could someone please explain this to me,,, i pulled of the pipe elbow from stove to chimney, and cold air is hitting me in the face, why does the draft come down the chimney? i understand the cold air comes in until its heated then the draft will go up , i guess what im saying do all chimneys do this when cold, and also it leaves a very bad smell in the basement , what is wrong if anything and what can i do to stop this,,,,,, i do have a chimney cap on