I just moved into a house in which the sprinkler system has been winterized. I want to get it going again, but I'm not sure what to do about these four valves here.

picture of pipes with four perpendicular valves

The previous owner told me that I need to go under the house and open a valve to deliver water to the sprinkler system. I did that that and may or may not have turned the two blue knobs (can't remember what state they were in originally), and water started spraying out of the four valves in the picture above.

I can tell from looking at it that I'm probably supposed to get a screwdriver and tighten or close those valves. But I don't want to make an educated guess and damage the system. Should I completely close off all four of them?

  • My goal is to get the system up and running, but any answer/comment/edit that explains what the various components in this picture are called and what they do will be greatly appreciated. Jul 1, 2012 at 21:04
  • 1
    my guess would be the 4 smaller ports on the manifold were left open to allow water to escape in case of a freeze. Not sure what their primary purpose is. I'd close them, then open the two blue valves.
    – Jason
    Jul 1, 2012 at 21:27
  • That's quite the assembly. Is there anything going into the ground between the two blue valves?
    – BMitch
    Jul 2, 2012 at 14:19

1 Answer 1


I'm no plumber, but I did just install my own sprinkler system. That looks like a reduced pressure assembly used for backflow prevention. the little screwdriver valves at bleeder. You should only need to touch them if Water comes out. With the main water under the house on, turn on the the big valve closest to the house first, then the second valve closest to the sprinklers. That should do it.

Google RP (watts makes them) and you should find plenty of info. Poetically no exact matches on pictures, but ask the right parts in the right places

  • 4
    It is a pressure reducing backflow preventor. From the picture all the bleeder valves are open. They need to be turned 90 degrees to close them. This type of backflow preventer will occassionaly spit water out of the bottom. This is a normal operation and does not mean it is leaking.
    – RSMoser
    Jul 2, 2012 at 14:35
  • Thanks, @RSMoser, that's what I needed to know. Works great now. Jul 3, 2012 at 0:26
  • The little valves are to enable testing that the backflow device is working correctly. When it comes time to winterize, it's important that all ball valves are opened. Water trapped inside a closed ball will freeze and break the valve case. Larger valves sometimes are not solid, there are voids on either side, so these valves need to be left half open so the voids can drain. Hopefully you also know how to drain the pipe that goes underground.
    – bcworkz
    Jul 7, 2012 at 3:03

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