife's flower gardens, and uses (I guess??) several hundred dripper emitters and low volume sprayers.For drip irrigation, there are special low-flow valves that are supposed to work better and not clog up as often. Anyone have experience with them?
This is awkward, but...
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