Creosote in fire box

[vallieweck]

Hello all. I run my BK hot for about 45 min on cold start or after reloading, STT at around 600-650 and then I start turning down the thermostat for temps to run around 400. Is it normal to still have creosote like this in the fire box and on the glass? Burning fir at 18%, I would like that to be drier but it’s what we have, still in acceptable range.

Thinking about using rutland’s creosote spray during a cold start for when catalyst in bypassed. Thoughts?

Thank you in advance!

 

[Dieselhead]

That’s perfectly normal, it’s part of the “low and slow” lifestyle. On that note how do you measure the MC of your firewood?

 

[vallieweck]

That’s perfectly normal, it’s part of the “low and slow” lifestyle. On that note how do you measure the MC of your firewood?

Took a split of wood that had been inside the house over night. Chopped her in half and took a reading with a probe on the ends and in the middle.

 

[Dieselhead]

Took a split of wood that had been inside the house over night. Chopped her in half and took a reading with a probe on the ends and in the middle.

Perfect method, 18 is acceptable. Even with drier wood you still get sheets of creo peeling off the inside of the firebox. A nice hot fire like your doing helps keep it in check.

 

[stoveliker]

Don't use Rutland creo spray - it's bad for the cat.
Even in bypass mode, how are you sure all bypasses the cat, and all is gone before you close the bypass?

BK says not to use it.

Creo in the box is fine. Your flue should remain clean if you use the stove/cat properly.
At the end of a season I run one load full throttle and then (steel) brush the crisped up creo out of there and vac it up to not have that oxidizing creo sit there all (humid) summer.

 

[vallieweck]

Don't use Rutland creo spray - it's bad for the cat.
Even in bypass mode, how are you sure all bypasses the cat, and all is gone before you close the bypass?

BK says not to use it.

Creo in the box is fine. Your flue should remain clean if you use the stove/cat properly.
At the end of a season I run one load full throttle and then (steel) brush the crisped up creo out of there and vac it up to not have that oxidizing creo sit there all (humid) summer.

Thanks for the reply. Even burning hot..this creosote doesn’t “crisp” so that I can brush it off, seems like a lacquer!

 

[vallieweck]

Perfect method, 18 is acceptable. Even with drier wood you still get sheets of creo peeling off the inside of the firebox. A nice hot fire like your doing helps keep it in check.

That’s the thing though, there’s no peeling going on here with the creosote, it seems glued on there pretty good

 

[stoveliker]

A full load white open throttle?
I've had sticky goo but after loading the firebox full and burning it down in a hurry, it's all coming off

 

[vallieweck]

A full load white open throttle?
I've had sticky goo but after loading the firebox full and burning it down in a hurry, it's all coming off

Open all the way for about 45-60 min yes. Then I dial it down. Let it die over night last night and opened it up and this what I see, pictures posted.

When you say die down in a hurry, what do you mean?

 

[stoveliker]

No dialing down. Cold start, full load, close bypass when the cat is active, keep the thermostat fully open, let it do its thing.

Literally a full load wide open thermostat. Not 45-60 minutes. Just the full load. I.e. 8 hrs or so for me (depending on wood species).

 

[vallieweck]

No dialing down. Cold start, full load, close bypass when the cat is active, keep the thermostat fully open, let it do its thing.

Literally a full load wide open thermostat. Not 45-60 minutes. Just the full load. I.e. 8 hrs or so for me (depending on wood species)

No dialing down. Cold start, full load, close bypass when the cat is active, keep the thermostat fully open, let it do its thing.

Literally a full load wide open thermostat. Not 45-60 minutes. Just the full load. I.e. 8 hrs or so for me (depending on wood species

Thanks again but I am confused I think. Wouldn’t I risk burning way too hot for way too long? I imagine it would get over 1,000 degrees on the STT easy. Unless we are talking about just a couple smaller logs? I burn fir btw.

 

[stoveliker]

No. A full box. I've done pitch pine and oak (just what I had).

This is how the thermostat works: it'll close the air when things get too hot. Setting it at "fully open" means "the highest temperature where the flapper will close up", it does NOT mean "the air is and remains fully open".

Basically the thermostat of the BKs protects a stove against overfiring (as long as the stove is properly sealed (gaskets etc), proper fuel is used (dry pure wood), and the flue does not draft beyond specs (hence the flue recommendations - which are a proxy for the actual measured draft range in which the stove works well).
Of course doing any of this wrong (leaky stove and a 50 ft flue) will result in the system not being able to do what it was designed to do.

But doing things right you can burn a full load down wide open throttle without issue.
There was a guy here from Alaska who said that he burned like that months at a time.

 

[vallieweck]

No. A full box. I've done pitch pine and oak (just what I had). This is how the thermostat works: it'll close the air when things get too hot. Setting it at "fully open" means "the highest temperature where the flapper will close up", it does NOT mean "the air is and remains fully open". Basically the thermostat of the BKs protects a stove against overfiring (as long as the stove is properly sealed (gaskets etc), proper fuel is used (dry pure wood), and the flue does not draft beyond specs (hence the flue recommendations - which are a proxy for the actual measured draft range in which the stove works well). Of course doing any of this wrong (leaky stove and a 50 ft flue) will result in the system not being able to do what it was designed to do. But doing things right you can burn a full load down wide open throttle without issue. There was a guy here from Alaska who said that he burned like that months at a time.

Huh, interesting, logic makes sense. I get nervous when I see temps nearing 700* and always choose to turn the thermostat down. Guess I would really have to trust the process. At what temperature should I be concerned?

Our stove was installed by a qualified installer to spec so I feel good about that. Just swept it a couple weeks ago.

 

[vallieweck]

No. A full box. I've done pitch pine and oak (just what I had).

This is how the thermostat works: it'll close the air when things get too hot. Setting it at "fully open" means "the highest temperature where the flapper will close up", it does NOT mean "the air is and remains fully open".

Basically the thermostat of the BKs protects a stove against overfiring (as long as the stove is properly sealed (gaskets etc), proper fuel is used (dry pure wood), and the flue does not draft beyond specs (hence the flue recommendations - which are a proxy for the actual measured draft range in which the stove works well).
Of course doing any of this wrong (leaky stove and a 50 ft flue) will result in the system not being able to do what it was designed to do.

But doing things right you can burn a full load down wide open throttle without issue.
There was a guy here from Alaska who said that he burned like that months at a time.

I did not know this about the thermostat by the way, thank you! I thought you must turn it down some so it wouldn’t get too hot. Owners manual I don’t think went over this so now I need to read again!

 

[stoveliker]

Huh, interesting, logic makes sense. I get nervous when I see temps nearing 700* and always choose to turn the thermostat down. Guess I would really have to trust the process. At what temperature should I be concerned?

Our stove was installed by a qualified installer to spec so I feel good about that. Just swept it a couple weeks ago.

That's fine. We all learn things here.

How tall is your chimney from stove top to chimney cap?

 

[Murray01]

Is this a new stove?

I had creosote as you described then after 30 or so fires it started to peel off. Big “peels” 2”-3” by 5”-6”. Can’t explain why it happened, maybe the creosote has to be a certain thickness before it starts to peel off?

 

[vallieweck]

Is this a new stove?

I had creosote as you described then after 30 or so fires it started to peel off. Big “peels” 2”-3” by 5”-6”. Can’t explain why it happened, maybe the creosote has to be a certain thickness before it starts to peel off?

It is a new stove. This is the second year of burning. Interesting……

 

[vallieweck]

Huh, good question that I don’t know the answer to, I’m guessing around 12-14 feet??

That's fine. We all learn things here.

How tall is your chimney from stove top to chimney cap?

 

[stoveliker]

Okay. No worries about overfiring due to a flue with too much draft

 

[vallieweck]

Okay. No worries about overfiring due to a flue with too much draft

So is there a temperature that I should be looking to not go over on my STT?

 

[stoveliker]

I don't know.
I think you're worrying too much.
I don't even have a stove top thermometer; they're not very useful for a system with a 1600 F cat right below. Temperature variations are large on the stove top depending on location, and catalyst state (you can see the cat change temp based on what happens in the firebox, e.g. wood resettling after having burned a bit etc.). You can't control on that. And you shouldn't. That's what the thermostat is for.

What matters is whether the cat is in the active regime. And if you want to monitor something, have a flue probe. That's more useful.

I think you have the Sirocco?.
If you have the fan, switch it on when you do your crisping burn for additional peace of mind.

@BKVP ?

 

[Tron]

So is there a temperature that I should be looking to not go over on my STT?

What's SST? Stove top temperature? That's a very unreliable metric as it heavily depends on the stove, even within the BK line. For example, some stove tops are the top of the firebox and some like my Chinook have an air channel between stove top and firebox. Plus, the super hot cat skews measurements anyway.

I measure the actual flue gas temperature in my double-pipe stack (mostly when starting up) and I dial it down around 900F. It does get smelly if it goes any higher.
That said, I've never burned a whole load at full throttle, it'd bake us out of the house pretty soon.

 

[vallieweck]

I don't know.
I think you're worrying too much.
I don't even have a stove top thermometer; they're not very useful for a system with a 1600 F cat right below. Temperature variations are large on the stove top depending on location, and catalyst state (you can see the cat change temp based on what happens in the firebox, e.g. wood resettling after having burned a bit etc.). You can't control on that. And you shouldn't. That's what the thermostat is for.

What matters is whether the cat is in the active regime. And if you want to monitor something, have a flue probe. That's more useful.

I think you have the Sirocco?.
If you have the fan, switch it on when you do your crisping burn for additional peace of mind.

@BKVP ?

lol I see this a lot actually in the research I’ve been doing, folks don’t have a need for the thermometers, it’s just a feeling. I grew up on a Fisher stove and am now new to burning with the cat so it’s all learning for me. So thankful for guys like you taking the time to reply and help.

The catalyst probe thermometer has an active range, but there’s an end to it and sometimes it goes over that spot, nothing to worry about? I have double wall pipe so I guess I’d need to buy and install a probe if it’s worth it.

That’s right, sirocco.

 

[vallieweck]

What's SST? Stove top temperature? That's a very unreliable metric as it heavily depends on the stove, even within the BK line. For example, some stove tops are the top of the firebox and some like my Chinook have an air channel between stove top and firebox. Plus, the super hot cat skews measurements anyway.

I measure the actual flue gas temperature in my double-pipe stack (mostly when starting up) and I dial it down around 900F. It does get smelly if it goes any higher.
That said, I've never burned a whole load at full throttle, it'd bake us out of the house pretty soon.

Yes, stove top, makes sense with that logic with the catalyst right under it, skewing measurements and all. We have to open a window anyways in our home, it’s 1,000 square feet and even with smaller loads it gets up to 75*.

 

[Tron]

We have to open a window anyways in our home, it’s 1,000 square feet and even with smaller loads it gets up to 75*.

That's exactly it: with the BK, you don't vary the load size to adjust temperature. That's because the thermostat does that, it varies airflow to set the combustion rate. You stuff it to the gills and set the thermostat accordingly and just let it be.
Of course, there's a limit to where you can dial it down, at some point the cat will drop out of active range. But that's entirely independent of the amount of fuel in the stove.

Turned down, the flue temperature is not a problem at all. Like I said, I mostly use it after a reload as not to overfire the flue/bypass with the bypass open. That's something that can happen, the bypass door hinge and gasket don't like having the door open and the thermostat at full for extended periods of time. I do that just enough to get the load going and then close the bypass and dial down the thermostat.

But a flue thermometer is easily installed: just drill a 1/4" hole through both pipes and stick this in there:

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