Problem replacing WC Cistern input valve

I'm trying to replace the water input valve on the side of my ceramic WC cistern. The problem is that I cannot undo the join (outside the cistern) where the short plastic pipe from the input valve screws or is glued into a copper/brass fitting on the copper pipe bringing in the water supply:
<http://s1027.photobucket.com/user/gayleard/media/DiY/WCinletvalve_zpsfnzberxz.jpg.html
(Not sure if I have this right - it is my first dip into photobucket. Any advice on this most welcome.)
Is the plastic pipe likely to be glued into the copper pipe? If so, do I need to cut through it?
--
Timothy Murphy
gayleard /at/ eircom.net
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On Thu, 19 Nov 2015 15:21:54 +0000, Timothy Murphy

Effectively glued by sealant I should think. Hacksaw the threaded plastic and replace the brass elbow with one with a screw-driver operated valve if there isn't one upstream.
--

Graham.

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Whoa with the cutting! Undo the nut on the copper pipe and pull the pipe ou t of the fitting. That will then allow you to undo the brass fitting off th e plastic pipe with a pair of pliers, wrench or mole wrench which ever you have that will fit. You will then be able to unscrew the white plastic nuts to remove the float valve. When reassembling the valve and reconnecting th e pipe discard that brass fitting and replace it with a 15mm compression to 3/4" BSP bend so if you ever have to replace the float valve again it will be a single nut to unscrew rather than having to undo the whole fitting. I f you do not have an isolating valve in the pipe run up to the cistern cons ider putting one in that way you do not have to turn all the water off to c arry out any maintenance on the cistern.
Richard
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On 19/11/2015 16:12, Tricky Dicky wrote:

The fitting required will need to be 15mm compression x 1/2" BSP (not 3/4) and it should be a proper bent tap connector with a swivel nut rather than comp to FI which he appears to have at the moment.
Since he's replacing the valve anyway, cutting through the old one may be the easiest way of getting it apart - it doesn't need to be done non-destructively.
--
Cheers,
Roger
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On 19/11/2015 15:21, Timothy Murphy wrote:

It look to me as if the wrong sort of brass fitting has been used. I'm pretty sure that you've got one of these: http://www.fwb.co.uk/pipeline-fittings/copper-pipe-fittings/compression/c-x-fi-elbow-brass-compression-fittings- whereas you should have one of these: http://www.homebase.co.uk/en/homebaseuk/compression-bent-tap-connector---brass---15mm---05in-157987
With the proper tap connector, the nut which screws onto the ball valve's inlet pipe rotates on its shaft, and a spigot fits inside the ball valve pipe, and a seal is made with a fibre washer.
With the wrong sort, the female threaded part is integral with the elbow, and cannot be rotated independently. This would be a bodge, and would probably have been sealed with PTFE tape or goo of some sort. The only way to unscrew this would be to disconnect the compression joint at the bottom first, and then rotate the whole fitting.
But since you're replacing the valve anyway, it will be easiest just to saw through the valve inlet pipe and then disconnect the compression joint. Then replace the ball valve *and* fit a proper bent tap connector in place of the existing elbow. [If you're lucky, the existing olive and compression nut may fit the new fitting - and can be re-used without disturbing the olive,]
--
Cheers,
Roger
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On 19/11/2015 17:32, Roger Mills wrote:

Agreed that that's what the OP needs. It costs £10, whereas the fitting that was actually used was probably £1-2, so you can see why somebody bodged it.
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On 19/11/2015 18:16, GB wrote:

Blimey. A flexi connector costs a lot less than that. Easier for the amateur too
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On Thu, 19 Nov 2015 23:27:40 +0000, turdey wrote:

connector---brass---15mm---05in-157987

Even B&Q do them for £3.27:
http://goo.gl/grWIrG
All Homebase prices are a piss take.
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Timothy Murphy brought next idea :

It looks to my eyes as if a male to female elbow has been used, so the only way to unscrew the elbow, is to first release the nut between copper pipe and elbow, then unscrew the entire elbow from the plastic thread.
--
Regards,
Harry (M1BYT) (L)
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Timothy Murphy brought next idea :

Or release the outer plastic nut a little then rotate the whole valve (removed the float arm first) to unscrew it from both outer nut and brass elbow. Remembering to turn off the water supply first! I would then replace that elbow with a service valve 90 degree tap connector.
Mike
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