Modern EPA stove runaway ?s

A runaway stove is not a chimney fire though it could cause one if your chimney is overdue for cleaning. This is mostly a modern noncat stove problem.

The fire runs away because the intake system can not be closed far enough to control the burn rate. The hotter the fire gets the stronger the draft which pulls more air through the intake which causes more fire and on and on in a spiral.

Usually it’s safe, just way hotter than the operator wants.

 

Is it really a "runaway" stove if it is just hotter than you want? To me a runaway stove is almost certainly fueled by a chimney fire...or some really weird draft event that maybe could be caused by wind direction/weather...maybe?
"Runaway" makes me think of something uncontrollable, and rapidly increasing in intensity, to the point of some eventual catastrophe...like an old Detroit diesel next to a broken gas line!

 

Makes sense. A little draft reduction or damping should eliminate the possibility. I guess its a concern if you have a very tall chimney and no way to restrict air flow. Even if safe, i wouldn't want to overheat my stove.

 

If a stove control can slow the incoming air, as well an mpd (manual pipe damper) can do the same, then surely both working together is a plus in any condition or scenario.

I can think of scenarios where they are not necessary, but even at that I can’t think of a single scenario or set-up where I wouldn’t install one just as a back-up. That is, NOT a single person alive can talk me out of putting one in place. I don’t have to use it, but it is there if I need it...modern stove or not.

It’s been said that the manual pipe damper was the first stove control and that is true (actually it was the amount of wood that was first), and to use it in that manor can certainly work, but when used together with actual stove controls the pipe damper now does more than one thing. It does more than just slowing the incoming air. It can be fully closed and increase the stove temp and not change the actual draft at all. I’ve done it and with a manometer to prove it.

We shouldn’t forget it is on the other side of the fire. If you crank up the air controls on the stove and close the damper more than one thing happens. They just don’t cancel each other out like some might think. Now it’s trying to slow the draft down but also allowing the stove to build heat in the stove and to a lesser degree in the pipe...which continues build the draft to a point...called the sweet spot. I can’t tell you where that is...you just have to find it.

 

Ding ding ding....

We have a winner!!!!!

 

I like this explanation.

It’s anything that makes you uncomfortable from a norm.

I have seen 3 nice splits of oak seasoned 10-15 years on a bed of coals absolutely make a stove got nuclear in a hurry on a -27F night with some wind....

...and is precisely why I have never, and will never, load a stove clear full. I see no reason with my old pre-epa stove let alone a new modern catalyst stove.

A forum member on another forum is local to me. He just bought a used BK King model and put a brand new cat in it. He sent me a picture of a milk crate that had 5 medium splits in it standing upright. The top of the wood he covered with his hand...that’s the size of those 5 splits.

Now I have heard the talk/hype on forums about BK stoves. I will tell you first hand that just being on the outside looking in it is hard to process some of what is written about these stoves...BUT...

...I seen first hand pictures that those splits loaded on a bed of coals produced a 24 hr burn and afterwards he sent me a picture with 3 of the 5 splits (though a different load of 5 splits) left and two of them hadn’t even charred on the ends yet... over half of a couple pieces still looked like he just threw them in the stove. If I hadn’t seen the picture I wouldn’t have believed it.

Edit: He just gave me permission to post the picture. Not sure he is a member here, but he is on hearth.

Edit:The 5 pieces he showed me may not have been the same as in the picture below.

The point is you have a metal box inside your home with a fire in it. There are times when you can load it fully, but it isn’t at all necessary with these long burn time stoves and it isn’t needed of you’re the type that likes to monitor the stove.

Again, NOT saying you shouldn’t, I am saying most times I would not load a stove full. That keeps me monitoring the stove. I’m afraid I would get lazy on a 40 hour + burn. Might be fun to try being lazy though. LOL!

 

To say I am impressed is an understatement. Being he is close to me gives me a better understanding of what these are capable of in my own home.

NOTE:
The above 2 pictures do not belong to me, but I was given permission to post them.

 

A runaway wood stove . Is Not a chimney fire, as High beam said.
We get weather systems that can really cause a fire to really burn in a stove Hot.

Short of throwing pitchers of water on the fire and slamming the stove door. There sometimes isn't any way to get the fire under control before it catches the house on fire.

Air tight stoves solve that problem by being able to shut the air off to the fire.

 

Some hump day humor

 

My stove will be uncontrollable with certain wind conditions. It doesn't happen very often but when it does the pipe thermometer gets well into the red zone. Those times I've been glad I was home and had a manual stove pipe damper. Closing the damper gets it under control in short order. I've had the stove 17 years and I'm guessing it has happened maybe 10 times.

 

theburtman, these wind conditions that make the stove uncontrollable....are they usually drastic conditions....really high sustained or gusts, or is it from a certain direction? Are they usually forecast, or do they come up unpredicted and catch you by surprise? If they are forecast, do you take precautions by loading the stove differently?

 

It seemed to happen when the wind was very strong out of the northwest. I would have loaded the stove to either go to bed or go to work and closed the draft but it would not slow down until I closed the stove pipe damper. It was like it was sucking the heat up the chimney. As far as forecasting, we get strong NW wind a lot so it's not unusual. I'm guessing barometric pressure, strong wind, and cold temperatures combined were just right and caused this these few times. So to answer your question, I watch the weather regularly but nothing tipped me off this was coming any more than the hundreds of times we've had strong NW wind. I hope this all made sense and answered your questions.

 

I've burned probably 25 different stoves in the last 40 years . Maybe more. Some of them were just looking for a chance to take off it seemed. Others were easy pie to control. Had a Solar Key stove back in the 80s that was very good. Also had a Fisher that was good.
I haven't had very good success with some stove pipe dampers. They are great for smoking up a house ( when someone forgets to open the damper ) but they haven't made a huge difference in corkin down the fire when it really wanted to go.

 

All that said, I do think I want to get a cat stove for the long burn times . Mostly for when we go to town or something. And of course have shed seasoned wood. Birch when ever I can get it.
But I want to have a lot of head knowledge about the stove before I plunk down thousands of dollars on one.
I don't deal with buyer's remorse very well.

 

I have an Ideal Steel, installed in 2014 on a masonry chimney, 8" X 8" in a two story house. My stove is on the first floor and so there was not all that much chimney above the stove. Control was no problem, and especially any type of [non throttleable] condition just did not happen. Just not enough draft to be troublesome. Fast forward a few years and the house now has a much taller chimney that is stainless steel inner and outer, with 1" of insulation in-between the SS layers. A very efficient and easy to heat chimney compared to the original oversized, masonry, far shorter chimney. So now the chimney drafts really well but I am finding that with a hot fire, shutting the draft all the way down (such as it shuts down, not all the way to -0-) does not seem to be slowing the burn rate as I watch. Not a runaway stove by any means but the lack of ability to slow the burn rate, which I find worrying. So I installed a stove pipe damper, and when it is cold out and the stove is burning fairly hot, shutting down the draft as well as the key damper will have an immediate affect on the stove and back it down from the current burn state. After toying with the flue damper for a bit I have found it is most useful when it is very cold outside and the chimney is drawing hard on the stove. Otherwise I leave it open for all normal use although slightly closing it will increase the efficiency of the stove (higher stove top temps., lower flue exit temps.).

I guess I would look at it this way: if you install a key flue damper for something like $20, you can leave it open and ignore it for all time. If on any occasion you do not feel you have sufficient control of your stove, you can close the damper down all the way to horizontal which is not closed but greatly reduced regarding flue flow. So if you have one installed, you can use it as you feel the need. If you do not have one, it is simply not an option. Personally I am a big fan of control solutions if they can be ignored or bypassed when not needed, and a flue damper is exactly that. So in the end, I am not at all sure I need one but I am glad to have it and the ability to further control a stove without any downside that I can see.

All of this is entirely about self- interest: I sleep in the building that the wood stove heats and I would rather like to think I can control, of if needed, shut it down at will without ever feeling the stove is uncontrollable.

YMMV

 

We had our first wind storm experience with our new Lopi a couple weeks ago. It was full of oak and started to take off. I was concerned because the damper didn't bring the air down like I was used to with our old stove. It eventually came down but I sure learned something!

 

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Makes sense. Thanks for the comments. A control to keep the draft optimal and as a big slowdown if needed