Isolation valves - problem making a good seal

[Rollerball]

The hot and cold water pipes under my kitchen sink (that go to a mixer tap) don't have any isolation vales.

I'm tempted to fit some, but as my plumbing knowledge is about zero I want to do this in the easiest (and cheapest) way possible. I'm pretty handy though and can work through most things if help is at hand (if required).

The pipes to the taps are copper, but these are short and connected to those are plastic pipes with connectors:

First pic to show the lower portion of the plastic pipes:

http://i59.photobucket.com/albums/g319/Dalek99999/P1020606.jpg

Second pic to show more of the upper portion where the copper pipes can be seen (these of course connect to the mixer tap):

http://i59.photobucket.com/albums/g319/Dalek99999/P1020607.jpg

Would it be easy enough to remove those upper plastic connectors and simply do a straight swap with some valves?

If so, what valves should I use?

Thanks

 

[HERTS P&D]

Take out the plastic fittings between the plastic and copper and fit these:

http://www.screwfix.com/p/15mm-full-bore-isolating-valve/46860

They are full bore.

Andy

 

[Whitespirit66]

Put the isolators in place of the couplers connecting plastic to copper pipe. Up to you what you use. Speedfit ones would be easiest, or compression ones with copper olives would be another option. Just make sure that you refit the pipe insets into the ends of the plastic pipes before fitting isolators, if you need to shorten the pipe.

http://www.tradingdepot.co.uk/DEF/product/!!SPDSERVVALVE!!/?gclid=CN-Pjqj_37sCFYbHtAod2QkAoQ

http://www.screwfix.com/p/15mm-isolating-valve-pack-of-2/65251

 

[Whitespirit66]

If you have gravity (hw cylinder) fed hot supply to sink, Andy's suggestion for full bore would be better.

 

[Rollerball]

Take out the plastic fittings between the plastic and copper and fit these:

http://www.screwfix.com/p/15mm-full-bore-isolating-valve/46860

They are full bore.

Andy

Thanks you you Andy and the other posters for their replies.

A few questions based on the above valve:

a) Would that be a straight swap for the existing plastic pipe connectors? No pipe shortening required, etc?

b) Presumably there would be no problems with the metal fitting connecting to a plastic pipe on one end and a copper pipe on the other?

c) How do I remove the existing plastic fittings? Do I pull up/push down on the plastic 'lip' at each end?


I see there's also a plastic isolation valve:

http://www.screwfix.com/p/jg-speedf...m_mmc=AffiliateWindow-_-DeepLink-_-Na-_-58258

 

[Whitespirit66]

A) Unlikely. Pipe may need shortening.

B) No problem - just make sure that the pipe inserts that you should find in the end of the plastic pipes are inserted again if pipe shortened. Copper pipe doesn't need inserts.

C) Undo the collars anticlockwise, then pull pipes out.

 

[Rollerball]

Thanks very much, shortening the plastic pipes will be easy enough.

Now, do I get the metal valve or the plastic one ...........

 

[Whitespirit66]

Now, do I get the metal valve or the plastic one ...........

A hint.....................

If you have gravity (hw cylinder) fed hot supply to sink, Andy's suggestion for full bore would be better.

 

[Rollerball]

Take out the plastic fittings between the plastic and copper and fit these:

http://www.screwfix.com/p/15mm-full-bore-isolating-valve/46860

They are full bore.

Andy

Andy (or anyone) - will the above valves have copper or brass olives?

 

[Whitespirit66]

Take out the plastic fittings between the plastic and copper and fit these:

http://www.screwfix.com/p/15mm-full-bore-isolating-valve/46860

They are full bore.

Andy

Andy (or anyone) - will the above valves have copper or brass olives?

Probably copper, but if not, they're available seperately from plumbers' merchants, etc.

Just read your other thread re, airlock on hw. I would definitely choose the full bore version.

 

[HERTS P&D]

The new isolation valves will come with olives.

Andy

 

[Rollerball]

Thanks chaps!

 

[Charnwood]

The new isolation valves will come with olives.

Copper or brass?

 

[Rollerball]

Stop it!

 

[Rollerball]

Well that was an unmitigated fisaco ....... I received the new isolation valves today and proceeded to fit them underneath my kitchen sink in plastic of the current plastic connectors as pictured in my first message above.

Five hours later and I THINK that they are finally making good seals!

Part of the problem was the awkwardness of tightening up the nuts due to the limited space. I had a hell of a job using my wrenches and turning them enough. However hard I tried the occassional small bead of water was appearing on the seal between the valve nut on the cold water pipe and the valve.

I then decided to remove the valve on the cold water pipe and put back on the plastic connection, but I couldn't. Why? Because the olive was tight on the copper pipe so I couldn't remove it in order to attach the plastic connector components.

So I thought I'd re-attach the metal valve and put a bowl underneath the pipe to catch the very rare drips and then call out a plumber tomorrow. However, since re-attaching the metal valve the seals are holding - maybe I finally managed to tighten the nut enough? I don't know.

Some questions though:

a) When a small bead of water accumulates around a metal nut with olive, is the only option to tighten it? Thinking about it I do have some plumber's tape so if the problem had continued could I have used that?

b) Just for future reference, is it possible to remove the olive from the copper pipe once it's on? I'm guessing not but am curious.


EDIT: Hmmm, not quite there yet - there's still a very tiny film of water forming around the metal nut where the cold water copper pipe attaches to the metal valve (said copper pipe also gets a moderate amount of condensation on it).

Would it be a good idea to dismantle it again tomorrow and wrap some plumber's tape around the olive and the end of the copper pipe and re-attached it?