Vacuum Pressure Breaker Part 2

Discussion in 'Irrigation / Sprinkler Forum' started by vaman, Aug 1, 2009.

  1. vaman

    vaman New Member

    Messages:
    41
    Location:
    NJ
    Hi I posted a question about 2 weeks ago on a leaking wilkins vacuum pressure breaker. The breaker was spraying water out the top. Bought a wilkins repair kit and replacement bonnet.
    When I saw the new bonnet at the store I could tell the old one was clearly damaged. It was bent upward.Now I understand why the canopy was cracked amd I had such a difficult time lining its screw holes with the bonnet.So I assume by the time I had the system winterized last year(done later than usual in Nov here in NJ),water had already froze in the system.
    I replaced all the above and water is still spraying out the top of the breaker. Don't know if the placement of the poppet in the spring is the cause. I placed the spring in first and then sort put the poppet in it.
    The breaker body itself shows no cracks or signs of leaking.
    Any suggestions are appreciated. Am ready to pull out my hair.:confused:
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,054
    Location:
    Cave Creek, Arizona
    Pvb

    If it froze, then the surface that the poppet seals against is "domed" so it cannot seal. The fact that the screws do not fit reinforces that diagnosis. A new brass cap will cure it.
  3. upper

    upper DIY Senior Member

    Messages:
    154
    Location:
    Fresno, CA
    I am thinking new,new.new.....Let us know,,,,,,,,Upper
  4. vaman

    vaman New Member

    Messages:
    41
    Location:
    NJ
    Replacing pressure vacuum breaker

    I assume the brass canopy is the same thing as the bonnet. I replaced that and while it has reduced the leaking significantly water is still spraying around the outer circumference of the bonnet. So I'm fearing the threads on the breaker itself are damaged.Looks like I'll need to replace the whole unit.
    As is obvious from my questions I'm not a plumber. Where do I saw the PVC pipe?

    Thanks for any help.:confused:
  5. tomm

    tomm New Member

    Messages:
    41
    pictures would help
  6. onedrop

    onedrop New Member

    Messages:
    11
    The bonnet on the Wilkins Pressure Vacuum Breakers is brass, the canopy is plastic piece on top. You can see a PDF of the parts breakdown that might be helpful here: http://www.sprinkler.com/files/720A Repair Parts.pdf
    By the way is it a 420 or a 720?
    If I were to guess what the problem is I would say that the housing is warped and a whole new unit is needed.
    Like tomm said, pictures could be helpful.
  7. vaman

    vaman New Member

    Messages:
    41
    Location:
    NJ
    Vacuum Pressure Breaker

    I finally got pictures of the leaking Wilkins pressure vacuum breaker. You may notice teflon tape on the bonnet circumference.Wanted to see if it would help any and of course it did not.
    The unite is a 720A and as some have said I think I'll need to replace the whole thing but wanted others to see this first. If I need to replace it I will post another picture showing the connections so I know what kind of PVC parts to purchase.
    Thanks again for all your help.

    Attached Files:

  8. onedrop

    onedrop New Member

    Messages:
    11
    Possible issue

    As I look at the picture you posted it looks like the bonnet might not be screwed in all the way. I can't tell for sure-- the picture might be playing tricks on me. Here is a picture that I took of a new one. Notice how far the bonnet is seated into the body.
    [​IMG]
  9. tomm

    tomm New Member

    Messages:
    41
    Get the teflon out. Is the o-ring and big plastic washer installed? Find a diagram of the internal parts to make sure you have them all installed correctly. Otherwise, install new one or get a pro out to your place.
  10. vaman

    vaman New Member

    Messages:
    41
    Location:
    NJ
    Vacuum Pressure Breaker Bonnet

    Will remove the teflon tape. I did replace the o-ring and plastic washer. But looking at the picture posted by onedrop makes me realize I have not screwed the bonnet in far enough. Just how tight is it supposed to be? Maybe I'm a weakling but hand tightening the thing is not enough. Now I can use a wrench to get it in tighter but just want to make sure that's the thing to do
  11. BRD

    BRD New Member

    Messages:
    53
    Location:
    northeast
    Pressure vacuum breaker.

    As suggested by Tomm, remove the teflon. The bonnet is sealed via the "o" ring. The bonnet should thread in by hand until the "o" ring comes in contact, then give it a little extra tightness. You should not have to crank down on it with a big wrench. Compressing the "o" ring is what seals it. If the bonnet does not screw in relatively easy and flush with the top as was noted also then I would say, as others have suggested in previous posts that the body is warped from being frozen and you need to get a complete new unit. Good luck.
  12. onedrop

    onedrop New Member

    Messages:
    11
    I agree with BRD. You should't have to use much force to crank it down. So, if its is taking that much effort it leads me to believe that it doesn't fit correctly because the body is likely warped.
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