After seeing what I thought was a piece of metal in my combustion box in the rear of the stove, I have a new combustor here and have removed the old one. The piece that looked like metal is actually a piece of the combustor brick that broke off the inside. My question now is, with the combustor out, there is a square hole in the rear most part of the stove that I can look through and see the floor. Along the seem directly behind the combustor brick some of the stove cement came out when I ran my stove vac through. Is it important for that seem to be cemented with a 1 1/2 x 1 inch hole there anyway?