enter image description here Crack in bottom part of backflow preventer can you just replace this part or do you have to buy entire unit??

Thanks, Eileen enter image description here

  • The crack is in the valve body not the "backflow preventer". The two units are not one unit. The valve can be replaced. Not sure what the thing on top is. How do you use it ? Is there a connection on the side we can not see ?
    – Alaska Man
    Jun 27, 2019 at 20:03
  • 1
    The visible crack is in a valve not the backflow preventer. Replace just the valve for that.
    – Tyson
    Jun 27, 2019 at 20:04
  • Tks didnt know what to call it, I knew top part was back flow.
    – iameadams
    Jun 27, 2019 at 20:33
  • Thanks, The added photo helps to understand how to disassemble the units.
    – Alaska Man
    Jun 27, 2019 at 20:49
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    You'll need to undo the Union below the ball valve (short piece of copper pipe between them) in order to be able to unscrew the valve from the backflow preventer.
    – brhans
    Jun 28, 2019 at 0:15

1 Answer 1


That's just a basic quarter-turn ball valve that's been tossed in there for shutoff purposes

The cracked part isn't part of the backflow preventer proper; it's simply a quarter-turn ball valve that's been put there to allow the preventer to be shut off as part of winterization or testing procedures. Simply replace it, preferably with a version that has a drain cap on the side for winterization purposes, and you'll be good for a good, long time afterwards. Note that you'll need to undo the union below the valve in the process of replacing it in order to be able to unscrew it.

  • Instead of a regular quarter turn ball valve, get one with a drain/bleeder cap on the side to prevent water from accumulating when the valve is closed and freezing and causing this again. You'd install it in a way that removing the cap in the winter drains the water.
    – Dotes
    Jun 28, 2019 at 0:30
  • Perhaps you could explain how to replace it by undoing the union so that it can be unthreaded from the backflow preventer.
    – Alaska Man
    Jun 28, 2019 at 3:18

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