There is water constantly coming from the external overflow pipe that comes from my worcester 35cdi combi. The pressure gauge is reading 3 bar, which I know is not a good sign from reading so other threads. Any ideas??

smilingsaint, May 2008

Also add to the above the plate heat exchanger may be passing, common fault on these boilers

Geoff, May 2008

well, at 3bar your boiler will be venting water from the '3bar safety valve' .....clue is in the name!

Make sure your filling loop is switched off (removed even better, as it could be faulty)
Reduce your system pressure, by bleeding water from a radiator venting valve (slow but easy!) until it is 1 - 1.5 bar
when the system is TOTALLY COLD.
Check then that the water releasing from the overflow valve has completley stopped, if not it will need to be removed and cleaned or replaced. Then......

Start up the boiler, watch the system pressure, if it is still rising
to 3bar and passing water, the either the expansion vessel needs recharging or replacing ...or the filling loop (if still attached) is passing water and gone faulty.

T, May 2008