pressure guage showing zero?

you will have to refill the system usually 1 to 1.5 bar.take a look around or ontop of the boiler for a silver flexi refill pipe.it is possible that this pipe is already connected to the system.one end of the pipe is connected to the water supply and other end is connected to the water inlet valve on the boiler.when connected simply open both valves and fill system to required bar/pressure.run the boiler and bleed radiators if bleed valves are fitted.

ozone
December 2011