I was going to shut off the angle stop valve (shown in figure a) but it did not budge. I tried every possible method but it did not work so I decided to replace the whole valve. I could successfully take out the valve (which is shown in figure c) but ran into several problems

a) First of all, what is the type of this angle stop? Is it compression type or threaded type? The nut and the yellow ring (indicated by the blue arrows in figure b) could not be taken out. The pipe is smooth and does not have any thread. The threads are inside the nut. I was wondering whether I should buy the thread type and connect it to the nut or whether I have to take out the nut and the ring and connect the compression type to the pipe.

b) Because I was not sure about type of the valve, I decided to put the old valve back but now have leak around the connecting nut (indicated by red arrows in figure a). What should I do to make the leak stop? Or, is there any way to cap the end of the pipe ?

Thanks a lot in advance!

enter image description here


The connection to the pipe is a compression fitting. Buy a new valve with the compression style connection (and, of course, matching outlets) and thread it into your existing nut and ferrule (compression ring). You need to tighten with a fairly heavy hand here, they are designed to form a metal-to-metal seal with the ferrule actually being squeezed down onto the pipe permanently.

If it leaks, tighten more. if it still leaks, cut below the old ferrule and use the new nut and ferrule that came with your new valve.


That looks like a brass compression ring around the copper pipe that extends out from the wall. It is not uncommon that the internal thread compression nut, the compression ring and the mating faucet part do not fully seal upon attempted reuse.

Your best bet is to procure a replacement equivalent faucet unit and a new compression ring and compression nut. The old compression ring can be removed by filing through it with corner of a triangular file. Use extreme care when filing so as to not nick the copper pipe.

  • In the UK, there are special tools for removing copper compression rings (UK: "olives"). Example 1. Example 2. You may be able to buy, borrow or hire something similar locally. The tools are sized to match the pipe diameter. Jan 12 '16 at 14:14
  • 1
    Filing off the compression ring is rarely successful. You would be better off cutting the pipe below the compression ring, removing the nut, and starting with a new valve. Jan 13 '16 at 6:10

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