I have a Blaze King Prncess model PTJ-203. There is a part inside of the wood box that hangs from the top. It is shaped similar to a "u" and I believe I read at one time that it protects the flue from direct flame. Last year this part started falling down into the fire (or just after the fire burned out). I am thinking that it has warped over the years and doesn't fit like it should. I took it in and had a welder add an additional 1/2" of metal to the length of one edge to keep it from falling down. That worked. It has begun to fall again. I am wondering what the part is designed to do and what I am doing wrong that it is falling. Thank you for any assistance offered.