Second year in operation, zero problems until now. I just happened to be watching while it did an autoclean today (thank God) and I noticed that the firepot bottom plate stopped about an eight inch before closing and stopped, leaving a gap. I cleaned the stove, firepot and bottom plate as well as I could, turned it on and it did the same thing. I checked the autoclean mechanism from underneath, nothing obvious, and I can manually return the plate to position, but autoclean still leaves the gap. What is wrong with it?