Totally perplexing plumbing

The outside tap has stopped working. It is fed by a T off the mains pipe. So, on the inside of the garage I have a live T(**) that feeds a pipe that goes straight through the garage wall and connects to the outside tap. Nothing comes out of the tap, though. In case there was something stuck inside, I have taken the whole top of the tap off, and by rights I should nearly have drowned from the mains water, but nothing.
So, what's going on?
** That T also serves the downstairs loo cistern which fills up nicely when required, so I know the T is live.
--
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turns out that it would have been better if it had gone wrong.
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On 28/03/2011 14:02, GB wrote:

Is there a double check valve that might have become blocked or jammed?
Colin Bignell
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Nightjar <"cpb"@" < wrote:

It could also be that the jumper (the bit with the washer attached) has stuck to its seat and didn't come out with the valve top.
http://en.wikipedia.org/wiki/File:Tap.png
Often a bit of a clonk with a hammer to the side of the tap can be enough to free up any jams. Otherwise, you need to turn the waer off at the mains and stip it down properly.
Tim
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If it hasn't worked since the frosts I would bet you have a check valve in the valve which has been jammed when the ice within it expanded
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Ditto
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newshound wrote:

Hmmm. I took the whole of the taphead off - that's the handle, the bit that screws up and down, the washer, etc. I could see the valve seat and poked my finger in the hole. Do you think I should poke a piece of wire in and see how far that goes? Where would the check valve be?
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On 29/03/2011 12:02, GB wrote:

Curent taps intended for outside use usually have it as part of the tap body. Otherwise, it could be anywhere in the pipe leading up to the tap.
Colin Bignell
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Oh, guys, well done! I'm so impressed.
As you can gather from that, the problem is solved. I removed the valve entirely. Do you think I need to replace the tap with one with a valve in? I'm inclined to leave well enough alone, but I'd be interested to hear your views. The tap is used to fill the watering can and opccasionally for a hose used to water the garden.
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On 29/03/2011 14:50, GB wrote:

The water regulations require there to be a backflow prevention device, but it does not have to be in the tap. Nothing much will happen if you ignore the regulations, but you should be able to buy a replacement valve or a tap with an integral valve for under a fiver.
Colin Bignell
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Nightjar <"cpb"@" < wrote:

Just been to the local DIY shop, and their outside taps don't have a valve in. Guess I'll add it to my Toolstation order.
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