michaelanthony wrote:If you can imagine 2 inches of ash inside the bottom of the exhaust path along the sides and possible the back, that is a lot of stove not getting heat transfer and also shortening the path of the exhaust= less efficiency!
MA, now that you have the sides cleared of fly ash, with your IR thermometer measure the bottom of the side in the middle. Keep the IR "gun" the same distance from the stove each time. Record that temp and the reading taken on the center of the griddle. Take several more measurements on the side along the same vertical line until you get close to the top and right them down too. As the weeks pass, compare newer measurements at the same points on the side to the set of "clean" measurements you recorded. You can gauge the effect of the ash accumulating inside the chamber by the cooler temperatures.
Rich W., I don't think you could burn enough coal in one season to fill the heat exchange chambers but that would depend on how much fly ash your coal gives up and your shake down process. The stove would progressively give off less heat and eventually the draft would be affected. None of this is likely IMHO. I've not cleaned mine for the entire season an in the spring I'd estimate about six inches had built up in the side chambers. It pays to do it every ton or two in better heat transfer.