turn power off the boiler, then release the pressure off the water with the pressure relief valve. look in the boiler manual where the components are. should see more water coming out the overflow pipe, and the gage should drop to 0. then check the expansion tank with a tyre gage should be 1 bar pressure on most combis if its not put air back in with a bike pump check manufacturers instructions for technikal data. then fill boiler again with filling loop and gage should go up to around 1.5 bar in the green. turn boiler back on and should do the trick ;0)
Andy, January 2011
