I recently moved into a new house. I was trying to test out the sprinkler system. I turned on the sprinkler valve in the utility room. I also turned on the valve on the backflow device (I think - never done this before). When they are both open the backflow device sprays water everywhere. In the video below I have it only slightly turned on so the spray is much less than full blast.

Am I opening the valves incorrectly? Is the backflow device broken? Or is it something else?

Video of issue: https://youtu.be/FHcr1fxBZqk

Backflow picture: enter image description here

  • A vacuum breaker like yours has several valves -- which ones did you turn on, and from where on the device was the water spraying? Commented Jul 21, 2016 at 0:13
  • Did you watch the video? If so, I can try to explain further. It not, it might do better than what I can describe.
    – rys
    Commented Jul 21, 2016 at 0:36
  • Sorry, didn't see the video link -- now that I've watched it -- does it do this if you set the downstream valve (on the right in your photo) open before introducing water through the bottom (upstream) valve? Commented Jul 21, 2016 at 0:45
  • With this device spraying like that there may be something stuck in it , or the valve is bad.
    – Ed Beal
    Commented Jul 21, 2016 at 0:46
  • Actually -- disregard my last comment. Say, does the water continue to come out if you open the inlet valve all the way quickly with the outlet valve closed? Commented Jul 21, 2016 at 0:49

1 Answer 1


If the inlet valve (bottom, in your picture) isn't opened enough, or if the other valves aren't set right, there's not enough pressure to activate the backflow preventer, so water just spews out the top and/or sides. Check out this video on how to properly "turn on" the pressure-vacuum breaker (PVB).

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