look for a flexible metal braided pipe somehwere under the boiler or on nearby pipework. At either one end, or at both ends there should be a black plastic tap - across the pipe is off and inline with the pipe is on. Sometimes installers have fitted a slotted ball-valve and there is no tap but screwdriver slots instead, these will turn either way and again inline with the pipe is on and across the pipe is off. Turn both taps on and you should hear water rushing into the boiler. Hopefully you know where the pressure dial is and are able to stop it before it goes too high. Aim for around 1 bar but don't worry if it shoots up to 2 bars. In the unlikely event there is no metal braided pipe then kopefully the installer left one near the boiler or with the instruction book and you'll need to fit this first. Hope this helps - robbie.
Robbie Repairs, December 2008