Advice please; Hymer dump valve problem

Discussion in 'Motorhome Chat' started by offwego, Oct 12, 2011.

  1. offwego

    offwego Read Only Funster

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    Hi all,
    Hoping that some of you experienced funsters can help with a fresh water dump valve fault.
    In May this year, I purchased a Hymer T656, which was first registered in November 2007. In preparation for a winter lay-up, I attempted to drain down the fresh water tank only to find that the dump valve was seized. As I live in a hard water area of France, I believe that a build up of calcium carbonate around the valve(inside the tank) has caused the seizure. I think that the previous owner must have had difficulty in opening the valve since the square brass shaft (on which the operating wheel sits) has been damaged.This is shown in pic 001.
    I have managed to expel most of the water by opening the sink and wash basin taps and letting the pump do the rest.
    I believe that this model of motorhome was not sold in the UK, but I am sure that Hymer vans imported into the UK (circa 2007,2008) would have had a similar if not an identical fresh water system fitted.
    My questions are as follows:-

    a) Would it be worth trying to free up the dump valve with a solution of vinegar and water and/or gentle tapping? I ask myself the question, if this is what has happenend to the valve in what state is the pump, although at the moment it appears to be working fine.

    b) Is the complete dump valve assembly a replaceable item ? There is some access to the shaft inside the tank, which may just be visible in pic 004. I have not been under the van to see what part of the mechanism is visible from there.

    Most grateful for any advice or your experience of this problem.

    kind regards,
    offwego
     

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  2. scotjimland

    scotjimland Funster Life Member

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    Soaking in neat vinegar overnight may work.. if not, measure the diameter of the valve and buy a new one from CAK tanks... http://www.caktanks.co.uk/
     
  3. philk

    philk

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    dump valve

    hi offwego,

    From memory, the shaft or the valve is square, have you tried turning the valve using the shaft and also, try turning it backwards.

    Philk
     
  4. offwego

    offwego Read Only Funster

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    Hi Philk,

    Thanks for your reply. You are correct, in that the part of the shaft visible outside the tank is a square brass shaft onto which the operating wheel sits. As this shows some sign of damage already and it does not appear very strong, I am reluctant to try and turn it by force in case it shears.
    Inside the tank, there appears to be a cylindrical keyed shaft which opens/closes the valve. I have tried turning this by hand without any success. Perhaps the idea of soaking overnight in vinegar may loosen up the mechanism.

    regards,
    offwego
     
  5. Allegro83

    Allegro83 Read Only Funster

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    We use a solution of water/wine vinegar in ratio 2/1 to descale the hot water boiler however you then heat the water. Same with the kettle when we have been to France/Spain. Could you add hot water/wine vinegar and then leave overnight?

    Jan
     
  6. Geo

    Geo Trader - Funster

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    Just add the water and vinigar
    Drink the wine
    You wont care if it works or not:Rofl1::Rofl1:
     
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  7. JockandRita

    JockandRita Funster Life Member

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    Hi Jim,

    I am sure that this is a Hymer specific item, and it doesn't appear to be available from the CAK Tanks catalogue.

    Being an older model, ours is just a wee plug on the end of a chain. :Smile:

    Cheers,

    Jock.
     
  8. Jaws

    Jaws Funster Life Member

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    I thought for a minute you had been peeking.. then I realised what you meant :Wink::BigGrin:
     
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