Sounds like you have forgotten to turn the water off again when you added water to increase the pressure. There should be a small tap on a flexible loop filler pipe(where you added water) check it truly is turned off i.e. the handle points precisely across the pipe. (Has the handle slipped on the valve?)Once this is turned off the water will stop discharging in a short while.To lower the pressure to say 1.5bar, pull the front off the boiler, find the pipe which was discharging water, it's at the bottom, and follow it back to a valve with a red plastic handle, twist this to realease some more water(pressure) Hope this helps.
Damian
February 2008