Lost water pressure after fitting outside tap

[ashtons99]

I fitted a new outside tap in my lads house today. The house is a new build (18 months old). I turned the under sink valve off, did the job and turned it back on again. Since then the water (hot and cold) runs but hardly any pressure. There is an in line PRV on the flow side of the stop tap and something like an anti syphon device after that.
When I turn the cold tap on the pressure gauge drops from 2 bar to almost zero. It builds back up when demand turned off.

I’m thinking the issue is either the stop valve has failed internally or the PRV is acting up

I’m not sure why it has the PRV as the heating system is a conventional combi boiler there is no storage system on the heating. Any ideas as to investigation or solution

 

[Wayners]

Pvr is to stop the boiler being over pressurised I think. Probably is that playing up

 

[Madrab]

The PRV is just after the mains so will be to protect the whole house would be my guess, new larger estate builds these days tend to have excellent water pressure as they have a new district mains etc. so the PRV will be to throttle that

Stop tap open fully? The set needle on the PRV is down at 1bar, is that just because it's never been set to the working pressure?

Only way to test the PRV really would be to bypass it and see what happens, rare that a PRV would fail just after 18 Months but never say never. There may be a filter in there too, could be that.

 

[ashtons99]

Sorted - it turned out to be a collection of debris that had partly blocked the inlet port into the PRV held back by the mesh screen.