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Exposed shower valve - 22mm inlets?

Discussion in 'Plumbing and Central Heating' started by raine, 26 May 2017.

  1. raine

    raine

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    Need a bit of help replacing an old leaking exposed shower valve, specifically finding something to replace it with.

    It's a round type of valve (old Bristan Pisa) rather than a bar-shaped valve, see attached pic. The inlet pipe centres appear to be about 155mm.


    I bought a new valve before but the pipes in the wall were too big to fit the new valve. Foolishly, I didn't take photos or notes at the time, and now I'm coming back to it a few months later, I can't remember what size the pipes were either in the wall or on the valve that I bought.

    I'm going to assume that the valve I bought had 15mm inlets, as that seems to be that standard - it was just a cheap one from screwfix.

    1. As long as I get my inlet pipe sizes and centres right, can I replace a round exposed valve with a bar-shaped one? I guess the round valve is probably screwed in through the tiles so I'll have to fill the holes in the tiles? Any other issues that I'll need to address?

    I'm not too familiar with plumbing so I've been reading up about different pipe sizes online. I'm guessing that the pipes in the wall are either 3/4" (19mm?) or 22mm.

    2. From what I've read online, 22mm seems like the more common size than 3/4". Does that sound right?

    3. Does anyone know about the Bristan Pisa exposed valve, specifically what size inlets it uses, and what pipe centres? I can't find anything about it online at all.

    4. So, I'm thinking I should buy a shower valve that uses 22mm inlets. If it turns out that the pipe is only 3/4", can I just pop a 22mm olive on and it'll work ok? Or is the size difference too much, and it won't seal?

    5. Pipe centres: My research shows that most (all?) valves are based on 150mm centres. I've measured repeatedly and I'm pretty sure the existing one is at 155mm centres. The wall is masonry, and I don't want to remove any tiles. Is it likely that I'll have sufficient "wiggle room" to fit a valve with 150mm centres?

    Then my challenge will be finding a valve - none of the online stockists that I've found allow you to filter by inlet size or pipe centres, which means trying to read the installation instructions for all of them. What a pain.

    6. Does anyone know of a cheapish exposed valve with 22mm inlets?

    7. Would it be easier and better to replace the cartridge and seals? The body of the unit leaks, and the thermostat doesn't work properly.

    Thanks guys.
     

    Attached Files:

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  3. terryplumb

    terryplumb

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    do you have access to the pipes on the other side of the wall ? pics would be good. anyway a few things...the hot and cold have to enter the new valve on the correct side, so establish what you have .as you look at it say hot to left cold to right. most horizontal bars need this ,at 150 mm centres and 15mm supply pipes. when removing existing valve there are screws thru tiles, fill holes with silicone. screwfix do bar valves for about 70quid ,I would also buy an easy plumb kit as the fittings that come with most bar valves are a joke.
     
  4. raine

    raine

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    Thanks Terryplumb.

    No, this is a solid masonry wall unfortunately.

    I attached a pic of the valve in-situ with my original post, but can't take pics of the exposed pipework yet, as the shower is in daily use, so I don't want to dismantle it until I've got the replacement.

    Yes, confirmed existing is hot on left, cold on right.

    Ok, great, so sounds like ok in theory to swap from round valve to bar.

    Any advice on these questions please?

    - If I buy a shower valve that uses 22mm inlets, and it turns out that the pipe in the wall is only 3/4", can I just pop a 22mm olive on and it'll work ok? Or is the size difference too much, and it won't seal?

    - Does anyone know of a cheapish exposed valve with 22mm inlets?

    - Would it be easier and better to replace the cartridge and seals? The body of the unit leaks, and the thermostat doesn't work properly.
     
  5. terryplumb

    terryplumb

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    IF your pipes are 3/4 you use a 3 /4 olive. not 22mm. but you really are only guessing the pipe sizes I suspect they are 15mm. they may or may not be compression fittings. as you can't easily alter any pipework you are stuck with whatever is there. if I were you I would take off the valve and establish what exactly you have then you can plan your next move. which would be like for like replacement or re furb the one you have ,assuming parts available. I would be inclined to replace.
     
  6. terryplumb

    terryplumb

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    check this out www.showerdoc.com. they do bristan Pisa spares /replacement valves and offer repair service .mail the valve to them. got a help line too !!
     
  7. raine

    raine

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    Resurrecting this thread as I've re-removed the shower valve and remembered what the problem was.

    As you can see from the attached photo, after removing the valve, I'm left with pipes with nuts. The nuts are held captive by an olive. The pipes are 15mm, but the nuts are the wrong size / thread for the new valve that I bought.

    So, my problem / question is - how do I remove the existing nuts and olives from the pipe, in order to be able to fit new ones? There is no movement on the pipes, and I can't push the nuts back far enough to expose any of the olive.
     

    Attached Files:

  8. well you have made some progress :!:

    Have you got a pliers like this one ? channel lock.jpg

    IF you have then stand in front of the pipes grip a nut at top and bottom and gently rock the nut up and down and gently pulling on the nut,it will pull off the olive and you will fall backwards.
     
    Last edited by a moderator: 26 Jun 2017
  9. terryplumb

    terryplumb

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    i assume the chrome behind the nut is free to rotate behind the nut .is it metal or plastic chrome plated ? you will almost certainly have to get that off .can you lever it away ,gently ,from the tiles .maybe two wide bladed scrapers as levers. if its plastic just cut it off. once off ,the nut should go far enough back to expose the olive.
     
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  11. bristan make 155 ctr surface mounted valves (not bar valves) bristan capri revs to mind.
     
  12. raine

    raine

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    I do have some pliers like those Old&Bold. I had a little go at what you suggested but didn't try too hard as I don't yet have a new valve, and I need to use the shower in the interim.

    I've ordered one of these:
    https://www.wayfair.co.uk/Hudson-Reed-Twin-Exposed-Shower-Valve-REQ1064.html

    Should be here by the weekend so I'll have another go at the nuts & olives then. The discs are plastic, so I will also cut those off and see how much olive that exposes.

    Getting there!
     
  13. The existing nuts may just fit the new shower mixer :idea:
     
  14. raine

    raine

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    Let's hope so! That was the problem I had with the first valve I bought.
     
  15. Aquaheat

    Aquaheat

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    Use an olive puller.

    Jon
     
  16. raine

    raine

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    Success!

    OldBuild was right - the existing nuts are identical to those supplied with the new valve. :):)

    So no need for olive pullers or cutting.

    New valve is now on and working. Just need to "soak test" it for a couple of days to make sure no leaks.

    Thanks so much for the help guys.
     
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