doug if you are having to bleed the system every week then you have a problem, after you bleed them this time

try turning the pump down to a lower setting ( this if on the pump and if new will be from 1 to 3 )most people leave on 3 but this can cause problems on older systems as the new pumps are stronger than the old one it replaced and can pump water in to your expanshion tank in the loft doing this brings fresh water down in to your heating system and with that also air which ends up in your rads, so if you can turn pump down a setting and try that as long as all your rads get warm the pump will be fine set at this.

ps have you got an old system ?