Fire bed AHS/AA 130 - what should it look like?

 
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Retro_Origin
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Post by Retro_Origin » Wed. Jan. 03, 2024 12:13 pm

I recently changed the bronze linkage bushings in the ashing assembly since it was very sloppy and I was having some ashing problems.

My question may not relate to it, or it might. Is it normal for the bottom of the fire to be 'sloped' as in, it's not like a big 2" thick circle of ash with the firebed neatly atop. I noticed that if I open the ash door I can sometimes see a slight glow, like the bed is sloped downward (or following the air path) and peeking out toward the anthrastat.

Is this normal? it seems to me like it would be pretty hard to maintain a flat bottom of the fire, like it's going to want to have a slope/drift effect as it ashes.

I did a full restart when I changed the linkage, completely emptied everything out, took the grate out and all. started with 3" of solid ash and let it burn several hrs without ashing, then when I saw the stack temp started to droop I turned the ashing back on. That was Sunday.

*edit* a dipstick test revealed at least 3" of ash on the front side


 
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Post by Retro_Origin » Thu. Jan. 04, 2024 6:46 pm

Upon further investigation, I don't think the fire is as sloped as I initially thought, I left the dipstick in longer and got a better reading.

I believe my low flue temps are due to a buildup of fines due to my new coal bin (auger must be grinding it up) , because the sight port flapper is pulling shut a lot stronger than normal, and the fire depth is quite deep. Since I'm also running buckwheat I think I'm getting a fair amount of choking, which may be allowing fire to be thick and cool, hence getting the ashing too low.

buckwheat + deep fire = lower than normal flue temps can only mean lack of air.

also the dipstick is usually almost white hot, this time it was only orange/red.

I should probably drop the anthrastat a good bit until I fix the fines problem. Fines is either from letting the bin get too low or the actual design.

I bet if I was burning pea I might not notice.

 
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Post by Lightning » Thu. Jan. 04, 2024 6:59 pm

So, even if all that is true, what is the problem that you are trying to solve? Do you feel that it's running inefficiently?

Currently my bin is a mix of pea and buckwheat.. but it's not a homogenous mixture.. depending on which part of the bin I rake towards the feed tube sometimes it gets buck, sometimes pea, and sometimes a mix of both. Sometimes it gets a lot of fines too. I don't change any settings based on what it's using, I just let it do it's thing.
Retro_Origin wrote:
Thu. Jan. 04, 2024 6:46 pm
my low flue temps are due to a buildup of fines
What are your flue temps? And why do you think it's grinding coal up any more or less than usual?

 
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Post by Lightning » Thu. Jan. 04, 2024 7:14 pm

Retro_Origin wrote:
Thu. Jan. 04, 2024 6:46 pm
because the sight port flapper is pulling shut a lot stronger than normal, and the fire depth is quite deep. Since I'm also running buckwheat I think I'm getting a fair amount of choking, which may be allowing fire to be thick and cool, hence getting the ashing too low.
So many variables are at play that ultimately determine the amount of combustion air coming up thru the fuel bed. One of them being clinkers. Long combustion runs will form clinkers, short runs not so much. An ash layer loaded with clinkers will have more voids in it while a powder ash layer won't.

 
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Post by Lightning » Thu. Jan. 04, 2024 7:20 pm

At the end of the day, the fire's job is to just keep up with heat demand.. I don't think there is much we can do to push or pull the efficiency of these units given that something isn't way off, such as the ashing temperature or speed. I think the combustion efficiency varies slightly with heat demand, but not a whole lot. That's just my opinion..

 
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Post by Rob R. » Thu. Jan. 04, 2024 8:17 pm

I think you are overreacting. If the fire height looks good and the boiler is meeting demand just let it run.

 
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Post by Retro_Origin » Thu. Jan. 04, 2024 8:59 pm

Lightning wrote:
Thu. Jan. 04, 2024 6:59 pm
So, even if all that is true, what is the problem that you are trying to solve?
I'm not chasing efficiency here, safety and reliability.

I had some puffbacks that blew my baro out twice and stank up my basement (this within the past few weeks), I'm gone 12 hrs on a work day and with my wife and 2 kids home alone...well I don't need problems.

I had my anthrastat below 100 and so was suspecting the ashing mechanism slop was not helping, so I replaced the bushings and restarted the fire. - a few other details which are too long to go into...

But when the fire is healthy the flue temp runs about 325-350, wednesday I had a monster pile of fines under the transfer head, took off the transfer head and the fiber/paper ring is still intact and fine, so since I built my new bin I'm suspecting the extra abundance of fines is causing both the spillage and the slow fire issue. A little bit ago my flue temp didn't get about 275 after a full run.

I don't think the current fines issue is related to the puffbacks, so kind of have some multiple quandries overlaying eachother, which never helps!!

I'm not 'worried' about the fines, I'd like to fix it, but my original post was basically under possible suspicion that an odd shaped fire (underneath) was causing the ashing system to not be behaving properly, hence building a super deep fire and causing puffbacks....

Rob, I did make a confession to my wife, that I think EFM makes the best stoker design from what I've seen. Although AA's tend to draw in people (like me) with a fascination for steampunk and classic retro nonsense... EFM definitely makes a very reliable "set it and forget it" system. I don't think I would recommend an AA to many people, but I myself would be bored beyond doubt with an EFM.... :clap: :clap: :clap:


 
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Post by Lightning » Thu. Jan. 04, 2024 10:36 pm

Anthrastat below 100?
How many clicks on the ratchet?

 
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Post by Rob R. » Thu. Jan. 04, 2024 11:08 pm

I don’t think the Anthratube requires more adjustments than anything else. If you changed coal it makes sense that an adjustment may be needed, but you shouldn’t have to stray far from the factory settings.

 
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Post by mozz » Fri. Jan. 05, 2024 7:58 am

100 is too low.

 
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Post by coaledsweat » Fri. Jan. 05, 2024 8:25 am

Biggest problem I see here is the start fire height. The fire tube MUST be half full of ash. Deviate from this and you will have issues. I don't like seeing a glow down below, long enough run of that and the lower lip is gone.

 
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Post by Retro_Origin » Fri. Jan. 05, 2024 8:32 am

Lightning wrote:
Thu. Jan. 04, 2024 10:36 pm
Anthrastat below 100?
How many clicks on the ratchet?
2 clicks, seems to be right, it catches up to the anthrastat on a long heat call, and the fire stays away from the transfer head opening.
Rob R. wrote:
Thu. Jan. 04, 2024 11:08 pm
I don’t think the Anthratube requires more adjustments than anything else. If you changed coal it makes sense that an adjustment may be needed, but you shouldn’t have to stray far from the factory settings.
For clarification, I've been running the same brand buckwheat since summer.
mozz wrote:
Fri. Jan. 05, 2024 7:58 am
100 is too low.
I know that sounds true, but Don and Lee both seem to have much success running 105-110 with the INKBIRD (which is what I have, I would never have gone below 120 with the stock anthrastat) . Since I'm getting pretty thick fire with a dipstick measurement and sometimes see a glow in the ash pit - how can I justify going higher?

My guess Mozz, is that the buckwheat must affect the ash temperature setting

Currently seems to be running pretty decently - Just had a 20 minute run and it got up to 325 flue temp. I haven't made any changes, but would like to not have a pile of fines.

So to kind of hit the refresh - I'm not trying to make fancy alterations here but I do like running buckwheat more due to the noise being less in the tube (and my buckwheat bin is a lot closer than my pea bin - haha) if I remember correctly once when I talked to Pete about whether buck or pea was ok, he was kind of like "just use pea-don't stray into buck". So possibly pea is more forgiving for various reasons. Since most people are running Pea they wouldnt be having the same questions as me.

 
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Post by StokerDon » Fri. Jan. 05, 2024 9:59 am

Retro_Origin wrote:
Fri. Jan. 05, 2024 8:32 am
Don and Lee both seem to have much success running 105-110 with the INKBIRD
I ran the ashing temp at every different setting you can think of. I ended up running between 120 and 130 degrees with 0.3 hysteresis on the Inkbird. 125 - 130 worked real good in the Winter and 120 in the Summer.

At the stock 2875 RPM fan speed you shouldn't have any problem running Buckwheat size coal.

-Don

 
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Post by mozz » Fri. Jan. 05, 2024 3:03 pm

You didn't say Inkbird, you said anthrastat. Big difference. Anthrastat run at 140. I run the Inkbird at 115, seems to work fine and no need to adjust it. I also have the extra long probe which is the same length as the anthrastat, anything shorter i guess you would run it lower but then you are no where near the fire.

 
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Post by Retro_Origin » Sat. Jan. 06, 2024 12:04 pm

mozz wrote:
Fri. Jan. 05, 2024 3:03 pm
You didn't say Inkbird, you said anthrastat. Big difference. Anthrastat run at 140. I run the Inkbird at 115, seems to work fine and no need to adjust it. I also have the extra long probe which is the same length as the anthrastat, anything shorter i guess you would run it lower but then you are no where near the fire.
Yes, that is true, I was saying anthrastat but should have said "inkbird acting as anthrastat" :oops:


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