Burning a Jotul Oslo

[aaron1]

Hey,

I think I've been burning my Oslo sort of wrong/sub-optimally. I usually let it get to the point where there are a ton of flames and maybe 400-500 and then drop it down to 3/4 damper then down to 1/2 and maybe 1/4. Doing that I get up to maybe 500s temps. Last time, I decided to just let it go at 100% damper open and it climbed up to like 525-550, just kept getting hotter with tons of yellow flames. I then dropped to 3/4 damper, and it went to 600 and then dropped to 1/2 damper and it settled in at 612ish and is resting there or climbing slightly. It's heating me out of the room. I must be getting a lot more of the heat into the room and before I was letting more of the fuel go up the chimney?

 

[2fireplacesinSC]

Sounds like it. Check the manual, but with the F3 you're supposed to get the top (check manual where to measure, and use an IR gun) temperature up to 400-600 to get best burn and good heating.

Otherwise you're throwing a lot of air and heat up the chimney and outside. It's a little counterintuitive but to get the best/most efficient heating, you turn it down as low as you can while keeping a good stove top temperature and burn inside.

 

[BrotherBart]

As you back it down more of the gases are burning at the baffle using the secondary air instead of just heading up the flue un-burned. A thing called latency. The gases are going to take the path of least resistance. Forced to stay back in the firebox they hit the secondary air and you get more complete combustion. Above around 450-500 degrees stovetop temp which is around 1,100 in the firebox.

 

[firefighterjake]

Hey,

I think I've been burning my Oslo sort of wrong/sub-optimally. I usually let it get to the point where there are a ton of flames and maybe 400-500 and then drop it down to 3/4 damper then down to 1/2 and maybe 1/4. Doing that I get up to maybe 500s temps. Last time, I decided to just let it go at 100% damper open and it climbed up to like 525-550, just kept getting hotter with tons of yellow flames. I then dropped to 3/4 damper, and it went to 600 and then dropped to 1/2 damper and it settled in at 612ish and is resting there or climbing slightly. It's heating me out of the room. I must be getting a lot more of the heat into the room and before I was letting more of the fuel go up the chimney?

Each person's set up will be a bit different . . . depending on the chimney, amount of wood, type of wood, etc. used in the burn.

However, generally you get longer burns and more heat by going lower than the air control opened up to the halfway point. Most folks find the stove burns longer, more efficiently, cleanly and hotter once you dip down to the quarter mark. The key however for me is when I start turning down the air.

What I have found is that if I turn down the air earlier rather than later in terms of temps, the stove will never be as hot as when I wait a bit longer for the temps to increase before turning it down. However, regardless of when I turn down the air control -- it can almost always be turned down to the quarter mark (or lower) and still maintain a clean and efficient burn.

In my case I use my flue thermometer and on a reload allow the wood to reach at least 400 degrees F (this is a probe style thermometer in doublewall) before turning down the air. At this point the woodstove is running and stays running around 450-650 degrees. If I wait a bit longer before turning down the air it will run more towards the high side -- high 600 degrees at which point I begin to get a little antsy and start hovering around the stove to insure it doesn't get much hotter.

I suspect if you had run your stove up to the higher temp as you did the other day and then dropped it down as you normally do to the quarter mark you would have had the hotter temps you experienced before, but the burn would have been longer due to less air/heat going up the flue.

Now it is possible that your wood is less than optimally seasoned and when you have reduced the air control it choked back the fire enough to not allow it to get the full potential heat out of the wood . . . but I honestly doubt this since you do not mention a sooted up glass, hissing wood, trouble getting the fire started and your temps seem pretty good.

 

[Wallace]

With my Oslo it depends on a couple things. The biggest with my stove is how it's loaded. If it's loaded E/W then it takes longer to get the wood charred enough (producing products of combustion) and stove hot enough to get all the secondary tubes firing consistently once it's dampened down. I also have to make sure the middle logs are charred enough or else the glass will get creosote film on it. Loading N/S on some coals 3/4 open gets the stove hot and wood charred much faster. It's not very long before I need to shut it down to about 1/3 open and all the tubes are blasting flames. After about 15 mins of that I am able to shut the damper almost all the way down and get a long secondary flame display. This seems to produce the most usable heat the stove can supply. Right now I have been using a mix of oak and juniper. The juniper burns hotter and faster and the oak lasts much longer. I put the bigger oak splits in the middle and smaller juniper ones to the outsides.

 

[aaron1]

Thanks for all of the input! I will keep experimenting with when I turn down the damper. One of my gauges is whether I see any smoke coming from my chimney. If I turn down the damper too much, it will start producing some smoke. My goal with the stove is to produce a lot of heat from after work to when I go to bed. I don't care about long burns. I care mostly about getting a lot of heat and making sure I'm not polluting the air any more than I need to. I don't want to just throw away heat either of course.

I've also been burning it a little differently compared with past years. I get some coals going and then scrape them to the front somewhat, onto the air intake (as I have read on here before.) I then put in 3 splits, two on bottom, one on top. The splits do vary a lot in size and type of wood. I think most of my wood I have used so far is around 15% MC on my cheap moisture meter. None of it is over 20%. In the past, I have loaded it up more to the top. I definitely got a lot more secondaries when I would load the stove up all of the way.

I am just wondering if I have been a little to antsy to turn down the damper.

My only temp gauge is a stovetop one on the front left corner of the top of my stove.

 

[Burnmeister]

Been searching the forum for a related post to my issue. This seems like the closest one without starting a new thread, so here goes.

I have an Oslo, and this started a few days ago. Wood is good and dry (I took readings at around 11-13% give or take) but recently when I load up, its doesnt get roaring without cracking the door. When the temp does finally creep up and when I start to cut the air back, it seems to want to snuff out so I have to open the air all the way or crack the door again to get it going again. Im also getting no secondaries unless the air is wide open. It seems like this has coincided with two things.
1: the outside temp has been in the teens during the day and single digits at night. So a real cold snap has set in.
2: I went a little longer than normal to do a cleanout and was wondering if the doghouse can get filled with ash.

Dont know if either of these thing can hinder a stoves performance? I tend to be "theres no such thing as coincidences" theres always a cause and affect kind of guy.

The stove is on a short leg kit. It BARELY sits in the fireplace an inch. I do not have a flu damper (no room for one), and my stove is back piped out to a 90° and straight up the chimney, so all I really have is the air control on the stove itself.

Thanks in advance

 

[firefighterjake]

Been searching the forum for a related post to my issue. This seems like the closest one without starting a new thread, so here goes.

I have an Oslo, and this started a few days ago. Wood is good and dry (I took readings at around 11-13% give or take) but recently when I load up, its doesnt get roaring without cracking the door. When the temp does finally creep up and when I start to cut the air back, it seems to want to snuff out so I have to open the air all the way or crack the door again to get it going again. Im also getting no secondaries unless the air is wide open. It seems like this has coincided with two things.
1: the outside temp has been in the teens during the day and single digits at night. So a real cold snap has set in.
2: I went a little longer than normal to do a cleanout and was wondering if the doghouse can get filled with ash.

Dont know if either of these thing can hinder a stoves performance? I tend to be "theres no such thing as coincidences" theres always a cause and affect kind of guy.

The stove is on a short leg kit. It BARELY sits in the fireplace an inch. I do not have a flu damper (no room for one), and my stove is back piped out to a 90° and straight up the chimney, so all I really have is the air control on the stove itself.

Thanks in advance

You've been here for a while so I am guessing you know how to check for moisture (resplitting the wood and then taking a reading on the fresh split face) and have been running your stove for a while now so you know how to run the stove (although I should mention that I often leave the door cracked when I load up until the temps get high enough to close the door.)

Generally I find that the Oslo works the same regardless of temps . . . only it needs to be loaded more frequently (like most other stoves) when the real cold sets in.

Some ash can and will work its way into the doghouse . . . but generally the amount is not all that much and it seems that the symptoms of this happening is the air control lever starts to bind up and moves harder than normal.

I suspect it's a no brainer, but have you recently inspected and/or cleaned the chimney? Also, on your last clean out did yo clean out the ash that builds up above the baffle board and insulation wrap? I find that a fair amount of fly ash tends to build up above my baffle board . . . enough so that I clean it annually (generally in the Fall) as it can build up to the point where it limits the air/smoke venting out of the stove and into the chimney.

Good luck.

 

[Burnmeister]

You've been here for a while so I am guessing you know how to check for moisture (resplitting the wood and then taking a reading on the fresh split face) and have been running your stove for a while now so you know how to run the stove (although I should mention that I often leave the door cracked when I load up until the temps get high enough to close the door.)

Generally I find that the Oslo works the same regardless of temps . . . only it needs to be loaded more frequently (like most other stoves) when the real cold sets in.

Some ash can and will work its way into the doghouse . . . but generally the amount is not all that much and it seems that the symptoms of this happening is the air control lever starts to bind up and moves harder than normal.

I suspect it's a no brainer, but have you recently inspected and/or cleaned the chimney? Also, on your last clean out did yo clean out the ash that builds up above the baffle board and insulation wrap? I find that a fair amount of fly ash tends to build up above my baffle board . . . enough so that I clean it annually (generally in the Fall) as it can build up to the point where it limits the air/smoke venting out of the stove and into the chimney.

Good luck.

Hi, yes. I did do a split to check moisture. First thing I did. The chimney is done every year. Acually, my sweeper has told me that I have one of the cleanest flus that he does.
BUT, I have never cleaned abou e the baffle board and insulation. So a problem could be lying in there.

How do I go about doing that? I'm going to do it tomorrow.
thanks Jake

 

[firefighterjake]

Hi, yes. I did do a split to check moisture. First thing I did. The chimney is done every year. Acually, my sweeper has told me that I have one of the cleanest flus that he does.
BUT, I have never cleaned abou e the baffle board and insulation. So a problem could be lying in there.

How do I go about doing that? I'm going to do it tomorrow.
thanks Jake

What I do each Fall before lighting the stove for the first time is to remove the center oval plate in the top (two bolts with retainer clips which hold the plate in place . . . I leave the bolts in place and just loosen them enough to swivel the retainer clips out of the way and then remove the oval plate.)

At this point I have a halfway decent view of the top of the baffle and insulation blanket. Being very careful to not tear the blanket (or make too much of a mess) I remove the blanket and then use a shop vac with a dry wall filter or more often my ash vac to such up the pile of ash . . . being sure to keep areas where flue gases exit and fresh air enters as clear of ash as possible.

I still might suggest checking your chimney just to be sure it is still clean and unobstructed . . . but that's just me.