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Discuss DIYer - need help with toilet pipe air-valve install in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. pc__upf

    pc__upf New Member


    New to the forum - hoping to get some help here.

    I am rerouting my toilet to have the pipe work hidden in the eaves.


    Bath/shower/basin waste connects to the toilet drain via Barco Bos.

    I need help with the air vent.
    - Do I need one for toilet, and another for shower/bath/basin waste?
    - Do I need one for each bath, basin and shower?

    Where is the best location for the air valve (or valves)?

    Many thanks for your help.
  2. chris watkins

    chris watkins Plumber

    Is the stack vented to outside air or is there another stack on your system that vents?
    What is a Barco Bos?
    What size is the waste float picking up the bath & shower & how long is the run to the bath?
  3. Rob Foster

    Rob Foster Top Contributor!!

    I fink op means a strap on or glue boss to put the 1 1/2 inch waste into the 4 inch. If its inch and quarter ..uck. chking
  4. Chuck

    Chuck Well-Known Member

    Four 90-degree bends and no rodding-points? Sewage doesn't run up-hill, and it doesn't like corners much either.
    • Agree Agree x 2
    • Like Like x 1
  5. Rob Foster

    Rob Foster Top Contributor!!

    Yea, Op probably needs a re think, maybe we can help him
    off out chking
  6. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Boxing and run to the right off the toilet
  7. Rob Foster

    Rob Foster Top Contributor!!

    logical, cheaper and better chking
  8. pc__upf

    pc__upf New Member

    Gents, thanks for your replies.

    Yes, perhaps not the most logical approach but I'd like to try before giving up. This will make space available that was previously unavailable.

    The bos (or boss) connects the 40mm on to the 4 in pipe.

    It is not going uphill - there is a drop of about 450mm from toilet outlet to outside stack. Is this sufficient?

    The stack can be vented outside, but will it take care of the basin/bath/shower pipe venting?

    Adding rodding point to the planning.
    Last edited: Apr 17, 2019
  9. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    I would say it will block in no time at all have you contemplated 45° bends
  10. pc__upf

    pc__upf New Member

    I have contemplated 45° bends, but they really complicate things. Pipe going in between joists, etc.

    For what it's worth, i'm using wide 90° bends (don't know the actual name). Still bad?

  11. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    It’s more the proximity of the bends. Every turn causes resistance and friction to the nasties trying to run away. Sometimes the easy option isn’t the right one
  12. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Swept bends (what there called)
    • Like Like x 2
  13. pc__upf

    pc__upf New Member

    Thanks ShaunCorbs.

    Riley -
    would swept bends solve the problem in my planned setup, or do you still find them a problem?
  14. pc__upf

    pc__upf New Member

  15. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    I wouldn’t were it me and based on the angle there you are eating up more and more space
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