2017-18 Blaze King Performance Thread PART 3 (Everything BK)
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SculptureOfSound
Feeling the Heat
I guess I'm just wondering if it is possible to coast on coals longer than the formula (10k btu hr / 1.6 lbs of wood /hr) would suggest. I've never owned a stove or insert before.
So in theory 5 lbs of wood at the min rate would last just over 3 hours (3 hours being 4.8lbs of wood). My question is, would you still have coals you could light off of after say 4 or 5 hours?
Ashful
Minister of Fire
The answer to that likely depends more on your patience, than anything else. I can relight a load off a single glowing grain of rice, if I have nothing better to do for ten minutes. But usually, I just toss a super cedar into the box, even when I have a half decent little pile of coals. It’s just quicker, when you want to get the stove going and get on your way.
jetsam
Minister of Fire
I don't worry about any of that. Rake what's in there flattish, put in as much wood as fits, come back in 10 or 15 hours when you feel like it. Wood's in flames by the time you're done putting it in there. No need for measuring or planning reloads when you have a stove that goes 20+ hours on one tank.
I don't know how much coal would be left from a 5# split after 3 hours. If you started with a cold stove, the answer is zero. A warm stove with a belly full of coal can cruise for a lot more than 3 hours putting out nice heat. Adding a 5# stick to that scenario will make the coals go much longer on low, because that little piece of wood's offgassing will provide the cat with fuel to keep the stove up to temperature for quite a while.
That said, there's probably not much efficiency gain to be had from sitting there feeding in one small split at a time. Using the fuel efficiently is the thermostat's job, and it does good work.
I don't know how much coal would be left from a 5# split after 3 hours. If you started with a cold stove, the answer is zero. A warm stove with a belly full of coal can cruise for a lot more than 3 hours putting out nice heat. Adding a 5# stick to that scenario will make the coals go much longer on low, because that little piece of wood's offgassing will provide the cat with fuel to keep the stove up to temperature for quite a while.
That said, there's probably not much efficiency gain to be had from sitting there feeding in one small split at a time. Using the fuel efficiently is the thermostat's job, and it does good work.
Shayne
New Member
That is what I guessed understanding that you will never get 10 years out of a cat for normal woodstove burners that burn for heat not joy and want to be efficient for environmental reasons. Possibly if you run at 80% throttle, all the time, it will keep eating smoke but for normal operation in the spring and fall it becomes noticeable that you are using more wood and the stove is less efficient (then a new cat) having to increase the air to stay in the active zone. A 2 to 3 season warranty is all that is really offered in that case as other have noted 10 to 12000 hours is all you should expect to get. Has a cat ever stayed in a stove for 10 years (operated at 5000 hours a year) and operated at 81% efficiency in warmer temps keeping the home at the correct temp? Or will you just need to increase the air flow and heat output as the cat degrades on it performance attributes?
What is the average number of hours on a cat where you should think about replacing it for the environment? Do the cat get re-plated (should I return it to the dealer)?
Regards
BKVP
Minister of Fire
I did run my cat for 18 years. Did it burn less efficient, yes. A whole bunch less, no. Did it still burn clean? Yes. No visible emissions after 20 minutes or so. So why did I replace it, to try out a new prototype.
A study was commissioned by the CHC, OMNI Test did the study. BeGreen can probably post a link faster than I can. In short, multiple cats of various ages were studied by OMNI and were found to still burn cleaner after 9.5 years than most new stoves.
Certainly they can be abused...just like any stove. So we need the Rule of 4!
1) Burn dry wood 18% or less. Burn hot right after loading to deal with moisture early.
2) Go out and look up. Operate your stove as per the manual. Not all stoves are the same and ol veteran wood burners need to recognize stoves have changed.
3) Maintain your stove and inspect and replace parts as needed.
4) Install the stove to the Owners manual recommendations and acknowledge all installs are unique, so more stack, draft of fresh air may be needed.
I'll look for the study...and post a link.
One thing I learned today. Just like the combustion in an internal combustion engine, burning wood creates h2o (water vapor) during the exothermic reaction.
I'm going to do some math eventually on the 3 sources of h2o that go up the flue pipe. Not having an OAK definitely adds some but it's not as much as I though as a percentage of total.
I know wood stoves run about 40% excess air but does anyone know the stoich AFR? I can't seem to find it.
I'm going to do some math eventually on the 3 sources of h2o that go up the flue pipe. Not having an OAK definitely adds some but it's not as much as I though as a percentage of total.
I know wood stoves run about 40% excess air but does anyone know the stoich AFR? I can't seem to find it.
The combustion air is governed by the thermostat setting. The air fuel mix might be way off but the cat cleans it up. A neat trick the BK does is at high fire the high velocity airs weeps across the glass area and then goes to the burning wood. When the thermostat is throttled down, a lot of the air gets sucked directly into the cat to deal with the particulates, etc. This is kind of an "automatic changeover" of the air supply and I believe -loosely- attempts to maintain a favorable air/fuel ratio. I believe it is by this mechanism, and many other constructional features too, the BKs achieve the unprecedented burn times, high efficiency and extremely low particulate numbers. The thermostatic combustion air controller can't produce the extreme burn times all by itself.
My guess about how a BK actually functions so well.
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Well I have completed my wood rack and stacked all of my downed split cherry on it. Hopefully this will be ready by late November for some good heat.
Alpine1
Feeling the Heat
BKVP
Minister of Fire
What, no rain gutters either? Sharp looking....I’ll bet you can’t fill mine and make it look that nice...I dare you!
Do any of you bother with a stovetop thermometer? And if so where would you place it. It's the Princess I am interested in.
jetsam
Minister of Fire
I keep an infrared thermometer near the stove. I use it for all kinds of stuff, including checking stovetop temperatures and checking dogtop temperatures when they are roasting by the stove.
I tried one for most of a year before removing it. See, the cat sits under the stove top and is pretty much always at the same temperature. Changing thermostat settings seems to just make more of the stove get hot, not increase the stove top temp much. That stt gauge was much less informative than the stat setting, cat meter, and flue temp gauge.
Shayne
New Member
Thanks for the reply as this is my first Cat.
1) My wood is sugar maple 15 to 24% +/-, air dried 2 years and brought inside thru a wood shoot and dump trailer for the winter. Wood not a problem.
2) Yes we noted it still burns clean (noting with more air) this is the question.
3) I have my stove on marble with felts on the feet along with a 6" cheater pipe to slide it forward. I sweep from the top (this type stove moved before) and clean the stove also. Have not opened the black box. The stove works and has from the beginning. Stove not a problem.
4) I have had good draft with all my stoves this one is exceptional. The clear distances and pipe all meet Canadian code. This is not a problem.
The observation noted was it falls out of the active zone at dial settings it use to not to and requires more air = faster burning times/load.
I note I need to increase my air by about 12% to keep it in the active zone after about 10000 hours. What should I expect that it will keep running clean but I need to increase the air by 24%, over a new cat, after 20000 or should it reduce initially like this and then stay consistent for the next 7.5 years. If you can not get the burn times that you use to in warmer weather (3-4 hrs less a day than before) I would say it is a not a whole bunch but is noticeable. Will this degradation continue (on a equal gradual trend) or will it stabilize if I leave this cat in.
Regards
I figured they would be pretty useless. I have one on my VC but don't pay attention to it at all. The Princess will not be getting one. She will get spot checked with the IR once in a while.
Same here. The stove is so predictable it’s simply not needed.
lsucet
Minister of Fire
This season I removed it from the stove. I wasn't looking to it no more for long time. Like others here I just set the tstat to those little/magic marks by eyes.lol
My second install never had been seeing one on top, not even the flue probe. Sometimes I want to install a flue probe but then say, nahh is ok I don't need it.lol. too lazy to drill the holes.
My second install never had been seeing one on top, not even the flue probe. Sometimes I want to install a flue probe but then say, nahh is ok I don't need it.lol. too lazy to drill the holes.
BKVP
Minister of Fire
I would not touch the cat until you have to. The cleaning process would normally only be used after 5-6 years...depending on how much you use the stove of course. A person burning 3 cords a year might clean it much later than someone burning 5 cords a year. Remember, any time you pull a cat, you’ll need a new gasket.
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