glow worm 30cxi?

i would like know where the pressure valve is. the pressure is on 0.3 at the moment. there are no water tubes or valves underneath as i was first told by service centre. i was told to turn the blue end of a pipe anticlock wise. but this blue end is not connected to any water pipe as far as i can see. my pressure has been adjusted before, and this was done behind the panel. any ideas where it might be?