BK Sirocco 25 Help Please

[BKVP]

Thanks. I read previous posts talking about "switch" performance of BK thermostats and was wondering if that applied here (I also missed the part about fan and reading, thanks also for that).

I'm still having trouble reconciling that with what I see on my Ashford 25 insert, though. When I have a new load and I turn down thermostat, I get a good glow on the cat and the thermom sits at 12-1p as you describe (and no higher). As the burn progresses and less cat glow, the needle moves down to sit at the edge of the red zone for an extended time period. And when cold (or late burn/coals) it sits in grey zone (~10 o'clock). All of which is to say that I'm seeing it move between 3 distinct zones, whereas if it were a switch I would expect it to only be in 2 different positions. Am I missing something here?

.

Glowing is an indication of a pool of yet to burn gases loading up in front of the combustor. If you turn down the thermostat and slow the gases going through the combustor, you are increasing "residence time". This slower rate of movement can result in the bright glowing of the combustor. Very often running at a higher burn rate and then cutting back on the thermostat will increase the likelihood the combustor will start getting very bright.

Also, this slowing of the gas flow and increased residence time results in the combustor temperatures being elevated. Oddly, you might have lower surface temperatures of the stove, but the ct itself gets hotter, maybe much hotter.

BKVP

 

[helmingstay]

Glowing is an indication of a pool of yet to burn gases loading up in front of the combustor. If you turn down the thermostat and slow the gases going through the combustor, you are increasing "residence time". This slower rate of movement can result in the bright glowing of the combustor. Very often running at a higher burn rate and then cutting back on the thermostat will increase the likelihood the combustor will start getting very bright.

Also, this slowing of the gas flow and increased residence time results in the combustor temperatures being elevated. Oddly, you might have lower surface temperatures of the stove, but the ct itself gets hotter, maybe much hotter.

BKVP

I get all of that. What I don't understand is how the thermometer dial will rest at 3 different positions if it's really an on-off switch.

We have no problem with stove putting off heat. My challenge is understanding when (& why) temps drop below cat active range. I will turn it down to about 2-2.5 at bedtime and leave fan running. 8 hours later i have coals (and no unburned wood), but the thermometer is way down in grey zone. Wood is right around 20% moisture, I will experiment with lower thermostat (down below 2?).

Thanks all!

 

[Tron]

8 hours later i have coals (and no unburned wood), but the thermometer is way down in grey zone.

Not surprising, your fuel has just been consumed.
The thing is that the thermostat range is smaller than the range you can adjust with the knob. So if you turn the stove down with the knob overnight, the thermostat can't open enough to allow enough air in to keep the burn rate of the coals high enough to keep the cat active.
I see the same thing.
So in the morning I just turn the knob to wide open (bypass closed) and it'll get back into active range eventually and output some heat. If that's not enough heat or if you want to speed up the burndown process, you can add a fresh split on top of the coals and keep the knob wide open.

 

[crstrode]

Inserts are different than the "big" stoves. The biggest difference is the interior volume. In essence, there is little to no belly for the ashes. I have been running a Sirocco SC25 for about 5 years now and the behavior of yours mimics mine. I have found that emptying ashes about once every two weeks is easiest. Due to the shallow belly, fluffy ashes tend to "puff out" when reloading if I'm not very very careful.

My chimney is about 25 feet from the insert to the cap, so the draft is good. Even with a good draft, on reload I have found some smoke comes out unless I open the thermostat, open the bypass and get the remaining coals as hot as possible. Slowly open the door, stir up the coals and move them forward to help get them hot. Then; close the door but leave it cracked open to the first notch on the handle and let the insert "percolate" for about 5 minutes . This gets the hot air to warm the chimney and encourage a better draft.

Have your reload wood ready and have a plan on where to put each chunk. Ease the door open, then reload. Do it fast.

By the way; I burn Ponderosa Pine splits. Since I live in a Ponderosa Pine forest, it just seems to be the thing to do. Three or four splits added to a bed of coals when Gunsmoke reruns are over at midnight, gives me heat all night long and a bed of coals to get the next load going by itself at 9AM each morning. The manual tells you to adjust the thermostat slowly in small increments - this is written that way for a reason - the reason is because it works. Once the cat is glowing and the thermostat is turned down just enough so there are no visible flames (or some ghost flames now and then) my Sirocco insert cruises along all night. For me, the sweet spot for a long slow burn is at the very end of the "swoosh" on the thermostat dial.

Don't forget; this is a wood stove. There will be some smoke and ashes floating around no matter what. What the Sirocco insert lets escape is absolutely inconsequential compared to the god-awful mess from the log-eating open hearth fireplaces and Rube-Goldberg Franklin stoves I grew up with.

Running a Blaze King is an art that has taken me several seasons to get the hang of. Some say it is a "set-and-forget" process, however, I think of it more as a Zen-like experience. Every reload, and every fresh start, is unique and is a little bit different from the last one. Adjustments and tweaks are to be expected every time.

Be one with your Sirocco and luxuriate in your mastery of heat .

I love my Sirocco insert (-:

 

[Tron]

then reload. Do it fast.

Now it gets challenging. He'll need to play Tetris while on the clock then, essentially?
;-)

 

[crstrode]

Here is another tip I have found to be helpful when it comes to the inevitable smoke and floating ash. I have a box fan to circulate cool air from the floor of an adjacent hallway into the room with the insert. A 20" x 20" furnace filter bungee-cord attached to the back of the box fan catches a lot of dust/ash. Set the fan on the lowest speed and run 24-7 whether the insert is burning or not.

 

[helmingstay]

Inserts are different than the "big" stoves. The biggest difference is the interior volume. In essence, there is little to no belly for the ashes. I have been running a Sirocco SC25 for about 5 years now and the behavior of yours mimics mine. I have found that emptying ashes about once every two weeks is easiest. Due to the shallow belly, fluffy ashes tend to "puff out" when reloading if I'm not very very careful.

My chimney is about 25 feet from the insert to the cap, so the draft is good. Even with a good draft, on reload I have found some smoke comes out unless I open the thermostat, open the bypass and get the remaining coals as hot as possible. Slowly open the door, stir up the coals and move them forward to help get them hot. Then; close the door but leave it cracked open to the first notch on the handle and let the insert "percolate" for about 5 minutes . This gets the hot air to warm the chimney and encourage a better draft.

Have your reload wood ready and have a plan on where to put each chunk. Ease the door open, then reload. Do it fast.

By the way; I burn Ponderosa Pine splits. Since I live in a Ponderosa Pine forest, it just seems to be the thing to do. Three or four splits added to a bed of coals when Gunsmoke reruns are over at midnight, gives me heat all night long and a bed of coals to get the next load going by itself at 9AM each morning. The manual tells you to adjust the thermostat slowly in small increments - this is written that way for a reason - the reason is because it works. Once the cat is glowing and the thermostat is turned down just enough so there are no visible flames (or some ghost flames now and then) my Sirocco insert cruises along all night. For me, the sweet spot for a long slow burn is at the very end of the "swoosh" on the thermostat dial.

Don't forget; this is a wood stove. There will be some smoke and ashes floating around no matter what. What the Sirocco insert lets escape is absolutely inconsequential compared to the god-awful mess from the log-eating open hearth fireplaces and Rube-Goldberg Franklin stoves I grew up with.

Running a Blaze King is an art that has taken me several seasons to get the hang of. Some say it is a "set-and-forget" process, however, I think of it more as a Zen-like experience. Every reload, and every fresh start, is unique and is a little bit different from the last one. Adjustments and tweaks are to be expected every time.

Be one with your Sirocco and luxuriate in your mastery of heat .

I love my Sirocco insert (-:

This is such a great, detailed post

Inserts are different than the "big" stoves. The biggest difference is the interior volume. In essence, there is little to no belly for the ashes. I have been running a Sirocco SC25 for about 5 years now and the behavior of yours mimics mine. I have found that emptying ashes about once every two weeks is easiest. Due to the shallow belly, fluffy ashes tend to "puff out" when reloading if I'm not very very careful.

My chimney is about 25 feet from the insert to the cap, so the draft is good. Even with a good draft, on reload I have found some smoke comes out unless I open the thermostat, open the bypass and get the remaining coals as hot as possible. Slowly open the door, stir up the coals and move them forward to help get them hot. Then; close the door but leave it cracked open to the first notch on the handle and let the insert "percolate" for about 5 minutes . This gets the hot air to warm the chimney and encourage a better draft.

Have your reload wood ready and have a plan on where to put each chunk. Ease the door open, then reload. Do it fast.

By the way; I burn Ponderosa Pine splits. Since I live in a Ponderosa Pine forest, it just seems to be the thing to do. Three or four splits added to a bed of coals when Gunsmoke reruns are over at midnight, gives me heat all night long and a bed of coals to get the next load going by itself at 9AM each morning. The manual tells you to adjust the thermostat slowly in small increments - this is written that way for a reason - the reason is because it works. Once the cat is glowing and the thermostat is turned down just enough so there are no visible flames (or some ghost flames now and then) my Sirocco insert cruises along all night. For me, the sweet spot for a long slow burn is at the very end of the "swoosh" on the thermostat dial.

Don't forget; this is a wood stove. There will be some smoke and ashes floating around no matter what. What the Sirocco insert lets escape is absolutely inconsequential compared to the god-awful mess from the log-eating open hearth fireplaces and Rube-Goldberg Franklin stoves I grew up with.

Running a Blaze King is an art that has taken me several seasons to get the hang of. Some say it is a "set-and-forget" process, however, I think of it more as a Zen-like experience. Every reload, and every fresh start, is unique and is a little bit different from the last one. Adjustments and tweaks are to be expected every time.

Be one with your Sirocco and luxuriate in your mastery of heat .

I love my Sirocco insert (-:

This is such a great post, and confirms my initial experience. Thanks for the details.

@Tron yes, the speed tetris is kinda stressful. Just chuck a few logs in: no smoke. But with hit coals and open door, the bottom pieces quickly start to smolder and smoke spill is an issue.

@crstrode Question: for your overnight burns, where do you set the fan? Low, off, doesn't matter?

 

[crstrode]

This is such a great, detailed post

This is such a great post, and confirms my initial experience. Thanks for the details.

@Tron yes, the speed tetris is kinda stressful. Just chuck a few logs in: no smoke. But with hit coals and open door, the bottom pieces quickly start to smolder and smoke spill is an issue.

@crstrode Question: for your overnight burns, where do you set the fan? Low, off, doesn't matter?

I usually set the fan about half-speed. However, I run the insert thermostat low and slow in the daytime as well, or the room temperature gets way too hot for me . . .

I should have noted that the temperature indicator on the thermostat is always out of the active zone after an all-night burn. In the morning, the thermostat is opened all the way, bypass is opened, reload, then walk my dog for half an hour. By the time I return, the reload is burning well, temp is up, and the bypass can be closed.

Easy -peasy.

 

[begreen]

Inserts are different than the "big" stoves. The biggest difference is the interior volume. In essence, there is little to no belly for the ashes. I have been running a Sirocco SC25 for about 5 years now and the behavior of yours mimics mine. I have found that emptying ashes about once every two weeks is easiest. Due to the shallow belly, fluffy ashes tend to "puff out" when reloading if I'm not very very careful.

My chimney is about 25 feet from the insert to the cap, so the draft is good. Even with a good draft, on reload I have found some smoke comes out unless I open the thermostat, open the bypass and get the remaining coals as hot as possible. Slowly open the door, stir up the coals and move them forward to help get them hot. Then; close the door but leave it cracked open to the first notch on the handle and let the insert "percolate" for about 5 minutes . This gets the hot air to warm the chimney and encourage a better draft.

Have your reload wood ready and have a plan on where to put each chunk. Ease the door open, then reload. Do it fast.

By the way; I burn Ponderosa Pine splits. Since I live in a Ponderosa Pine forest, it just seems to be the thing to do. Three or four splits added to a bed of coals when Gunsmoke reruns are over at midnight, gives me heat all night long and a bed of coals to get the next load going by itself at 9AM each morning. The manual tells you to adjust the thermostat slowly in small increments - this is written that way for a reason - the reason is because it works. Once the cat is glowing and the thermostat is turned down just enough so there are no visible flames (or some ghost flames now and then) my Sirocco insert cruises along all night. For me, the sweet spot for a long slow burn is at the very end of the "swoosh" on the thermostat dial.

Don't forget; this is a wood stove. There will be some smoke and ashes floating around no matter what. What the Sirocco insert lets escape is absolutely inconsequential compared to the god-awful mess from the log-eating open hearth fireplaces and Rube-Goldberg Franklin stoves I grew up with.

Running a Blaze King is an art that has taken me several seasons to get the hang of. Some say it is a "set-and-forget" process, however, I think of it more as a Zen-like experience. Every reload, and every fresh start, is unique and is a little bit different from the last one. Adjustments and tweaks are to be expected every time.

Be one with your Sirocco and luxuriate in your mastery of heat .

I love my Sirocco insert (-:

Nice summary. Several points are true with a variety of inserts, not just BKs. A little smoke rollout happens with some, especially those with shallower fireboxes during weak draft days. Flush inserts, with little or no ashlip are prone to spilling ash on the hearth. If the ash is not cleaned right up, the blower is bound to pick it up and spread dust.

 

[crstrode]

Nice summary. Several points are true with a variety of inserts, not just BKs. A little smoke rollout happens with some, especially those with shallower fireboxes during weak draft days. Flush inserts, with little or no ashlip are prone to spilling ash on the hearth. If the ash is not cleaned right up, the blower is bound to pick it up and spread dust.

The blower: Don't forget to turn it off whenever the door is opened - or else!

 

[begreen]

The blower: Don't forget to turn it off whenever the door is opened - or else!

Yes, always turn it off before opening the stove door.

 

[Dieselhead]

The only time I get any spillage is when my chimney starts to get gunky. A quick sweep and any spillage goes away. I burn spruce which takes off FAST. It lets me know when I need to run the sooteater.

 

[m37charlie]

Automatic fan control
I see lots of mention and concerns about fan control.
Read my post (above).
The Inkbird device is $35.
The results are: never having to turn fan on and off again; fan only operates when necessary; ambient noise reduction; optimizing the decrease in net wood consumption that a properly used fan will deliver.
For heating something bigger than a single room, Ecofans are also helpful, they obviously only function when there’s heat available to be distributed.
PS: with an insert I’m not sure the top of the air plenum just before it blows over the top of the stove is accessible after installation.

 

[helmingstay]

I usually set the fan about half-speed. However, I run the insert thermostat low and slow in the daytime as well, or the room temperature gets way too hot for me . . .

I should have noted that the temperature indicator on the thermostat is always out of the active zone after an all-night burn. In the morning, the thermostat is opened all the way, bypass is opened, reload, then walk my dog for half an hour. By the time I return, the reload is burning well, temp is up, and the bypass can be closed.

Easy -peasy.

This makes sense. I guess I was assuming that "12 hr burn" meant that the cat was active the whole time.

In line with your morning routine, I made a fun discovery this evening. I just cleaned out a big load of ashes about 44 hrs after last load and then filled stove on top of remaining coals. I had some very dry tulip poplar stashed away for the bottom along with a bit of bark for kindling. Fast-forward 20 minutes and I have a merry fire. I'm impressed by your set-and-wait restart method!

 

[helmingstay]

Automatic fan control
I see lots of mention and concerns about fan control.
Read my post (above).
The Inkbird device is $35.
The results are: never having to turn fan on and off again; fan only operates when necessary; ambient noise reduction; optimizing the decrease in net wood consumption that a properly used fan will deliver.
For heating something bigger than a single room, Ecofans are also helpful, they obviously only function when there’s heat available to be distributed.
PS: with an insert I’m not sure the top of the air plenum just before it blows over the top of the stove is accessible after installation.

I was looking into this after reading your post. With the insert there's not a great place to out an external thermoprobe that's gets hot but not *real* hot. I did discover that Amazon sells magnetic snap switches for cheap. Now I'm considering adding one of these inside the bottom fron fan assembly (no external wires is a plus).

https://a.co/d/054O7CpQ

 

[m37charlie]

I often leave the house for hours with a full load of wood, air control set at whatever setting to keep main living area comfortable for my 3 cats, depending on outside conditions.
However, I’m not sure leaving bypass door open and walking the dog is a good idea (unless dog does their thing very rapidly). If stove is completely refilled, and air/heat knob is set to 2.5 or 3, you could come home to a red hot stack (if single wall) and/or a stack fire.
Those poor souls who don’t have BKs (due to poverty or ignorance) are well advised to not leave the house with anything other than a dying fire in their uncontrollable wood stoves. A BK with door cracked open or bypass open needs careful observation. IMHO.

 

[m37charlie]

I was looking into this after reading your post. With the insert there's not a great place to out an external thermoprobe that's gets hot but not *real* hot. I did discover that Amazon sells magnetic snap switches for cheap. Now I'm considering adding one of these inside the bottom fron fan assembly (no external wires is a plus).

https://a.co/d/054O7CpQ

I first tried side of stove, just before side wall makes a bend. With duct tape. It got way too hot. Then I thought about it and decided to use the temperature of the actual air that gets blown over the top deck by taping to probe to the sheet metal of the plenum. With the right kind of tape.
I’m rather irritated with myself that it took me about 30 years of bending over to turn the fan off and on, to think of this.

 

[crstrode]

I was looking into this after reading your post. With the insert there's not a great place to out an external thermoprobe that's gets hot but not *real* hot. I did discover that Amazon sells magnetic snap switches for cheap. Now I'm considering adding one of these inside the bottom fron fan assembly (no external wires is a plus).

https://a.co/d/054O7CpQ

With a flush insert like the BK Sirocco, the fan is a necessity. No fan, and not much heat makes it into the room. Just let the fan run. When the wood is burned down and is covered in ash, the residual heat will still make a significant contribution for hours - as long as the fan is running.