30-Sept-2013 ?Why a picture of a dirty burner you might ask? Well, we found that after hard running with the oil valve open, then throttling down to a pilot flame caused problems - we could not re-increase the oil amount, no matter how much we opened the oil valve. We think the burner is getting very hot under heavy firing, causing the oil to carbon/soot up right at the outlet when the oil is turned down. Since the oil is gravity fed, re-opening the oil valve does not push the carbon/soot away. We start the habit of blowing air through the burner before starting in the morning, and decide to add a steam blow-back valve like the prototype had so we can clean away the soot when needed. I also think the pulling the burner out further of the firepan may help, but that requires pulling the firepan and re-welding brackets.