how can i sort my worcester 28cdi?

Try bleeding radiators to get rid of air, Then with system cold try to increase pressure, you should hear the water going in, same as you do running a tap or after flushing the toilet. Might take a minute to start to increase, If not and pressure does not increase, could be a valve problem, with the fill loop. close it off, disconnect from boiler end, should be a valve/one way fitting to stop any water coming out of system. then open the valve to a bucket or something, see if you get water out, if not valve fault or 1 way fault or some other valve. Pressure to about 1 bar COLD

SD
April 2012