closing down w/o getting black glass - oslo

[bostock]

hey friends - i am unfortunately very much OCD about dirty glass. In my defense - i spent 10 years as a residential window washer so i HATE dirty glass. HATE it. I'll even open a low-coaled stove and let the door cool for an hour just so i can clean it. Anyway - i can get 9+ hrs on an overnight burn with the oslo - but glass is (mostly) black in the morning. It cleans off fine w/ ash & damp newspaper or paper towels. So is this a big problem? NOPE. I can live with it if there's no way around that. But if you experts know of a way to get a 9-10 hr burn on a stove like the oslo without the dark dark glass, i would love to hear it.

My normal routine before bed: coals forward then load it up w/ 3-4 medium splits or similar volume, damper at 1/2 and intake at 1/2 for about 20 min - then damper "closed" and intake at maybe 1/4. What am i doing wrong?

 

[firefighterjake]

hey friends - i am unfortunately very much OCD about dirty glass. In my defense - i spent 10 years as a residential window washer so i HATE dirty glass. HATE it. I'll even open a low-coaled stove and let the door cool for an hour just so i can clean it. Anyway - i can get 9+ hrs on an overnight burn with the oslo - but glass is (mostly) black in the morning. It cleans off fine w/ ash & damp newspaper or paper towels. So is this a big problem? NOPE. I can live with it if there's no way around that. But if you experts know of a way to get a 9-10 hr burn on a stove like the oslo without the dark dark glass, i would love to hear it.

My normal routine before bed: coals forward then load it up w/ 3-4 medium splits or similar volume, damper at 1/2 and intake at 1/2 for about 20 min - then damper "closed" and intake at maybe 1/4. What am i doing wrong?

What are your temps like? And are you seeing a secondary burn? If I had to guess it sounds like you're not giving things enough time to reach adequate temp and/or are closing things too soon so that you suffocate the fire . . .

You'll still have some black once in a while to clean up -- when a split rolls up against the glass or sometimes there will be a smudge in the two corners where the air wash is weaker . . . and if you're a dirty glass hater -- and who can blame you . . . it's nice to see the fire through clean glass you will want to clean off the fly ash once ina while.

About once or twice a week I clean my stove and glass . . . I don't really even let the "glass" cool . . . after an overnight fire I open it up and clean it with a damp balled up newspaper . . . just being very careful since the glass is still quite warm.

 

[WellSeasoned]

I had dirty glass problem last year toward the end of the season using sub par wood. Big difference this year though, as my wood is seasoned properly. My corners are all that gets dirty (less air as said) OR if I close it down too early. Good luck

 

[bostock]

wood is 18months seasoned (C/S/S), mostly oak with occassional locust. I know i should shoot for 2yrs seasoned but this is the best i got for this winter (next year i'll be much better off at 2+yrs seasoned).

FFJ what temps do you look for? i'm usually at about 400 when i shut down. I'm not used to firebox this big (i'm used to the little F3 that i used for last 2 years, this is my first season with the Oslo) so i have a hard time hitting 450-500 unless i'm specifically trying for it. And them my wife wonders why i'm so obsessed with my stove LOL.

 

[bostock]

and nope i usually am not seeing 2ndaries (at shut down) - should i be waiting until i see them before shutting down?

 

[rdust]

and nope i usually am not seeing 2ndaries (at shut down) - should i be waiting until i see them before shutting down?

Yep, you always want to see a flame in the stove on a non cat stove when it has a firebox full of wood imo. When I had a non cat 400 was when I started dialing the air down, not closing it. Once it hits 400 back it down half way, another 5-10 minutes back it down some more and maybe one more fine tuning adjustment. When turning down the air back it down until the flames get lazy you don't want a dark stove when it's a non cat.

 

[BrotherBart]

Get that stove hot, over 500, turning it down in steps. And don't worry if you have to leave it with 1/4 open to maintain stove top temps. The primary air is the airwash that keeps the glass clean. Just like it was with the F3.

 

[bostock]

rdust - makes good sense. What might your final setting be when you're done - for example - intake air at 1/4 and damper full "shut"? do you shut intake all the way down? What's your target combo of intake setting and damper setting (if you have a damper, anyway)...

 

[BrotherBart]

And why are you using the damper anyway?

 

[bostock]

BB - i don't see an airwash on the oslo - are you sure, or maybe i'm just stupid i always thought airwash meant air flow across the inside face of the glass. Oslo doesn't have that - only a doghouse at the bottom that blows straight at the coals...maybe my definition of airwash is wrong though....

 

[rdust]

rdust - makes good sense. What might your final setting be when you're done - for example - intake air at 1/4 and damper full "shut"? do you shut intake all the way down? What's your target combo of intake setting and damper setting (if you have a damper, anyway)...

I assume you mean a manual damper in the pipe? I would suggest not using it at all and allowing your stove to control the air. Unless you have a tall chimney and the stove likes to runaway I wouldn't bother with the damper.

 

[bostock]

sorry BB - posts are crossing. Good question about the damper - i guess i close it off to keep heat in the stove - are you suggesting i should leave it open?

 

[jotul8e2]

BB - i don't see an airwash on the oslo - are you sure, or maybe i'm just stupid i always thought airwash meant air flow across the inside face of the glass. Oslo doesn't have that - only a doghouse at the bottom that blows straight at the coals...maybe my definition of airwash is wrong though....

The "doghouse" is not open at the front of the stove. The normal air circulation is down the front across the glass - this can be quite easily seen with a new load producing secondaries.

For an overnight burn I bring the temperature back up - I seldom see 500 deg (at least according to my thermometer), but I get it up to 450 deg. Once the secondaries are going good I start to back off the air. In my case, if I slide the air control much to the left of the 1/4 mark I can visually see the secondaries dying; the exact point probably varies a bit with your particular setup. For me, nine hours is pretty much the limit on a full load and still get an easy start up. I can go 10 hours, but it requires kindling. Never any black glass, only a film of ash that coats the surface. I clean it about three times a season with just damp paper towels. Or when company comes.

Oak may not be fully seasoned after just 18 months. I know my white oak needs a minimum of two years after being cut, split and stacked; three is better.

EPA secondary combustion stoves are designed to work without a flue damper. Only if you have excessively strong draft should one be used, and then you set it to bring the draft within normal parameters and leave it there.

 

[HotCoals]

Really well seasoned wood can and will off gas faster then lesser wood.

 

[Billybonfire]

Hi Bostock,
try this -
fill the stove with good well seasoned hardwood, run the stove HOT for a couple of hours until no flames, just a big coal bed, then close the air down.
In the morning open up the air and once the coals start glowing again, re load.
I have had my small stove go overnight without black glass using this technique.

Hope this helps

Billy.

 

[bostock]

The "doghouse" is not open at the front of the stove. The normal air circulation is down the front across the glass - this can be quite easily seen with a new load producing secondaries.

the F3 primary air is oriented to specifically blow across the glass, i assumed that was "airwash". The oslo doesn't have that - just the doghouse orienting the air straight towards the fire, near the bottom. I know air in the box will circulate across that window regardless, i was specifically referring to the inbound air.

EPA secondary combustion stoves are designed to work without a flue damper. Only if you have excessively strong draft should one be used, and then you set it to bring the draft within normal parameters and leave it there.

Thats a good point. I think i'm definitely using my damper too much. I left it wide open last night, and intake at 1/4: no black glass but only 1 red coal LOL. I probably just didn't load as much wood in there as i could've. Reading all these comments i think my biggest bad habit is, overusing the damper.

 

[jotul8e2]

the F3 primary air is oriented to specifically blow across the glass, i assumed that was "airwash". The oslo doesn't have that - just the doghouse orienting the air straight towards the fire, near the bottom. I know air in the box will circulate across that window regardless, i was specifically referring to the inbound air.

The little holes in the doghouse are just part of the system. Most of the air which passes through the doghouse air control run through a channel across the front, then up the corners on either side, then into the perforated tubes at the top. The holes in those tubes are oriented toward the top of the glass. This forces a rolling circulation pattern down the front, across the bottom and up the back. If you are not seeing this you are not getting secondary burns. It does, in fact, air wash the glass and does it very effectively.

 

[Backwoods Savage]

hey friends - i am unfortunately very much OCD about dirty glass. In my defense - i spent 10 years as a residential window washer so i HATE dirty glass. HATE it. I'll even open a low-coaled stove and let the door cool for an hour just so i can clean it. Anyway - i can get 9+ hrs on an overnight burn with the oslo - but glass is (mostly) black in the morning. It cleans off fine w/ ash & damp newspaper or paper towels. So is this a big problem? NOPE. I can live with it if there's no way around that. But if you experts know of a way to get a 9-10 hr burn on a stove like the oslo without the dark dark glass, i would love to hear it.

My normal routine before bed: coals forward then load it up w/ 3-4 medium splits or similar volume, damper at 1/2 and intake at 1/2 for about 20 min - then damper "closed" and intake at maybe 1/4. What am i doing wrong?

Bostock, I don't want to confuse anyone and I was not going to post but just had to because of how you are loading and running the draft. Like others, I say forget the damper and try to run that stove without it. Also, when starting from a cold stove and when reloading, full draft is called for until you get a good fire established.

In addition, that oak is the reason you have dirty glass. Until you burn properly dried wood you will be having black glass. This also sets the flag: Be sure to check your chimney monthly! Once you burn better wood then you won't have to check so often but poor fuel = poor results.

 

[bostock]

Indeed - burning with damper open i'm seeing no more dark glass (but burning wood quicker - still not getting an overnight but i think i'm just not loading enough fuel in there. Easily rectified).

And agreed - 18months on oak isn't enough but it's the best i have this year, got caught "in between seasons" I guess. We moved twice in 8 months and had other things that took most of my attention

 

[firefighterjake]

wood is 18months seasoned (C/S/S), mostly oak with occassional locust. I know i should shoot for 2yrs seasoned but this is the best i got for this winter (next year i'll be much better off at 2+yrs seasoned).

FFJ what temps do you look for? i'm usually at about 400 when i shut down. I'm not used to firebox this big (i'm used to the little F3 that i used for last 2 years, this is my first season with the Oslo) so i have a hard time hitting 450-500 unless i'm specifically trying for it. And them my wife wonders why i'm so obsessed with my stove LOL.

My probe style thermo in my double wall pipe is usually at 500 degrees F when I start to close the air control. I tend to rely more on my flue temp than I do my stove top temp.

 

[firefighterjake]

and nope i usually am not seeing 2ndaries (at shut down) - should i be waiting until i see them before shutting down?

I would . . . or rather I should say that it is by slowly shutting the air control that I get secondaries . . . but there is a line . . . open all the way and you may get no secondaries . . . close too much and don't provide enough oxygen to the fire and you get no secondaries and a suffocated fire.

 

[firefighterjake]

BB - i don't see an airwash on the oslo - are you sure, or maybe i'm just stupid i always thought airwash meant air flow across the inside face of the glass. Oslo doesn't have that - only a doghouse at the bottom that blows straight at the coals...maybe my definition of airwash is wrong though....

It's there . . . just nothing you really see . . . it's like magic.

 

[firefighterjake]

I assume you mean a manual damper in the pipe? I would suggest not using it at all and allowing your stove to control the air. Unless you have a tall chimney and the stove likes to runaway I wouldn't bother with the damper.

Ditto.

 

[firefighterjake]

Best bit of advice is to skip the use of the damper for now . . . and load 'er up.

 

[Backwoods Savage]

Indeed - burning with damper open i'm seeing no more dark glass (but burning wood quicker - still not getting an overnight but i think i'm just not loading enough fuel in there. Easily rectified).

And agreed - 18months on oak isn't enough but it's the best i have this year, got caught "in between seasons" I guess. We moved twice in 8 months and had other things that took most of my attention

Wow! Moving that quickly must have been interesting. Hopefully that is all behind you now and all will be well.