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Discuss Leaking Zilmet 11A solarplus expansion vessel in the Renewable Energy area at

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  1. Allgoode

    Allgoode GSR

    Hi all,

    Got a customer with a leaking expansion vessel on the solar thermal side of the system that is installed.

    The solar thermal system is a Kingspan solarplus with a flat roof collector and the expansion vessel has started to leak on the weld area.

    There is an indirect solar tank by kingspan that is augmented by a Ideal Logic heat 15 boiler and both the expansion vessels on this are fine with correct pressure and no leaks apparent

    As I am G3 registered am I allow to change this vessel or is it a more specialized job.

    I have also contacted kingspan direct and awaiting contact back from them for tech advice.

    Any advice as always appreciated,


  2. Gray0689

    Gray0689 Trusted Plumber GSR

    If installed as a kit there will be a non return valve on the fitting for expansion vessel it will shut off when you loosen it so easy to change
    But if it has lost pressure will need flushed/filled again
    • Like Like x 1
  3. Allgoode

    Allgoode GSR

    Hi Gray.
    spoke to Kingspan re this and they said that as long as I have G3 I am good too go to replace for customer.
    They are sending the manual to me as we speak so I will have a good read first as thought that it would be a different qualification for solar servicing work.

    If I am going up the wrong path can someone correct me.
    • Like Like x 1
  4. Gray0689

    Gray0689 Trusted Plumber GSR

    It's easy to do
    But as I said if pressure down it will need refilled
    Solar don't like air in system so better to fill with a proper filling unit to expel all the air properly
    • Like Like x 1
  5. gassafe

    gassafe Plumber GSR

    Not sure how well those built on check valves work... Not sure I'd trust one?

    Solar glycol is messy, sticky stuff, use disposable gloves! If it needs repressurising you'll need a solar fill pump type tool as said above!
  6. Gray0689

    Gray0689 Trusted Plumber GSR

    There great
  7. PhoenixServices

    PhoenixServices Plumber GSR

    Always love solar job all ones I get are in unboarded lofts or right at the back of airing cupboards where you can't reach.
    Makes it a lot more entertaining...
  8. Allgoode

    Allgoode GSR

    Cheers Guys,
    Part is ordered & should be with me in day or two.
    Will have to borrow wifes marigolds or if I can find them the long arm spare pair I have for messy loo jobs.
    Access is good, near door by rhs frame. Fingers crossed it is going to behave itself when I change it when part turns up.
    Fluid leaking from expansion vessel smells like normal inhibitor from heating system.
    cheers for all the advice,
  9. Allgoode

    Allgoode GSR

    Hi all,
    Finally got the expansion vessel swapped over as stacked out with other work.
    System was switched off following leak & now with new vessel fitted and system turned on there is no pressure, no surprises there.
    What is the best way to fill/flush the system properly and what is best fluid to use?
    Checked plumbcenter and they have baxi fluid which is quite reasonably priced.
    Also tried hiring locally but no joy with that so looking at making my own refill kit if any one can advise on parts needed,
  10. Allgoode

    Allgoode GSR

    Hi all again.

    Can any of you give me a parts list to make my own filing unit/pressurization unit as tried all local hire places and no joy down here in Cornwall & it is beginning to p**s me off big time.

    System is currently turned off as when I fitted the new expansion vessel and turned on system it worked but you could hear/detect air noises as fluid was moved around the system.

    The heat transfer to the cylinder was working even though it was a cloudy day just want to get it working as designed without any air in the system and new fluid.

    Tried a couple of companies and they are about £200 minimum to come and look/service if they even want to.

    Most seem to be solar pv companies and not a lot of solar thermal companies out there to service/recharge the solar thermal systems installed on the affordable housing.


  11. gassafe

    gassafe Plumber GSR

    I made my own pump a few years ago... With a 20 litre barrel, Clarke pump & washing machine hoses!

    If your desperate maybe a powerflush machine would do it but I'd like to clean it out after!
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