Washing machine drain pipe long run

Discussion in 'Plumbers' Talk' started by Ian_Dorset, Jul 19, 2017.

  1. Ian_Dorset

    Ian_Dorset New Member

    Hello all,

    Any advice / layout diagram(s) greatly appreciated.

    I've got a washing machine (WM) that needs to be installed approximately 2m from the sink.

    Q1) Is it best to use a 'fixed' 40mm pipe than smaller diameter flexible hose (21mm)?

    Q2) What should the pipe (or flexible hose) 'fall' be per metre?
    ... I've seen different drop/metre values quoted (and don't have access to any guide which I assume is BS 12056 -2:2000).

    Q3) I also saw this video clip (PSB) where the advice was to connect the washing machine drain hose/pipe as high up underneath a sink worktop as possible.
    ... after a 2m run the WM drainage pipe/hose could be quite low height by the time it reaches the sink area!


    Q4) Also why should the standard sink u-bend be as "high up as possible under the sink"?

    Thanks in advance -

    Cheers,
    Ian
     
  2. KIAB

    KIAB Super Member

    Would definitely use 40mm pipe, but you can get 21mm extension hoses up to several metres in length.
    The u bend prevent siphoning the water from the appliance, I personally dislike standpipe as there a risk of flooding if you have a blockage.
     
  3. CGN

    CGN Screwfix Select

    Don't forget that the outlet from your washing machine is pumped, so under pressure, it is not relying on gravity for water drainage. For a couple of metres, you could just use an extension as Kiab suggested.
     
  4. The Teach

    The Teach Screwfix Select

    some washing machine manufactures make a note about extension drain hoses,extract from a WM manufacture

    ! We advise against the use of hose extensions; in case of absolute need, the extension must have the same diameter as the original hose and must not exceed 150 cm in length. Ensure that if the drain hose is pushed into a standpipe, that the end does not go down more than 15cms (6 inches). If the hose is pushed down too far, this may cause the machine to self -syphon ie. continuously empty.

    The 40mm stand pipe arrangement is the traditional setup but an extension drain hose can be used although it would need periodic checks for water leaks as they can leak (pin hole or cracking).

    So its do able but check your WM instructions.

    TT
     
  5. Dr Bodgit

    Dr Bodgit Super Member

    I much prefer to use the original hose plumbed into the sink waste so there's zero chance of it overflowing. I can't see an issue with using an extension frankly.
     
  6. Ian_Dorset

    Ian_Dorset New Member

    You're correct 'The Teach'

    It is a Hotpoint (BHWM 1292) and their customer support has been poor to put it mildly.

    The manual does state:
    "We advise against the use of hose extensions; in case of absolute need, the extension must have the same diameter as the original hose and must not exceed 150 cm in length.
    ...
    Ensure that if the drain hose is pushed into a standpipe, that the end does not go down more than 15cms (6 inches). If the hose is pushed down too far, this may cause the machine to self-syphon ie. continuously empty as it is filling"
    .
     
  7. The Teach

    The Teach Screwfix Select

    just advisory then :)

    Have seen WM's where the drain pump has not been able to shift enough drain water out in a timed cycle on extended 21mm tubes and going to fault status.
     
  8. Simon Quin

    Simon Quin New Member

    I must be being a bit dim here but... I wanted to plumb in my daughters washing machine to the existing waste outlet under the sink. The under sink spigot has a diameter around 22mm. However the supplied hose is too short. So I purchased the hose extension from SF along with a 22mm to 22mm hose connector. When I get to do the job it transpires that the extension has 22mm at one end and 29mm at the other. I can join the hoses together but cannot now attach the end of the hose to the outlet under the sink. I see in the recommendations for this product that others have used it without issue. Presumably their fittings would take a 29mm hose?
     
  9. Tilt

    Tilt Screwfix Select

    You use the original hose with the extension that you have been given and fit one 22mm end of the original into the 29mm of the new extension, using a plastic strengthening insert and jubilee clip.
    Just chop the connector in half and use this as the insert.
    This leaves 22mm at both ends.
     
  10. nigel willson

    nigel willson Screwfix Select

    That’s because the 30mm end is to gonn by onto the pump in the machine
     
  11. Simon Quin

    Simon Quin New Member

    So it is a replacement and not (as advertised) an extension. Looks like I shall have to return it and buy an extension elsewhere. The machine is new so I don't want to start taking it apart. Thanks for your help.
     
  12. Tilt

    Tilt Screwfix Select

    Take it back if you like but the above works just fine.
     
  13. Simon Quin

    Simon Quin New Member

    Thanks I will try it
     

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