Fitting an Isolating Valve

[Shutpa]

Am about to install a new sink and fit isolating valves in the process. Problem is, I have never worked with plastic pipes before and am wondering if the valves can be fitted to the grey pipes in the same way as they would be fitted to copper. The piping is shown above and I would be grateful for advice.

 

[jedi]

I dont see why not, you have compression joints on there now......I personally hate plastic pipes

 

[Shutpa]

Thanks for the quick reply. Neighbour thought that you had to use some sort of insert to join the plastic to the copper valve. I take it that that is not the case..

 

[jedi]

yep there an insert you need to put into plastic side of the pipes.

 

[Shutpa]

yep there an insert you need to put into plastic side of the pipes.

Thanks. Are the threads on valves universal fitting? I was thinking that if I bought for example Screwfix 65251, I could leave the upper nut of the existing valve on and attach the isolated to that.

 

[jedi]

you could but it might leak, if it did you would have to replace the olive, if you had to replace the olive, you might aswell fit the whole valve, or you could,as some dodgy plumbers do, wrap the old olive it in ptfe tape

 

[polesapart]

98% chance you'll be fine. Only the more rarely used and older "Prestex" compression fittings had a different (finer) thread.
Given the flexibility of the plastic (with it's pre-existing insert) odds are good that you can simply swap out the central portion of the compression coupling for the body of an iso valve with no pipe modifications at all.

 

[Shutpa]

Given the flexibility of the plastic (with it's pre-existing insert) odds are good that you can simply swap out the central portion of the compression coupling for the body of an iso valve with no pipe modifications at all.

Now that is good news. Are there some isolating valves better than others?

 

[iamlee2002]

You can also get push fit isolation valves if you not comfortable With replacing with compression type

http://m.screwfix.com/p/jg-speedfit-15svp-isolating-valve-15mm/12372

 

[Madrab]

I wouldn't recommend unsettling those couplings.

If you want to fit iso's just cut the plastic further down and pop them in there. Plain polyplumb inserts in either side of the plastic pipe and use copper olives if possible, just nip them up, don't over tighten.

 

[jay679]

Just use a pushfit tap connector with an integral isolating valve.
Jay

 

[Shutpa]

...........you can simply swap out the central portion of the compression coupling for the body of an iso valve

I wouldn't recommend unsettling those couplings.

Have swapped the the central portion as suggested by polesapart and since I am replacing the existing sink and tap I would have to undo the couplings anyway.

Job now done so thanks to those who replied.