Webasto Dualtop Leaking Drain Valve

Discussion in 'Heating and Air-Conditioning' started by jonandshell, Dec 12, 2010.

  1. jonandshell

    jonandshell Funster

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    We own a Chausson Welcome 35 with a Webasto Dualtop heating sysyem fitted.
    Whilst filling up prior to a trip weekend away, we noticed water discharging from the drain valve of the boiler.
    No amount of playing with the manual drain selector would make any difference and the water continued to flow.
    We contacted our local dealer who then referred us to Webasto technical who were brilliant! They called us back at 6pm on a Friday night and talked us through the problem! After half an hour on the phone, after running several checks, the technician from Webasto diagnosed that our unit was probably furred up and would require descaling. We thanked him profusely (no charge for all his help!) and headed to Tesco for some vinegar!
    The newer owner's manuals for the dualtop detail a descaling proceedure using white wine vinegar. We used malt, but what the hell! It worked!
    The valve, however, was still sticking. Like everything else that sticks, I reckoned it needed working to free it off.
    I must emphasise the following advice is not from Webasto!
    If you hold the selector dial on the control panel to the left and hold it in the manual drain position, the valve will operate every five seconds.
    Clip a pair of molegrips lightly on the switch, holding it in that position and go and watch Eastenders! During your break, the valve would have been open and shut 180 times, thus freeing it off and allowing it to seal once more!
    We live in a hard water area and wild camp a lot. Therefore we always fill our water tank before we go. A 6 monthly descale looks like a small trade-off for having an otherwise brilliant heating system!
    A bit shout out also for Webasto for the best customer care we have ever experienced in the field of motorhoming!
     
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  2. scotjimland

    scotjimland Funster Life Member

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    A good post .. :thumb:

    and welcome to the forum


    I've always used vinegar for descaling kettles, coffee machines etc .. cheap, non toxic and very efficient .. :thumb:
     
  3. jonandshell

    jonandshell Funster

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    Malt vinegar

    We made sure we didn't taint the cold water system by disconnecting the cold water feed to the boiler and introducing the vinegar directly to the boiler using a small funnel.
    We had a vinegar smell from the hot taps until after a few flushes, but it worked wonders at cleaning the stainless steel sinks!
    I might well modify our pipework to incorporate a couple of shut-off taps and a tee-piece to allow easier descaling in the future.
    Glad you liked the post.
     
  4. Terry

    Terry Funster

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    Welcome from me as well :thumb:
    terry
     
  5. Bailey58

    Bailey58 Funster Life Member

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    Hi from near neighbours in Norfolk, there's a lot of us in the county as you'll discover. If you post in "Introduce Yourself" you'll get warm welcome from lots of the cast, just beware of The Nutters. :thumb:
     
  6. jonandshell

    jonandshell Funster

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    Thanks for the warm welcome! Hope our paths cross soon!
     
  7. morocco bound

    morocco bound Read Only Funster

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    webasto dual top drain valve

    We have the same problem but it must be a later or different model. The control panel is electronic and only has a button to activate drain, so cannot force the valve to keep repeating.
    Although hand book suggests the vinegar method followed by heating and then soaking this won't work because as fast as liquid is added it comes straight out the other end and therefore will not soak.
    would be glad of any other suggestions. This only manifested itself today so could not contact Webasto and we are off to Devon tomorrow am

    regards morocco bound
     
  8. jonandshell

    jonandshell Funster

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    I can only suggest not watching TV and switching the dump valve manually!

    I know my way round a Dualtop now after having removed the burner for cleaning. You can access the drain valve by removing the black plastic cowling at the front of the jeater. Its not a job for the faint-hearted. You need a set of torx drivers and a good mechanical aptitude.
    I have a PDF workshop manual somewhere on the PC.

    PM me your email and I'll send it to you.

    -Jon
     
  9. jonandshell

    jonandshell Funster

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    Another suggestion-

    To stop the contents of the boiler emptying whilst you are descaling it you can switch off your water pump to reduce the pressure on the valve.

    You can also push something into the end of the silicon drain hose to bung it up too. You will find the drain hose end just up inside the recess under the heater where the water is coming from.
     
  10. jonandshell

    jonandshell Funster

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  11. 1939baldylocks

    1939baldylocks Read Only Funster

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    Leaking Dual Top

    My van is only just over 2 years old and I have had the same problem with my dual top leaking from the dump valve on several occasions, the hand book does not tell you at what intervals and dilution of vinegar you should use to stop scale forming but I did find this out after visiting an approved repairer to rectify a leak high up in the water jacket. Webasto does publish this kind of information to their repairers but not to us mere mortals who buy their products.
    Webasto have now changed the dump valve to incorporate a filter to stop scale from blocking it, in my case the piece of scale was about the size of a pinhead the valve is less than a quarter inch across! They have also changed the method of descaling using citric acid instead of vinegar. I took my van to an approved Webasto repairer because like you I could not put in the descaling liquid as it just drained straight through. This repair cost £550 and Webasto do not accept that the valve was not fit for purpose as this seems to be a fairly common fault I wouldn't recommend the Dual Top to anyone.
    For details on descaling ring their technical dept or beware the consequences.

    1939 baldylocks
     
  12. jonandshell

    jonandshell Funster

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    As mentioned above, you could have blocked off the silicon drain hose to keep the vinegar in!

    Also we have had no problems since stopping using water sterilisation products on every tank fill. I think these caused more problems than limescale alone!

    It also sounds like you had problems with your air valve, this failed on ours. The silicon rubber ring was too soft for the job. I replaced ours with an o-ring and all is OK now.
     
    Last edited: Aug 16, 2013
  13. PhilandMena

    PhilandMena Funster

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    Funny this thread should come at this time. I was talking with my dealer yesterday about the same problem I had on my Autotrail. he said this was a common problem with the Webasto heaters and the solution was to repeatedly open and close the valve. This worked for me but took a couple of days before it totaly shut off. I now run the system for at least one hour per month.
     
  14. jonandshell

    jonandshell Funster

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    This thread is 2 1/2 years old!

    Your dealer saw it here first!:thumb:
     
  15. Chiefsausage

    Chiefsausage Read Only Funster

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    Hi,

    Turn pump off, drain boiler and cold water tank, open drain on boiler.
    Wait till water is just dripping, use large syringe to inject vinegar backwards through silicone discharge pipe, 1 litre should do, close drain valve and let the magic happen.
    Open drain valve, refil cold tank and flush pipework out.
    No contamination of cold water tank or cutting into pipes needed
     
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