Ok, if it's the same fault code on both burners that indicates it is fuel related, unlikely to be both photocells, it boxes. I can hear bearings starting to play up, if so on the fuel pump that could be a problem, the pump coupling could be broken and not constantly catching, it could be the pump drive key as well. I'd also check the capacitor as well. When serviced did you notice how thorough they were in cleaning the burner out. It's possible, certainly have seen it many times but not certain the blast tubes are dirty and not reflecting the light to the cells as well. Just another thing to consider.
The report suggests the figures are ok. The boiler side has quite a high O², low CO² and subsequent high excess air, although not what one would usually aim for I'm not convinced it's enough to cause your problem and certainly wouldn't knock both burners out.
The report suggests the figures are ok. The boiler side has quite a high O², low CO² and subsequent high excess air, although not what one would usually aim for I'm not convinced it's enough to cause your problem and certainly wouldn't knock both burners out.
