Stopcock turns off, needs closing off then back on to regain pressure

The house stopcock under the sink appears to be closing off when there is a sudden demand in the house, toilet flush for example. I have replaced the stopcock and fitted it the same way as the original with arrow in the direction flow, which although I can see enough piping, looks like the correct direction. This has happened only in the last year or so, since we moved in ten years ago. Any suggestions?
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The house stopcock under the sink appears to be closing off when there is a sudden demand in the house, toilet flush for example. I have replaced the stopcock and fitted it the same way as the original with arrow in the direction flow, which although I can see enough piping, looks like the correct direction. This has happened only in the last year or so, since we moved in ten years ago. Any suggestions?
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On 30/03/2018 15:14, Rodp wrote:

Are you certain there isn't some other device that might be causing the problem? Re-check the direction (look for the drain cock on the house side), if correct then it's probably a loose jumper or washer. Dismantle to inspect and repair or replace as appropriate.
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On 30/03/2018 17:59, snipped-for-privacy@aolbin.com wrote:

The OP says he's already replaced the stopcock. I'd try turning it round. They are designed to prevent back-syphoning.
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On 30/03/2018 18:32, GB wrote:

True, but new items can be faulty - although I admit that it's unlikely for a new one to have the same problem as the old one.
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On 30/03/2018 20:54, snipped-for-privacy@aolbin.com wrote:

There may be nothing wrong with the new stop cock, as it's displaying the correct symptoms for a working stop cock that is installed teh wrong way around. The old one may have worked for ten years because the jumper was seized up inside! :)
Tim+ has given an easy way to find out which way the water is flowing, so I'd check that.
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