The problem with mine was when I did the first several cleanings I only used the brush to the end of the elbow and not farther. This resulted in the square tube that connects the left to the right side completely plugged. After several of these cleanings the left side of the insert was cold and the right side was hot. I knew something was not right and was trying different settings. By then I had burnt my first ton and went to do the major cleaning of pulling the insert out and cleaning the back side. This is when I found the moisture covering everything behind the stove. I was nervous about the moisture being all over it fearing that I had ruined it. First thinking my chimney was leaking then reread the owners manuel. When I read the maintenence instructions and realized I was not cleaning it thoroughly enough. That was 4 years ago and stove has not had any problems since. (Wish I found this site years ago, would have helped by my reading all the info here then applying to my stove....Thanks)