How can I fix my boiler?

Try manually moving the lever on the three way valve(usually located near pump in cylinder cupboard)
Feel for heat on flow pipe into valve and with system calling for htg and hot water both pipes should heat up, one to coil in cylinder for hot water and other to heating circuit. The lever opens and closes the valve and you can lock in in the open position as a temp fix until you get a new valve or motor fitted. Obviously it could be many things but give it a go.

Dick Bindon
December 2008