I have a new yorker boiler heater that blows black soot out of air damper when it fires.The black soot looks like pepper.The heater is only 1 year old.I fully cleaned it and I replaced the line filter. I even replaced the nozzle and it still blows soot.Can the heater be burning too rich ? Do I have to adjust the air going into heater? If so ,How do I adjust the air band.Please help!!!!!!!!!