On the advice I received from this forum about my heating problems. The first step was to check the pressure in my expansion vessel,and increase by using a footpump if found to be low.On removing the plastic cap and depressing the valve when attaching the footpump to the expansion vessel valve,there was a spray of water under pressure issuing from the valve. Would I be correct in saying this should not have happened and my expansion vessel is faulty. ANY HELP ON THIS MATTER WOULD BE APPRECIATED.