If pump and fan are running,on start up the fault sounds like the air pressure switch,remove the front heat exchange cover slightly if the boiler works thats the fault.Or it could be a blocked venturi on flue
Bob Mortimer
March 2010
may be faulty electrode or flame detection on pcb
Ian
February 2010
I can answer this question...
my ferroli falcon fires up then after a couple of seconds shuts down again ?