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Discuss Run open vented hot pipe to tundish/waste pipe?? in the Fittings & Pipes area at

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  1. Jennie

    Jennie GSR

    Hi all,
    My customer has had a legionella assessment done, as part of renting out her house.
    She has a fairly new, open-vented CWST in the attic. The hot water vent pipe discharges over the CWST, as is standard practise. However, the assessor says this is a legionella risk, and has recommended the pipe be re-routed via a tundish to a suitable discharge point.
    Personally, I think the assessor is being overly thorough. I've never heard of the vent pipe being run in such a way.
    But maybe I'm missing something.
    Plus also the tank needs a clean. It has sediment on the bottom. It's loose, and easily wiped off (if I drained down). But would you recommend I do a thorough disinfection of the tank, and - in which case - what chemicals/method would you recommend.
    I'd be grateful for your thoughts on this.
    Thanks so much

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    Last edited: Dec 6, 2016
  2. Chalked

    Chalked Plumber GSR

    Blooming legionella assessments.
    They go on a day course, and know it all. If they went by the rules, we wouldn't be allowed any header tanks!
    Apparently,the worst place in any house for legionella is the spout of a tap. They have to note on a report of there is any scale build up.!

    Elf & safety!!!!
    Last edited: Dec 6, 2016
  3. snowhead

    snowhead Well-Known Member

    It standard practice in the Commercial buildings I work on to have Vent to drain not to tank.

    Stops the tank getting over 20 if there's any venting over.

    And all the spray tap spouts and heads are cleaned regularly.
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