AVB's

Discussion in 'Irrigation' started by rvsuper, Jul 25, 2002.

  1. rvsuper

    rvsuper Senior Member
    Posts: 930

    I was repairing a system today (a few heads got worn out). So I go to the timer to test the new ones. Well, I noticed that the system had an AVB insteds of a PVB. The system I believe has 6 stations. Last time I checked, aren't AVB's supposed to be after EVERY valve? I have never used these things before, so that is why I am wondering??????????
     
  2. HBFOXJr

    HBFOXJr LawnSite Bronze Member
    Posts: 1,712

    You are correct, OR an RPA or PVB at the point of connection.
     
  3. rvsuper

    rvsuper Senior Member
    Posts: 930

    I don't know who installed this system (it wasn't me) but do you think I should do something about them installing these?
     
  4. HBFOXJr

    HBFOXJr LawnSite Bronze Member
    Posts: 1,712

    Yes, it is good to upgrade to code. Makes $$$ and good relations. If elevation is not a problem just install 1 PVB before all else. Yes, you can blow thru them to winterize.

    If elevation is a problem, use an RPA but you must know if you can support the higher pressure loss the create before you do a deal. Sometimes under marginal conditions booster pumps or other changes might have to be made. In that case it may be more economical and practical to put an AVB after each valve.
     
  5. Ground Master

    Ground Master LawnSite Senior Member
    Posts: 505

    You could also install a master valve before the AVB, but my guess is the AVB is ancient, so go with the proper backflow device.
     

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