Hitzer 50-93

So I am looking for a little help, This is my 4th year with my stove I started it November 5th and it has been running fine I shake it and fill it twice a day, it has a manual damper that I keep barely open in the pipe. So today after I filled it I noticed that the pipe was getting really hot around 400-500 normally 150-200. I checked the doors to make sure they were shut correctly and that the damper was in the normal position, you know the obvious things... any idea what could be going on..

Had to get plenty of air in to get those high temperatures.
Dollar bill test for tight gasket seals is a good first test.

I have had that happen, like a run away train. I believe it's in the coal itself, when conditions are just right. Once gasses are burned off, it will settle back down to normal.

And that R--is a fact!! None of this stuff is carved in stone!! LOL---weather, coal, wind all play their lil part.