Heads not popping up without help

Discussion in 'Irrigation / Sprinkler Forum' started by gtwnguy, Jun 3, 2008.

  1. gtwnguy

    gtwnguy New Member

    Messages:
    3
    I have 2 pop-up sprinkler heads on one zone. Both heads will get plenty of water, and almost pop-up, but not quite. I have plenty good water pressure. When (rarely) one head pop-up on its own, then the other does automatically. Same when I slightly pull-up gently one head, then the other head on other side of the lawn does so on its own.

    It is not a water pressure (too low) issue; I measured and have plenty. Is there such a thing as too much water pressure? If that were the case, then why are they on the verge of popping-up, but just not quite.

    This has been the case since I first installed these oop-up heads years ago, and has not changed; I am out of ideas. Is there not something I can do that can make the pop-ups have an easier time rising (oil or lubricant or something?) Or keep them partially popped up at all time (if they go up just 1 inch, they will go up the full 4 inches.)

    Thanks for help.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,301
    Location:
    Cave Creek, Arizona
    heads

    I cannot imagine why you say it is not a low pressure issue, because from your description, that is exactly what it is. The pressure is enough to raise a head, but when you pull another one up, that reduces the pressure elsewhere and they retract. A weaker spring in the heads might help by needing less pressure to pop them up, but it also might not be enough to retract them completely.
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    What describe is a pressure issue. Are you sure you do not have a leak somewhere, including a big leakage around one or both stems before they get fully up?
  4. Gary Swart

    Gary Swart In the Trades

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    Location:
    Yakima WA
    You say you have plenty of pressure. Did you use a gauge to determine that? You may be losing pressure through a broken line.
  5. gtwnguy

    gtwnguy New Member

    Messages:
    3
    I did use a guage years ago, and all was well. Behavior has not change.

    The reason it isn't a pressure issue (at least no pressure loss) as that with a little nudge, they will pop-up just fine and stay up the entire duration of the cycle. If it was a low pressure issue, they would never stay up.

    Also, when 1 head pop-ups (whether by help on its own automatically), the other will instantly.

    Does anyone else have heads that simply don't pop-up even though pressure is fine?
  6. gtwnguy

    gtwnguy New Member

    Messages:
    3
    Exact opposite of what I desribed above. When I pull one up, the other rises on its own.

    I've been told I may have TOO much pressure, is that possible? Seems to make sense, since when one goes up it slighty lowers the pressure, allowing the other one to go up (opposite but same logic the quote above).

    Thanks again for any insights, this is very perplexing.
    Last edited: Jun 4, 2008
  7. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    Marginal design has come to bite you on the behind. Seals wear, and heads have more 'flow-by' than they did when new, and you get the unhappy scene you described. Buy new heads, is the simple answer.
  8. tomm

    tomm New Member

    Messages:
    41

    1. heads could be outputting more water than you have available(bad design), hence they don't popup all the way.

    2. A break/leak somewhere in the piping

    3. valve that does not open all the way

    4. valve that isn't open all the way, ie. your main turn on, prv is defective, etc.
  9. SteveW

    SteveW DIY Senior Member

    Messages:
    1,054
    Location:
    Omaha, NE
    Did this zone work OK last summer/fall? If so, you most likely have a leak somewhere. As others have said, this IS a pressure problem. You are saying, I think, that you have measured your house water pressure and it is OK - but you still have a "pressure problem" somewhere in that zone.

    Happened to me this spring - one zone had some heads that just couldn't quite get all the way up. I left it run a little while and found the leak by the large soggy patch in the lawn near one head, where a riser had developed a split.
  10. idrive67elky

    idrive67elky New Member

    Messages:
    1
    This is definitely a low pressure problem. I have the same thing happen on one of my bigger zones. I am guessing your pressure is fine if you measure while the system is off, or if all heads are fully popped up. But, if you were to measure while the heads were in the partial up position, you will see that you have very low pressure. This is because during the pop up process, there is water blow by of the seals. This blow by causes the heads to use much more water during pop up than they do once fully up and sealed. Your water supply can't keep up with the blow by.

    In short you need a larger supply line.

    I temporarily fixed mine by simply removing one of the retraction springs. That allowed one of them to pop up fully, and the rest followed suit. I dont really care that it doesnt always retract because it is hidden in shrubbery anyways.
  11. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    The springs should seldom be an issue. A typical pop up, if it is 5/8" diam, and the line pressure is a moderate 30 PSI, then you would have a total of 10 pounds of force acting to push up that stem. The spring pressure is considerably less than that.
  12. Wet_Boots

    Wet_Boots Sprinkler Guy

    Messages:
    798
    Location:
    Metro NYC
    If this is happening on only one zone of several identical zones, then you look for a leak, or maybe a faulty zone valve.
  13. garyl53

    garyl53 Engineer

    Messages:
    54
    Location:
    Colorado
    I think it could be a flow problem. The static pressure may be fine but once the water starts flowing it is dropping quickly and it is not enough to push the heads up. I would check to make sure the valve is opening fully as someone suggested and check that there is not a leak in the line somewhere. I would measure the pressure again at a head while the head is operating (add a "T" for the pressure guage) to verify something hasn't changed.
    G
  14. PEW

    PEW DIY Senior Member

    Messages:
    487
    Any repairs to the line? I have seen lines get small stones which lodged in an elbow reducing the flow.
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