Almost no pressure in 4 out of 6 zones

Discussion in 'Irrigation / Sprinkler Forum' started by texbob, Aug 16, 2020.

  1. texbob

    texbob New Member

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    Aug 16, 2020
    Location:
    Dallas, TX
    What would cause low pressure in 4 zones - 1, 2, 4 and 6 (entire front yard and zone 6 in the back of the house)? Water barely trickles out of each sprinkler head in these zones, but pressure is fine in zones 3 and 5. There are 3 anti-siphon values (see attached drawing indicated by v v in the right side of the front yard). When I open each one counterclockwise all the way, water starts to drip out. The water stops when I close the valve.
     

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    Last edited: Aug 16, 2020
  2. WorthFlorida

    WorthFlorida The wife is still training me.

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    Retired
    Location:
    Orlando, Florida
    Either debris inside the pipes or the irrigation valves are bad and may need a rebuild. If you know the first sprinkler after the zone valve, remove that sprinkler and turn in the water. If the water doesn't shoot up Several feet into the air, the valve could be the problem. The diaphragm gets stiff and may not be opening fully. If the four zones problem started at the same time then debris would be a suspect.

     
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  4. texbob

    texbob New Member

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    Aug 16, 2020
    Location:
    Dallas, TX
    Thank you. What does it indicate if water starts slowly leaking out from the valve when I manually open the solenoids? Also, the lawn guy recently replaced a sprinkler valve that got mowed over in a zone that is still working (zone 3) . Could debris from that sprinkler head opening travel and block a different zone?
     
  5. HudsonDIY

    HudsonDIY Member

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    Jun 19, 2019
    Location:
    Hudson, Florida USA
    If the valve itself is leaking you likely have a broken diaphragm in the valve.

    I've never heard of anything like this happening, its highly unlikely. It's a long way back up to the manifold set and into another zone even if it were the first head in the zone. On top of that the backflow preventer wouldn't allow much reverse flow if any at all.
     
  6. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
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    Occupation:
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    Location:
    Orlando, Florida
    All depends where the break was but for four zones to go out at once probably not. A lot of mud would have to entered the pipe. If you have pop up sprinklers, remove the nozzle only and below it there will be a filter screen. Remove it. If it’s full of mud that’s the problem. If not time to open valves.
     
  7. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Bad valves. As said before the diaphragms are dried out.
     
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