ferrolli gas boiler?

ferroli optimax?
ferroli modena?
ferroli falcon?
F40 could refer to high system pressure
depending on which boiler you have you can check if the digital display for system pressure corresponds with mechanical pressure gauge reading
if there is a discrepency between digital & mechanical its just a case of reprogramming the PCB via the user controls
but i would have to know the exact model of boiler you have before i could describe the procedure

manwithnoname
May 2012