Tap connector instead of a compression fitting

Discussion in 'Plumbers' Talk' started by mbrijun, Sep 2, 2019.

  1. mbrijun

    mbrijun New Member

    Had a failure of a compression fitting (90° elbow). Brass olive plus some jet blue. Looked solid, but failed under pressure and caused a mess in the kitchen.

    Mk II is a soldered elbow. I also soldered on a 15mm tap connector for a more reliable connection. This is shown in the picture.

    Question: is this acceptable? Sould a ball valve always be connected using a compression fitting? The tap connector relies on a washer - can these fail in the long run?

    Had a failure of a compression fitting (90° elbow). Brass olive plus some jet blue. Looked solid, but failed under pressure and caused a mess in the kitchen.

    Mk II is a soldered elbow. I also soldered on a 15mm tap connector for a more reliable connection. This is shown in the picture.

    Question: is this acceptable? Sould a ball valve always be connected using a compression fitting? The tap connector relies on a washer - can these fail in the long run?

    You should not have a tap connector there, it should be a nut and olive, the sharp edge of the isolation valve will dig into the fibre washer, as it is not a flat face.
     

    Attached Files:

    Last edited by a moderator: Sep 2, 2019
  2. dobbie

    dobbie Well-Known Member

    You should not have a tap connector there, it should be a nut and olive which came with the isolation valve.
    The isolation valve does not have a flat face, and using a tap connector could dig into the fibre washer.

    EDIT-Someone edited your post, putting two threads together and incorporating an answer I gave earlier making it look silly, there was no need for this and it has messed up your threads.
     
  3. mbrijun

    mbrijun New Member

    @dobbie - thank you very much, I had the same concern about the tapered edge the isolating valve has. Not sure how I can make this construction disaster-free. Originally there was a soldered-in gate stopcock, but it got damaged by limescale.
     
  4. dobbie

    dobbie Well-Known Member

    Cut off the tap connector a few inches from the isolation valve and sweat on a new piece of pipe using a straight connector.
    Use the old nut and a new olive onto the isolation valve with a smear of paste on the olive, do not tighten too much.

    There could be two reasons it was leaking previously, it was not tight enough, or I suspect too tight and you kpt trying to tighten making it worse.
     
  5. teabreak

    teabreak Well-Known Member

    Just cut below the tap connector fit compression nut and copper olive replace the copper tube above with a slightly longer piece job done!;)

    Ooo! snap! Spooky!:)
     
  6. mbrijun

    mbrijun New Member

    @dobbie - most likely I under-tightened it. The joint was not just leaking, the pipe slid out from the joint, leaving the olive behind. I also found some jetblue under the olive, possibly making it lose the grip.

    @teabreak - I agree with you on the use of copper olives. They seem to be more predictable.
     
  7. Heat

    Heat Well-Known Member

    What on earth are you doing using tap connectors (designed for flat face connections) onto compression joints designed and supplied with nuts and olives?
    You would be better to use a plumber to do any work.
    The original compression joint should not have failed. Brass olives are absolutely fine to use on copper pipe. Especially soft brass. In fact brass olives are best for hot pipes, - like on heating systems long term.
    (Copper olives must be used on plastic pipe though).
     
  8. mbrijun

    mbrijun New Member

    @Heat - I am guilty as charged. I have a lot of respect for the plumbing trade and this is why I would like to learn the proper way.
     
    Heat likes this.
  9. The Teach

    The Teach Well-Known Member

    Its always been good practice to use materials suitable for the job ;)

    Mains water pressure can vary and overnight it can peak at a much higher pressure,this is when its important to do the job properly :)
     
    Heat likes this.
  10. mbrijun

    mbrijun New Member

    Since we are talking about proper plumbing - what would be the recommended way of connecting a 20 mm cold water pipe (coming into the house from the mains) to copper? The only thing I could find in Screwfix (and the TS for that matter) is a JG Speedfit MDPE-to-copper adaptor.
     
  11. The Teach

    The Teach Well-Known Member

    only use Philmac mdpe adaptor fittings,never had a problem with them so not going to try any other manufactures :)

    The market is flooded with different transition fitting,there all made to known standards. Take your pick :)
     
  12. teabreak

    teabreak Well-Known Member

    suspect the main problem with brass olives is cost cutting by manufactures if they can save .00001p on a hundred olives by having a cheaper (harder) metal they will and to hell with the customer.
     
    Heat likes this.
  13. mbrijun

    mbrijun New Member

    The crime against plumbing has now been fixed. Will see how my under-/over- tightened compression joins hold. Thank you everyone for your helpful advice.
     
    teabreak likes this.
  14. Heat

    Heat Well-Known Member

    Simple way to always be 100% certain your compression joint is tightened correctly and olive full onto the pipe, - tighten the fitting and then undo the nuts and check the olives are compressed. Then just needs a nip back up.
    Use paste always
     
    The Teach and Joe the Plumber like this.
  15. The Teach

    The Teach Well-Known Member

    As above,do the joint :cool:

    then undo it and inspect the olive to ensure its been pulled in to the copper pipe. Then reassemble with a small smear of suitable jointing compound to add some more sealing properties between the water tight surfaces.

    Back in the day when copper pipe and their compression fittings were made for our home market here in the Uk. There was no need to add paste or sealant but now some outlets similar to SF sell unbranded pipe fittings.
    Those unbranded fittings need some more fitting consideration and buying unbranded material has no mention of the modern slavery act.

    SF wake up ;)
     
    Heat likes this.
  16. mbrijun

    mbrijun New Member

    @Heat, @the-teach - thank you for the tip. Pre-pressing and inspecting the olive makes sense, as the possibility of it slipping off is always at the back of my mind. Applying jetblue on an already seated olive will also prevent the compound from getting underneath the olive (not sure how big of a problem that really is...).
     
    Heat likes this.
  17. teabreak

    teabreak Well-Known Member

    As said undo the joint and check by sliding the nut a little way up the pipe and then slide back smartly against the olive it it stays put you should be fine.;)
     
    Heat likes this.
  18. mbrijun

    mbrijun New Member

    One more question if I may. What is the correct size of a washer for joining a 1/2 inch male to female? I have purchased a hammer arrestor and a 15mm x 1/2 inch x 15mm tee connector. Like the one shown here: https://images.app.goo.gl/nuHEwBvBxUEqy1W88

    There was no washer in the set. PTFE on the thread was not enough, the joint was weeping. I was able to resolve the problem by putting a sandwich of 2 fibre washers (1/2 inch) followed by a 1/2 inch rubber washer. The fibre washers help keep the rubber washer flat. A single washer was not thick enough, the thread on the female connector is quite long/deep.

    The joint seems to be watertight. But I suspect there must be a more elegant way than sandwiching washers.
     
  19. teabreak

    teabreak Well-Known Member

    A 15mm tap connector washer usually fits but quite thin, however lots of ptfe or locktite 55 would be what I use.
     
  20. The Teach

    The Teach Well-Known Member

    Tbh,using the correct materials is the idea.

    could mention the legal guff but who the flipping hell eck cares :)

    Cheap fixes can evoke many devils.
     

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