21.5 MM Waste / Condensate pipe in clear plastic!

Discussion in 'Plumbers' Talk' started by METRO MARK, Jun 16, 2020.


    METRO MARK Active Member

    Anyone seen or know a supplier that can supply 21.5 mm O/D pipe and fittings in clear plastic / acrylic ??

  2. just pumps

    just pumps Screwfix Select

    Caravan/ motorhome/ marine suppliers carry all sorts, would it be suitable though?

    METRO MARK Active Member

    I would think so,
    The water in the pipe is at room temperature under NO pressure

    Carrying only condense waste water from a Central heating combi boiler to the outside world / drain

    I have a look around the suppliers you mention


  4. Darkslider

    Darkslider Member

    You can buy 20 and 22mm clear acrylic on eBay, just had a look. Not cheap though, £14 per 500mm! If you want a clear section for inspection i.e spot if it's frozen easily you might only need the one bit and can use solid for the rest?
  5. just pumps

    just pumps Screwfix Select

    What about the acid content in the condense water?

    METRO MARK Active Member

    A good quality PVC Clear pipe will be the same spec as off the shelf white waste pipe
    The acid content is low, and not in contact with the pipe for long periods as its dispensed from the boiler in dripbs and drabs, into a incline to the outside world
    PH of the condense water is about 6, and neutral is 7 so wont be melting the plastic rapid
    Brick cleaner which is about 18% Hdrochloric acid (PH 0) is stored in PVC plastic containers no problem :)

  7. The Teach

    The Teach Screwfix Select

  8. just pumps

    just pumps Screwfix Select

    Always thought you couldn`t use normal 21.5 overflow pipe, guess I was wrong and isn`t there something about the size of the pipe in the MI`s

    METRO MARK Active Member

    Hi TT,
    Yes seen this site and yes they are the closest to the 21.5 MM spec....Buttttttt for the smallest amount I need to do this project the price would be over £16.00 + Carriage for 1 X 1 Metre pipe and 1 90 elbow...

    Tad overkill :)

  10. masterdiy

    masterdiy Screwfix Select

    eBay item number:

    METRO MARK Active Member

    Hows this look?

    Attached Files:

  12. Darkslider

    Darkslider Member

    Looks like a good job! So was this to visually check for blockage? What did it cost in the end?

    METRO MARK Active Member

    Yup a project I wanted to do before winter came, so I could monitor the flow of condense going out, or not!.. or backing up...like last year with frozen external pipe (now fixed with lagging)
    Total cost was £21.62 OUCH including VAT & Delivery.
    1 metre of 1/2 inch pipe equates to £6.65 or 0.67 per CM
    90 Deg 1/2 inch bend (overkill) £8.98 for 1
    I used in total 20 CM on project, 15 for the straight, and 5 for couplings. Got 80 CM over, what can I use that on Hmmmmmm...
    The straight is not solvent welded, it holds well just pushed in, no leaks... I wanted to be able to remove the tube in case it got coated in some kind of algae etc to clean it
    All other joints FP Solvent cement
    Set on a 1.5 Deg slope, all works well no drips, and meets all BS regs that I can see.
    Might market as the "WOW" product..... Or Window On Waste device :)

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