Small leak to isolation valve

Discussion in 'Plumbers' Talk' started by Gethin hughes, Feb 26, 2022.

  1. Gethin hughes

    Gethin hughes New Member

    Hi everyone, ive recently replaced the kitchen tap and have noticed the isolation valve is leaking ever so slightly. Ive tried to tighten it as much as i can but its still dripping slightly.

    whats the best way forward? Would i need to get some PTFE around the thread? Thanks
     

    Attached Files:

  2. Offshore

    Offshore Active Member

    That type of fitting is not designed for thread tape or sealant, it should seal as the olive is compressed around the pipe as it is tightened into the fitting. That's the theory, however, sometimes they do leak and although it is a bit of a cheat, you can apply sealant around the olive. This could be a couple of wraps of tape or a non-hardening compound (my preference). Note that it does not go on the threads but rather around the olive itself as that is where the sealing will happen between the olive and the internal face of the fitting.
     
  3. DIYDave.

    DIYDave. Screwfix Select

    ‘I’ve tried to tighten it as much as I can’ - maybe a quarter turn at first is best option usually, note that over tightening the fitting can also cause it to leak !

    The ‘magical’ plumbers tape won’t work here by winding it around the threads as the water is getting past the olive

    Get a spanner / grips / onto the flats of the fitting and ‘nip up’ a little the offending nut

    Dry with paper towel and see how things go at this stage

    Can turn valve off and remove the leaking end, take a look where olive sits on pipe and see if pipe has been ‘crushed’ under the olive (by over-tightening) As above, this can allow water to pass between olive and pipe - worth checking
     
  4. Gethin hughes

    Gethin hughes New Member

    cheers for the reply. I do have some Fernox LS-X, whether that will fix the issue is another thing!
     
  5. Gethin hughes

    Gethin hughes New Member

    i see! Ill have to take a look tomorrow and see if thats the case, cheers.
     
  6. Offshore

    Offshore Active Member

    Have a look for this "FLOMASTA GAS & WATER JOINTING COMPOUND 250G" on Screwfix website. Its great stuff and I've used it to resolve exactly the kind of issue you are having.
    As before, apply it to the olive or the face of the firting, not the threads.
    Another option of course would be to change the fitting and/or the section of pipework if it is easy enough to do so. A few fittings would probably cost less than the sealant.
     
  7. Offshore

    Offshore Active Member

    I've no idea why my last post was in that font. It looks like I'm shouting. I'm honestly not :)
     
    Last edited: Feb 26, 2022
  8. just pumps

    just pumps Screwfix Select

    Yes that will do fine, just a smear over the olive though, dont want it entering the pipe or on the threads.
     
  9. DIYDave.

    DIYDave. Screwfix Select

    If not used for a while, it’s probably instantly set solid in the tube !

    Annoying for us diy’ers as not in regular use and seems expensive for a 1 off hit (but cheaper than getting a plumber round I realise) :)
     
  10. Gethin hughes

    Gethin hughes New Member

    Would the PTFE be better than fernox stuff then? Thanks
     
  11. Offshore

    Offshore Active Member

    To be honest, PTFE around the olive is a bit of a bodge. Lots of people do it though and if it works on a small water leak then no real harm done. Give it a try, it will probably work fine and will be a cheap fix.
     
  12. Check as well it’s not weeping from the slotted part u turn, and forming on to the nut to look like it’s leaking from there. They are notorious for it. If so u would need to change the whole valve.
     
  13. Gethin hughes

    Gethin hughes New Member

    Cheers mate, ill give it a go and see how it gets on.
     
  14. Gethin hughes

    Gethin hughes New Member

    i see. From looking at it, it might have been leaking for a while without me knowing about it. See attached photo the condition around the nut.
     

    Attached Files:

  15. Teki

    Teki Screwfix Select

    If you can, isolate the water and undo the compression fitting near the elbow to see how the olive has compressed. Take a photo and post on here.

    As it is a kitchen tap, you probably want a WRAS approved compound so something like what was mentioned in this post or LS-X (has a long set time).
     
  16. just pumps

    just pumps Screwfix Select

    Can use it straight away
     
  17. Teki

    Teki Screwfix Select

    In the LS-X datasheet it says Allow a minimum of 2 hours to set.
     
  18. just pumps

    just pumps Screwfix Select

    Honestly try it sooner if you dont believe me.
     
  19. It is best to let it set if u can but in the real world u normally have to turn water back on asap. It’s brilliant stuff and will normally cure any small leaks on olives even without waiting two hours.
     

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