Plumbing: How can I fix my worcester 24CDi and 28CDi?

My boiler fires up for water and heating but keeps cutting off. May sound crazy but happened when I bled the radiator. I may have done it wrong because I also allowed the water to come out as well and realised afterwards this may have been a mistake. This may just be a concidence but it stop working straight away after this. I therefore have no heating or hot water. Can you help.