boiler pressure filling loop problem

27 Dec 2016
Reaction score
United Kingdom
hey I noticed that my combi boiler was on .5 bar so went to top up the pressure like I normally have before but nothing happens.

usually I hear the water running through the pipes but this time I can't hear nothing and the pressure doesn't rise.

the only thing that I can think of is that I had a water meter fitted a fair few months back and when we first used the taps a lot of air and sluge came through. could this be causing it and I've only came across it now as the sludge is still sitting in the pipes.

Im no expert and could be a silly guess but if it is a simple fix that others have came across I'd rather fix it myself before calling someone out.

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Forgive me for stating the obvious ,the two black handled valves in your pic are in the closed position ,and both need to be open. Assuming you did that and no water flowed ,try removing the screw that holds handles ,remove handles ,and this exposes the brass shaft ,which you can turn with a spanner. If the black handles ,or one of them, is damaged it may not be turning the shaft.
thanks for advise, yes the two black valves is what I turned and I have also removed the handles like you have advised (they turned freely) but still nothing happens.
So you have turned both shafts 1/4 turn and water is not flowing ? If so put handles back on and close both valves. You can then remove the copper pipe linking both and see if its blocked. Have a bucket and towels to hand ,as a little water will come out . Loosen the left side first ,that is the cold water mains feed ,a little water contained in the copper linking pipe will spill out , if water keeps flowing out under pressure dont go any further as the black handled valves may not be fully closing. Assuming it doesn't , you can remove the copper and examine it. I think its unlikely to be blocked. If you then open the left black valve ,SLIGHTLY , water should flow out ,thus proving that valve works. This leaves the right hand valve ,which has a non return valve within it ( a one way valve that allows water to enter the system but not out ) , dont do anything to that valve at this stage. There may also be filters present in the copper linking pipe / valve unions ,not sure on your boiler. Once you have got this far advise back your findings. If you are not confident or comfortable doing the above best call in a pro. Regards Terry.
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yes I turned the valves 1/4 turn and nothing. I removed the pipe and some water leaked out as you said. I turned the left valve while the pipe was off and still no water has came out even on a full quarter turn. hmmm

here is a pic
The white plastic is the non return valve ,which is likely stuck closed. Or the valve itself is kaput.
is there any way to make it work? or is it best to buy a new one ?

is it straight forward to replace? i presume to turn the mains water off and unbolt and replace.

what's the name to search for a replacement

thanks for your help
I would be inclined to fit a new one. You could try tapping ,lightly ,the brass housing at the side ,whilst opening / closing repeatedly the black handle wary as you will get wet if it does pass water ,its under mains pressure !!
Its the combined cold water inlet isolation valve / filling valve. Replacement would involve isolating the cold mains , and electric supply to boiler. Draining dhw and boiler. Undoing the valve and fitting new one including new seals

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