Managing Low Slow Burns

Managing Low Slow Burns

PostBy: Lightning On: Sun Mar 26, 2017 7:57 pm

So I thought I would give this a try. Tonight I put a blanket of fines (6 pounds) on top after shake and load in an attempt to keep the stove size idling healthier. It's been getting a little too warm in the house with the mild temps outside and it's difficult to keep stove size happy at real slow burn rates. Anyone else try a blanket of fines?
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Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

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Re: Managing Low Slow Burns

PostBy: windyhill4.2 On: Sun Mar 26, 2017 8:29 pm

When i want my stove to put out less heat, i usually go from shaking 2 times per day to only shaking the ashes out at nite when the heat demand will be greater than daytime demand. Works good for me. :)

I never tried topping the bed with fines.
windyhill4.2
 
Stoker Coal Boiler: 1960 EFM520 installed in truck box
Hand Fed Coal Stove: Crane 404 with variable blower
Coal Size/Type: 404-nut, 520 rice ,anthracite for both

Re: Managing Low Slow Burns

PostBy: Lightning On: Sun Mar 26, 2017 8:30 pm

It recovered quickly. The blanket seen here effectively doing its job of containing heat and gases in the fuel bed. Its only allowing them to come up around the sides where the blanket is thin to none.
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Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: Managing Low Slow Burns

PostBy: Lightning On: Sun Mar 26, 2017 8:35 pm

windyhill4.2 wrote:When i want my stove to put out less heat, i usually go from shaking 2 times per day to only shaking the ashes out at nite when the heat demand will be greater than daytime demand. Works good for me. :)

I never tried topping the bed with fines.


Cool, yeah I'm at 24 hour tendings currently also. I do it in the evening, like you, for the nighttime cool down. :)

The plan with the blanket is to keep the heat and gasses contained in the fuel bed longer by forcing them to find a longer pathway out. I'm hoping to alleviate the dead spots in the fuel bed from trying to run the stove size too slow.
Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: Managing Low Slow Burns

PostBy: oliver power On: Sun Mar 26, 2017 8:59 pm

Hi Lightning,

No doubt, the blanket of fines will slow the burn rate for a while. A layer of ash also slows the burn rate. Have an uncle who used ash in the military. Everyone liked when it was his turn to tend the fire, as they always woke up to a warm barrack. He never told his secret, so he says.

While playing with the D.S., I've noticed a weaker draft when over fire air is all the way open. This over fire air not only weakens the draft, but also, suppresses the weaker draft when traveling over the coals. Not to mention, the over fire air is taking un-wanted heat up the chimney as well.

I found cutting the primary air, and increasing the over fire air made a difference in keeping stove temp down. A drop in fuel consumption was noticed as well.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II), D.S. 1600 Circulator
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Re: Managing Low Slow Burns

PostBy: Lightning On: Sun Mar 26, 2017 9:22 pm

Interesting story about your uncle, Oliver. So he would put a blanket of ash on top? That seems crazy lol, but logical to work. :)

I don't have a problem slowing the burn per say, it's that slowing the burn with the stove size has some undesirable side effects. Dead spots in the fuel bed and some very long revving periods before shake down to bring it back up to health.

I actually use extra secondary air during warm spells to keep my draft from failing. Another thing that seems crazy but has completely solved my draft failure issues.
Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: Managing Low Slow Burns

PostBy: oliver power On: Sun Mar 26, 2017 9:31 pm

Lightning wrote:Interesting story about your uncle, Oliver. So he would put a blanket of ash on top? That seems crazy lol, but logical to work. :)

I don't have a problem slowing the burn per say, it's that slowing the burn with the stove size has some undesirable side effects. Dead spots in the fuel bed and some very long revving periods before shake down to bring it back up to health.

I actually use extra secondary air during warm spells to keep my draft from failing. Another thing that seems crazy but has completely solved my draft failure issues.
Gotcha, Dead spots in the fuel bed. Understood. Too spread out of a fire bed to burn even with low, low combustion air. Yes, I can see that happening.
oliver power
 
Stoker Coal Boiler: KEYSTOKER Kaa-2
Hand Fed Coal Stove: Hitzer 50-93 & 30-95, Vigilant (pre-Vigilant-II), D.S. 1600 Circulator
Baseburners & Antiques: MANY (Mostly when burning wood)

Re: Managing Low Slow Burns

PostBy: Seagrave1963 On: Mon Mar 27, 2017 8:46 am

I have done something similar to the OP but used rice coal over nut. Seems to work very well and when the the evening approaches, we just open the primary air up and the heat comes back quickly.
Seagrave1963
 
Hand Fed Coal Stove: Harman TLC2000
Coal Size/Type: nut
Other Heating: electric heat pumps, propane fireplace

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Re: Managing Low Slow Burns

PostBy: Sunny Boy On: Mon Mar 27, 2017 9:02 am

Banking a fire with ashes is an old method of slowing and holding a fire over night. My father told me that was one of his jobs setting up the coal furnace for the night. Come morning just open the dampers, shake the ashes down and the fire recovers nicely so that you can start adding fresh coal.

It's also very common to bank wood fires, too. I'd often do that at night when I used my fireplace and we do that with our camping fire pit. If buried in ash right, there's plenty enough fire left to easily get it going quickly the next morning.

I don't bank the coal stove fire with ashes or fines for over night, but I do use a shovel of fines placed in the middle of each round cover opening to slow a too-hot fire. Acts like putting a large piece of coal in the center and it works great at slowing, while still adding fuel. And it's a good way to get your money's worth of heat out of all those fines you paid for. ;)

To slow and extend overnight fires, when I'm getting the stove "ready for bed", I use a higher concentration of smaller pieces of coal. It works similar to blanketing with fines in that it gives a high concentration of smaller pieces not only increase the fuel density in the firebox, the tighter air spaces also add air flow resistance up through the firebed. Both contribute to slowing and lengthening the burn time. Using a blanket of fines just takes that to another level and slows it even more.

But, as Lee said, you have to leave some open space around the outer edges. Cover the firebed completely with fines and you risk smothering and putting the fire out.

Paul
Sunny Boy
 
Hand Fed Coal Boiler: Anthracite Industrial, domestic hot water heater
Baseburners & Antiques: Glenwood range 208, # 6 base heater, 2 Modern Oak 118.
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Re: Managing Low Slow Burns

PostBy: michaelanthony On: Mon Mar 27, 2017 9:21 am

My box stove is 35 ish yrs old so things aren't so square and tight, it requires using the small 'nut and pea mix that comes in the Tractor supply bags of 'nut instead of the stove size I normally use and closing the primary tight. A little more secondary air, an adjustment on both the baro and the mpd as well depending on the wind.
...now the Vigilant is a different story, I just close the bi-metal flap and do nothing for a couple of days.
michaelanthony
 
Hand Fed Coal Stove: Vigilant 2310, gold marc box stove, vogelzang pot belly coat rack
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Re: Managing Low Slow Burns

PostBy: freetown fred On: Mon Mar 27, 2017 10:25 am

I switched back to straight nut & got done with the stove mix. That didn't work worth a crap when tendin once a day in this weird weather. Took way to long to re-coup. Course I got a real simplistic, functional stove, not one of those silly ass--ya gotta mess with them all the time kind!! ;) I'm with MA! :)
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
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Re: Managing Low Slow Burns

PostBy: warminmn On: Mon Mar 27, 2017 11:48 am

Its easier to open a window :lol:

I too use over fire air to slow it down if I need too. If its in the bag it goes in my fire, so I dont have any fines in a pail to put on top. I should burn the bag too :)
warminmn
 
Hand Fed Coal Stove: Chubby Junior, Efel Nestor Martin, Frankenstove
Coal Size/Type: nut and stove anthracite. Soft coal
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Re: Managing Low Slow Burns

PostBy: freetown fred On: Mon Mar 27, 2017 11:51 am

Now you're getting to damn simplistic W!!! Of course, you also have a no muss, no fuss stove!! ;)
freetown fred
 
Hand Fed Coal Stove: HITZER 50-93
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Re: Managing Low Slow Burns

PostBy: Lightning On: Mon Mar 27, 2017 11:57 am

freetown fred wrote: Course I got a real simplistic, functional stove, not one of those silly ass--ya gotta mess with them all the time kind!!


Who visits their stove more than once a day in this weather? :lol:
Not me....
Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: Managing Low Slow Burns

PostBy: KingCoal On: Mon Mar 27, 2017 12:01 pm

and there are a certain # of stoves that are just the right size and layout that if you want you can do your shake and rev. cycle then get ahold of the corners of the long way on the bag and drop the whole thing cross wise or long wise, on the long narrow edge, right on top of the fire. if you have your base fire going good enough by the time the bag burns off and the coal slumps the fire just keeps right on rockin the blues and you walk away cause the bi-metal is going to handle it from there. :idea:
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Hand Fed Coal Stove: 1- Warm Morning # 617A, 3-Locke Warm Morning #120, 1-Locke Warm Morning #524B
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