I've got a valiant combi boiler and I usually top the pressure up every now and again as sometimes it's very low. however the last time we topped it up then pressure went too high and water was coming out of the over flow tap. now there's a constant drip and the pressure needs constantly topping up as I can't seem to stop it. Is there anyway to stop it??

andy, April 2011

The safety vent valve is letting by its a red and black valve inside the boiler usually you could try twisting the red knop all the way round it should automatically shut quite sharply this sometimes does the trick if not you will need to replace it

Brian Emian Plumbing & Heating Norfolk, April 2011