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Replacing an outside tap;...what a kerfuffle!

Discussion in 'Plumbing and Central Heating' started by Laurence Harvey, 11 Jun 2021.

  1. Laurence Harvey

    Laurence Harvey

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    A question regarding replacing an old outside tap.

    I’ve purchased a “15mm x 1/2inch outside tap” and a “compression adapting wall plate 90-degree 15mm x 1/2inch” both from S/Fix.


    My problem is the tap doesn't line up at the 12o'clock position. When it’s fully tightened it sits a 6o'clock and there appears to be a gap of 1.5mm between the face of the wall plate and the face of the tap connector,...and no amount of ptfe on the threads & boss white will pack it out enough so that I get a good tight compression that lets the tap sits firmly at 12o’clock.

    Would I be looking at adding fibre or rubber washers to achieve this vertical position when
    it's fully tightened?

    If so, what size washers would I need?...I’ve been trying to make sense of what size washers I’d need to fit the tap connector but I’m totally flummoxed to be honest! I can’t make head nor tail of it. Where the hell does 1/2inch enter the equation

    It must be 30+ years since I last fitted a similar outside tap and I can’t remember having this much kerfuffle. I think a few wraps of ptfe and a smearing of Boss White was all that was needed.

    What to do?...as ever all replies gratefully received.
     

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  3. JohnD

    JohnD

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    easy peasy

    you wrap PTFE tape round the male thread, increasing the overlap as you go down so the thickness tapers. The tighter you screw it, the tighter it will get until it is jammed enough not to come loose.

    but, better...

    you use a hose union back plate with attached pipe

    HoseUnion.jpg

    https://www.screwfix.com/p/hose-union-back-plate-15mm/56415

    and screw the tap onto it before poking it through the wall and marking the screwholes

    so you can adjust the fit before fixing it.

    And I strongly advise having a Tee-handle valve inside the house so you can turn it off, especially before winter

    PeglerTee.jpg
    https://www.screwfix.com/p/pegler-tee-ball-valve-blue-15mm/21860

    You can buy a ball valve at a tenth the price that is one-hundredth as good. If you like cheap, leaky rubbish.
     
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  4. Laurence Harvey

    Laurence Harvey

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    Thanks for the prompt reply JD, much appreciated. (y)

    I’ve actually tried the ptfe method you suggested,...perhaps I’m not putting enough on but I’ve tried half a dozen times and used yards of the stuff. I’ll give it another go. I’ve been using the normal ‘water’ ptfe,....any benefit in trying ‘gas’ ptfe?.

    I like the suggestion of the hose union backplate;...that might be an option but I’d need another hole through the wall as the present pipe, where it exits the wall, is quite low.

    Do you reckon this type of tap could be better option for me?...the tap/wall-plate are one solid unit.


    p.s. there is already a stop valve fitted inside (under the sink). It was fitted by a previous owner so I don’t know if it was cheap but it works fine and isn’t leaky in the slightest.
    upload_2021-6-11_17-36-39.jpeg
     
  5. Hugh Jaleak

    Hugh Jaleak

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    Have to be frank, if it's still leaking, you're doing something wrong. Ordinary PTFE should be ample for sealing that joint. Wind it on in the same direction as you'll tighten the thread, can never use too much in the grand scheme of things, when you've a nice thick layer, screw the tap into the elbow, hand tight, then finish off with a spanner, should feel it getting tighter to turn as the tape makes the seal.
     
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  6. Laurence Harvey

    Laurence Harvey

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    Thanks for the reply.(y)

    It just seems like the tap is easily screwed fully home before there is enough compression to make the tap tight, no matter how much ptfe I’ve applied.

    I’ve done many radiator tails without a problem like this.

    If no ptfe tape is applied should the face of the wall plate and the face of the tap connector make contact with each other when the tap connector is fully tightened?

    At the moment there is about a 2mm gap between the two faces when the tap connector is fully tightened.
     
  7. CBW

    CBW

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    The way I used to do it was try it at different start points, and not tons of ptfe.
     
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  8. Hugh Jaleak

    Hugh Jaleak

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    No, the PTFE should make the seal, I'd expect the tap to become quite tight and requiring a spanner for at least the last turn, and then a tweak so tap is vertical. It may not meet he outer face of the socket, this is normal. The seal is on the thread.

    If you've done rad tails successfully with PTFE before, it's not like you dont know what you're doing, cant understand why it's not sealing. The new tap is getting tighter as you wind it in?
     
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  9. sxturbo

    sxturbo

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    At least 24 turns of PTFE
     
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  11. Agile

    Agile

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    It is a lot more expensive but PTFE tape intended for gas fittings is much thicker ( and more expensive ).

    Usually come in a similar container but coloured yellow.

    Being thicker might actually alter the get tight point!
     
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  12. sxturbo

    sxturbo

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    Or use loctite thread sealant.

    Turn it to your required a set point and let the sealer go hard.

    Tap will be kept in place then
     
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  13. CBW

    CBW

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    Can actually get white gas ptfe now.
     
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  14. polesapart

    polesapart

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    Loctite 55 onto roughened threads.

    Hemp.
     
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  15. Laurence Harvey

    Laurence Harvey

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    OP here;...after taking all your sage advice onboard I tried several more times to tighten up the tap but no success. I just couldn’t get it tight enough with the tap at 12o’clock.

    Took the tap back to s/fix and got them to swop it (more in desperation than expectation!).

    The replacement tap tightened up first time;...hand tightened as far as I could then two full turns with the shifter;...solid as a rock at 12o’clock. No leaks.

    I’d given it 30! conical wraps of ptfe and a generous lick of Boss White.

    Many thanks for all replies/advice guys. Your expert help was very much appreciated.

    Kerfuffle concluded. (y)


    upload_2021-6-13_9-0-30.jpeg
     
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  16. CBW

    CBW

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    I guess it could have been a fault on the thread? Either way, glad you’re all sorted :)
     
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