Leaking Wilkins 720A PVB

Discussion in 'Irrigation / Sprinkler Forum' started by birdman65, Jun 15, 2011.

  1. birdman65

    birdman65 New Member

    Messages:
    2
    Location:
    New Jersey
    My PVB is leaking from the canopy. I disassembled the PVB components (bonnet, washer, o-ring, poppet assembly, spring) and checked for any damaged or worn items. One thing I noticed is that the rubber piece on the poppet assembly has a slight opening (slit). I did see this opening on poppet assemblies of other PVB diagrams, but not the 720A. It looks like it is manufactured this way, but want to verify. Can anyone confirm. Unfortunately, I can't submit a picture at this time. If this slit is correct, wondering how the PVB works to prevent water from going through this slit. Any other ideas of what could be the cause of the leakage?
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,351
    Location:
    Yakima WA
    Backflow preventer should be tested and repaired if necessary by a certified inspector each year. It is required in my city under penalty of disconnect of water service. Regardless of the legal requirement which may or may not be enforced where you are, it is the wise thing to do. Inspection cost me $35 per year and the occasional repairs are quite inexpensive when need. I think you might be wise to consider having your device repaired and tested by a certified inspector. It is not a complex job, but it does require special equipment as well as know how. The purpose of these devices is to prevent contamination of the water supply, so it should not be done by guess work.
  3. birdman65

    birdman65 New Member

    Messages:
    2
    Location:
    New Jersey
    Problem solved ... the outlet value wasn't closed completely preventing the system from fully pressurizing. Now, the next issue is that one of my zones is stuck open. Will clean the valve tomorrow. One down, one to go.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,691
    Location:
    Cave Creek, Arizona
    quote; the outlet value wasn't closed completely preventing the system from fully pressurizing

    If you are saying what I think you said, it makes no sense at all, since the valves downstream would create backpressure. But, the valve should seal from the incoming pressure, NOT backpressure.
  5. mike1059

    mike1059 irrigation tech.

    Messages:
    56
    Location:
    Portland, OR
    Just a side comment for hj, I have seen a case where a pvb will leak if the inlet valve is only partway open with an open valve downstream preventing the pressure from closing the pvb. If the inlet valve is opened fast enough it should seal.
  6. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,351
    Location:
    Yakima WA
    I did a little research on New Jersey regulations on backflows. It seems that they only require them to be inspected on "Non-residential" installations! From what I gathered from this was that homeowners can contaminate the water supply all they want, but a small business is required to have backflow devices inspected. Doesn't make sense, and hopefully I missed something. Just another example of how one area is very strict on something that another area pays no attention to. That's why you should always check with local code enforcement officials to see what is required and what is forbidden in your area.
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