I have a brand new Enerzone wood stove 1.8 insert , that was installed in August. I've burned 2.5 cords of seasoned oak since oct 08.all of a sudden i began to have draft problems.i have a 6" liner top to bottom.my stove guy said i probably have creosite buildup blocking the flue.is it possible to have that much buildup in such a short period of time? thanks for any input,great site!