although expantion vessel may have pressure in it, then cheque the pipe or tube connecting the vessel to the boiler is not blocked, as if this pippe is blocked with sludge then in effect the exp vessel is blocked off and canot operate, when charging the vessel make shure theres nothing in the system acting as a pressure against you, good luck, Eric, whitehouse-apartments, Glasgow.
eric craig eric@ericcraig.wanadoo.co.uk
January 2008