repair pvc supply line immediately after pvb?

Discussion in 'Irrigation / Sprinkler Forum' started by GSK, Aug 13, 2011.

  1. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI
    busted sprinkler line #2.jpg

    busted sprinkler line #1.jpg



    I noticed a leak coming from the outflow ball valve of my pvb leading to the pvc pipe that goes to the valve box. I tried to unscrew it, and when it came off, it was broken. The male adapter threads of the pvc are now in the copper ball joint thread, and I have a busted pvc pipe leading to the ground. any idea how I can fix this?
    Last edited: Aug 13, 2011
  2. Gary Swart

    Gary Swart In the Trades

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    7,296
    Location:
    Yakima WA
    Take the valve off (just) to make it easier to work on. Use a small saw blade, like a piece of hacksaw or a fine tooth jigsaw, and make several cuts through the PVC using care not to cut much into the valve threads. Then with a thin screw driver, you should be break out the PVC in pieces. FWIW, I make my transitions from copper to PVC in a bit easier place to work on. I also avoid PVC male threads.
  3. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI
    How do I reconnect the valve to the pvc? The threads on the pvc, which are male, are damaged. Is there a union or something I can use to screw into the valve and then go over the busted pvc thread?
  4. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    First, you have to figure out how to arrange all that so the pvc is not tweaked at an angle like that. The broken elbow has to be replaced...not enough threads left on it. Cut all that out and down past wherever you said you broke the pvc. Start with a male adapter or a slip x ips street elbow. Work your way around. If there is not enough movement on one end or the other, use a union or an 'expando' slip coupling.

    Go to HD and cruise the PVC aisle...all the necessary fittings will become apparent to you
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,826
    Location:
    NW Ontario, Canada
    Ja, we cannot see what is off to the right of those pics but it sure looks cocked up. It's hard to judge size but I'm guessing from the #1 on the valve body that it's a 1" fitting. If you could find a 1" braided hose with ends or using barb ends, you might prevent it from happening again.

    I'm not familiar with that PVC riser you call a pvb so not sure if it comes apart or not. Maybe it could be cut off and an elbow glued onto it? Maybe you could chase the threads with a home-made die. I've taken a threaded EMT coupler and cut small slits in it with a skinny disk in a Dremel tool to make a thread chaser.

    If you warm up a threaded PVC coupler in hot water it might expand enough to go over the damaged threads.
    Last edited: Aug 14, 2011
  6. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI

    It's a febco 765-1 pvb, with ball valves attached.builder installed. Previous homes built in this sub have all copper piping where I have the pvc.
  7. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI
    The existing PVC and the ball valve both say 1"- so would I need a 1" street elbow? You don't need it to be slightly bigger to fit over the PVC?
  8. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Oh Boy!! Are you sure you want to do this yoursef??? Well, we all started out somewhere.........Get on over to HD >>>>you will see that a 1"pipe fits INSIDE a 1" fitting. One of the mysteries of plumbing stuff: the numbers don't mean much! Nothing in this equation will MEASURE 1". It just IS "one inch" size. Get your hands on some pieces and this will all make sense to you! It really is doable.
  9. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI

    I thought that sounded wrong. That's what the guy at Lowe's told me I had to do! Glad I checked here first. Anyway, HD didn't have the street elbow (they've never heard of it), but Lowe's did. Before I do it, is there any way for me to replace most of the PVC with copper? Copper male thread, elbow, and then most of the way down to the ground before it joins to the existing PVC? How would I do that?
  10. Gary Swart

    Gary Swart In the Trades

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    7,296
    Location:
    Yakima WA
    I have no clue as to what you call a pvb, but I would put a copper street ell or copper nipple into a regular elbow, then a length of copper pipe. After than, I'd transition to PVC, avoiding a male threaded PVC fitting. The thread in a female are weak and easy to break under stain. Yes, the copper fittings will cost more than PVC, but they will give you a much better connection.
  11. Jerome2877

    Jerome2877 In the Trades

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    397
    Location:
    BC
    PVB, Pressure Vacuum Breaker. Its not visable in the photo. PVB.jpg
  12. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,296
    Location:
    Yakima WA
    OK, so it's a backflow preventer. Be sure you have it certified annually, they do fail after a time. Easy for the tester to repair, they usually have parts with them. Nothing wrong with PVC for an irrigation system, but as previous stressed, avoid threaded male adapters and don't PVC under the stress of bending. I'd stay with copper until below the ground level. Once under ground the PVC will have pretty good stability. You might want to consider a copper union on each side of the PVB in case you need to remove it for the winter or repair.
  13. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Around here, backflow preventers like a PVB installed on a single family residence, irrigation system, do not require annual testing. Loophole? maybe/
  14. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,296
    Location:
    Yakima WA
    It may be correct that these devices do not have to be annually certified. I based my statement on the requirements for a double check BF and my city's requirements. If they do not have to be inspected, then in my opinion, it is a serious loophole.
  15. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI
    No inspections here, either. Didn't even know that there were places that had to have them inspected.

    Thanks to everyone who has advised me. I cut off the busted piece of PVC today and made a dry fit of everything before I glued it all together, and it looks like it will still have some pulling away force on the male adapter once it's in the ball valve. The new pieces are just short from making a perfect fit, maybe less than a quarter of an inch, even after extending the riser up to make my PVB level (it was on an angle before, to meet the male adapter). If I put it together the way I have it ready to go now, I think the same problem will happen again. Is there a PVC union or some other small piece that would fit between the elbow and the ball valve that could make up the difference?

    Oh, and I couldn't get the busted threads out of the ball valve. I tried cutting it, but it wouldn't budge, and by the time I gave up I had started to cut into some of the threads. I bought a new valve instead.
  16. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    How bout this? imagesCAKN9CDB.jpg

    You should support the PVB though, it shouldn't be supported by the pvc.
  17. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI
    Right, that's the piece I meant. I guess I just couldn't find it at lowe's.
  18. GSK

    GSK New Member

    Messages:
    8
    Location:
    MI
    Fixed!

    fixed sprinkler line #1.jpg fixed sprinkler line #2.jpg

    As I was connecting the last piece I realized that I probably should have replaced the other ball valve too.

    This afternoon, I checked it and saw a very slow, tiny drip, more of a slow ooze, at the connection between the outlet ball valve and the PVB. It's slow enough that I haven't noticed my water meter move yet, so I'm not going to worry about it for the rest of this season. What are my options- removing the PVB to tighten the joint, or cutting out the PVC again?
  19. mike1059

    mike1059 irrigation tech.

    Messages:
    56
    Location:
    Portland, OR
    If you have enough room between the pvc and the wall cut the pvc 1" below the elbow, tighten the ball valve one turn then install a coupler below the elbow.
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