The “Right” fire height

Trumpeterb · Post by **Trumpeterb** » Wed. Dec. 11, 2019 9:02 am

I have read a lot about how to adjust fire height in the AA130 and AHS130 units by raising or lowering ashing temperatures and adjusting hysteresis settings. I currently have my ashing set point at 135 with a 5° hysteresis. It seems to be working well. The question I have is this: how do you determine the “right” fire height? For example, if I have a lower fire and am not getting puffbacks, the unit is running well, etc, is there any benefit to raising the height? Do you want the lowest possible fire that works? Or the highest possible fire that works? I am just curious about the criteria that everyone uses to determine the “right” height. Here are some pictures of my current fire while the boiler is firing. I have no idea if it is the right height or not, but it seems to be working,

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Trumpeterb · Post by **Trumpeterb** » Wed. Dec. 11, 2019 9:02 am

Trumpeterb wrote: ↑
Wed. Dec. 11, 2019 9:02 am
I have read a lot about how to adjust fire height in the AA130 and AHS130 units by raising or lowering ashing temperatures and adjusting hysteresis settings. I currently have my ashing set point at 135 with a 5° hysteresis. It seems to be working well. The question I have is this: how do you determine the “right” fire height? For example, if I have a lower fire and am not getting puffbacks, the unit is running well, etc, is there any benefit to raising the height? Do you want the lowest possible fire that works? Or the highest possible fire that works? I am just curious about the criteria that everyone uses to determine the “right” height. Here are some pictures of my current fire while the boiler is firing. I have no idea if it is the right height or not, but it seems to be working,

CC70DDA4-49AE-43CB-ACA6-F53A26FD601D.jpeg7A9FF776-19BD-4CE3-AC95-5CB8C2A8E637.jpegFB6695FB-AD02-4513-95F5-B20A8F6273F4.jpeg

Post by **Lightning** » Wed. Dec. 11, 2019 9:18 am

I'm relatively new with my AA, but from what I've seen so far, as long as the ashing isn't too fast the fire height will settle properly on its own.

Trumpeterb · Post by **Trumpeterb** » Wed. Dec. 11, 2019 9:27 am

Lightning wrote: ↑
Wed. Dec. 11, 2019 9:18 am
I'm relatively new with my AA, but from what I've seen so far, as long as the ashing isn't too fast the fire height will settle properly on its own.

Right. So how do you determine what is “too fast?”

Post by **Lightning** » Wed. Dec. 11, 2019 10:12 am

Trumpeterb wrote: ↑
Wed. Dec. 11, 2019 9:27 am
Right. So how do you determine what is “too fast?”

Too fast would reveal a lot of unburned in the ash tub, ash tub would be heavy, ect.. the only real way to determine completeness of burn accurately is to measure coal going in and measure ash coming out. Mine turned out to be 12% ash by weight which is pretty close to as good as it gets.

Too fast can also be justified by ash depth, you want a couple few inches on top the ash sled all the time. This can be determined with a dipstick test after a healthy combination call. Put a rod down thru the fire bed right down to the ash sled, let stand a minute or two, then pull it out and see how far down the orange goes.

McGiever · Post by **McGiever** » Wed. Dec. 11, 2019 11:08 am

Axeman do not have digital controls or a hysterisis setting...so comparing numbers is weak..but dipstick can tell or show much of how fire is presently.

Post by **coaledsweat** » Wed. Dec. 11, 2019 11:17 am

The Axeman manual states the bottom half of the firetube should be ash. Your fire looks good to me. Too low you get puff backs and eat the lower firetube ring up (the part that is below the waterline). To high and it will munch up the feed tube lower end. If the fire breaks the surface once in a while it should be fine. By this, I mean glowing coals at the outer edge of the cone of fed coal.

hotblast1357 · Post by **hotblast1357** » Wed. Dec. 11, 2019 2:47 pm

Here’s what mine looks like after a aqua stat call... ashing is set at 120 with hysteria of 1. I haven’t dipsticked the fire bed yet... this is a 260 though so bigger fire pit and size of fire..

Trumpeterb · Post by **Trumpeterb** » Wed. Dec. 11, 2019 3:10 pm

hotblast1357 wrote: ↑
Wed. Dec. 11, 2019 2:47 pm
Here’s what mine looks like after a aqua stat call... ashing is set at 120 with hysteria of 1. I haven’t dipsticked the fire bed yet... this is a 260 though so bigger fire pit and size of fire..

You have a nice “ring” of fire. I tend to get red coals and blue flame on the left side of the new coal, but not much happening on the right side.

Egghead · Post by **Egghead** » Wed. Dec. 11, 2019 4:44 pm

Trumpeterb wrote: ↑
Wed. Dec. 11, 2019 3:10 pm
You have a nice “ring” of fire. I tend to get red coals and blue flame on the left side of the new coal, but not much happening on the right side.

I’m new to my 130 and the ring of fire only shows up under long heat calls. Sometimes it doesn’t need to get up to full fire. Other times I have blue flame all the way around.

hotblast1357 · Post by **hotblast1357** » Wed. Dec. 11, 2019 4:45 pm

That sounds like a issue with the first initial fire being started, and it not having a large enough load to ignite the whole bed

Egghead · Post by **Egghead** » Wed. Dec. 11, 2019 5:17 pm

Here is a shot of 3 zones after 45 minutes straight.

hotblast1357 · Post by **hotblast1357** » Wed. Dec. 11, 2019 5:51 pm

Wow that’s way to high of a fire!!!

McGiever · Post by **McGiever** » Wed. Dec. 11, 2019 5:59 pm

Not much help since I don't know the particulars, but, Somewhere I heard where another owner added a controller w/ a "K" type thermocouple mounted inside at top of fire column to maintain fire height. It may of been an attempt of 'puff-back prevention...not sure.

Post by **coaledsweat** » Wed. Dec. 11, 2019 6:14 pm

Way too high, that burning coal is going to nibble away at the protruding portion of the feed tube. There ALWAYS needs to be some fresh coal on the top of the fire. Give that anthrastat a twist up.

The “Right” fire height

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