"andrewpreece" wrote in message
...

"Simmmy" wrote in message
k...
Thanks for the reply....do you suspect a release valve or expansion tank
leak?

It's to big a job for me but it will save me ripping up carpets and
boards...!

You could try pressurising your CH system with your filling loop, and see
if
the
pressure release valve blows at 3 bars ( don't go much above that whatever
happens ).

You could then try buying a new pressure relief valve as its very likley
that doing what you suggest will result in system dirt lodging under the
seat of the valve causing a slow drip which may not be curable:-(.
Never deliberately over pressure a relief valve on a system whuch has been
in use for any length of time.

I would suggest you fit a polythene freezer bag over the outlet pipe of the
relief valve with an elastic band to secure it. Then see if it collects
water in it when your boiler heats up. This will tell you if the water is
going out of the relief valve. Watch the pressure gauge after you have
charged the system while cold and switched it on to heat up the radiators.
An excessive pressure rise will indicate a lack of somewhere for the water
to expand into as the temperature rises. This means your expansion vessel
may have lost its gas precharge, it may have a blocked connector pipe
between vessel and system or it may never have been big enough in the first
place (more or less in that order)