Auf

[peterjd89]

So I have a 3 by 12 wood fired arch with a Auf system that has a 1and half hp motor on a 15 by 15 squirrel cage blower. I have a 6 in pulley on the motor. The air goes into the side of the arch and has three tubes that run with holes drilled in them under the grates. The back pan is raised flu d&g with sand under it. I can run between 120 and 140gph. My problem is I have a lot of sparks flying out of the stack rarely any smoke and at the end of the night hardly and ashes. So would a set of nozzles for aof at the back of the firebox help the sparks and distribute the heat on the front pan better and would a dapner in the stack or at the back of the arch slow some of the heat down from going up the stack? The heat gun reads the stack.at about 650 to 900 and I think a lot of heat is being wasted and suggusetions or ideas would be great also I had aof once but couldn't make it work quit right perhaps I had to much air over the fire?

[maple flats]

No damper on wood fired. You might well do better dampening the air inlet to the blower. Just make a slide gate and experiment.

[mellondome]

Aof will help a lot with evening out thenheat of the front pan.. will also help with some of your spark issues. Donot add a damper. If you want to control outflow air, build up under the base stack to restrict the flow.

[peterjd89]

I'll try that it makes sense

[maple flats]

Donot add a damper. If you want to control outflow air, build up under the base stack to restrict the flow.

????? I never heard of that.

[DougM]

"The heat gun reads the stack.at about 650 to 900"
You may know way more about this than I do, but a friend brought out a gun for us to use and we got vastly different readings on our stack within inches of each other. Turns out the guns was calibrated to read darker metals, so where our stack is rusty it reads closer to our wired stack temp gauge. Where it is more reflective it reads a lot different. He showed me the list of possible corrections & it was extremely long due to the difference in how different types of materials reflect the beam back. Even different types of stainless had different correction factors.
I'm not saying you're not potentially losing heat, just that I'm not convinced measuring with a gun is the best way to go.