Dealing with overfire

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fdjm

New Member
Jan 25, 2022
3
Southern Ontario
I've read the handful of threads about this, and the consensus seems to be "open the door" when the fire gets too hot too quickly. But here I am asking about it anyways, as my experience with that was not too pleasant!

Context: I've only had our stove for two weeks, and am still getting used to its quirks, how the re-load cycles work, etc. Thanks very much to this forum for all I've learned thus far.

The stove is small (Drolet Deco Nano, ~1.6cu ft firebox) that's connected to an ICC double-wall Excel chimney. I don't have a flue thermo but I do have an Imperial magnetic thermometer on the top of the stove right near the flue collar. When burning dry Ash/Maple, I see it go up into ~650-700F range for 15-20 minutes at the "height" of the burn, then settle in near 550F or so, and the secondary burn is excellent with no smoke out of the chimney, etc.

Today, I raked the (still red hot) coals while the stove was around 500F, and put two ~4x4" dry Ash splits and one larger ~3x6" split on top. Closed the door and turned the air intake down as I normally would (maybe 3-5 min open all the way then back it down to half-open; half-open for 10 minutes or so, then all the way closed). The temp kept creeping up and up even with the air intake all the way closed, until the stove was around 750F. I am used to the "pinging" noises of the flue expanding/contracting, but I could tell the temp was still going up pretty quickly. So as a "worst case scenario" test to see how rapidly the temp would reduce, I opened the door all the way.

The opposite of what I thought would happen, happened: within two minutes, the stovetop thermo was off the charts (roughly 900-1000F), smoke was coming from the flue pipe (presumably from the paint getting hit with temps it hadn't seen yet), and the stickers were melting off of it. I opened every door and window in the house and got my fire extinguisher, hoping I wouldn't have to explain to the neighbours that "yes, we did just get this stove installed two weeks ago, and yes, it did burn our house down."

Within 10-15 minutes, STT was back to 650 or so and my heart rate slowly went down. I know the pipe is rated to "3 x 30 maximum 2100F", but, whew.

My question is: what did I do wrong here? When temps are reaching ~800F or so, should I just have left the air intake all the way closed and let it burn down? Is opening the door all the way NOT the way to cool the stove down rapidly? What kind of damage did I potentially just do?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
I've read the handful of threads about this, and the consensus seems to be "open the door" when the fire gets too hot too quickly. But here I am asking about it anyways, as my experience with that was not too pleasant!

Context: I've only had our stove for two weeks, and am still getting used to its quirks, how the re-load cycles work, etc. Thanks very much to this forum for all I've learned thus far.

The stove is small (Drolet Deco Nano, ~1.6cu ft firebox) that's connected to an ICC double-wall Excel chimney. I don't have a flue thermo but I do have an Imperial magnetic thermometer on the top of the stove right near the flue collar. When burning dry Ash/Maple, I see it go up into ~650-700F range for 15-20 minutes at the "height" of the burn, then settle in near 550F or so, and the secondary burn is excellent with no smoke out of the chimney, etc.

Today, I raked the (still red hot) coals while the stove was around 500F, and put two ~4x4" dry Ash splits and one larger ~3x6" split on top. Closed the door and turned the air intake down as I normally would (maybe 3-5 min open all the way then back it down to half-open; half-open for 10 minutes or so, then all the way closed). The temp kept creeping up and up even with the air intake all the way closed, until the stove was around 750F. I am used to the "pinging" noises of the flue expanding/contracting, but I could tell the temp was still going up pretty quickly. So as a "worst case scenario" test to see how rapidly the temp would reduce, I opened the door all the way.

The opposite of what I thought would happen, happened: within two minutes, the stovetop thermo was off the charts (roughly 900-1000F), smoke was coming from the flue pipe (presumably from the paint getting hit with temps it hadn't seen yet), and the stickers were melting off of it. I opened every door and window in the house and got my fire extinguisher, hoping I wouldn't have to explain to the neighbours that "yes, we did just get this stove installed two weeks ago, and yes, it did burn our house down."

Within 10-15 minutes, STT was back to 650 or so and my heart rate slowly went down. I know the pipe is rated to "3 x 30 maximum 2100F", but, whew.

My question is: what did I do wrong here? When temps are reaching ~800F or so, should I just have left the air intake all the way closed and let it burn down? Is opening the door all the way NOT the way to cool the stove down rapidly? What kind of damage did I potentially just do?
I wouldn't worry about it at all until you get past 800. But to bring the temp down quickly you open the door for 30 seconds or so then close it. Repeat as many times as nessecary. How tall is the flue and do you have a pipe damper?

And generally loading a stove that is already 500 is asking for trouble. You certainly don't want to open the air all the way if you do.
 
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Hap Shaughnessy

New Member
Nov 30, 2021
22
Vaughn Washington
Just in my own experience I had problems with my secondary burn running too fast and hot resulting in undesirable stove top temps. I run DuraVent pipe so it was a simple switch of a non damper stove top adaptor to one with a damper installed. In specific DuraVent part #6DVL-ADWD. Made a night and day difference. When temps start to rise even with the air shut down the damper can be closed however much needed and if you need to stall the temps close it all the way. It still lets some exhaust out but will choke the fire down resulting in temps to drop. This is once again just my own experience.
 

fdjm

New Member
Jan 25, 2022
3
Southern Ontario
Ah, so it was the "closing the door" after 30 seconds that I clearly missed out on. I just left it wide open. I feel like an idiot, but this thread was the one I read and I either missed that part, or it isn't in there. Regardless, thank you.

Flue is not tall - I don't know exact height but it's a 36" or so tall stove that connects to a 90" ceiling with a short bend. We're just in a bungalow with a shallow roof, so the chimney is not that tall. I don't have a damper on the pipe.

Thanks for the help.
 

EbS-P

Minister of Fire
Jan 19, 2019
2,398
SE North Carolina
I've read the handful of threads about this, and the consensus seems to be "open the door" when the fire gets too hot too quickly. But here I am asking about it anyways, as my experience with that was not too pleasant!

Context: I've only had our stove for two weeks, and am still getting used to its quirks, how the re-load cycles work, etc. Thanks very much to this forum for all I've learned thus far.

The stove is small (Drolet Deco Nano, ~1.6cu ft firebox) that's connected to an ICC double-wall Excel chimney. I don't have a flue thermo but I do have an Imperial magnetic thermometer on the top of the stove right near the flue collar. When burning dry Ash/Maple, I see it go up into ~650-700F range for 15-20 minutes at the "height" of the burn, then settle in near 550F or so, and the secondary burn is excellent with no smoke out of the chimney, etc.

Today, I raked the (still red hot) coals while the stove was around 500F, and put two ~4x4" dry Ash splits and one larger ~3x6" split on top. Closed the door and turned the air intake down as I normally would (maybe 3-5 min open all the way then back it down to half-open; half-open for 10 minutes or so, then all the way closed). The temp kept creeping up and up even with the air intake all the way closed, until the stove was around 750F. I am used to the "pinging" noises of the flue expanding/contracting, but I could tell the temp was still going up pretty quickly. So as a "worst case scenario" test to see how rapidly the temp would reduce, I opened the door all the way.

The opposite of what I thought would happen, happened: within two minutes, the stovetop thermo was off the charts (roughly 900-1000F), smoke was coming from the flue pipe (presumably from the paint getting hit with temps it hadn't seen yet), and the stickers were melting off of it. I opened every door and window in the house and got my fire extinguisher, hoping I wouldn't have to explain to the neighbours that "yes, we did just get this stove installed two weeks ago, and yes, it did burn our house down."

Within 10-15 minutes, STT was back to 650 or so and my heart rate slowly went down. I know the pipe is rated to "3 x 30 maximum 2100F", but, whew.

My question is: what did I do wrong here? When temps are reaching ~800F or so, should I just have left the air intake all the way closed and let it burn down? Is opening the door all the way NOT the way to cool the stove down rapidly? What kind of damage did I potentially just do?
Is the deco designed to run with the door open ? I know my 1800i is as you can purchase a fire screen.

A Damper is the correct solution. I had one 900+ temperature excursion and I will be installing a damper during my next clean out.

I wonder if smaller fireboxes don’t respond as well to opening the door as fresh air can reach a larger percentage of the wood load this continuing to increase temps?

dry wood hot extra hot reload and not turning the air down soon enough can be an issue. When I went over 900 I turned the air all the down almost immediately. Less than 2 min after reloading. Off gassing on a hot coal bed and unregulated secondary air means it’s possible to over fire even when being attentive. (I have since found and stopped 3 small air leaks and I do believe the stove is now more controllable.
 

fdjm

New Member
Jan 25, 2022
3
Southern Ontario
Yes, there's a fire screen for the Deco Nano as well.

I think you're right: I must be leaving the damper too far open for too long. It's amazing the difference that a few minutes makes. I'll have to start playing around with the orientation of the logs when I reload. I'm finding that even 3 medium pieces of dry wood will get easily up over 600F within 20 minutes or so if I do not close the damper all the way almost immediately. It's like these things are built to produce heat, or something!
 

wagne223

Member
Jul 10, 2019
57
North Florida
I know your question has been answered, but I would like to give my thoughts and process as well.

If your stove is getting too hot and you feel you have lost control, there are 2 things you want to accomplish.
1. Slow the fire.
2. Get heat out of the stove.

So once you have decided that you are in, or are on your way to an overfire (an overheated stove, not a chimney fire) don't panic! The cool down is not instant!

First, fully close the air control.
Then put on your stove gloves. These should always be near the stove.
If your stove has a fan, turn it on high.
If not, and you have a portable fan quickly accessible, turn it on high and point at stove.

Release the stove door and open 2 inches for 30 seconds then close and latch again.
Opening the door, stops secondary combustion, and let's a bunch of heat up the flue, but it also flares up the fire.

A few minutes later you can open the door again for 30 seconds.

Repeat until you feel you have control of the fire and stove temp is normal.
 

neverstop

Member
Oct 11, 2020
123
new hampshire
I wouldn't worry about it at all until you get past 800. But to bring the temp down quickly you open the door for 30 seconds or so then close it. Repeat as many times as nessecary. How tall is the flue and do you have a pipe damper?

And generally loading a stove that is already 500 is asking for trouble. You certainly don't want to open the air all the way if you do.

Is the deco designed to run with the door open ? I know my 1800i is as you can purchase a fire screen.

A Damper is the correct solution. I had one 900+ temperature excursion and I will be installing a damper during my next clean out.

I wonder if smaller fireboxes don’t respond as well to opening the door as fresh air can reach a larger percentage of the wood load this continuing to increase temps?

dry wood hot extra hot reload and not turning the air down soon enough can be an issue. When I went over 900 I turned the air all the down almost immediately. Less than 2 min after reloading. Off gassing on a hot coal bed and unregulated secondary air means it’s possible to over fire even when being attentive. (I have since found and stopped 3 small air leaks and I do believe the stove is now more controllable.
In this scenario what is the right way to reverse this? Open the primary? That's counter intuitive. Had an off gassing event like recently. Had closed the air completely and stt had settled and then all of a sudden the box was full of secondary flames the next time I saw it.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
In this scenario what is the right way to reverse this? Open the primary? That's counter intuitive. Had an off gassing event like recently. Had closed the air completely and stt had settled and then all of a sudden the box was full of secondary flames the next time I saw it.
First thing close the air intake. And damper if you have one. If that doesn't work open the door briefly. That will kill the secondary combustion and flood the firebox and chimney with cool air. Then close the door after the temp drops. If the temp goes back up do it again.

Now if there is a chance you have a chimney fire absolutely do not do this. That is absolutely the wrong thing to do
 

snobuilder

Feeling the Heat
Dec 16, 2021
431
WI
After reading this thread I am really really happy with my decision to add shut off dampers to the secondary tubes.
Opening the door with a raging fire is counter intuitive to say the least.
 

kennyp2339

Minister of Fire
Feb 16, 2014
6,541
07462
You more then likely have the wrong type of thermometer on the stove top and are getting a false reading, these thermometers need to be mounted on single wall pipe about give or take a foot above the stove collar.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
After reading this thread I am really really happy with my decision to add shut off dampers to the secondary tubes.
Opening the door with a raging fire is counter intuitive to say the least.
It may be counterintuitive. But it works. Most people run their stoves just fine and never have this issue.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
Right, no problems , no need to be asking for help on a website.
I didn't say that at all it is something everyone should be aware of as a possibility. But it isn't something that is nearly as common as you are making it out to be. Just make sure the stove has the proper draft and it won't be an issue.
 

neverstop

Member
Oct 11, 2020
123
new hampshire
First thing close the air intake. And damper if you have one. If that doesn't work open the door briefly. That will kill the secondary combustion and flood the firebox and chimney with cool air. Then close the door after the temp drops. If the temp goes back up do it again.

Now if there is a chance you have a chimney fire absolutely do not do this. That is absolutely the wrong thing to do
What would be the signs of a chimney fire?

Flue skin temps are pretty much always 300-400. Some spikes to 450, and if i let the coals burn down too much sometimes reloads are slow. I never run it smoldering. However, I do have an uninsulated SS liner inside a clay liner in an external chimney.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
What would be the signs of a chimney fire?

Flue skin temps are pretty much always 300-400. Some spikes to 450, and if i let the coals burn down too much sometimes reloads are slow. I never run it smoldering. However, I do have an uninsulated SS liner inside a clay liner in an external chimney.
It's possible you had a small fire I would have to. Inspect the chimney for burnt creosote to know.
 
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