Burning my wood too quickly. Any thoughts?

[ClydesdaleBurner]

Hi everyone,

I need some guidance on this problem. At first glance you might think too much draft, but I dampered my stove down about 95% and the flames are flickering like crazy, its a very smooth and slow fire with secondaries. It just doesn't last as long as I would think. Here is a case an example.

I started my stove at 4:30 today. 3 splits and 2 bio bricks - they burned good, got the stove up to temp and got a nice coal bed after almost 2 hours. At 6:15 I added 5 splits to the good hot coals. 5 splits were all medium sized 4"-5" or so, I would say the firebox was 80% full. I could have put 1 more in maybe 2, but didn't think it was necessary. The splits went right up to the secondary burn tubes. I left the door cracked for 15 mins then I closed the door and the fire had almost completely consumed all the splits, I had fire going in the front, back and sides of the splits. I turned the air down 90% closed. It burned great, I had strong secondaries going by 6:45 they lasted until 8pm, then they stopped and the wood at that time was really just coals that still had the shape of splits. By 8:15 I poked the splits and they crumbled to big coal pieces. 1 hr later the coals were dimming, so I added 2 more splits.

My point here is that from 6:15 to 9:15 my stove consumed 5 splits and reduced them to coals. This is with the air turned down about 90%-95%. I don't think this is a case of too much draft though. During the short secondary burn the flames were not moving quickly or flickering a lot. They were blue and moving slowly as if there was not a lot of air passing through the fire.

What could be the reason for my short burning time? My stove is suppossed to be able to get 8 hr burns.

The stove is connected to an exterior chimney, fully lined 6" SS liner, non-insulated and no block off plate, but the damper area in the chimney was stuffed with insulation to act as a block off. The liner is about 30' to the top.

Please somebody diagnose the problem. I'm stumped... pardon the pun.

Thanks

 

[vasten]

My thought is what is the quality of the wood, is it intensly dry, pithy meaning partially rotted or taken from standing dead timber? Or is the wood a soft wood.

Do you have another load of wood that you can test with to see if you can repeat this proceess? If not might not be a bad idea to pick up a couple of bundles from a gas station etc, that sells the kiln dried hardwood and do a time comparison on it.

If you are convinced it is not the stove or the draft that only leaves the fuel.

 

[ClydesdaleBurner]

The wood was delivered to me in Oct of this year. Its not great, usually is even hisses a little. It is all hard wood.

The only reason I don't think it is the draft is because when the air is open I can see the flames flicking violently and the air passing through, but when I close the air the flames slow down and i get a nice blue secondary. I just assume that that means I don't have too much draft... but I'm new to all this so I'm not sure.

 

[jpl1nh]

Leaving the door cracked for about 15 minutes on a hot bed of coals seems a bit much to me but I've never burned an Oslo. Still... and I too would ask what type of wood are you burning? What type of chimney and how high? Do you have a stack damper?

 

[simisita]

What kind of stove are you burning the wood in?

 

[ClydesdaleBurner]

I'm burning in a hearthstone Clydesdale, soapstone lined insert. Firebox is 2.4 cubic feet.

Chimney is 30 feet high, exterior, wood is hardwood, oak and maple I think.

 

[Corie]

Of that load, which was consumed in 3 hours, what would you guess the weight would be?

Lets calculate the burn rate and see if it is out of the ordinary for a low burn.

 

[ClydesdaleBurner]

Lets say these splits weighed apprx. 5 lbs each... maybe 6 I'd say the load weighed 25-30 pounds. This is a rough estimate. I've never really thought of the weight of a load before... could be more actually. 35 lbs???

 

[Todd]

I'm burning in a hearthstone Clydesdale, soapstone lined insert. Firebox is 2.4 cubic feet.

Chimney is 30 feet high, exterior, wood is hardwood, oak and maple I think.

Maybe it's not Oak or the Maple is a soft Maple like silver which burns down fast? Sounds like you have a slow enough burn but the wood isn't dense enough to last. Any pictures of the wood?

 

[Rich M]

I left the door cracked for 15 mins then I closed the door and the fire had almost completely consumed all the splits, I had fire going in the front, back and sides of the splits. I turned the air down 90% closed.

15 minutes is much too long to have the door cracked. The "blacksmith fire" you get from cracking the door with a hot coal bed can warp things. Properly dried wood should ignite almost immediately, with no need for a cracked door. It's also best to close the air in stages, not all at once to 90%. Again, with dry wood you use the air to kind of slow the fire down as it becomes engulfed so quickly. Close it a third of the way, then half, then the rest of the way for your desired burn. Try doing a reload with one of those $5 packages of kiln dried supermarket wood and compare it's performance to the fuel you're using.

 

[webbie]

This does not sound too far off. One thing you didn't mention was how much are you were heating, etc...but, if this is a soapstone insert we have to consider that means a slower warm-up time.

Remember a couple things that affected this load - it was started from scratch...you can never really gauge a stove by the first load you burn when starting it.

Then there is the soapstone. Then there is the fact that 50% of the heat of wood is in the ember, so even through the flames and logs were burned down, there is still a lot of BTU's in the coals you describe.

A typical load in most stoves is 2-3 nice sized splits every 3-4 hours, and it does not sound like you are too far off that.

 

[JimWalshin845]

A typical load in most stoves is 2-3 nice sized splits every 3-4 hours, and it does not sound like you are too far off that.

Craig, what circumference would you consider 'nice sized'. We run a large stove and 8"-10" at the circumference is what we put in before bed. Any rules of thumb here?

 

[Robbie]

Craig is right about the time......about three decent sized "hardwood oak" splits every three to four hours........four hours with taking advantage of your coals BTUs.

Check your wood to make sure it is oak......smell it and see if it smells like a whiskey barrel.......if it's oak not seasoned it will really give off a smell.

Try banking and reburning your coals as you reload.....pull your coals to the front air entry area and then stack a couple splits "tee-pee" style long ways over them, this will extend the life of your coals and result in longer burns with more BTUs I think......it sure works for me.

Try not loading so much.......load a couple and make it stretch a while by banking and reburning your coals for more heat.

Robbie

 

[ClydesdaleBurner]

Thanks for putting my mind at ease with the 3-4 hr time frame before reloading. I guess I get frustrated hearing about 6-8 hr burns. But that begs the question... how do you get an 8 hr burn/coaling for overnight? I was trying to do an "overnight burn" during the day today to see what happens, but it just didn't work at all.

For overnight burns I assume you put more than 3 nice sized splits... I usually put as much wood in the fire box as I can fit and by morning there is just barely a coal bed left. It's 12:30, I've just put 4 good sized splits on and closed air 90%, I'll see what happens by tomorrow morning.

thanks for everyone's input.

 

[Robbie]

Do you have a blower ?

Are you using it ?

House SQ FT. ?


Robbie

 

[Todd]

I don't agree that reloading every 3-4 hours is the norm with a firebox of over 2cu ft. You should be able to pack that stove full, crank it wide open for 10 minutes, turn it down all the way, and after 8 hrs have a decent caol bed where you can just fill her up agian and do it all over again. This is of coarse if you have decent dry hardwood and no overdraft.

30' chimney is pretty tall. How hard would it be to take the surrounds off and put a thermometer on your pipe? Then you could see if you do indeed have an overdraft issue.

 

[Corie]

35 pounds in 3 hours, a burn rate of approx. 11.6 lb/hr or 5.3 kg/hr is very high for a low burn. Even assuming you didn't reach the original coal bed until 4 hours, that's still 8.75 lb/hr.


The burn levels should be approximately (This is test data, used, of course, with Douglas Fir test loads):


(Low Burn) Cat. 1 - Less than 1.76 lb/hr
(Medium Low Burn) Cat. 2 - Between 1.76 and 2.76 lb/hr
(Medium High Burn) Cat. 3 - Between 2.76 and 4.19 lb/hr
(High Burn) Cat. 4 - Maximum burn rate.

On a low or medium low burn, you should be burning about that amounts listed above. Something isn't right if 35 pounds of wood is going up in smoke that fast.

 

[webbie]

A typical load in most stoves is 2-3 nice sized splits every 3-4 hours, and it does not sound like you are too far off that.

Craig, what circumference would you consider 'nice sized'. We run a large stove and 8"-10" at the circumference is what we put in before bed. Any rules of thumb here?

Always in relation to the stove size. I am thinking a a mid sized avalon like Robbie has, which I have burned for many years. In general, that 2-3 splits will fill it loosely, especially when on top of a large bed of coals. Certainly you can get more wood into it, but that is something you plan, letting it burn down lower and then loading with perfectly formed splits.

Jim, in that monster I would think about 1/2 a load would be a normal attended firing.

 

[ClydesdaleBurner]

The house is 1800 sq feet.

I did get an overnight burn last night. I loaded 4 good sized splits on it at 11:30pm. Woke up this morning at 9:30, raked the dusty looking coals into a pile, opened the air, and put some small splits on it. Fire! I was at least happy about that...

 

[Moose]

I have a quad 5700 and an insert that I'm burning right now. And I have found that the way you stack the wood in the fire box really makes a difference. Both of my stoves have air introduced in the front. Now if I just stick the pieces straight in meaning the end of the pieces are by the window then I can get a real hot burn real quick but burn the wood much more quickly because all the wood is burning at the same time all arround. Now if I take the the coals and rake them forward and place the wood in side ways from back to front, the fire will burn the first few logs turn them to coals and slowly work its way back. I don't get the intense heat that I would befor but rather a nice steady heat for I would say almost twice the burn time. I am able to achieve an all night burn with this method in both stoves whereas the other method I am not.

 

[Todd]

The house is 1800 sq feet.

I did get an overnight burn last night. I loaded 4 good sized splits on it at 11:30pm. Woke up this morning at 9:30, raked the dusty looking coals into a pile, opened the air, and put some small splits on it. Fire! I was at least happy about that...

10 hrs sounds good to me. I think you just need to experiment with different loading technique's.

 

[jpl1nh]

The house is 1800 sq feet.

I did get an overnight burn last night. I loaded 4 good sized splits on it at 11:30pm. Woke up this morning at 9:30, raked the dusty looking coals into a pile, opened the air, and put some small splits on it. Fire! I was at least happy about that...

10 hrs sounds good to me. I think you just need to experiment with different loading technique's.

I agree and Moose's overnight loading technique is the same that I use. I time my loads so I'm down to a low bed of hot coals, rake them to the front where the glass is, put my biggest heaviest spit on the bottom farthest from the glass, where there are now virtually no coals, then pack forward and up very tightly from there. I generally put a small split of something very combustible directly on the coals right in front, but everything else can be the densest, biggest wood I can tightly fit in. I think Rich M is correct for many stoves in that turning the air down in stages can be important. It certainly is for my set up, otherwise at some point in the load I'll get some pretty substantial back puffing.