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Thread: DWV cleanout plugs weeping & test plug blowout during water test

  1. #1
    DIY Member jwray's Avatar
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    Default DWV cleanout plugs weeping & test plug blowout during water test

    I made a dry run (maybe I should say "wet run" ) of the water test on my complete DWV redo for my old house renovation project. I thought it wise to check it out beforehand and not try it the first time with the inspector there. It went pretty well except for a couple of problems.

    1. There are 2, 4" PVC cleanout plugs and one 2" cleanout plug in the basement that I could not get to completely stop "weeping" during the test.

    They started weeping pretty good at first. I was able to get it to slow down (especially on the 2" plug), but not stop completely, by tightening the plugs as tight as I could during the test. The 4" COs are especially hard to turn.

    There is about 30' of water head in 3" vertical pipe (the 4" pipe is just the horizontal building drain) above the cleanouts. There are many other cleanouts in the system, but none of them leaked at all (I'm guessing the lesser head pressure on the cleanouts at a higher elevation in the system have an advantage - although one that did not leak is only a couple feet higher, plus once these lower COs started leaking I sprinted around to tighten the others). They were all sealed with Rector Seal applied to both the male and female threads before tightening. Any ideas how to stop the weeping. I'm sure I'll fail the real inspection if the COs are weeping.

    2. (This one is more for entertainment value ) I setup the DWV so that the new can be isolated from the old by removing a 4" Fernco where they meet and capping the new system with a 4" cap. I then use a pneumatic plug in the CO wye just outside the building and fill away with the hose. The 4" cap I used was a rubber cap w/a hose clamp (like the Fernco). All was going well until I heard a loud "POP" in the basement. I ran inside and downstairs to find water pouring out where this cap USED to be. The cap was from Lowes and is American Valve brand I think (ironically made in China) and I'm guessing it is not rated to hold 30' of water head. Next time I'll use something like a Cherne mechanical plug that is rated to hold 30-35' of water. Fortunately no damage done by the water or the cap blowing out. Just a mess to cleanup. I'll bet that cap flying out would have been something to see. It was pretty loud outside even through the basement wall and scared my wife pretty good inside. Lesson learned.

    All joking aside, I guess that is a good reminder to be careful with test plugs as 30' of water head in 3" pipe creates about 100 lbs of force on the plug (if I did the math right). That could definitely cause some injury and maybe even get somebody killed if you got hit in the head at close range.

    Thanks,

    Joel
    http://www.cherneind.com/

    Last edited by Terry; 06-05-2010 at 04:47 PM.

  2. #2
    Plumber Cass's Avatar
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    Your right about someone being injured from the cap blowing out.

    The inspector will not pass your system with a fernco installed. It must be a banded coupling.

    Try using a teflon based pipe dope on the C/O threads and dope both cap and female threads.

  3. #3
    DIY Member jwray's Avatar
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    Cass,

    The Fernco is just a temporary so I can still shower and use the toilet while this project is in motion. Once the new stuff is good to go all the old will be torn out and the ferco will be replaced with a permanent CO adapter on the end of the new system at this point.

    I used Rector Seal which I think is teflon based and I understood to be the "good stuff" (it is priced like the good stuff). I did put on male and female threads originally and still got the weeping.

    Is it possible that once it started weeping the channel for the water was established and no amount of tightening will fix it? I'm not sure that is possible as this "channel" should be removed by further tightening I would think?

    I'm still puzzled as it seems I did everything right and still got the weeping. Will the inspector fail me over a few "tears" from the CO. It is not much at this point, but it is some.

    Thanks,

    Joel

  4. #4
    Plumber Cass's Avatar
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    A leak is a leak. Try using the white teflon based pipe dope and larger wrench.

  5. #5
    Moderator & Master Plumber hj's Avatar
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    Default force/pressure

    Force pushes the cap off. Pressure is what causes damage. Is that 30' of head pressure needed just to get the required 10' test at the fixture level?

  6. #6
    DIY Member jwray's Avatar
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    I'm basically testing the entire system as this is an entire replumb of the house (went from kitchen and 1 bath to rearranged kitchen and 2 1/2 baths). My understanding from the code was 10' above the fixture or the highest point in the system.

    So I plugged at the CO just outside the house (new work started just inside the house, used test plugs or glue on caps at all the outlets in the new system and filled it with water until it came out the vent stack in the roof.

    Is this the way to go or did I go astray at some point?

    Thanks,
    Joel

  7. #7
    Plumber/Gasfitter dubldare's Avatar
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    Thirty feet of vertical water column is almost 14 psi at it's base.

    A 5 psi air test would probably be more forgiving.

  8. #8
    Moderator & Master Plumber hj's Avatar
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    Default test

    Unless you have fixtures on an upper level, I just test 10' from the floor. When the stack is higher than that, I use a bushing into a test tee with a clear plastic hose hanging up about 12' and then fill with water until there is 10' of water in the hose.

  9. #9

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    What is the difference between a Fernco coupling and a banded coupling. Dosen't both have bands to tighten?

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