Basically a fan flued boiler has no means of ignition other than automated.If you pull the bottom flap down you may see a red push in button.This is the o/heat trip.Sometimes they pop out causing the boiler to go dead.If this is already in then you are looking at an electrical fault with the boiler itself.If the clock is on continuos the fan should be running.Can you hear it,is the spark ignition working.
Tony S
September 2008