2018-19 Blaze King Performance Thread Part 2 (Everything BK)

[KBW]

BK specs are pretty low, put a manometer on it and I think you will see that smoke spillage can occur past .06 on these stoves.

 

[Highbeam]

My stack is about 35', my draft before key dampers (s), yes, 2 of em, was .23-.26..
Right now it's 27.3 deg. F. And windy, Both dampers are shut as far as they will go, and I'm still @ .06-.09...
Far better than without them .........
There's no way in hell anyone should EVER put a barometric damper on a woodstove flue/chimney system no matter what you might read !!

Then why do you suppose baro dampers are often specified and even included with wood furnaces? What’s the difference? Turns out the biggest reason I can think of, which is cooling flue gasses, does not happen according to very smart furnace owners who have actually measured.

Have you ever used one?

I could understand fearing them in the event of a chimney fire. Same risk with a wood furnace.

 

[Woody Stover]

The results of not dampered .17” and if the thermostat on the stove it’s turned down lower to compensate for the extra draft all being equal I loose about 35% of the burn time to maintain the same room temp under the same conditions. Also the thermostat isn’t nearly as effective under high draft conditions.

When the draft is to high, under any thermostat setting, air to the floor of the stove is reduced. Glass also gets dirtier and in a more pronounced “V” pattern on the door. Correct draft glass stays pretty clean.

This is where I'm confused, with this post as well as your previous "smoke smell" post. Seems to me that air out of the box has to equal air in through the thermostat flapper. Therefore, with normal draft, if you set the thermostat to a given flow rate through the stove, the air flow patterns within the stove should be the same as when the draft is stronger, but you have cut more air to achieve the same flow rate and flow patterns through the box. High-draft potential at the flue exit shouldn't affect anything if it's not allowed to exert itself and change the flow rate or patterns, it seems to me.
My BIL has my old Fireview on a 13.5' stack, my SIL has one on 21' and they both look about the same on the glass and seem to burn down the coals similarly...but I don't run those stoves enough to have a lot of data points. The double glass in these stoves may keep them looking about the same even though draft may differ between the stoves. I'm not sure the air flow is altered that much by the tall stack with higher draft, not like what you are describing in the BK.
What do you mean that "the thermostat isn't nearly as effective under high draft conditions?" What happens?
I'd like to have a thermostat to open the air automatically on my coals but there may be other cases where it's preferable to have positive control over the air intake...?

Another byproduct of high draft is excessive coaling. I’ve heard many (including myself) have issue with coals taking to long to burn down and taking up valuable firebox space when the stove is being run hard during cold snaps. When draft is right I get oak at 20% moisture burn down to near zero coals. If draft is high in 2 days of running high I’m shoveling out coals to make room for more wood (coals don’t make enough heat for my needs).

If you're running flame in the box, more heat is going up the flue in any stove. So you get less heat out of a load before you're down to coals again. With the extra baffles inside the boxes of the BKs, I think the heat is slower to get out of the stove than it would be in a stove where the radiation of the flames and coals glowing are allowed to directly hit the exterior sides of the stove. And it may be worse the more you open the air. That could be why the BTU/hr. is lower on the BKs at high burn rates than many other stoves. They may get their best heat extraction at moderate burn rates. My stone stove does the same thing to a degree on the side opposite the door, which has double stones...heat move out of the stove slower there, and that outside stone isn't as hot as the single thickness stone in the load door.
I'm interested in how the BKs react when you open up the air on a load of coals. When I've been cruising on an air setting of .5 on a scale of 4, then open the air to 1 or so on the coals with the top about 300, the top and sides of the stove go up in temperature as much as 50* depending on what part of the stove I'm shooting with the IR gun. If you open up the air on a load of coals in your BK, how much do the sides and top of the stove go up in temp? I'm wondering if you get less temp increase on the outer surfaces of the stove due to the inner baffles, when you open up the air on the coals.
I never shovel coals out of my stove. I think they are handled pretty well since there is a 1/4" hole in the back of the ash pan housing which admits air up through the ash grate and helps burn the coals from underneath. At the end of the burn I can generally burn down the remaining coals without losing room temp, unless it's single digits and windy which makes it harder to keep up. That doesn't happen here too often. But if you reload too early in any stove you are eventually gonna have a box full of coals.

 

[Highbeam]

BK specs are pretty low, put a manometer on it and I think you will see that smoke spillage can occur past .06 on these stoves.

Also draft specs are set at high burn, smoke spillage usually occurs at low burn during a reload. The draft strength will be much lower then.

 

[Diabel]

Also draft specs are set at high burn, smoke spillage usually occurs at low burn during a reload. The draft strength will be much lower then.

Makes total sense. I suppose my theory goes out the window.

 

[bholler]

Then why do you suppose baro dampers are often specified and even included with wood furnaces? What’s the difference? Turns out the biggest reason I can think of, which is cooling flue gasses, does not happen according to very smart furnace owners who have actually measured.

Have you ever used one?

I could understand fearing them in the event of a chimney fire. Same risk with a wood furnace.

I have never used one because I see the results of them in chimneys. And yes they do cool the exhaust there is no way you can introduce fresh air to the stove pipe and not cool it. Some of the nastiest chimneys I have cleaned have barometric dampers on them. And I have never worked on one that didn't have at least 1/8" of glaze with a baro.

How many have you had experience with?

 

[lsucet]

Then why do you suppose baro dampers are often specified and even included with wood furnaces? What’s the difference? Turns out the biggest reason I can think of, which is cooling flue gasses, does not happen according to very smart furnace owners who have actually measured.

Have you ever used one?

I could understand fearing them in the event of a chimney fire. Same risk with a wood furnace.

I did use one for two weeks in the past, it was a good experience. The flue keeps its temperature with no probs. If draft will be lower than the set point it closes and have no effect at all. It just takes care the overdraft.
We are seeing chimney fire cases here all the time and they are not using a baro damper. About creosote creation, I have no saying cause I didn't use for long.
About supplying air in case of chimney fire is true, but it can be capped if you around. All the stoves have in some how a certain amount of air that nobody has control over, with tube/secondary burn stoves being the worse. In case of chimney fire they supply a good amount of air to the flue through tube/baffle, dog house etc, making things worse and not many have a way to control that.

 

[aaronk25]

Hey not sure what you did but the first paragraph is my words and the second is your quote. What ever you did made it look like I said the whole post which is not the case.


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[aaronk25]

This is where I'm confused, with this post as well as your previous "smoke smell" post. Seems to me that air out of the box has to equal air in through the thermostat flapper. Therefore, with normal draft, if you set the thermostat to a given flow rate through the stove, the air flow patterns within the stove should be the same as when the draft is stronger, but you have cut more air to achieve the same flow rate and flow patterns through the box. High-draft potential at the flue exit shouldn't affect anything if it's not allowed to exert itself and change the flow rate or patterns, it seems to me.
My BIL has my old Fireview on a 13.5' stack, my SIL has one on 21' and they both look about the same on the glass and seem to burn down the coals similarly...but I don't run those stoves enough to have a lot of data points. The double glass in these stoves may keep them looking about the same even though draft may differ between the stoves. I'm not sure the air flow is altered that much by the tall stack with higher draft, not like what you are describing in the BK.
What do you mean that "the thermostat isn't nearly as effective under high draft conditions?" What happens?
I'd like to have a thermostat to open the air automatically on my coals but there may be other cases where it's preferable to have positive control over the air intake...?
If you're running flame in the box, more heat is going up the flue in any stove. So you get less heat out of a load before you're down to coals again. With the extra baffles inside the boxes of the BKs, I think the heat is slower to get out of the stove than it would be in a stove where the radiation of the flames and coals glowing are allowed to directly hit the exterior sides of the stove. And it may be worse the more you open the air. That could be why the BTU/hr. is lower on the BKs at high burn rates than many other stoves. They may get their best heat extraction at moderate burn rates. My stone stove does the same thing to a degree on the side opposite the door, which has double stones...heat move out of the stove slower there, and that outside stone isn't as hot as the single thickness stone in the load door.
I'm interested in how the BKs react when you open up the air on a load of coals. When I've been cruising on an air setting of .5 on a scale of 4, then open the air to 1 or so on the coals with the top about 300, the top and sides of the stove go up in temperature as much as 50* depending on what part of the stove I'm shooting with the IR gun. If you open up the air on a load of coals in your BK, how much do the sides and top of the stove go up in temp? I'm wondering if you get less temp increase on the outer surfaces of the stove due to the inner baffles, when you open up the air on the coals.
I never shovel coals out of my stove. I think they are handled pretty well since there is a 1/4" hole in the back of the ash pan housing which admits air up through the ash grate and helps burn the coals from underneath. At the end of the burn I can generally burn down the remaining coals without losing room temp, unless it's single digits and windy which makes it harder to keep up. That doesn't happen here too often. But if you reload too early in any stove you are eventually gonna have a box full of coals.

On my I phone so might have to condense multiple quotes into one....

You’re right air out of the box equals air in though the thermostat opening. That’s 1/2 of the equation, (volume of air) the other part is air pressure. Certainly to get the same volume of air though the stove under lower draft the thermostat has to be open farther, which is more efficient at putting heat into the room vs high draft and a more closed thermostat.

Follow me for a second....air pressure though the stove is similar to snaking a rope though it. Imagine running a rope though the OAK, ducting, thermostat, though the air tubes in the top of the box, over the air wash and then lay 5’ of rope coiled up in the bottom of the fire box on the middle of the wood, then run the rope thought the. Cat up the collar and out the chimney.

Now under .03 flue conditions there is very little pull on the rope and it lays where it was left.

Now run up to .15 or some high number and pull 10lbs of force on one end, oh and the other end is tied to a tree or car or somthing solid outside. Once the rope goes tight the biggest noticeable difference is it goes from the air wash straight to the cat and out. The 5’ of rope laid in the fire box is gone. Secondly when the rope goes out the flue collar it is tight to the front edge, no where near the thermostat so the thermostat becomes less effective which could lead to over firing.

If draft is high I get coals, when low it burns them to zero at almost the same rate as logs above.


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[Highbeam]

I have never used one because I see the results of them in chimneys. And yes they do cool the exhaust there is no way you can introduce fresh air to the stove pipe and not cool it. Some of the nastiest chimneys I have cleaned have barometric dampers on them. And I have never worked on one that didn't have at least 1/8" of glaze with a baro.

How many have you had experience with?

I wasn’t asking you. But since you asked me a question, I have never used a baro damper but might use one in a wood furnace per the directions.

 

[kennyp2339]

Low of 17 early this morning, the winds have been crazy, consistently gusting to 30 mph out of the northwest for the past 2 days, the house though is a comfy 70 deg upstairs, downstairs in the stove room its closer to 80, loving it, just for ease of use I switched to 12 hr loads, no worries with running out of fuel, or running the stove hard. So happy I got my draft issue dialed in, it literally feels like I'm running a whole different stove.

 

[bholler]

I wasn’t asking you. But since you asked me a question, I have never used a baro damper but might use one in a wood furnace per the directions.

Yes and what wood stove says to use one in it's directions?

 

[maple1]

Perhaps you have seen my prior posts. It's a violation of Federal law for manufacturers and commercial owners (that means distributors and dealers) to encourage in any way the use of any device or install that was not part of testing done in the certification tests. I have mentioned that agencies are seeking comment and input of the sales of dampers of any sort and any endorsements provided by the parties listed above.

With this is mind, I cannot offer any opinion on dampers or the use of them in our appliances.

I am sensing a bit of a conundrum here.

I do get your point.

But, if the install added a key damper to get the draft into spec AS WAS TESTED, on an install that otherwise would have had too much draft - well, I guess that's where I see a conundrum. Then also, there must be a line to cross somewhere where the 'not part of testing' would not come into play - example, someone using a chimney cap where one wasn't used in testing.

 

[chemie]

After seeing some pics posted, I just found these in our frozen backyard. Can you tell if it is just a creosote came off the chimney top because of strong wind we have recently or indicates chimney fire? My installer had told me once a year sweep is needed no more than that. The stove is running 24/7 almost everyday since mid October. Do I need a mid season sweep?
PS. I realized my hands need some hand creams of the wife after the post

 

[Ashful]

This is where I'm confused, with this post as well as your previous "smoke smell" post. Seems to me that air out of the box has to equal air in through the thermostat flapper. Therefore, with normal draft, if you set the thermostat to a given flow rate through the stove, the air flow patterns within the stove should be the same as when the draft is stronger, but you have cut more air to achieve the same flow rate and flow patterns through the box.

Nope. Throttling to the same flow rate with a higher pressure head will always result in greater velocity at the inlet.

An analogy might help, here. Let’s say you can achieve 2 gallons per minute (gpm) thru an open garden hose. Put a nozzle on there, and it might achieve 1 gpm. Now, if you could increase pump pressure you can get back to 2 gpm thru that hose nozzle, but it’s going to shoot a lot farther than that open garden hose did at 2 gpm.

Now, point that nozzle at the door gasket, and you’re going to get some leakage, even if the firebox is under net negative pressure. Like all analogies, this isn’t a perfect one, but it demonstrates the point in terms to which everyone can relate.

 

[Ashful]

So...installing a key damper would be a viable option for maximizing efficiency by allowing one to fine tune Draft? How many BK owners do this? Because I agree, I bet there are lots of BK owners, basically anyone whose setup goes through 2 stories, who experience over draft conditions, I being one of them.

Yes, a key damper is a viable option for maximizing efficiency, as well as solving a few other issues. I’ve said before that all stoves are a compromise, and the engineers who design them have to pay penalties in one area for performance gains in another. It’s up to the buyer and the retailer to choose the best compromise, or combination of performance factors, for a given installation.

I’m betting they took years of feedback given on the “black glass” experienced by the owners of some of their older models, and decided they were going to get a little more aggressive with their air wash on the newer line of stoves. It worked very well, but there are now some new issues introduced for the small percentage of people with very tall pipes.

The good news is that these new issues (fly ash plugging SteelCats and possible efficiency hits) can be dialed out by many means, a key damper being the most practical among them.

Don’t take BKVP’s lack of response on key dampers as his personal admonishment of these options, it’s just that as a manufacturer, he is bound to not suggest any deviation from the configuration under which the stoves are tested and approved. It is fun to watch bholler push that button, though. [emoji6]

 

[MissMac]

After seeing some pics posted, I just found these in our frozen backyard. Can you tell if it is just a creosote came off the chimney top because of strong wind we have recently or indicates chimney fire? My installer had told me once a year sweep is needed no more than that. The stove is running 24/7 almost everyday since mid October. Do I need a mid season sweep?
PS. I realized my hands need some hand creams of the wife after the post
View attachment 237949

So that could be off of your chimney cap. Or possibly out of your pipe. I hope off your cap for your sake (and it probably is), cause you wouldn't want your flue full of that stuff.

I think the more important thing here is that your installer doesn't know your burning methods, the quality of your wood, the amount your're burning etc., so I wouldn't bet your home and your family's safety on his comment. As a new burner running a new appliance, I suggest you visually inspect your chimney frequently, so that you can assess what's happening in your chimney in relation to how you've been running the stove. This will give you valuable feedback that may allow you to tweak your burning practices to make them even better, but in general, it gives you piece of mind and takes away the "what is going on up there" roll of the dice.

The fellows on here are super knowledgeable, but they cant tell you what you need to do just based on some words. Now, if you could take some pics of what the inside of your pipe and your cap looks like, you'd likely learn something, and then maybe these fellows could guide you a bit better. Many people are fine sweeping once per season - some choose to do mid-season sweeps for piece of mind, especially when transitioning from the fall low-and-slow to winter let-er-rip fires. I did, although it didn't really need it. But I felt a lot better for having done it, and it was simple.

I am in my second season of running my BK, and I checked my pipe every couple weeks at first last year, now every 4-6 weeks, and am starting to relax a bit because i'm seeing repeatable/predictable accumulation. But I would never put my faith in someone making an assessment of whether or not you need to sweep unless they are actually visually inspecting your system.

Is your cap/flue accessible to you? Climb up there!

 

[lsucet]

Low of 17 early this morning, the winds have been crazy, consistently gusting to 30 mph out of the northwest for the past 2 days, the house though is a comfy 70 deg upstairs, downstairs in the stove room its closer to 80, loving it, just for ease of use I switched to 12 hr loads, no worries with running out of fuel, or running the stove hard. So happy I got my draft issue dialed in, it literally feels like I'm running a whole different stove.

I did return one of the adapters with damper. And I will keep the other to install it on my tube stove that will be installed in the shop when done.
I am going to go with key dampers to can install them higher in the pipe. I have two ecofans on each stove on top of deck and interferes with the damper and it looks to close to the deck anyway for me.
I will install them this weekend.

 

[MissMac]

all you guys that have your draft dialed in using manometers - what factors besides wood quality would make it so that all your stoves behave differently, have different min. settings etc? If you all have the same WC spec on high draft, shouldn't your stoves all have the same turn-down potential? i'd love to understand this more. also, i imagine that how you adjust your key dampers depends on the weather outside (temp). So for an average user, how would they achieve the recommended draft spec. year round, when the temp varies which therefore causes the draft to vary? Just trying to understand better (given that my draft meets spec. but i still have creo smell issues when i turn down).

 

[bholler]

all you guys that have your draft dialed in using manometers - what factors besides wood quality would make it so that all your stoves behave differently, have different min. settings etc? If you all have the same WC spec on high draft, shouldn't your stoves all have the same turn-down potential? i'd love to understand this more. also, i imagine that how you adjust your key dampers depends on the weather outside (temp). So for an average user, how would they achieve the recommended draft spec. year round, when the temp varies which therefore causes the draft to vary? Just trying to understand better (given that my draft meets spec. but i still have creo smell issues when i turn down).

Outside temperature and barometric pressure will change it. Wood species will as well.

 

[chemie]

So that could be off of your chimney cap. Or possibly out of your pipe. I hope off your cap for your sake (and it probably is), cause you wouldn't want your flue full of that stuff.

I think the more important thing here is that your installer doesn't know your burning methods, the quality of your wood, the amount your're burning etc., so I wouldn't bet your home and your family's safety on his comment. As a new burner running a new appliance, I suggest you visually inspect your chimney frequently, so that you can assess what's happening in your chimney in relation to how you've been running the stove. This will give you valuable feedback that may allow you to tweak your burning practices to make them even better, but in general, it gives you piece of mind and takes away the "what is going on up there" roll of the dice.

The fellows on here are super knowledgeable, but they cant tell you what you need to do just based on some words. Now, if you could take some pics of what the inside of your pipe and your cap looks like, you'd likely learn something, and then maybe these fellows could guide you a bit better. Many people are fine sweeping once per season - some choose to do mid-season sweeps for piece of mind, especially when transitioning from the fall low-and-slow to winter let-er-rip fires. I did, although it didn't really need it. But I felt a lot better for having done it, and it was simple.

I am in my second season of running my BK, and I checked my pipe every couple weeks at first last year, now every 4-6 weeks, and am starting to relax a bit because i'm seeing repeatable/predictable accumulation. But I would never put my faith in someone making an assessment of whether or not you need to sweep unless they are actually visually inspecting your system.

Is your cap/flue accessible to you? Climb up there!

It is about 25 feet and dont have that high ladder or experience about the sweep.

 

[MissMac]

Outside temperature and barometric pressure will change it. Wood species will as well.

Yup for sure, but assuming that each of these fellows is adjusting for the weather using their key dampers/manometers, that just leaves wood species.

I guess i'm just trying to understand more about the draft, and extending flue height. I've read on other threads about people having draft problems, but let's say you only had draft issues when it was milder out - adding more pipe would put you way above the recommended draft spec in the dead of winter, so what is better to do for the average user? More pipe for more draft and then just be exceeding the draft when cold out? Or struggling to turn down the stove when warmer out? Just trying to think from an average user's perspective. I guess probably most people have higher than recommended draft?

 

[MissMac]

It is about 25 feet and dont have that high ladder or experience about the sweep.

time to buy a new ladder! or get one of those soot eaters that the guys talk about, and give it a run up your chimney for piece of mind

 

[bholler]

Yup for sure, but assuming that each of these fellows is adjusting for the weather using their key dampers/manometers, that just leaves wood species.

I guess i'm just trying to understand more about the draft, and extending flue height. I've read on other threads about people having draft problems, but let's say you only had draft issues when it was milder out - adding more pipe would put you way above the recommended draft spec in the dead of winter, so what is better to do for the average user? More pipe for more draft and then just be exceeding the draft when cold out? Or struggling to turn down the stove when warmer out? Just trying to think from an average user's perspective. I guess probably most people have higher than recommended draft?

You need to have at least the min draft at the warmest outside temps you want to burn in. High draft is much easier to deal with than low draft.

 

[MissMac]

You need to have at least the min draft at the warmest outside temps you want to burn in. High draft is much easier to deal with than low draft.

That makes perfect sense and was what i was thinking. With all this talk about the guys fiddling with manometers lately it just got me thinking about the other 99.9% of owners who likely pay no attention or understand any of this stuff, and just stuff wood into the box, run it as per the manual, and call it good enough. This makes me think that unless there's a mass outcry of smokey houses, most people must exceed the draft requirements for at least part of the heating season, because they do nothing to monitor or fiddle with their set ups.