Water pouring out of inside mains stopcock !

[Terrywookfit]

Correct.

 

[flutterbye]

Will I need an insert also or is it likely to be strong enough? Or perhaps when I get it off I will see if an insert was previously used?

 

[spraggo]

Will I need an insert also or is it likely to be strong enough? Or perhaps when I get it off I will see if an insert was previously used?

If you do need a new insert on 1/2" black alkathene pipe make sure you get the right one by checking the colour of the writing on the side of the old pipe, Blue indicates that it is class C and green indicates class D.
inserts must be used

 

[flutterbye]

Unfortunately, there isn't any writing on the bit of the pipe that is visible.

Can I reuse the old insert ?

And I take it there is no way either a 20mm stopcock or 22mm isolating valve (both of which I've got) will fit ? The diameter is about 21mm. I'm just afraid about how long it will take to get the correct part tomorrow - already taken a morning off work.

 

[spraggo]

And I take it there is no way either a 20mm stopcock or 22mm isolating valve (both of which I've got) will fit ? The diameter is about 21mm. I'm just afraid about how long it will take to get the correct part tomorrow - already taken a morning off work.

The 20mm stop tap should fit with original insert.

 

[flutterbye]

Thanks Spraggo.

I guess I'll need to remove the old olive and nut from the pipe? Maybe if I can't fit the 20mm olive over the pipe I should put the 22mm olive (from the other stopcock I have) into the 20mm stopcock ? Or perhaps sand down a bit the pipe ?

Sorry for all these seemingly daft questions !

 

[spraggo]

Thanks Spraggo.

I guess I'll need to remove the old olive and nut from the pipe? Maybe if I can't fit the 20mm olive over the pipe I should put the 22mm olive (from the other stopcock I have) into the 20mm stopcock ? Or perhaps sand down a bit the pipe ?

Sorry for all these seemingly daft questions !

Yes it is best to remove the old olive, but do not try cutting it off for fear of damaging the pipe, try twisting it to and fro as you pull it of with a pair of grips with out squatting it. The 22mm olive wiill not fit inside of the 20mm stop tap and you should not sand down the pipe.

 

[flutterbye]

So I should be able to get the 20mm olive on the 21mm pipe? Perhaps with lots of wd40 ?

 

[JohnD]

compare the old to the new stopcock. If you are lucky, they will be near enough identical so the old olive and nut fit the new cock even with the olive not moved. If so, this may be better than risking mangling the pipe and having a poor olive fit. It is acceptable, if re-using an old olive, to put a few turns of PTFE tape on it, overlapping slightly onto the pipe. This helps the olive seal against the seat in the compression fitting. You should not use any jointing pastes or compounds on plastic pipes.

Check the insert depth of the pipe into the cock, though. It is supposed to go all the way in.

 

[spraggo]

So I should be able to get the 20mm olive on the 21mm pipe? Perhaps with lots of wd40 ?

You should find that the 20mm olive will fit, failing that try the 22mm stop tap and to be on the save side before you start I would obtain a 3/4" x 22mm compression straight adaptor with about 150mm of 22mm pipe just in case, as the outside diameter of the black pipe could be the old imperial 3/4" size but hopefully not as you would have to shorten the house side 15mm pipe to adapt..

 

[flutterbye]

Hi

Just to say I "fixed" the problem by leaving the original stopcock in situ and fitting a new 15 stopcock downstream.

However, the alakthene pipe part of the original stopcock is weaping very, very slightly. About 1 drop per 2 hours. So to do a proper job in the future I'm thinking of using this http://www.philmac.co.uk/products/details/?type=2&sub=33 to connect the alkathene to regular 15mm copper.

I don't think I'll need any inserts with this. Do ppl agree ?