Axeman-Anderson Anthratube 260m disection

UPDATE After one full week of burning, I consumed about 500# of coal, but this should have been less, since I still have a problem with unburnt coal in my ashpan.

I started on last monday night, seven days ago, with a full coal hopper. I left Tuesday morning for a five day assignment at work. I had my caretaker keep track of the weight of the coal added to keep the hopper full, and to keep an eye on the ash pan. The coal use was on average about 80# per 24 hour period, but the ash pan was about 80% unburnt or partially burnt coal... %%$%$^$&* !!

So when I got home on Saturday afternoon I looked at the ashpan, and sure enough the report was right, there was a significant amount of fresh shiney coal and a lot of partially burnt coal in with the ashes. The ashes were everything from small golfball sized clinkers, very soft and fragile, an a lot of fine ashes, like powder.

I thought about HOW fresh unburnt coal could make it's way through the firepot, and the only idea I came up with was that the firepot was not burning all the way around, there had to be a portion of the coal bed that I could not see that was not burning, and the shaking action of the ash drawer/grate was pulling this fresh coal from the bottom of the coal bed as it was replaced on the top by fresh coal.

So I stopped the auger from feeding fresh coal and let the fire burn down several inches, and I did see some areas that were not burning as hot as the others.. Then I did the cardinal sin with a coal bed.. I got a poker and stired the hot coal bed, moving the hot coal all around, to get the fire burning all through the firepot... or so I thought.. I started up the auger again and an hour later looked at the fire, it appeared to be burning all the way around... and I went to bed..

On Sunday morning I awoke to a cooling house.. The boiler water was down to 65* and the fire was out... Lots of fresh shiny unburnt coal in the firepot, and no fire..

So I reached in through the inspection port and pulled all the fresh new coal out and only 3-4" down found solid ashes with coal mixed in.. Aparently when I stirred the fire I upset and closed off the remaining air passageways through the ashes to the fire ... So the fire went out

I found as I dug out the ashes that there was a lot of big clinker in the ash, I think this was from the previous week when for five days the fire sat and burned while I was gone and the motor had failed. I think that as the fire burned down the clinker was formed around the central core of the remaining fire. When I replaced the motor, and found the fire still alive, I just let the boiler start up again, not thinking that any problems existed in the ashes.

I had turned down the anthrastat to hopefully make the coal burn more completely, but this caused the ash to deepen and eventually make the fire very shallow, and fragile, my stirring the fire was all it took to kill the fire.

I completely cleaned out the firepot and the ashdrawer, and started over again with a fresh fire, and fresh coal.. I imediately noticed that I had higher flue temps than before, I can see over 300* after a 10-15 minute burn, before the highest I saw was 250*..So I do think I did have a partial fire in the fire pot.

But two days later, I still have lots of unburnt coal in the ashpan.. so I called a coal boiler service person that a fellow forum member had given me then phone number for. I learned that the AA 260M boiler often has a lot of unburnt coal in the ashes when the weather is warm, and that I may have to live with this untill the cold weather really sets in... The firepot holds a lot of coal and the short time that the fan runs is not enough to get a full burn in the coal.

But I can adjust the aquastat to have a slightly higher temp and make the temp differential higher, I had it at 10*, I adjusted it up to 20*, so the fan should run longer and maybe burn the coal more completely. I will adjust the anthrastat to near the factory setting and see what transpires..

The coal consumption I am burning or using is pretty low, should work out to about one ton a month at the current temperatures and weather. If I double this for the three really cold months of Dec. Jan. and February, then my winter consumption should be around 7-8 tons.. less than half what I burnt last year.. not bad, and if I do manage to get the boiler to burn all the coal then I should burn even less...

So I'm still learning, and experimenting, I hope to cure or significantly reduce the unburnt coal issue soon.

Greg L.

Thanks ,keep us posted . Unburnt coal isn't that as bad as a unfinished beer laying around ? Dave

Greg there are two things that affect ashing 1) how hot the coal is and if it's cool enough to ash, 2)how hot the boiler is believe it or not the hotter the boiler the higher you have to turn the ashing or the unit won't ash and the same goes if it cool then you have to turn the ashing down. Second thing if you don't have a timer I really recommend one warm weather or not because it keeps the fire hot remember there really no draft thru the fire bed when the fans not running I use a intermatic C8865 runs the unit 1min every hr. Since Friday at 9am I've used about 150-200lbs of coal, I went down and dug thru the ashes and got only a handfull of fresh coal that was pull under while ashing.

One more thing that I wanted to add is that water that is too cool coming back in on the return seems to cool the ash down two quick and causes some of the clinkers

One more one more thing. I move the grate 2 notches and the anthrastat is at 3.4 which should work out to 128 to 130 on the newer ones.

It makes sense that if the water temperature is higher, and therefore the boiler itself is hotter, that the anthrastat would have to be turned up to a higher temperature to get it to respond to ash temperature instead of the boiler temperature.

Right now my boiler runs a minumum of twice an hour for at least ten minutes. So for now in this weather a one minute timer per hour wouldn't do much. If I decide to run in the warm weather in the spring or if the weather turns very warm then I will have to install a timer.. [where is that fabled Global Warming??' ] I have 3-4" of snow and 25* and it 's not December yet!!??

Currently I'm still using the old 'Big Bertha' boiler to heat the shop's floor. This week I'll hook the shop heat to the AA boiler to increase the BTU load on the boiler. Hopefully this will increase the burn time and burn the coal more completely.

Greg L

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LsFarm wrote: This week I'll hook the shop heat to the AA boiler to increase the BTU load on the boiler. Hopefully this will increase the burn time and burn the coal more completely.

That monster won't settle down until she sees about 100K load continuously. Now that you have massaged her, she is "chomping at the bit."

I can't believe you broke the "Cardinal Rule"!!!

Greg L called me about switching his grate control from the A-A anthrastat control to the AHS timer control. I looked up the specific control AHS uses. It's a Paragon brand model JW10-100. On the manufactures web site it even tells you how to adjust it. I quote:

HOW TO DETERMINE TIMER SETTING
A:
Multiply the number of 1000 pound cows in the barn by 250 and divide product by the fan CFM (manufacturer’s
rating). The resulting number is the timer setting.
B:
Multiply the number of four pound birds by 5 and divide product by fan CFM (manufacturers rating). The resulting
number is the timer setting.
C:
Multiply the age of the birds (in weeks) by the number of birds and divide by the fan CFM (manufacturers rating).
The resulting figure is the timer setting for that age. This will be increased as the birds grow.

End quote.

Of course I left out something A=DAIRY BARNS, B=LAYING HOUSES, C=BROILER HOUSES

Is the weight of the birds laden or unladen?

ARTHUR: Whoa there!
[clop clop]

GUARD #1: Halt! Who goes there?
ARTHUR: It is I, Arthur, son of Uther Pendragon, from the castle
of Camelot. King of the Britons, defeator of the Saxons, sovereign
of all England!
GUARD #1: Pull the other one!
ARTHUR: I am. And this my trusty servant Patsy.
We have ridden the length and breadth of the land in search of knights
who will join me in my court of Camelot. I must speak with your lord
and master.
GUARD #1: What, ridden on a horse?
ARTHUR: Yes!
GUARD #1: You're using coconuts!
ARTHUR: What?
GUARD #1: You've got two empty halves of coconut and you're bangin'
'em together.
ARTHUR: So? We have ridden since the snows of winter covered this
land, through the kingdom of Mercea, through--
GUARD #1: Where'd you get the coconut?
ARTHUR: We found them.
GUARD #1: Found them? In Mercea? The coconut's tropical!
ARTHUR: What do you mean?
GUARD #1: Well, this is a temperate zone.
ARTHUR: The swallow may fly south with the sun or the house martin
or the plumber may seek warmer climes in winter yet these are not
strangers to our land.
GUARD #1: Are you suggesting coconuts migrate?
ARTHUR: Not at all, they could be carried.
GUARD #1: What -- a swallow carrying a coconut?
ARTHUR: It could grip it by the husk!
GUARD #1: It's not a question of where he grips it! It's a simple
question of weight ratios! A five ounce bird could not carry a 1 pound
coconut.
ARTHUR: Well, it doesn't matter. Will you go and tell your master
that Arthur from the Court of Camelot is here.
GUARD #1: Listen, in order to maintain air-speed velocity, a swallow
needs to beat its wings 43 times every second, right?
ARTHUR: Please!
GUARD #1: Am I right?
ARTHUR: I'm not interested!
GUARD #2: It could be carried by an African swallow!
GUARD #1: Oh, yeah, an African swallow maybe, but not a European
swallow, that's my point.
GUARD #2: Oh, yeah, I agree with that...
ARTHUR: Will you ask your master if he wants to join my court
at Camelot?!
GUARD #1: But then of course African swallows are not migratory.
GUARD #2: Oh, yeah...
GUARD #1: So they couldn't bring a coconut back anyway...
[clop clop]
GUARD #2: Wait a minute -- supposing two swallows carried it together?
GUARD #1: No, they'd have to have it on a line.
GUARD #2: Well, simple! They'd just use a standard creeper!
GUARD #1: What, held under the dorsal guiding feathers?
GUARD #2: Well, why not?

King Arthur: serious thread drift!!

Well the unburnt chronicles continues... I noticed today that looking through the inspection port that the left side and under the inspection port of the coal fire was dark and not burning. I thought that was a bit strange. The only thing unique about that part of the boiler is that it is where the return cold water comes into the boiler. this water is about 135*, I can't believe that this is cool enough to keep the steel of the firepot cool enough to keep a fire from burning next to it... seems far-fetched..

Anyway, I pulled out the ashpan and looked at the back of the boiler base under the end of the ash drawer, and there was a pile of fresh shiny coal. So the coal was making it's way dowh the side of the firepot along the steel and getting to the ash drawer.

So I decided to try raising the temperature, I moved it up from 160* to 175* and turned up the thermostats in the house, I wanted to create a long hot burn. I also stirred the coal alongside the steel wall to get hot coals over and mixed with the unburnt coal.

After about three long burns the line of dark coal returned, narrower, but still there. So I decided it must be blocked air to the fire.

So I unbolted the end of the boiler base, disconnected the ashdrawer linkage and pulled the ashdrawer out about 8", it was full of fresh coal, the entire surface of the ash drawer was covered in fresh unburnt coal, and this is the BOTTOM of the fire pot.. ???? WTF:??...

As I scooped out the fresh coal I found that it was only about an inch deep, and underneath was hard, compacted ashes. powdery ash packed hard. There was my ash I had been expecting to see in the ashpan.!!..

I pulled the ashdrawer out another few inches and let the whole load of coal, fire and all fall on the floor, I shoveled it up, cleaned out the ash drawer and started over again with another fresh fire. This time the water was pretty cold, around 50*, and I now have the shop floor heat hooked up to it too. So when I started the new fire, Ir burned a long time about 45minutes. the flue temps got up to 330*, highest yet. The fire was burning rught up against the steel.

Apparently the ash was blocking the air flow to that end of the fire. I'll see if I can keep the ashes moving, and not get so compacted.

With a longer burn time I think maybe I can burn the coal completely, we'll see.

I've attached several photos, so you can see what I've been talking about.

I just watched the second burn after the boiler got up to temp after the new fire was started. The fire is right up against the steel firepot wall, The flue temp got up to 333* when the boiler was at 170* water temp. The fan shut down at 175*, it had an overshoot up to 189*, as the flue temp dropped rapidly from 333* to below 200*,

Hopefully with a full fire and some extra load on the boiler it will burn fully.

I also hooked up a timer to the grate action controls, the grate will work as a percentage of the combustion fan run time instead of trying to sense the ash temperature while the sensor is surrounded by the heat of the boiler, boiler water and the ashes... Not a great design. My Anthrastat is probably not very good either.

Tomorrow the new coal hopper, it will hold more than a week's worth I think.

Greg L

LsFarm wrote:King Arthur: serious thread drift!!

Sorry, just wanted to qualify Coldsweat's laden or unladen bird comment.
I was just studying the AA Anthratube brochure pdf, which I have saved. Trying to understand how the Anthratube works. I'll understand it better when I can see one in action.

Is it possible that the grate is not level which is causing the ash to stay in? If I understand how the shaking gets rid of ash it should allow a natural progression of the ash off the end as new coal comes in the top. It seems that the deep bed of ash may be resulting from the grate not letting it fall off the end.

Just a thought, not sure if I know enough to make this question valid.

I'm thinking of removing the ashdrawer/grate, and polishing it to make is slippery-er . The base and drawer are level. It moves freely on the nice new rollers It seems like the coal needs more time to burn than the boiler wants to give it .

Greg L