I have a steel approx 7 1/2" chimney, and a 4" s/s insert going all the way up it. This year I noticed that when I was running my sweep up the liner (a dryer vent brush with flexible poles attached to my drill) that a good amount of ash was spilling down the outside of my liner and spilling out the chimney pipe. Is this normal? was it spilling over the top of the liner and down the chimney? or do I have a hole in my liner? It is only 2 years old.