A burning question - Jotul Oslo

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J

jotul8e2

Minister of Fire
Feb 2, 2008
595
Ozarks
Like most of the midwest we had a severe cold snap the last 48 hours or so. It is early in the season for me, but I took the opportunity to fire up the Oslo for the first time this season. I had already checked the flue and thought I was good to go. However, on my initial load I could not get the temperature up into the operating range. My split and stacked oak is property seasoned and quite dry. Then I thought to check the ash pan; sure enough it was almost full. Once I emptied the pan it took right off and there were no other issues.

Now, let's set aside the issue of how and why the pan went unemptied since last April (and the glass not cleaned either!), and concentrate on the poor performance of the stove with full pan. This is something I noticed the very first season, five years ago. The stove simply will not burn properly with the pan full. I have no interest in resuming the ash pan wars, I simply want to know how it is that some people can burn successfully by leaving the pan full, or even blocking it off, while mine will scarcely burn at all.

I have an excellent, fully insulated flue (6" Excel, full stainless), just over 30' tall with plenty of clearance to all sides that is totally straight up except for the shortest possible 45 deg. offset, clean spark screen, plenty of combustion air, seasoned and dry wood. I can get 500 deg. on the stovetop in well under an hour from a stone cold start, quite good burn times on a load, and good overnight burns - everything you want from a stove. But let the pan get full and even hot reloads will not take off.

I do not classify this as a "problem", I just find it interesting and maybe a bit confusing.
 
Unfortunately, the only logical answer is that wood might not be as dry as you think and the pan gasket leaks ever so slightly. A small leak is really the only logical explanation.
 
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I agree with webby. Sounds like you need to get air from the ash pan in order for the fire to burn properly. Does the wood catch fire readily and burn well when you leave the door open? What happens when you close the door? What is your setting of the air control? How fast do you close the air?
 
I left my ash pan full all last winter and never experienced this problem?
 
The only answer is that you may have air leaking through the ashpan door area. Theres absolutely no other reason why a fire would burn better with it emptied, other than once it is empty more air is coming through to stoke the fire. My ashpan stays full until spring because it just works out easier for us. We shovel every other week or so and leave it at that. Been on the forum for a couple years and my brother and best friend run Oslo's, never heard of this occuring before, but definately something to look into. Have you tried the dollar bill test around the ashpan door?
 
I just entered a ash pan question in this forum too, how funny! To answer some of his question, I have never seen any relationship to having a full Oslo ash pan and the burn being affected. My F500 will burn either way, must be something else.
 
webby3650 said:
Unfortunately, the only logical answer is that wood might not be as dry as you think and the pan gasket leaks ever so slightly. A small leak is really the only logical explanation.
Click to expand...

That does sound plausible. Against that is the fact that the fire will simply go out if the air control is shut down much under the 1/4 open mark. It would have to be a VERY small leak, so it will be hard to find.

Re: wood. No, the wood is definitely quite dry.

As I said, when the ash pan is less than full, everything works as it should - the fire is perfectly controllable, burn times are what you expect, temperatures are as expected, secondaries are strong.

But I am going to take a look at that ash pan gasket.
 
If your wood is as dry as you say I am wondering whether your air path is blocked somehow. Certainly, the fire should not go out if you close the air control. Maybe someone who knows Jotuls better than I can tell you where to look.
 
I concur that the ash pan door sounds leaky. Small chunks of charcoal can get embedded and crushed into the ash pan door gasket. Look and feel for this when checking. Also, ash can get compacted behind the ash pan, pushing it slightly forward. That prevents the door from closing tightly. The cure is a thorough removal of the packed ash in the back of the ash pan drawer.
 
The fire should not go out if the air control is turned to low. That in itsself is a sign if under seasoned wood.
The reason I bring this up is because its the issue almost always. How long has it been split and stacked? Species?
 
If the fire's going out Id say its the wood as well. We hear so many people on here say their wood is seasoned and low and behold, they figure out down the road that the wood was the problem. Id try a bag or two of dry store-bought wood just to see if theres a difference. Oak can be finicky to season well.
 
Been burning in the Oslo for a few years . . . haven't noticed any correlation between empty, partially full or completely full ash pans and the burn.
 
Castine is a smaller version but with ash pan full I crack the front loading door just as little as possible.
It gives a bit of a draft and it takes off. Unless the ash pan gasket leaks, it shouldn't help or hinder better lighting.
 
I have run an Oslo for several years now and have found a few tricks that are NOT factory approved, but work great for me. First, I never clean the ash pan as it is difficult to do. When you take out the drawer you get lots of detritus falling down behind the drawer, which are difficult to clean out before you reinsert the drawer. The stove seems to burn slightly better with a clean ash drawer, but not by much, so I find the tradeoff acceptable. Second, I almost never open the front glass door as it tends to spill ash, coals and even partially burned wood out the front; not an ideal situation, to say the least. I only open the front door to clean out the ashes. I only load from the side door, which is almost totally clean and without even smoke coming out; just make sure the draft control is fully open first. Now for the unconventional, not factory recommended procedure; when starting a cold stove I put in splits, then a few ounces of diesel fuel, then light 'er up. Instead of closing the door fully I leave it cracked a bit and the draft control fully open. This allows a lot of air into the fire box (duh) and the fire catches quickly. Pay attention because you don't want to do this for more than a few minutes! Once you have a good fire going, then simply close the side door and latch it. Leave the control fully open at this point. Once my stove top thermometer reaches about 300 degrees I turn the draft down to half or less depending on my heating needs. Please be aware that this is not a procedure you have to do very often; once the stove is up and running then it's not usually required, just feed more wood in from the side door as necessary. If, however you burn down to just a few coals then rake them towards the side door, add splits and again leave the side door open a crack. I use the thickness of the inside latch to prop the door open just that much. The wood will catch quickly, so, again don't leave the stove unattended. Great stove other than that.
 
Kenneth Reed said:
I have run an Oslo for several years now and have found a few tricks that are NOT factory approved, but work great for me. First, I never clean the ash pan as it is difficult to do. When you take out the drawer you get lots of detritus falling down behind the drawer, which are difficult to clean out before you reinsert the drawer. The stove seems to burn slightly better with a clean ash drawer, but not by much, so I find the tradeoff acceptable. Second, I almost never open the front glass door as it tends to spill ash, coals and even partially burned wood out the front; not an ideal situation, to say the least. I only open the front door to clean out the ashes. I only load from the side door, which is almost totally clean and without even smoke coming out; just make sure the draft control is fully open first. Now for the unconventional, not factory recommended procedure; when starting a cold stove I put in splits, then a few ounces of diesel fuel, then light 'er up. Instead of closing the door fully I leave it cracked a bit and the draft control fully open. This allows a lot of air into the fire box (duh) and the fire catches quickly. Pay attention because you don't want to do this for more than a few minutes! Once you have a good fire going, then simply close the side door and latch it. Leave the control fully open at this point. Once my stove top thermometer reaches about 300 degrees I turn the draft down to half or less depending on my heating needs. Please be aware that this is not a procedure you have to do very often; once the stove is up and running then it's not usually required, just feed more wood in from the side door as necessary. If, however you burn down to just a few coals then rake them towards the side door, add splits and again leave the side door open a crack. I use the thickness of the inside latch to prop the door open just that much. The wood will catch quickly, so, again don't leave the stove unattended. Great stove other than that.
Click to expand...
The reason that coal and ash fall out if the front door is opened is only because you never use the front door. If you used it regularly, ash wouldn't be able to pile up there.

It's never a good idea to use diesel fuel to start a fire!!! Whats wrong with a simple firestarter?
 
Webby3650,

I don't use the front door even if there is no danger of anything falling out because it will pull smoke into the room; a lot if you open it quickly, but even if I open it very carefully and slowly I still get some smoke out the top of the opening. There is really no good reason to open it with the side door being quite simple and clean.
 
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Kenneth Reed said:
but even if I open it very carefully and slowly I still get some smoke out the top of the opening. There is really no good reason to open it with the side door being quite simple and clean.
Click to expand...
It sounds like you have some chimney issues if you can't open up the front door.
Most people act like the front door on the Oslo is particularly messy, my point is that it's no more messy than most other stoves. With the side door, the front door doesn't get used very often, therefore lots of ash piles up there. I do love the side door!
 
I actually enjoy a little wiff of cherry or red oak smoke in the room:cool:
 
webby3650 said:
The fire should not go out if the air control is turned to low. That in itsself is a sign if under seasoned wood.
The reason I bring this up is because its the issue almost always. How long has it been split and stacked? Species?
Click to expand...

I burn white oak and hickory. It is cut, split, and stacked three years ahead. I also am a woodworker and have plenty of kiln dried stuff. I know what what unseasoned, seasoned, and rotten wood is like. I always get strong secondaries, and this is very hard to achieve with unseasoned wood in the Oslo.

My point about the air control is that the stove will starve for air if the air control is turned all the way to the left, which suggests any air leak must be very small. My normal "cruising" position is just a tiny bit to the left of the 1/4 mark. I have carefully examined the gasket on the ash pan door and can find no indication of a gasket problem. As this is my fifth season with this stove I think I will replace all the gaskets come spring, just because.

Re: front door. I can open the front door without draft problems as well. The stove is designed to also function as an open fireplace.

Re: Ash pan hard to clean. I find the ash pan is very easy to clean, and it is needed only about twice a week when burning 24/7. It is perhaps my favorite feature of the stove.

Re: Starting with the side door open. My manual does, in fact, suggest this; somehow they failed to mention diesel fuel. For a cold start, I throw in a few strips of cherry, oak, aspen, or whatever I am working with, light that (I usually have some stuff thin enough I do not need paper), and once it catches add my splits. With the side door cracked open I am up to operating temperature in 30 minutes at most.
 
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I am very happy how mine operates. 1/4" open after it reaches 400 or 500 degrees. Cruises until I need more dry seasoned wood.
 
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