I have a pressure fault on my Bxai combi 80e, pressure dial was showing 3 and it should be between 0.5 - 2.5. I was advised to bleed the radiators, which we did and the pressure is now reading 0 when cold and 0.5 when in use. It is also making some loud and strange noises. The filler loop is not connected to the boiler, does any one know how this can be connected? which symbols relate to this?[/b]