Turning off the direct cold feed valve to worceter combi boiler

[kendo10]

I'm in the process of going to fit a shower mixer bath tap .I need to remove old bath taps. Recently had a gas service plumber in he said all I have to do ist turn of the cold feed to boiler and this will enable me to change the hot tap as there is no stop cock in upstair flat. cold wter has inline valves on all cold taps. Sounds easy at least thats what i thought you just turn the screw on the dcw valve.
No, valve seams locked I can only think by the plastic black notched ring above the bottom valve screw.
How do I free the ring hopefully without breaking it and then hopefully I can turn screwthen and stop hot flow ?
Job held up.

 

[deadshort]

Hi, nip onto the plumbing forum !

DS

 

[terryplumb]

photo of the underside of the boiler and the valve you are talking about please

 

[PrenticeBoyofDerry]

I think you are talking about the check valve test screw, which is not a valve.
But a picture or boiler make/model would be helpful.

 

[davelx]

It's the second inlet from the right on mine (27CDi). Behind the filling link assembly - there should be a square white plastic filling tap at the front, behind which on the underside of the inlet port you should see a screw operated valve.

IMG_0051

• davelx
• 4 Jun 2017

WB CD27i mains water inlet/filling link