Cold water tap problems

[sdgpage]

Hi all, I hope someone can help me out here with a mystery cold tap working/not working.

I have had my bathroom re-plumbed (first fix) by a pro - waste, hot and cold feeds. Cold is off mains with great pressure, hot is through combi boiler. I installed the shower and loo with no problems, but last job was the basin. I have a wall mounted 3 hole tap, which I fitted with no problems - the hot water flow is fine, but the cold is totally erratic. At first I thought the tap might be faulty, so got a replacement spindle from the manufacturer. The problem persists.

When testing the system, I open the cold basin tap and then turn on the main stopcock. Water flows freely, but as I close the basin tap the pipe jumps, and the water flow cuts off (before the tap is fully closed). Then only turning the mains off/on again will restore the flow.

I figured it must be an airlock, but having read various threads have seen over and again that it's practically impossible on a mains cold system. It can't be a blockage because the pipework is brand new (and I've taken the tap off to check the pipe's flow, which is fine). So in my confusion I turn to you all, and ask for help!

Cheers for any advice!

 

[lame plumber]

might want to check your mains pressure, over 3 bar and put on a prv on the incoming main, additionally you might need to use a few more pipe clips.

 

[sdgpage]

Thanks lame!

Mains is under 3 bar, and the pipe (has been) well clipped. Don't understand how the prob can reoccur and then be fine like this...

 

[supper plumb]

is there a filter in the tap cold feed?? or the iso valve not full open or faulty flow restricer

is it on flexis?? you mite have a kink or crushed pipe

 

[spanner]

Sounds like a stuck jumper

 

[glenno1]

Have you installed a check valve

 

[spanner]

Sounds like high pressure with stuck on jumper

 

[stevetheplumber]

sounds like a stopcock is on backwards to me

 

[spanner]

Try fitting a prv

 

[glenno1]

Is there an iso-valve on wrong way round causing the jumping pipe

 

[sdgpage]

Hi all,

Thanks for the advice and apologies for going awol there. Full house reno coming to an end, it's a bit chaotic...

So I just fitted a prv, turns out I couldn't be more wrong about the pressure - was a 6 bar!! So reduced pressure = problem solved!!

Thanks for the help guys, couldn't have done it without you.

Now to finish off the bathroom...

 

[Paulus]

Nice one mate, and great to see someone leaving feedback and appreciation.