I think you have the explaination right here.. I'd slow the feed and see what happens.. you have a very big fire for a fairly small heat exchanger.. Or you can try some PRB coal like you mentioned..
Let us know what you find out.
steinkebunch wrote:I cannot adjust the feed rate. The stoker/auger just turns at a constant rate. No step pulleys. Some could certainly be added. But to lower the feed rate, I'd need a smaller pulley on the motor, or a larger pulley on the gearbox, I think. I'll have to give that some thought. These stoves were made in Sheridan, WY, which has local Powder River Basin coal, more in the 8,000 btu range. I'm using coal on the other side of the BigHorn mountains. It is way different. Maybe i need to do some tweaking, or just try a few weeks of the PRB coal.