Low Water Pressure Irrigation System?

Just installed an anti-siphon valve and brass shut-ff valve.

2. Three zones are getting water (not worried about the fourth), but the flow is very poor and none of the heads bother to pop up much.

3. I don't use the solenoid in the pic, but I do rotate it CCW to open up the valve there. The arrow next to the brass valve shows the direction of water flow.

Q: What is happening? Is the water valve causing a restriction? This low pressure never happened before.


It had nothing to do with the anti-siphon valve or shut-off valve. The 4 valve solenoids on the ground were not tight enough, and were "stealing" some of the pressure off of a fully turned solenoid in another valve. The pressure in one zone was being slightly offset by other solenoids that were slightly loose.  I removed the four solenoids, cleaned them, then reinstalled them to get a tight fit. Dirt through the years had accumulated in the solenoid threads that prevented a tight fit.  

Attachment image

2 Answers

  • 8 months ago

    How many sprinklers are you serving with that valve?  Cap off some of the sprinklers and see it the others will work right.  About 3 or 4 sprinklers is full capacity for a residential system.   You might have a mix-matched system.

  • 8 months ago

    if the valve is too small, it will reduce the pressure at the heads, yes. it also will reduce the volume of flow

    Source(s): grampa
Still have questions? Get answers by asking now.