Honest question - how would you stop runaway Jotul?

[Soundchasm]

So far as I know my 550 insert can't be completely shut off for intake air. 99% of the time I'm trying to get it to burn, but I had one sobering occurrence. Don't worry, nothing happened.

It was cold, below 20, maybe 10. I had some dry cherry which always burns well. Air flow open, things get going. Cut the air halfway, need to leave in a few minutes.

High speed wind comes HOWLING (40 mph?). I cut the air all the way back. Fire is growing. Wind continues to pick up, fire gains intensity. I've finally got nice secondaries but I don't really WANT them! ;-)

I poked around in there and destroyed the layout of the fire, and that got it back to predictable and I could leave.

My philosophy is that if the firebox or chimney are too hot, open the door and let in cool air and temps come right down (at least 100 degrees just from opening a door). Once, a probably chimney fire in my old downstairs unit, I cut the air completely to kill the fire if there was one. That was before I understood creosote, wet wood, dry wood, etc. I changed everything to prevent that from ever happening again.

Anyway, is the only strategy for stopping a runaway Jotul to have a spray bottle of water nearby to gently mist the combustion and knock it back?

I'll believe that it's theoretically possible that high-speed cold winds could super-charge that unit, and if I did nothing, it could possibly get too hot.

Thanks,
Greg

 

[Prof]

I've had a similar experience where crazy winds keep the fire going even when the stove is shut down. This is why I have a key damper in the pipe. I've only needed it once in 2 years, but I was glad to have it. I think of it as $7 fire insurance. I also keep a bag of ABC fire extinguisher stuff in the stove room in the event that there is a chimney fire. If a chimney fire starts, I'd throw it on the fire in hopes of suppressing it while I call 911. Fortunately with dry wood, an EPA stove, and proper burning techniques I really don't get much creosote (maybe 16 ounces a year). I think how lucky I was in my smoke dragon days before finding this forum--no pipe thermometer, marginal wood, and doing plenty of things wrong. But hey--I never burned pine ;-)

 

[Ashful]

A pair of magnets placed over the air intake holes, under the stove. No air = no fire.

This was bro. Bart's invention, I think, although he's using them to partially close off the holes (always kept in place) on a somewhat unruly stove.

Do note the curie temperature of your magnets! They won't stick above that temp. Some are as low as 130C (266F), but most are above to 700F.

 

[webby3650]

I've finally got nice secondaries but I don't really WANT them! ;-

Why didn't you want nice secondary combustion? How hot was the insert when it had the run away fire?

 

[Grisu]

What kind of chimney cap do you have? Maybe a different type would solve a lot of problems with runaway stoves due to high winds. One possibility could be this one here:
http://www.chimneycaps.com/Final images/sts1.pdf

 

[mellow]

Some have reported wet newspaper will work to help calm down a runaway fire, keep it in a zip lock bag near the stove. With an insert having a damper is about impossible to install. Knowing where the main and secondary air inlets are located is a plus in case you need to block them, Roxul would work in a pinch if you have a piece pre-cut out you can stuff in the air hole.

 

[webby3650]

Just because the fire became more active than normal doesn't mean that any action on your part is required. What would really matter is the temperature of the stove when this happened. How hot was it?

 

[begreen]

Why didn't you want nice secondary combustion? How hot was the insert when it had the run away fire?

I have the same question. At this point I'm not sure this is a runaway. A modern EPA stove is not supposed to do the low smolder at the initial stage of the burn. That is highly polluting and can lead to creosote buildup. Is there a thermometer on the stove and if so, what kind of temps were you seeing at that point? What is your normal burn cycle procedure?

 

[Researcher1]

throw some ashes on the fire, they will suppress it quickly

 

[stovelark]

This sounds like a normal Jotul at work. Remember when initial fire is going, air open at max, big flames and little secondary combustion happening because max airflow through the stove and up the chimney. When air is cutdown, air through the stove slows and more secondary air is pulled in, and more sec comb occurs. Air staying in the stove longer too, which builds temperature. That is the design achievement, sounds like she was operating normally.

 

[Soundchasm]

Thank you for all the responses. I'll try to hit them all.
I'm always trying to get secondaries, and I was beginning to think they were a myth until I got some dry wood. But I had minimized the air yet the fire continued to grow. Every other time I had done this the fire slowly loses steam, but this time I was sensing that I was no longer the driver of the vehicle!

I didn't get my IR gun to take temps (can't say if i had one then), so I don't know if it was actually hot or not. It was rattling me to realize that I don't know how many places (or where) this stove gets air from, and at least in theory, I can't starve it 100%.

My wife has thrown out the Post-It note where I kept my temp records. ;-( All that data, gone... I aim the IR dot inside the blower vents on the top of the stove, and track the temps back to the round pipe, and shoot that too. I've probably never gotten to 500. I think I've never been able to run the stove as intended, generally seeing 450 as a high point. I'm sure there's plenty of headroom left. A buddy had mentioned the magnet trick, but upstairs it's an insert.

I have finally gotten ahead of the wood curve, and I'll have dry wood this winter. Got a MM as well. I load the stove with some 2" limbs N/S, then put a couple 3" splits E/W on the top, and ignite from bottom center. After 45 minutes I have enough coals to add splits with a little technique. I then waffle between adding wood as soon as it's possible or letting a burn mature and then reloading.

This stove does have a round chimney cap. Don't think there's anything elaborate in there.

Had I been able to stay and monitor the thing, I'm sure it would have been fine, but it did get to me that my strategy for slowing the stove was being overridden by outside wind velocity.

 

[webby3650]

It sounds completely normal to me. This is common to hear from people that have been burning wet wood or an old stove without glass. When you can see the fire or when you finaly get ahold of dry wood, the difference is unbelievable!

 

[begreen]

Agreed. The temp will rise as the secondaries kick in, that is by design. If you want to slow down the fire, when refueling add larger splits and pack the stove tightly

 

[Backwoods Savage]

Thank you for all the responses. I'll try to hit them all.
I'm always trying to get secondaries, and I was beginning to think they were a myth until I got some dry wood. But I had minimized the air yet the fire continued to grow. Every other time I had done this the fire slowly loses steam, but this time I was sensing that I was no longer the driver of the vehicle!

I didn't get my IR gun to take temps (can't say if i had one then), so I don't know if it was actually hot or not. It was rattling me to realize that I don't know how many places (or where) this stove gets air from, and at least in theory, I can't starve it 100%.

My wife has thrown out the Post-It note where I kept my temp records. ;-( All that data, gone... I aim the IR dot inside the blower vents on the top of the stove, and track the temps back to the round pipe, and shoot that too. I've probably never gotten to 500. I think I've never been able to run the stove as intended, generally seeing 450 as a high point. I'm sure there's plenty of headroom left. A buddy had mentioned the magnet trick, but upstairs it's an insert.

I have finally gotten ahead of the wood curve, and I'll have dry wood this winter. Got a MM as well. I load the stove with some 2" limbs N/S, then put a couple 3" splits E/W on the top, and ignite from bottom center. After 45 minutes I have enough coals to add splits with a little technique. I then waffle between adding wood as soon as it's possible or letting a burn mature and then reloading.

This stove does have a round chimney cap. Don't think there's anything elaborate in there.

Had I been able to stay and monitor the thing, I'm sure it would have been fine, but it did get to me that my strategy for slowing the stove was being overridden by outside wind velocity.

Looks like most of this has been covered well. I'll add that 450 is a long ways from the point where you should begin to feel there is a warning about something bad happening. Most stoves can withstand 700 degrees very well and most of the fires we have during the winter months will take our stove top temperature to 650+. At 450, we aren't too far from wanting to add some wood.

On you lighting procedure you could possibly improve that a bit. First, I never try to light a fire using rounds, even if they are only 2" limbs. I always use splits when starting a fire. Our procedure is to lay 2 small splits on the bottom of the stove and we form a slight Vee with those 2 splits. We then lay 1/4 of a Super Cedar (a sample can be had for the asking) and light it immediately. At this point we might or might not add a couple pieces of kindling (optional). Then we add 2 or 3 splits on top of this. If they are small splits then I might add 4 or 5. We then close the firebox door and let the fire do its thing. Naturally the draft is full open. Once the fire gets going pretty good we cut the air to 50% or possible even more. Usually within 10-15 minutes we will cut the air a bit more. With our stove we aim at 250 degree stove top. Once this is attained, we cut the draft to about 25% or less open and we also have a catalyst so we then close the bypass too. Then we can forget the stove for hours.

I've never understood why folks seem to feel the need to build a coal bed before they add much wood. For sure the coal bed helps but when starting a cold stove, forget it. You are making the coal bed as the wood is burning. We do not go back and add wood say in 1/2 hour after some coals are built up. We simply build the fire and let it burn. So far this has worked well with us for 50 years or so.

 

[webby3650]

I've never understood why folks seem to feel the need to build a coal bed before they add much wood. For sure the coal bed helps but when starting a cold stove, forget it. You are making the coal bed as the wood is burning. We do not go back and add wood say in 1/2 hour after some coals are built up. We simply build the fire and let it burn.

I couldn't agree more! Since I started using those little alcohol starters, I don't even use kindlin! But that also takes some real dry wood!

 

[Soundchasm]

I guess in real estate it's location, location, location. For firewood, it must be dry, dry, dry. To conclude my original thought, I don't believe it's possible to 100% cut the air to the Jotul. I think cold temps and high winds could drop the outside pressure and start to supercharge the firebox despite the air control being "closed". If it happens again, I'll monitor the temps and if they approach 700, I now have some methods to cool down the fire.

On my ancient downstairs freestanding model, I can smell 500 degrees almost exactly. It's a hot-metal smell. And the room temp will rise to 80+ degrees very quickly. At 600, it's a little too interesting for me. It may be perfectly safe, but I can't vouch for the first 30 years of the stove's life, although it's cleaned/inspected annually with double wall SS liner all the way up.

With the insert, it's all new information to me. If I had a skilled operator to learn from, I'd be miles ahead by now. This forum comes close, but nothing beats hands-on. I don't want my ambition to outpace my skill level in this arena.

 

[BrotherBart]

On runaways I swing the doors wide open to break the vacuum in the secondary tubes and cool the thing down. Takes guts to do it but it works. The in-rush of cold room air settles things down pretty fast. Not good for the heart though. And if you close the doors too soon it is off to the races again.

 

[webby3650]

I can smell 500 degrees almost exactly. It's a hot-metal smell.

No, that's more like a hot dust smell! If it was ran continuously, it wouldn't have any smell at 500. An old steel stove can run up to 800-900 without any trouble. Then it's really rocking!

 

[webby3650]

On runaways I swing the doors wide open to break the vacuum in the secondary tubes and cool the thing down. Takes guts to do it but it works. The in-rush of cold room air settles things down pretty fast. Not good for the heart though. And if you close the doors too soon it is off to the races again.

This happened with my Fisher. I got up at 2 A.M. to a smell of a hot stove, I came into the living room and the entire stove was glowing red! I opened the door for a few and all was well again. I added a gasket to the door channel, it fixed the problem.

 

[BrotherBart]

With a free standing stove you can block off the secondary air intake but with an insert you ain't gonna get to it. And getting to it on the 30-NC buried in the fireplace is burned arms and face cheeks just waiting to happen. I have done it but opening the door just works better and safer. Just be aware that embers can pop out.

 

[Grisu]

I guess in real estate it's location, location, location. For firewood, it must be dry, dry, dry. To conclude my original thought, I don't believe it's possible to 100% cut the air to the Jotul. I think cold temps and high winds could drop the outside pressure and start to supercharge the firebox despite the air control being "closed". If it happens again, I'll monitor the temps and if they approach 700, I now have some methods to cool down the fire.

With the insert, it's all new information to me. If I had a skilled operator to learn from, I'd be miles ahead by now. This forum comes close, but nothing beats hands-on. I don't want my ambition to outpace my skill level in this arena.

One idea: Next winter take off the surround for a few days. Get the stove up to temp (700 F at the top) and search with your IR for the hottest spot in the usually accessible front. (With my PE Super its in the center above the door.) Take note of the temp difference between top and the point in the front. Do that a few times. When you put the surround back on you have now an idea when you measure e. g. 500 F in the front that means x F stove top. I have about a 100 F differential that means I try to get my insert to about 550 F in the front with maxing it out at 600 F which should mean the insert runs between 650 and 700 F.

 

[Soundchasm]

No, that's more like a hot dust smell! If it was ran continuously, it wouldn't have any smell at 500. An old steel stove can run up to 800-900 without any trouble. Then it's really rocking!

I don't doubt you for a second! I've had the top of this up to 650, and you're telling me I'm closer to Karen Carpenter than John Bonham?? Gawd, the flash really makes the stove look ugly. But it's beautiful in January.

 

[webby3650]

I don't doubt you for a second! I've had the top of this up to 650, and you're telling me I'm closer to Karen Carpenter than John Bonham?? Gawd, the flash really makes the stove look ugly. But it's beautiful in January.

I'm not sure what you're trying to say, but ya, that's pretty much the deal!
Sorry, I couldn't resist. It was a joe dirt quote.

 

[Soundchasm]

Here are some shots of where I'm getting my temps from on the Jotul. I'm definitely sure I got 450-500 there on these aim-points. So I'm still a couple hundred degrees away from concern and 100 away from doing normal work? I did indeed like the hot dust thing. Breaking in the Jotul I was able to smell every new temp threshold.

 

[Grisu]

Here are some shots of where I'm getting my temps from on the Jotul. I'm definitely sure I got 450-500 there on these aim-points. So I'm still a couple hundred degrees away from concern and 100 away from doing normal work? I did indeed like the hot dust thing. Breaking in the Jotul I was able to smell every new temp threshold.

Maybe someone else knows what the temp differential between front and top is for the Jotul. May be quite a bit different than for my PE Super. The opening is quite a bit larger for me so I can laser in and measure the top as well as the flue collar. That is how I found out about the difference between temp on the top versus front. I now use the front temp almost exclusively because it is much easier to measure.