Hi I need some help. I have a hearthstone Mansfield that all of a sudden is letting smoke in the house. I open the door to put wood in and smoke rolls out and even when the door is closed starting to get a little smoke as well. I cleaned the pipe going to the chimney it wasn't really dirty. The chimney is clean and has a lot of draw. I have been burning with the same set for the past five years and all of a sudden getting a lot of smoke. I think something is plugged up in the wood burner itself. Not sure though. If anyone can help I would also need to know what needs cleaned and how to go about doing it. If you think that's the problem. Thank you so much.