Hot cylinder leak

Discussion in 'Plumbers' Talk' started by BobCr, Oct 21, 2017.

  1. BobCr

    BobCr New Member

    I just had to change my heating valve which is next to the indirect foam lagged cylinder and when I finished I now have a leak on the cylinder on the top heating coil to cylinder connection
    I cut the foam away so I can see clearly where it’s coming and it’s between the face of the copper cylinder and the coil connection
    Before I try to take it off which I assume will need a large socket just wondering if it’s going to be possible without destroying the coil as it’s an old tank never touched for twenty plus years or would I be better trying to drain it and epoxy around the joint or any other solution ?
     
  2. teabreak

    teabreak Well-Known Member

    If it is where the coil actually enters the cylinder body not on a thread that's not really a repairable job I'm afraid that is a factory made joint.
    A 20 year old cylinder has no chance of standing up to you trying to work on it.

    A temp repair might be possible with Fernox LSX sealant but A new cylinder is the safest bet.
    https://www.fernox.com/plumbing-consumables/ls-x-external-leak-sealer-50ml
     
  3. The Teach

    The Teach Active Member

    Your not the first person to suffer the dreaded cylinder leak after changing valves,seen a few of them connections pop out during valve changes,thats what you call a very hot flush.

    Can you post a couple photos ?
     
  4. just pumps

    just pumps Member

    If you mean smear LSX around the joint on the outside it won`t work whilst a 2 part epoxy resin might hold it at bay for a short time.
     
  5. KIAB

    KIAB Well-Known Member

    New cylinder time.
     
  6. BobCr

    BobCr New Member

    Just tried to drain it so I can epoxy to get the hot water back on and the drain isn’t working when you unscrew it no water comes out and the connection to the tank on the drain looks damp so if I try to drain it from the 22mm connection instead I will probably have two leaks
     
  7. just pumps

    just pumps Member

    Drain is full of crud.
     
  8. The Teach

    The Teach Active Member

    Have successfully in the past just nipped up the coil back nut,no more leaking :)

    Cant see the condition of your cylinder leaky flange,it could be beyond repair.
     
  9. KIAB

    KIAB Well-Known Member

    Cylinder has 20+ years of crud...:)
     
  10. The Teach

    The Teach Active Member

    Just another challenge in life o_O

    Usually siphon the contents out when the drain off has not been touched since installation,then unblock the drain off.fit new drain off washer so its ready for a quick drain out if needed.
     
    Last edited: Oct 21, 2017
  11. teabreak

    teabreak Well-Known Member

    It can be done by applying a smear of lsx smoothing a strip of rag into it and building up a layer at a time, the rag helps to slow the water and give time for the salant to work. I have done it in an emergency but it is only a temp bodge!:(
     
  12. BobCr

    BobCr New Member

    IMG_0791.JPG Drained the cylinder of a few buckets full and it’s stopped leaking if I try to turn the back nut it feels like the cylinder body is flexing and something might give so gave up with that
    The water was coming out between the copper cylinder body and the first connection
    I think epoxy for now and a new cylinder ordered is the solution most new ones seem to be 90x45 but mine is 90x50
     
  13. KIAB

    KIAB Well-Known Member

    I've used Plumbers Gold & mesh tape to seal leaks in the past.
     
  14. KIAB

    KIAB Well-Known Member

    If it's sat on timber runners, just add a strip of ply to runners, or find a some thicker timber runners to make up the difference.
     
  15. Pollowick

    Pollowick Well-Known Member

    900x500 are available - RM Cylinders make them, just call them and get a local stockist. http://rmcylinders.com/product/standard-indirects/

    You could consider going taller too - if you have space!


    Where in the country are you - I may be able to suggest a decent wholesaler who stocks them or can get one in a couple of days.


    As a temp fix, now you have stopped the leak by draining down, use a warm air gun or hair dryer to dry the area off. The use a plumbing sealant as mentioned already, ALL ROUND, and with a piece of thin wire try to get some under the fitting and build up a few layer before each one dries.
     
  16. Pollowick

    Pollowick Well-Known Member

    The difference is diameter rather than height!
     
  17. KIAB

    KIAB Well-Known Member

    :oops::D

    Well spotted!
     
  18. BobCr

    BobCr New Member

    Iam right up in the far north of Scotland so not a lot of outlets up here so might have to order online
    Screwfix do the RM cylinders but not the 90x50 it seems
    What’s the best copper or stainless ?
     
  19. The Teach

    The Teach Active Member

    Thanks for the photo,The fitting next to the back nut is not helping.

    Tightening the backnut will compress the gasket/washer inside the cylinder but you dont want to turn that copper fitting so hold it firm,worth trying.
     
  20. BobCr

    BobCr New Member

    Not sure what copper fitting you mean as all the fittings are brass
    I have disconnected the other end that goes on to the valve so could turn the whole cutting together no problem but it feels solid when I put pressure on it
    If you pull up or down on the fitting you can see the gap between cylinder copper body and brass nut opening slightly as though the washer has disintegrated but the thread connection is still solid
     

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