The Oslo Nuclear Reactor

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That was my wife story a few years ago. She went up to the cabin alone, cleaned the stove and started a fire, as she has done lots of times. In a short time she heard the stove top water pot boiling. It never does that. She knew there was a issue. Long story, 3 fire trucks, ambulance, community security. They were thinking chimney fire. They almost dumped water on it. Luckily they gave up as it ran out of fuel.

My wife called me that night and explained what happened. I got it. Go over to the stove. Get down and look at the ash door. The latch is turned but the door is open. Pull the ash pan out. A pile of ash behind the pan. You can run this stove with the side or front door open, but never have the ash pan door open.
 
By design you are not supposed to have too much control over the modern noncat. Otherwise we would smolder these things like smoke dragons and pollute. This means that the minimum throttle setting is supposed to be actually pretty warm for clean burning during normal weather conditions. Then when it gets really cold and draft strength is stronger that fixed orifice that was just enough to support clean burning temperatures will now let way more combustion air in and temperatures will rise well beyond that minimum clean burn setting.
 
My cooker is going nuts right now but it's a load of very dry paper birch. I should have closed the air earlier, but 750df cook top isn't a big deal. My wife will wonder why the paint is curing again, but this is the hottest it has gotten so far. It's new to me still, like your Jotul, but now I know on dry birch that it can turn down within minutes. The firebox is settling now, but it peaked pretty high.
 
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With my temp alarm set at 650 and a blower I have to load it and leave the house, which is completely inappropriate and something I will never do. I might add heater controller to the fan to turn it on full blast at 650. I’m comfortable running it this way.
Yeah, I don’t think I would be comfortable without a way to completely choke it off in such a situation.
 
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I agree so if your draft doubles or (even more) so does your heat output. I really think the draft is the most critical component of an install that almost never gets measured and quantified. How many burn issue would be eliminated at time of install if it were measured?


By design you are not supposed to have too much control over the modern noncat. Otherwise we would smolder these things like smoke dragons and pollute. This means that the minimum throttle setting is supposed to be actually pretty warm for clean burning during normal weather conditions. Then when it gets really cold and draft strength is stronger that fixed orifice that was just enough to support clean burning temperatures will now let way more combustion air in and temperatures will rise well beyond that minimum clean burn setting.
 
I grew up with a stove that had one air control and a steel door "gasket" which as you can imagine is not all that airtight, especially once the stove is 20 years old. We used to use a roll of tinfoil and a key damper to get things under control if someone screwed it up. My grandmother taught me that you could tell proper stovetop temp by turning the lights out, and the stove should be just barely glowing by the flue collar.

Now I load my stove anytime I want with anything I want, no matter where it is in the burn cycle, and never worry about it. Go technology!
 
I agree so if your draft doubles or (even more) so does your heat output. I really think the draft is the most critical component of an install that almost never gets measured and quantified. How many burn issue would be eliminated at time of install if it were measured?
Too low or too high draft can both cause problems with fixed air inlets that most noncats have. If it’s not too hot it’s too cold and polluting. It’s mostly pretty good though.
 
This post got me thinking. If you really did have a nuclear reactor for a stove and it was 100% efficient at converting wood to energy, I figured you should be able heat your home for 20 years with about 7 round toothpicks.
 
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Yup, was cold last night. I'm up at schroon, so probably not too far from you. My load last night went up fast too, but with not as much excitement.
Or as much stack. ==c
Controlled heat, that’s more my style and the others that follow this BK thread...Load it and forget about for a LONG time.:)
That's your style, but others of us like to live life on the ragged edge. It's such a thrill when we can actually get away with it and escape unscathed. >> Or "excape," as we say in IN. ;)
Yeah, I don’t think I would be comfortable without a way to completely choke it off in such a situation.
Yeah, I need to get a failsafe control on my SIL's T5, just in case..
By design you are not supposed to have too much control over the modern noncat. Otherwise we would smolder these things like smoke dragons and pollute.
Well, we wouldn't but they would. ;)
 
Now I load my stove anytime I want with anything I want, no matter where it is in the burn cycle, and never worry about it. Go technology!

Really? Seems opposite of the standard advice that's given here. Good for you that your setup is so dialed in. Gotta love it when things work so effortlessly!
 
Not sure if this is the best idea but I've cooled mine down before by fully opening the door (slowly) and running it in "fireplace mode" for a while to let a volume of cooler air up the chimney. Once the fuel burns down and the stove mellows out I closed it back up and the temps were normal again.

Around the 5th or 6th fire on the new Jotul F45 I put the hammer down and loaded it fully with bone dry pine (10% moisture) on top of a hot coal bed to get it fully up to temp and cure the paint since I was tired of the smell. With 30+' of chimney the draft is strong and it pulled up to the mid 700F range, this was with the primary air fully closed and the secondaries going wild as you described.

1574180419543.png
 
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Really? Seems opposite of the standard advice that's given here. Good for you that your setup is so dialed in.
He's got a BK with the thermostat controlling the air, so never has to worry about a runaway stove. In fact, any cat stove can be loaded like that, and the air cut low enough so it won't be a problem.
 
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I found my IR gun yesterday. The stove top thermometer is reading about 150-200 degrees low as I suspected. Stove top temps were likely in the 700-750 F range. Too close for comfort!
 
I found my IR gun yesterday. The stove top thermometer is reading about 150-200 degrees low as I suspected. Stove top temps were likely in the 700-750 F range. Too close for comfort!
The IR will provide better guidance until you get a good thermometer. Read the flue temp 24" above the stove too. As noted, that is more meaningful.

FWIW, 700º is not too hot for this stove. When temps drop into the low digits you may be striving for this temp with each loading. We get reports of stoves going nuclear every year about this time. Then, as the owners learn more about how to run their stoves these posts die down. By January they are bragging how well they are heating the house at zero degrees. ;lol
 
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Really? Seems opposite of the standard advice that's given here. Good for you that your setup is so dialed in. Gotta love it when things work so effortlessly!
That is how I have always run my stoves. Yes I try to run full cycles but there are times I need to load partway through a load. And I have always been comfortable with my setup enough to do that.
 
Really? Seems opposite of the standard advice that's given here. Good for you that your setup is so dialed in. Gotta love it when things work so effortlessly!

I am cheating; my stove has a thermostatic air control, so I can behave badly and rely upon it to take care of things.

That said, if you are trusting the stove like that, you better have verified that your gaskets are good and everything else, including draft and thermostat, is working properly.

We have seen forum posts from people who did manage to severely overfire their BKs through poor gaskets and/or high draft, so owning a certain stove isn't a magic bullet.
 
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Really? Seems opposite of the standard advice that's given here. Good for you that your setup is so dialed in. Gotta love it when things work so effortlessly!

Really. Me too. Even when it's 5 degrees out and blowing wind. Some stove designs are way more controllable than others. Some chimney systems "the engine that drives the stove" provide way more consistent and reasonable levels of draft. This isn't just a cat stove vs. noncat vs. thermostatic draft control issue either.
 
Im not saying I follow the standard advice or need to. I can choke a fully raging fire down to a smolder with my air control. I just thought mine was odd.
 
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I’ve been wondering if you can overfire with the primary air full closed. Even with a flue that meets draft specs it seems possible.

I had it happen a few times under certain conditions. Keep a rag handy to stuff in the secondary opening in the back of the stove.
 
I kept a big foil ball to stuff into the Castine's outside air intake for this purpose. Like you I only needed it a couple of times and they were when I was experimenting and learning the stove.

Begreen, could you please post a photo or diagram of the foil ball arrangement? I feel like my Castine could benefit from that but I have the bottom and rear heat shields in place and I'm not sure about the correct air intake spots.
 
Begreen, could you please post a photo or diagram of the foil ball arrangement? I feel like my Castine could benefit from that but I have the bottom and rear heat shields in place and I'm not sure about the correct air intake spots.

If the Castine is like the Oslo . . . and I suspect it is. The air hole is located towards the very back in the center. I have both rear and bottom heat shields as well.
 
If the Castine is like the Oslo . . . and I suspect it is. The air hole is located towards the very back in the center. I have both rear and bottom heat shields as well.
Yes, that is exactly right. I sold the Castine about 11 yrs ago, so no photo possible. I'll see if the wayback machine here still has my postings from back in 2006/7 on this topic but it has been dubious since the last update.
 
Oslo, with rear heat shield, and main air intake highlighted. A quick look up of previous threads on the castine mentioned a similar setup and location
 

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I don’t have heat shields on my F400 but the primary air intake is rear center behind the ash pan. You can see hole ( top right quadrant of the photo).
 

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