i have a glow worm 30ci boiler. every morning the red light flashes and i have to put 1 bar of water pressure in it, whilst on the pressure rises high, i bleed the radiator several times until it holds its own. when switched off the red light flashes within a few minutes the pressure has gone. the overflow pipe is not dripping. the other day when the boiler was on it lost pressure when the hot tap was running but this could have been a one off i\\\'m not sure yet? can anybody help, is it the expansion tank? and what can i do? please help