Cannot lower pressure on boiler

9 May 2015
Reaction score
United Kingdom
I opened filling loop and now pressure has gone to 3.5. Cannot lower it, it just increases again after bleeding radiators. The filling loop has only one tap. I had to use spanner to open filling loop and actually turned opener 360' even though its only a quarter-turn valve. I cannot turn water off because I believe I only have a cold water stop cock, which doesn't seem to affect the hot supply.

I have tried to remove the filling loop from the central heating outflow pipe but water just gushes out.

Any thoughts or ideas to lower the pressure?


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Turn your mains stop tap off.

Your filling loop needs to be replaced
I don,t know how to turn off mains. Have one stopcock which controls cold water only.
That's the one
your filling loop will be between cold main and htg pipe

If you don't do something it will potentially cause damage to the boiler parts

Will probably have to call someone out to change the filling valve
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