How can I fix Firebird 120 boiler problem?

I had a similar problem back in 2005 (my Firebird was installed in early 2004) but since I insulated the oil inlet pipe OUTSIDE the house (ie where it came through the wall to the boiler) I have not had the problem.
The reason I am on this site today is that my boiler left a puddle on the floor this moring and has lost pressure completely. I re-pressured up to 1 bar, but it slowly lost it again. The red pressure vessel inside feels absolutely full of water. Anyone any ideas?

Steve
December 2008