I'm trying to find an owners or repair manual for my lang 6302A. One specific question I need the answer to is when I disassembled the stove, inside the firebox on the bottom was a plate, under the plate were fine particulates that looked to me like there may have been fire bricks that deteriorated over time. My question is, was there bricks under the bottom plate or some sort of granular version of an insulating material? Or was it just ash that packed under there for years? It didn't look like ash. If I remember correctly it looked kinda like sand. Any help is appreciated.