reporting 12-17 hour burn times with a stove top over 400 degrees

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kenny chaos

Minister of Fire
Hearth Supporter
Apr 10, 2008
1,995
Rochester,ny
What's with them Harmon 300's?

Could these claims possibly be true?

Even remotely possible?
 
Anything is possible, I think the big Blaze King can do it?
 
The TL-300 has a big firebox, top loading and downdraft re-burn. If you packed it with the right wood and managed to get the afterburner to light off at a low enough temp ya might be able to do it.

And if the afterburner stalled it might smolder at 400 for a long, long time.
 
CZARCAR said:
depends on outdoor temp

Only if it is 400 degrees outside.
 
I dunno Kenny sounds fishy to me...
 
Sure, just put it in a small well insulated room.
 
When I thing of the term "burn time," I think they are referring to how long you can get usable heat from the stove (or in my case, insert). I load my insert at 10 pm and when I get up in the morning the automatic blower is still blowing heat and the stove is warm to the touch. When I return at 4:30pm I can stir the coals and add some splits and I'm off to the races! I can go for days without using a match and the only time I load it in the am is when I'm working a 12 hour shift. I think the concept of keeping a fire going for 8-12 hours (with flame) is overstated. I hope somebody will correct me if I'm wrong, as I am new to the wood burning scene.
 
CTburns said:
When I thing of the term "burn time," I think they are referring to how long you can get usable heat from the stove (or in my case, insert). I hope somebody will correct me if I'm wrong, as I am new to the wood burning scene.


The claims are for 15 hour burn times over 300-400 degrees!
 
kenny chaos said:
CTburns said:
When I thing of the term "burn time," I think they are referring to how long you can get usable heat from the stove (or in my case, insert). I hope somebody will correct me if I'm wrong, as I am new to the wood burning scene.


The claims are for 15 hour burn times over 300-400 degrees!

People really buy that?
 
kenny chaos said:
CTburns said:
When I thing of the term "burn time," I think they are referring to how long you can get usable heat from the stove (or in my case, insert). I hope somebody will correct me if I'm wrong, as I am new to the wood burning scene.


The claims are for 15 hour burn times over 300-400 degrees!

Yes, but are they admitting to loading the stove at least 2x during that "burn time"? ;)
 
My inserts been burning 3 months straight,,,inside a fireplace!
 
Youhuuuu TL300 owners where are you? Sure would be nice to hear the other side.
 
Todd said:
Youhuuuu TL300 owners where are you? Sure would be nice to hear the other side.
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I use the stove (TL-300)to heat a house under renovation. I leave at 6Pm and do not return until 9-12 the following morning. A span of 15-18 hours. I order for me to see a stovetop temp of 300+ after 15 hours i need to have a full load of good hardwood The previuos day and a low burn rate setting on the primaty air control. If i use soft wood you can cut those times by 40%. When the stove is fully loaded and the air setting is on low ,just about all that is burning is the smoke. The wood itself will burn very slowly at this setting.The smoke will only burn if the temp in the AB chamber is 1100 Deg. or above. The AB pulls the smoke through the bed of hot coals to super heat it and then injects fresh heated air at the base of the AB to maintain a prolonged smoke burn. When you look through the front glass it almost looks like the wood is not burning at all, but if you can happen to see into the afterburner through a opening between the wood you will see a bright cherry red glowing AB chamber burning smoke at 1100 Degrees+
While the wood itself is hardly burning, more like smoldering.
THe stove top will hover around 450 in the first 3/4 of the burn cycle and fall to around 300 for the remaining hours after most of the gasses in the wood burns off. This is the second location for this stove in the 5 months iv been using it and the draft is different in each location so it affects the burn time. Better draft allows you to set the primary air lower and still maintain AB performance.
Iv already restarted this stove after 27 hours without relighting just by stirring the ash out of the remaining charcoal and turning up the air.
 
On the flipside i also have (my first stove) a KING stove made by US Stove and sold at TCS farm supply stores. This thing is basically a metal box with a hole in the top. 2-3 Hour burn and its out. I guess you get what you pay for. When i got the Harmon it was like Going from a yugo to a Rolls Royce. I also made a wood stove out of an old oil tank (275 Gallon) This thing throws some serious heat i guess cuz it has a lot of Sq feet of steel heat exchanger area. Works great for a large garage or out building for burning scrap wood.
 
Assuming, as I do, that it will take something close to 30,000 btu/hr to maintain 400 deg. stove top temps, and assuming further that you are burning oak at ~ 6,000 btu/lb., then IF you could load 60 lbs. of wood into the stove, and IF you could adjust the air control to burn the initial load at a rate to achieve 400 deg. stove top temperatures (and not more), and IF you could keep the air adjusted to continue to maintain that temperature as the wood burns down (and not less), then you could, in theory, get a 12 hour burn as specified.

Granted, that 30,000 btu/hr figure is little more than a guess. I doubt it is less than 20,000, and might well be higher than 30,000.

If the post above is correct, and the firebox is three cubic feet, then you could theoretically pack in well over 60 lbs of firewood; however, I think you would pretty much have to cut it into blocks to make that much fit.

Mark
 
jotul8e2 said:
Assuming, as I do, that it will take something close to 30,000 btu/hr to maintain 400 deg. stove top temps, and assuming further that you are burning oak at ~ 6,000 btu/lb., then IF you could load 60 lbs. of wood into the stove, and IF you could adjust the air control to burn the initial load at a rate to achieve 400 deg. stove top temperatures (and not more), and IF you could keep the air adjusted to continue to maintain that temperature as the wood burns down (and not less), then you could, in theory, get a 12 hour burn as specified.

Granted, that 30,000 btu/hr figure is little more than a guess. I doubt it is less than 20,000, and might well be higher than 30,000.

If the post above is correct, and the firebox is three cubic feet, then you could theoretically pack in well over 60 lbs of firewood; however, I think you would pretty much have to cut it into blocks to make that much fit.

Mark
=================
I have reported 300 Deg stovetop at the tail end of a long burn , mishmouse has reported 400 Deg. This is the first Quality stove i ever owned,so i am fairly new to this wood heat thing. This stove continues to amaze me as my previous stove The king Stove was such a poor performer. As i said im convinced that the AB performance is the key to the whole thing. If the AB is burning smoke at over 1100 -1500 degrees, possibly more as the ceramic is cherry red and the air surrounding the AB chamber is traveling up the inside back of the stove and exiting out the front just behind the top loading door, i do not think it is a stretch to think the stovetop would maintain 300-400 degrees. I have reduced draft in this new location so i can not turn the stove down all the way,as my AB goes out and i lose the extra effeciency it provides. But mishmouse reports that he can turn his air all the way down and still maintain AB performance so i would assume he will get a longer and possibly hotter burn than myself. And about packing the stove ,yes with the top ;loading feature you can pack it right up to the lid solid.
 
There are quite a few TL-300 Users posting here from time to time on different threads and subjects on this site and i am interested myself to hear from them as to their performance with this stove.
 
jotul8e2 said:
Assuming, as I do, that it will take something close to 30,000 btu/hr to maintain 400 deg. stove top temps, and assuming further that you are burning oak at ~ 6,000 btu/lb., then IF you could load 60 lbs. of wood into the stove, and IF you could adjust the air control to burn the initial load at a rate to achieve 400 deg. stove top temperatures (and not more), and IF you could keep the air adjusted to continue to maintain that temperature as the wood burns down (and not less), then you could, in theory, get a 12 hour burn as specified.

Granted, that 30,000 btu/hr figure is little more than a guess. I doubt it is less than 20,000, and might well be higher than 30,000.

If the post above is correct, and the firebox is three cubic feet, then you could theoretically pack in well over 60 lbs of firewood; however, I think you would pretty much have to cut it into blocks to make that much fit.

Mark
Jotul8 The 6000 Btu/lb figure may well change depending if you are burning the wood in a cat stove or AB stove like the TL-300 or just a regular wood stove that sends much of the woods BTU,s up the chimney. i go through a lot more wood with my older not very efficient wood stove than i do with the harman.
 
Sounds like according to Trump, draft makes all the difference in these stoves. Efficiency must be pretty high, I didn't see any efficiency or gph numbers on Harman's site, anybody know? Gota love that grill/rotisserie option.

The wife yelled at me today when she was dusting the house. Seems I've been accumilating alot of dust throughout the house from unloading ash from my stove. She's ready for a new stove with ash pan, I'll have to look into this TL300 more, but really don't want to give up my soapstone yet.
 
trump said:
Jotul8 The 6000 Btu/lb figure may well change depending if you are burning the wood in a cat stove or AB stove like the TL-300 or just a regular wood stove that sends much of the woods BTU,s up the chimney. i go through a lot more wood with my older not very efficient wood stove than i do with the harman.

No, 6000 btu is 100% of the available heat potential of oak - give or take. That is all there is. The catalyst improves the efficiency, but does not manufacture btu's out of the air.

In re: the post reporting 300 deg. after a long burn. The btu requirements for 400 deg. output is something more than double that of 300 deg.

I am not saying it can't be done, I am just saying that a 12 hour burn in a 3 cu. ft. stove with a maintained 400 deg. output, first to last, is going to require such an exact set of circumstances as to be virtually unobtainable for the ordinary person.

Mark
 
I think you guys are a little light on those BTU numbers. 0% moisture wood of any type has 8600 BTU's. So I'm thinking 15%-20% should have over 7000 BTU's per lb. Then there is the efficiency factor of the stove, we don't know what the TL300 is, but cat stoves are around 80%, so maybe the 300 is about the same? And I also wonder about the stove temps on the 300, I bet they are much hotter in the back where the AB is located so the top could be cooler than the back? I think it might be easier than you think to maintain that 300-400 temps for 12 hours.
 
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