Double Check Valve Cuts Off Supply

20 Dec 2010
Reaction score
United Kingdom
On my mains supply I have a Stopcock, Double Check Valve and PRV in that order. The mains pressure is around 5 bar and the PRV is set to 3.5 bar. The double check valve and PRV are the right way round.

This is in a new build so all pipes currently have isolator valves fitted to the pipe runs to bathrooms, kitchen etc. The only working tap is located in the garage.

When the tap is turned on, it runs for a short time then the check valve cuts in and cuts off the mains supply. The PRV pressure drops to zero. The only way to restore the supply is to turn off the stopcock and turn it back on a small amount until the pressure rises to 3.5bar again then open the stopcock fully.

Turn on the garage tap and the same thing happens.

I have tried increasing and decreasing the pressure on the PRV but same problem.

Any ideas anyone ?

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take the DCV off and clean it through as most likely debris in it if no filter fitted up stream, you can blow through it as this normally works, i have come accross this before
Thanks guys,

The DCV was a new one (Screwfix). These seem cheap compared with say Pegler DCVs. Is it worth spending the extra for Pegler?
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