high pressure?

Hi , we have a worcester 24cdi at home and one of the heater pipes had a leak making the pressure drop. This lated for a few days and I would regularly top up the pressure. Again I topped the pressure up (1 bar) a couple of hours before I resolved the leak. when i later looked the pressure had gone to 2 bar and it is now at 2.5. I have bleed the radiators but the pressure doesn't go below 2 bar even when it is not on. Please help my husband understands less than i do about boilers