simple leak question

Discussion in 'Irrigation' started by justgeorge, Jun 11, 2005.

  1. justgeorge

    justgeorge LawnSite Senior Member
    Posts: 352

    I've got a head at the end of the zone that is really soaking the ground around it. I replaced the head once which was leaking badly. The ground is still totally saturated around that head. The head is a Hunter I-20, which has the drain check valve (plus the lot is flat). If the PGV valve for that zone is slowly leaking, would the drain check valve prevent water from seeping out?

    I'm about to head over there again and I'll be able to check the water meter to see if it's moving which will also tell me if the PGV valve is leaking.

    It's not a leak in the lateral; last time I was out there I had the last 6-8 feet exposed and found nothing. I chalked it up to ground saturation from the initial faulty head (which I took apart when I got it home and there was a lot of grit in the filter screen; cleaned it out then tested it on my system and it was fine).

    Anyway, my question was hidden above; will the drain check valve prevent water seepage from a leaky valve?

  2. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    You better take that valve apart and check the diaphragm and the exhaust ports under the solenoid.

    The check valve is supposed to be good for 10' of elevation which is about 4.3 psi. A valve leaking by will in all likelyhood create more pressure than that. Check valves are installed to prevent 'low head drainage' after the zone waters, not to hold back a leaking valve.

    Jerry R
  3. justgeorge

    justgeorge LawnSite Senior Member
    Posts: 352

    Yep it was the valve. Note in the picture (if I attach it correctly) the small piece of debris in the upper left corner of the diaphram. Strangely enough the water meter wasn't moving; it must need more flow than was leaking thru to register.

  4. Uh oh...galvanized pipe particle!
    Get used to taking these valves apart.....heh heh heh.
  5. F6Hawk

    F6Hawk LawnSite Member
    Posts: 195

    Think about how much the customer could save on water bills if every valve had one of those! Talk about getting over...
  6. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    System have a MV? I see a lot of wet areas from leaky valves on systems w/ a MV and you won't "see" the leak at the meter because the system is de-pressurizing through the leaky valve. Manual the MV open or use the clock to open the mv without another zone on and then check the meter.
  7. justgeorge

    justgeorge LawnSite Senior Member
    Posts: 352

    Actually if it had a master valve I don't think the problem would have shown up at all. With the MV closed and no pressure on the leaky PGV valve, the drain check valve on the I-20s should have kept any water from coming out anyway. Perhaps a good reason to always install a master valve.


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