Blaze King - Poor Burn Time

Howdebody89

New Member
Jan 22, 2020
11
19096
Hello,

New to the forum, but have been reading a lot before and after my recent Blaze King Princess 29 Insert purchase. It was installed about a week ago in my Philadelphia area 1930's stone home with 25-30 chimney and new insulated liner. Burn times are very poor compared to what I have been reading . . . On the order of 6-8 hours at the most. Using seasoned oak (per salesman), 14- 16 inches long and 3-5 inch splits. Moisture content per meter on ends/face (no raw exposure) 16-22%. I open damper (turn off combuster), turn thermostat on high, light kindling, load woold fully when kindling established, close door, close damper only when gets in active zone, leave on high for another 30 minutes or so, lower thermostat to lowest possible setting and turn fan on lowest possible setting. Still cannot get beyond 6 hours with heat (if that much), MAYBE 8 hours with embers and no heat. Could the thermostat be broken? Is there something obvious I am missing? I know I am new to this and burning is a skill that takes time and experience (like any), but my burn times seem pretty lame even with that handicap.

Thanks for any help you can provide.
 

jetsam

Minister of Fire
Dec 12, 2015
4,720
Long Island, NY
youtu.be
You have wet wood and strong draft, and your split size is kindling.

You'll have to suffer through the wet oak this year. Get some pine split and stacked now, and it'll be ready for next year. Oak takes 3 years to season in our part of the world. Split it bigger and buck it longer. You can fit an 8" tall slab in even if the belly is completely full. The stove can hold 18" lengths in the belly, 21" above the belly. I usually try to buck at 18 and if the split comes out a little long it can go on top.

The good news is that I have the same stove and I started with much worse wood than that, and it worked out fine. :)

Even under those difficult circumstances, you should be able to get 12 hours easily. Step one is to start with a hot stove (when you have a stove that can go over 24 hours on a load, why let it go out?). So do a short hot fire like you have been doing to get a belly full of coals, then pack her completely full of the biggest splits you have, and wedge little ones into the cracks. Then let 'er burn on high until the load is on fire, then turn it down to a low setting in a couple steps. Turn the fan off and you'll probably hit 18 hours even with poor wood and high draft. (But it's not magic- a long burn releases the heat slowly. )

Bear in mind that if you want to burn marginal wood super low, you are going to get a lot of creosote. Get a brush/sooteater and sweep the flue often!

This time of year, I'd suggest shorter hotter burns if you are heating only with wood. My cold weather schedule is (roughly) a ~12 hour burn while I'm at work, then a big hot 4 hour load of pine if needed, then a medium 8 hour one overnight. I do 24 hour loads in warmer weather.

If it's supplemental heat, two 12 hour burns per day is a convenient cycle that puts out good heat.
 

Woody Stover

Minister of Fire
Dec 25, 2010
12,160
Southern IN
My guess is, wet wood and too strong a draft. You can buy some "BioBricks" or the like, compressed hardwood sawdust bricks. Make sure they are 100% wood. Let the Oak sit, top-covered in the wind for two years. Then test a large split which is at room temp, re-split and test on a fresh face. You might then have to let it sit another year. Try to score some soft Maple right now, maybe hook up with a tree service, and if split and stacked right away it should be pretty dry by fall.
As far as the excessive draft, you might put a 6">5.5" reducer on the top of the liner. I've heard that suggested but have never tried it. Not sure if it would cut the draft enough. You could also install a pipe damper, but with an insert you would either need the surround removed, or would have to drill a hole in the surround for a rod to open and close the damper. One flue damper still might not be enough to get the draft under control.
 

weatherguy

Minister of Fire
Feb 20, 2009
5,757
Central Mass
I'm not sure you get a 21 inch split in a princess insert, I had some 20 inchers I had to cut down to fit, the free stander maybe with its bigger belly.
 

spudman99

Feeling the Heat
Jan 26, 2018
326
Yardley, PA
I have the same stove and installed it in Nov 2019. Fortunately I had been planning this stove for a while and had cut and stacked several cords a year earlier. I am burning cherry and now hard maple with no problem. My chimney is 30' and I have an extremely strong draw through the BK. From the beginning I was able to get 12 hour burns, sometimes more when it was warmer in November. Last night when it got down to 18deg I got a 12 hour burn with the thermostat set around 5pm, fan about 25%. Lots of coals left, top of unit was around 240deg when I reloaded. That is not peak heat but it is a constant source of warmth.

PM me if you are close by and I can give you some dry wood to see if that makes a difference. Hopefully we can get you into the happy zone!
 
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Highbeam

Minister of Fire
Dec 28, 2006
17,512
Mt. Rainier Foothills, WA
You have wet wood and strong draft, and your split size is kindling.
I agree. This is my princess stove loaded properly for a long burn. 3" splits will burn off too fast. That 30 minutes on high thing is surely too long given your wood, flue length, and goal of a longer burn.
 

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bholler

Chimney sweep
Staff member
Jan 14, 2014
21,947
central pa
I agree. This is my princess stove loaded properly for a long burn. 3" splits will burn off too fast. That 30 minutes on high thing is surely too long given your wood, flue length, and goal of a longer burn.
I agree the wood is small. But it is also wet it may take 30 mins to get the firebox to temp. My splits are typically more like the small ones you have and I can get plenty long burns if I want.
 
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Ashful

Minister of Fire
Mar 7, 2012
15,715
Philadelphia
16% - 22% on exposed end grain and faces may be 30% inside. Or 20%, or 40%. bring a few pieces indoors for a few hours, to get them to room temperature, then split them and test the freshly-exposed face.

That will give us a number, although I guess we already know the verdict. Try a load of that kiln-dried grocery store wood, to get a sense ofhow your rig will burn on proper dry wood. It won’t hit the numbers of a free-standing Princess, but it should do a heck of a lot bettee than you’re seeing.
 
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Woody Stover

Minister of Fire
Dec 25, 2010
12,160
Southern IN
bring a few pieces indoors for a few hours, to get them to room temperature, then split them and test the freshly-exposed face...Try a load of that kiln-dried grocery store wood, to get a sense ofhow your rig will burn on proper dry wood.
It'll take more than a few hours to warm a big split all the way through..more like a day, at least.
There's no guarantee that store-bought wood will be dry, either. I went to a party where the guy had bought some wood from the Kwik-E Mart, we threw it in the fire pit and it was bubbling water out the ends of the splits.
 

weatherguy

Minister of Fire
Feb 20, 2009
5,757
Central Mass
Or if you can get NIELS!
That'll give you a proper reading. Not sure if you can find them where you live, I burn a pallet or two every year.
 

jetsam

Minister of Fire
Dec 12, 2015
4,720
Long Island, NY
youtu.be
I don't think you can get them out east unless you pay for LTL shipment. OP is in Pennsylvania, I think.

In related news, I just learned that Pennsylvania not only has towns with Welsh names, but also has Welsh Quakers!

Tractor supply carries Ecobricks. I haven't tried them, but they are also a compressed sawdust firewood product.
 

rwhite

Minister of Fire
Nov 8, 2011
1,612
North Central Idaho
I will also add that there is the advertised burn time vs reality. I love my princess and can get 12-16 hour burns when the temps are 30 and below using red fir and tamarac. We have a local distributor that sells BKs and they constantly advertise 40 hour burn times on their radio ads. Not sure what world they live in but no stove has that kind of magic!
 

Woody Stover

Minister of Fire
Dec 25, 2010
12,160
Southern IN
In related news, I just learned that Pennsylvania not only has towns with Welsh names, but also has Welsh Quakers!
That's great news! I've heard that they can't be beat when it comes to checking wood moisture! But don't bet with them..they may welsh on it! ;lol
 
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BoilerBob

Member
Jan 14, 2011
134
SW Nova
I will also add that there is the advertised burn time vs reality. I love my princess and can get 12-16 hour burns when the temps are 30 and below using red fir and tamarac. We have a local distributor that sells BKs and they constantly advertise 40 hour burn times on their radio ads. Not sure what world they live in but no stove has that kind of magic!
I know who would believe 40 hrs?
This is my temps after Only 36 hrs, not much heat coming out of the BK.
House is at 23c, outside is 0c.
Actually didn’t pack the stove tight as I could have and my splits are a bit smaller than the BK loves.
So maybe 40 hrs might be possible??
44283450-6FFF-4941-BE70-A58BC62BF090.jpeg
 

BKVP

Minister of Fire
The long, low burn times are achievable in shoulder heating seasons. Clearly once greater heat demand is called for, the actual burn times are shorter.

Our literature shows both low and high burn times.
 

Highbeam

Minister of Fire
Dec 28, 2006
17,512
Mt. Rainier Foothills, WA
Right, the 30 box stoves can do 30 hour burns at the minimum burn rate. 40 is just the king. Whether that minimum burn rate can keep your house comfortable is irrelevant. This is a stove performance specification.

Burning our low btu wood species is a handicap to getting those maximum burn times but not much.
 
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Howdebody89

New Member
Jan 22, 2020
11
19096
Thank you everyone for your thoughtful replies. VERY helpful.

So, it would seem there are a few take-aways from the above conversation - and from my additional reading. Please feel free to correct me if my understanding is wrong!

- Use largest splits possible.
- Pack the stove fully when loading.
- Use the fan minimally, if at all.
- Turn the thermostat down as soon as combuster is in the active zone - assuming the goal is long burn times> maximal heat. No need to run on 'high' for 30 minutes after combuster is in active zone if the goal is long burn time and gentle heat.
- Try to keep the stove continuously hot during the season if intending to use as primary heat source.
- Use fully seasoned/dry wood. Don't rely on testing an existing face . . . split it and then test.
- Oak/hardwood takes a long time (several years) to season/dry fully, despite what the dealer may say. Splitting and testing on fresh face may show wood is not as dry as I thought.
- Try to use softer wood now. This is a problem for me given the time of year as there is/may be a limited supply of such wood in my area in late January and I would not have the opportunity to let sit for a year to season as I would like to use the stove now (it Christmas gift for the family).
- Try BioBricks, BioBlocks, NIELs (or similar products) - though financially this does not seem doable for the long haul (though I have not priced). Maybe trying a full load of these x 1 (vs indefinitely) will give me some information on burn times, but will not necessarily be reflective of 'real wood' burn times.
- The draft is excessive. That being said, there doesn't seem to be a definitive way to limit that (pipe damper or reducer were mentioned as options - but no consensus and would be a hassle/costly with ? return on investment).



I do have some additional questions and concerns . . . . I have included some pictures for reference - the stove fully loaded and pictures of the fire ~ 30 minutes into active zone, fan off, thermostat at 7 o'clock (lowest setting possible).

- I assume everyone is saying the draft is excessive because of the stated length of my chimney. I don't know if there is a way to measure draft, or if there is a way to modify it (damper, reducer) that has been shown effective.
- My house is from the 1930's and leaks. Would sealing those leaks - assuming I could - reduce the draft?
- It is not quite clear to me why unseasoned/wet splits would result in a SHORTER burn time. I am not the sharpest knife in the drawer, but I would think wetter/unseasoned splits would take LONGER to burn (though less efficiently) than fully seasoned/dry wood. I assumed - appparently erroneously - that seasoned/dry splits would actually REDUCE burn times given that no heat energy is 'wasted' in dissipating the wood-contained water. Obviously I am missing something here (physics and/or common sense), so please clue me in!
- My picturesshow flames that are quite vigorous ~ 30 minutes into active zone, fan off, thermostat at 7 o'clock (lowest setting possible), damper closed/combuster activated. It would seem the stove is getting too much air. The installer reportedly checked the door seals. Short of adjusting the draft as per above - or removing half of my chimney - is there anything else I can do to limit the draft. Could the thermostat be broken/poorly calibrated? I don't think Blaze Kind performs house calls, and I certainly cannot return the unit for a refund :) !


I have another question - not necessarily related to burn times per se . . .

- How do I OPTIMALLY RELOAD the stove when the current load is down to embers. I have been waiting until the needle drops to almost the inactive zone while leaving the T-stat on low. I open the damper, wait 1 minute, open the door, fully load the stove without adding additional kindling, close the door but leave cracked, turn the thermostat up high, and hope it catches. Usually the indicator drops to inactive during this process and I leave the damper open until it goes back to active . . . and then lower T-stat to low. That being said, there have been several/many times when the embers are not enough to restart the fire. This AM it was smoldering from last nights reloading attempt with the above procedure. There was no fire/flame. I took all the wood out and restarted it is if starting a new fire (newspaper, fatwood, kindling, damper open, T-stay on high, door cracked until kindling flame established, load fully with wood, wait until active zone reached, close damper and turn down T-stat to low - etc (as per my initial post above).

Again, thanks for all of the help you have provided . . . and will provide!


Tom
 

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Diabel

Minister of Fire
Jan 11, 2008
2,755
Ottawa, ON
Right, the 30 box stoves can do 30 hour burns at the minimum burn rate. 40 is just the king. Whether that minimum burn rate can keep your house comfortable is irrelevant. This is a stove performance specification.

Burning our low btu wood species is a handicap to getting those maximum burn times but not much.
Very well said @Highbeam. People often cannot differentiate this from their individual heating load requirements.
 
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Highbeam

Minister of Fire
Dec 28, 2006
17,512
Mt. Rainier Foothills, WA
- It is not quite clear to me why unseasoned/wet splits would result in a SHORTER burn time. I am not the sharpest knife in the drawer, but I would think wetter/unseasoned splits would take LONGER to burn (though less efficiently) than fully seasoned/dry wood. I assumed - appparently erroneously - that seasoned/dry splits would actually REDUCE burn times given that no heat energy is 'wasted' in dissipating the wood-contained water. Obviously I am missing something here (physics and/or common sense), so please clue me in!
I'll try to answer this one.

Wet wood has a lot of water in the wood. It takes energy to boil water off into steam. That energy comes from the wood that would otherwise be released into the room as heat. The energy used to boil water is in no way recovered to heat the room and it's a lot of energy. Your stove has a thermostat that will automatically open the intake to maintain a firebox surface temperature chosen by you to keep your home warm. The thermostat has to open the throttle blade farther to burn enough wood to heat the stove AND boil water than it does to just heat the stove. That's why wet wood burns up faster for a given thermostat setting and/or heat demand in the home.

At any time, I can shut the thermostat fully and completely extinguish the flames. It appears that you cannot do this because your draft is so strong that even at the minimum setting it is sucking enough air into the firebox to support a vigorous fire.
 

jetsam

Minister of Fire
Dec 12, 2015
4,720
Long Island, NY
youtu.be
I will also add that there is the advertised burn time vs reality. I love my princess and can get 12-16 hour burns when the temps are 30 and below using red fir and tamarac. We have a local distributor that sells BKs and they constantly advertise 40 hour burn times on their radio ads. Not sure what world they live in but no stove has that kind of magic!
https://www.hearth.com/talk/threads/blaze-king-sirocco-25-insert.157802/post-2122138

We hear from lots of King users who can get 40+. On LOW. Not in the middle of winter. ;)

If you want a silly long burn like that, start with a hot stove with a good cat, pack it full of the biggest dry hardwood splits available, crank it down to minimum and don't touch it. You do need to know in advance how low you can go without stalling the cat- if you stall the cat, you lose a lot of burn time.

Agreed that in the real world, not many people will ever care to do that. It's easier to do a smaller reload on a shorter schedule, and you don't have to worry as much about the cat dropping out that way.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
21,947
central pa
False. They can get 40 on low anytime. They just might get cold if their house needs more heat.
Yeah but most of us are trying to heat our house so long burn times and a cold house don't help much. But I get your point