Have a new 2 x 5 AA evaporator. Came with auf and I added aof. Did a boil with water and then had my first boil with sap yesterday. There was a lot to watch but it was after dark and I went out to get wood and had sparks coming out the stack. Always fired at 7 minutes on a 2 x6 that I had, last night after firing stack temp would go to 1050 then in 7 minutes would be down to 850. Started adjusting the blast gates I have but really not sure what I should be looking for. I have a bouncy house blower outside for air. Any suggestions would be appreciated. Ron