All things being equal, what's most important to a long burn? Is it firebox alone or is there somet

[53flyer]

Assuming the exact same wood, insulation, OAT, etc. what would be the biggest factor irt getting a long burn time? Specifically, are cats generally similar enough that 2 cat stoves (with similarly firebox size) should be capable of an equally low/slow burn?

I've referenced Solar&Wood;'s description of his old cat having a firebox roughly half the size of his new cat and attributing that to getting twice the burn times with the new cat. That makes me wonder if the thermostat feature has much of an impact on the longer burns or if the firebox size is the only factor that people think really matters and causes the better burns with the BK cat?.

[quote author="SolarAndWood" date="1258768354"][quote author="53flyer" date="1258763510"]Rich L- Given 8 cords of wood:
1) If Solar avg'd 30hr burns (which is hard to even type) he'd only be using 3/4 cord per month because he'd be using 4cuft loads. That equates to 10 months 24/7 and a few shoulder months. Wowsa...
2) If Solar "only" avg'd 20hr burns (half the optimal burn he recorded-and still hard to type btw-) he'd be using 1 1/4 cords per month which equates to burning 5 months 24/7 and a 2-3 shoulder months OR 4 months 24/7 and 4'ish months shoulder .

Solar- I'm guessing #2 is pretty close to the actual situation. Does that sound about right?[/quote]

Because the BK burns so low and is easily adjusted with the tstat, I have been burning 24/7 since October 2nd with only two relatively brief exceptions. The reality is that the effective load is only 3 cu ft as opposed to the 4.3 advertised in the brochure. Meaning, that I can recreate 3 cu ft of my stack in my stove without getting out the band saw and dremel. The effective load of the old stove was about half that, so I expect to get about twice the burn time which should be about 12 hours when it gets cold. We heat exclusively with wood, so the variance is much greater than your #2 suggests. Burning 1/2 a cord per week is easy if it is blowing 30 miles an hour and below 20 highs. That would be 3 loads per day with the new stove and 6 with the old.

I understand your uneasiness in typing those burn times, I didn't believe it either after my previous 2 stoves. It is a pleasure to operate this stove which is a good thing because it makes up for having a monstrosity in the middle of our living space. It is easily twice the size and has none of the visual appeal of the old stove.[/quote]

 

[Dune]

Air regulation.

 

[Todd]

Yeah, air regulation is the biggy and cat stoves can be turned down lower than the non cats and still burn clean. I don't know if the t-stat will give you a longer burn but it should keep it more constant or even burn.

 

[savageactor7]

You must have well seasoned wood ...

...now that can be consumed in a low burn process, like simmering, as opposed to smoldering less than fully seasoned wood.

 

[Hogwildz]

Yeah, air regulation is the biggy and cat stoves can be turned down lower than the non cats and still burn clean. I don't know if the t-stat will give you a longer burn but it should keep it more constant or even burn.

I'm sure it depends on conditions, set up, craft etc. But I do not necessarily agree with this statement. Once wood is in a hot, charred stage, I can turn the air lever all the way down on my insert and achieve a clean burn.
Yes dry wood is a must, but cat or non cat both will do better with dry wood compared to less than optimal wood. Unless cat stoves do not have a stop on the air control lever as a non cat does, which limits how far you can cut the air back? I'm curious to know if they are set up the same as far as how far you can cut the air back?

 

[[email protected]]

Log size, too -- the bigger around, the better.

 

[BrotherBart]

Unless cat stoves do not have a stop on the air control lever as a non cat does, which limits how far you can cut the air back? I'm curious to know if they are set up the same as far as how far you can cut the air back?

There has to be air getting in there somewhere. Both to the wood to keep the smoke coming and to the cat so it has oxygen to ignite said smoke. I have never seen an anaerobic wood stove, and never will.

 

[Todd]

Yeah, air regulation is the biggy and cat stoves can be turned down lower than the non cats and still burn clean. I don't know if the t-stat will give you a longer burn but it should keep it more constant or even burn.

I'm sure it depends on conditions, set up, craft etc. But I do not necessarily agree with this statement. Once wood is in a hot, charred stage, I can turn the air lever all the way down on my insert and achieve a clean burn.
Yes dry wood is a must, but cat or non cat both will do better with dry wood compared to less than optimal wood. Unless cat stoves do not have a stop on the air control lever as a non cat does, which limits how far you can cut the air back? I'm curious to know if they are set up the same as far as how far you can cut the air back?

There is no stop for the primary air or seperate secondary air supply inlet on my stove, it can be completely shut off but it's not like it's air tight with gaskets so I guess some air would have to seep in around the air slide.

 

[53flyer]

Unless cat stoves do not have a stop on the air control lever as a non cat does, which limits how far you can cut the air back? I'm curious to know if they are set up the same as far as how far you can cut the air back?

There has to be air getting in there somewhere. Both to the wood to keep the smoke coming and to the cat so it has oxygen to ignite said smoke. I have never seen an anaerobic wood stove, and never will.

HW- Here's something from another thread that addresses air flow :

The thing cat stoves have going for them is that they don't have that freakin unrestricted air inlet that non-cats have to have to pass the EPA testing when shut all the way down. Do away with that and everybody's idea that they need to close down the primary all the way for a night burn and 50 pounds of wood burns as long as, well, fifty pounds of wood.

And with the non-cat the heat is distributed and transferred from the whole stove body. Not just from a hot spot in the top of the stove and migrated to the rest of the stove. And it goes on and on and on.

 

[Dune]

Well, I just put some very dry oak in my airtight stove. I can either leave the air vents open and burn it all in 2-3 hours or adjust them so that the wood lasts for 12-14 hours or anywhere in between.

 

[Lanningjw]

I e-mailed Chris at BK corp headquarters and asked him the following question concerning my princess inserts burn times. Thought you may find his response interesting.

Chris,
Do you have any advise to get a 20 hour burn time with my PI1010A? so far I have not gotten anything better than 12 hours before the cat goes into the inactive zone.
Jim

Reply

Good morning Jim. The 20-hour low burn times we got were using large sections of tamarack. The firebox was empty of ash so we were able to place a large amount of wood into the firebox...about 70 lbs. Typically 12-15 hour burn times are seen when using the stove (insert) in the the average home with 12'-15' chimney. A longer chimney can create more draw and shorten burn times (even though you may have the thermostat in the lowest setting).

As you get to know the unit, you'll find the idiosyncrasies and be able to fine tune it for you needs. Clearly the larger the pieces of wood, the longer the burn time. Also, our test fuel averages around 18% moisture content. If your wood is dryer, it will burn cleaner, but will also burn hotter and faster, which is still better for the environment.

I hope the Princess is keeping you and your family warm....enjoy the Holidays!

Chris

 

[SolarAndWood]

Lanning, how much fuel is still in the box after 12 hours? I find that once you get down in the active range, it helps to rake the wood out of the corners and sides towards front center kind of like you do with coals. I find that doing this takes the cat thermometer from somewhere around 10 to somewhere around 12 for another 3-4 hours and reduces the amount of ash.

 

[SolarAndWood]

Flyer, I highly doubt that we would be able to measure any appreciable differences in efficiency of modern cat stoves. I bought the BK because of the truck like build, automation of the air control, large range of efficient burn rates and firebox size. I am sure you can achieve the performance of the tstat manually; it just isn't practical for this family with young kids and jobs heating exclusively with wood.

The firebox size and species of wood puts a theoretical limit on how many potential BTUs you can put in the stove at any given time. My woodpile has pine and black locust and everything in between. I can get a lot more pounds of locust in the stove than pine. BTUs in the box/how fast you draw them out dictates your burn time. It is hard to get around that one. The beauty of the King is that you have a stove with a large firebox that can put out big heat that is also capable of burning very low this time of year.

 

[Todd]

I e-mailed Chris at BK corp headquarters and asked him the following question concerning my princess inserts burn times. Thought you may find his response interesting.

Chris,
Do you have any advise to get a 20 hour burn time with my PI1010A? so far I have not gotten anything better than 12 hours before the cat goes into the inactive zone.
Jim

Reply

Good morning Jim. The 20-hour low burn times we got were using large sections of tamarack. The firebox was empty of ash so we were able to place a large amount of wood into the firebox...about 70 lbs. Typically 12-15 hour burn times are seen when using the stove (insert) in the the average home with 12'-15' chimney. A longer chimney can create more draw and shorten burn times (even though you may have the thermostat in the lowest setting).

As you get to know the unit, you'll find the idiosyncrasies and be able to fine tune it for you needs. Clearly the larger the pieces of wood, the longer the burn time. Also, our test fuel averages around 18% moisture content. If your wood is dryer, it will burn cleaner, but will also burn hotter and faster, which is still better for the environment.

I hope the Princess is keeping you and your family warm....enjoy the Holidays!

Chris

Whats the stove temp when it hits the inactive zone? Does that mean it's under 500? Just because the thermometer is under the cat active zone doesn't mean that's the end of the burn time, does it? I always considered burn times as enough coals left to load regular splits without the use of kindling or fire starters.