hi guys hope some one has information on what the problem could be i have ariston genus 27 mffi it has been good for the past 3 years and all of a sudden the yellow light has come on and i think it means fumes indication i have checked all the flue pipe and cleaned all the inside of boiler and still no joy also checked pcb to me it it looks good there is no ign fireing when i reset the boiler for start , would appreciate some info on this thanks guys