Osburn runaway?

[Grisu]

I only know it's the way mine works. I'm not after an argument or anything, and I'm the first to admit my limited experience, but I'm used to being able to fairly quickly stop any temperature rise that I'm experiencing at any temperature I want. I've always been able to do that and I've done it over a wide range of situations. I can control the temp of my stove at any temperature that I choose regardless of the load. If I want to stop my temps at 300, I can. He can't. I just know that I'd be very uncomfortable if I couldn't.

Your stove then behaves very differently than mine. When I burn a good load of dry pine in a hot stove I have the air closed usually at 350 to 400 F. Nevertheless, the stove keeps climbing to about 700 F. I learned from experience that I had to close the air that early. In fact, the most valuable lesson I learned is to look at the fire and not at the temps to decide when to cut down the air more. I never had it beyond 750 F so I am sure I am ok.

 

[BrowningBAR]

I only know it's the way mine works. I'm not after an argument or anything, and I'm the first to admit my limited experience, but I'm used to being able to fairly quickly stop any temperature rise that I'm experiencing at any temperature I want. I've always been able to do that and I've done it over a wide range of situations. I can control the temp of my stove at any temperature that I choose regardless of the load. If I want to stop my temps at 300, I can. But he can't. I just know that I'd be very uncomfortable if I couldn't.

The maximum temps that the OP has been experiencing so far have been moderate, but that's been with only a very small load because he's been afraid to load it up.

I don't like the idea of messing with air controls. But I can understand his concern. With greater than 30' of flue, his draft must be pretty strong and I'd be a bit concerned about loading to the gills, too.

Please do not take my comments as an argument. I am simply trying to communicate firmly that OP has not experienced anything troubling, yet.

I have three chucks of wood in the 30 right now. The air is closed off and the stove top is sitting at 640. Nothing wrong with that.

 

[Sprinter]

I am simply trying to communicate firmly that OP has not experienced anything troubling, yet.

I agree with that. I'm really just saying that I can understand the OP's reluctance to load 'er up with a 30+ foot flue and I think that's what is the issue here. I guess the only way to know if he has a real problem or not is to do just that. Four or five splits won't tell the tale.

When I burn a good load of dry pine in a hot stove I have the air closed usually at 350 to 400 F.

Me too, even at 300, but not quite completely closed. I can stop it at 500 if I want to, but I usually don't. I can let it sail if I want. Of course, so much depends on the wood density and load. Your stove and mine should have pretty similar characteristics if given the same installation and fuel.

My flue is only 13' and that probably makes a difference in control. Draft is everything. These EPA stoves are designed around a standard built on moderate draft. The so-called Florida Bungalow Syndrome. That's why I've become a little concerned for the OP although I wasn't at first.

 

[Bagelboy]

I know in the original post, I started the conversation about temperature. This was something to show my wife because I knew the responses from everyone would be not to worry. I figured this would be to put her at ease. I know from my Jotul, that I can get temperatures up pretty high (to be honest, up til now, I had never owned a temperature gauge). Don't forget, when I say I hover around 400 degrees, that's with a stovetop thermometer and the fan on the insert running, so those temps are probably higher. The thing that I am concerned about is controlling the fire once the air control is shut down. Once completely shut, the flames are still out of control, something not experienced in my Jotul. This is why I am concerned.

 

[Bagelboy]

From some of the posters here, they suggest I wait til the stove gets down to around 250 degrees and then reload. If I reload, putting in a full load, keeping an eye on the air control and scaling it back, the fire will approach 600 degrees. What happens when I have to leave for dinner, or a day out and the box has to be reloaded and it's 350 or 400 degrees? It just seems there should be a way to better control the rate of burn.

 

[FyreBug]

Before you start modifying the stove, spend more time with it. Every winter there are many threads created about "my stove is running away from me", when in actuality, the stove is operating correctly and it is user error or user expectations.

600 degrees is no where near a runaway. That is its prime operating temperature. You reloaded the stove when it was 400 degrees. This has the tendency to make a stove shoot up in temp quickly. When doing this, you should plan accordingly.

Start to worry when the stove gets above 750. But, even then, the stove will most likely settle.

If you start modifying the stove before you understand how it should actually run, you will only create problems for yourself in the future. I ran a pre-EPA Vigilant for a few years. There is a huge difference between a pre-EPA stove and a modern stove. Modern stoves are designed so you can not completely shut them down. This is done so for a variety of reasons. Once you learn more about your stove, maybe you will decide to restrict the secondary air to alter the burn. But, doing so now, will only cause you to try to run a modern stove like a pre-EPA stove, and odds are it will be a bit of a mess.

Modern Stove Burning or: How I Learned to Stop Worrying and Love A Hot Stove

+1 that...

This is a hobby forum where folks love to discuss stoves and tweaks and stuff. But for the most part, there is really no need to monitor the steel temp of an insert. However, It's really useful to monitor flue temps on a stove, something that is difficult to accomplish on an insert.

A 'runaway' insert is a rare thing. It's an indication of overdraft and/or burning some weird fuel. You'll notice an overfire when the burn tubes start sagging. Other than that there is not need to worry and stick ugly thermometers on otherwise nice looking inserts.

 

[Bagelboy]

This is my stove as I leave for work. 500 degrees, loaded, air control all the way in. Without the plug I put in the air hole I found, this would be engulfed in flames. As of right now, this is the most I can shut it down, but it is a great improvement from when I plugged the hole!

 

[BrowningBAR]

View attachment 118201 This is my stove as I leave for work. 500 degrees, loaded, air control all the way in. Without the plug I put in the air hole I found, this would be engulfed in flames. As of right now, this is the most I can shut it down, but it is a great improvement from when I plugged the hole!

Again, the stove should be north of 600. That photo almost looks like it has lazy flame with no secondary combustion taking place. I would not be surprised if there is smoke coming from your chimney. You are not operating the stove correctly.

 

[Bagelboy]

so then what's wrong?

 

[BrowningBAR]

so then what's wrong?

I thought you had the air hole plugged. I read it wrong. I apologize.

 

[BrowningBAR]

It looks like you shut it down too quickly possibly out of fear or this if further along the burn cycle. How long was that burn in place? What was the peak temp? Peak temp should be around 650 (maybe a little less, maybe a little more) and then the temp will slowly drop over the course of the burn.

Again, I apologize for the confusing first post as I thought you plugged the hole again.

 

[Bagelboy]

You were correct, BrowningBar, the hole is plugged. Without plugging it, this would be a lot more intense! Now without sounding foolish, why would the hole plugged make this a better situation?

 

[BrowningBAR]

Wait. In that pic, is the hole plugged or not?

If it is plugged, unplug it. If it is not plugged, it seems like you might have shut the air down too quickly or that burn is further along in the cycle.

 

[Bagelboy]

It is plugged.

 

[FyreBug]

Hi Bagelboy, just as a suggestion get back the stove in the condition when you installed it. (no holes plugged). Then tell us step by step what is your fire starting procedure, what is the humidity of your wood in % (get a cheap moisture meter), then show us how much wood you put in there, when you start dialing down the unit etc... Better yet post pics or videos. At the end of the day, I have a suspicion your stove works perfectly as designed; you may just need to get used to its workings.

 

[Bagelboy]

Sounds good! I realize this is a pain for all involved. I will post tonight, and prior to firing up, I will remove the bolt from the air hole and start all over. Thanks for everyone's concerns and patience!

 

[HatboroPaul]

Sounds good! I realize this is a pain for all involved. I will post tonight, and prior to firing up, I will remove the bolt from the air hole and start all over. Thanks for everyone's concerns and patience!

View attachment 118170 This is my insert, with the air control closed all the way, and the bolt I installed into the air hole opening. It is under control, and I don't have a runaway firebox. Prior to this, this box would be lit up!

Just a thought, when my 2000 was installed the door was not that tight. it was letting more air sneak in thru the seal. I noticed because with the light off I could see light thru the top. It was a simple adjustment. Have you checked how tight your door closes? Perhaps this is the air that needs to be cut off?

 

[Bagelboy]

Seems really tight, in fact, when the stove is cold, it needs a little xtra to close it.

 

[Bagelboy]

OK, so tonight I came home to coals at 4 PM and the stove at 200 degrees.After filling it with 5 pieces, it goes to 400 degrees. At this point, it's 4:30, andI have the air control cut back to 50%. Shut the air down all the way.After that, I throw in 2 more pieces and the stove goes to 500. It hovers here for a while and starts to come down to 400. At 7pm, it's around 350. So, where do I go from here? Reload, let it come down a little, or pack it with 1 or 2 pieces? Don't forget, these temps are with the fan blowing and a cheap stovepipe thermometer sitting on the insert!

 

[Grisu]

Unless you are cold let the coals burn down some more. Would not hurt to turn off the blower. Then load it up full for the night. Take a look at this thread for good tips on how to run a modern woodstove most efficiently:
https://www.hearth.com/talk/threads/fireplace-insert-burn-techniques-best-practices.117055/

 

[BrowningBAR]

OK, so tonight I came home to coals at 4 PM and the stove at 200 degrees.After filling it with 5 pieces, it goes to 400 degrees. At this point, it's 4:30, andI have the air control cut back to 50%. Shut the air down all the way.After that, I throw in 2 more pieces and the stove goes to 500. It hovers here for a while and starts to come down to 400. At 7pm, it's around 350.So, where do I go from here? Reload, let it come down a little, or pack it with 1 or 2 pieces? Don't forget, these temps are with the fan blowing and a cheap stovepipe thermometer sitting on the insert!

Why are you adding more wood an hour into a burn? Why are you adding wood after you have the air closed down?

 

[Bagelboy]

Because I was trying to increase the temperature of the stove. It was at 400, and my house was 68. Putting more wood in brought the stove temp to 500 and my house to 70.

 

[BrowningBAR]

Because I was trying to increase the temperature of the stove. It was at 400, and my house was 68. Putting more wood in brought the stove temp to 500 and my house to 70.

This seems odd. I can get three chunks of wood to 700 degrees on my 30NC. You should be able too do the same. I think you are cutting the air WAY to quickly because you are afraid of a "runaway."

 

[Grisu]

Because I was trying to increase the temperature of the stove. It was at 400, and my house was 68. Putting more wood in brought the stove temp to 500 and my house to 70.

I don't think the heat was due to the additional wood but more cutting down the air. Leaving it open 50% means a lot goes up the flue.

When you come home to a barely warm stove do the following:
Rake the coals to the front. Put some smaller and medium size splits on the coals until the firebox is about half full. Wait until most of the wood has caught fire with the door open (Little trick: If the wood is slow to catch fire and you have good draft, almost close the door and the air rushing in will act as a bellow. Once you have a fire, open it up a little bit again to give it more air.) Close door, wait a few minutes with air fully open until wood is engulfed. Start closing down air maybe by a quarter until flames become "lazy". Wait a few minutes until flames are more vigorous again. Close about another quarter and so on. At the end, leave air open somewhere in the 10% to 20% range. You should have some primary fire and secondaries. Temp should be at least 500 F after maybe 15 min. Burn down the load for one hour or two until you have nice coals.

For an overnight reload: Essentially do the same as above but load the stove full with medium to large splits, cut down the air sooner (shorter steps) and have the air completely or almost completely closed at the end. Again, stove temp should be above 500 F. Most of the fire should be secondaries.

 

[FyreBug]

Hi Bagelboy, we dont recommend multiple loading of wood during a combustion cycle. I pm'd you a document that shows some of the basic principles of wood burning.

We hired one of the top industry guy - John Gulland - to write the 'definitive' guide to how to burn wood. It's part of our new manuals and eventually will be ported to our other manuals.

For those of you that would like to read it, you can download the instruction manual for the Osburn Matrix for example and there's quite a bit of info on there. http://www.osburn-mfg.com/upload/documents/manuels/45593A_20-11-2013.pdf