Mine was. A simple solution I have found, is to block off the barometric damper. If I burn oil, I leave the damper functioning. If I'm burning wood, I close the barometric damper, and block it shut. This seems to have made my boiler less of a creosote factory. It also seems to burn more efficiently for some reason. I don't quite understand the physics of it all, but I know that I like NOT cleaning my chimney and boiler tubes once a week.