overfire questions

[Black Jaque Janaviac]

OK, I've got a Rutland magnetic thermometer for my NC-30. I put it on the angle of the step and the first real fire (other than break-in fires) ran away to 800*. I shut the air down at 600* and it kept climbing. At 800* I put foil over both air intakes and it slowly cooled down. I turned the lights down low and did not see anything on the outside of the stove glowing when it was at 800*. Today I put a strip of foil tape over the secondary air intake and it seems to be behaving a bit better.

The particulars are . . . Outdoor temps in the 20s. 27 feet of Flex King liner, 90* elbow, 24" of horizontal, another 90* elbow and 22" of black single wall to the stove. I'm burning oak that has been dead in the woods for years, cut, split and sat for one summer/fall.

Now I have a ton of questions:

*The Rutland thermometer shows anything over 550* as overfire. From what I read on these forums it seems like normal operating temps can be higher than that. What is the high end of "good burning temps"?

*Where should I put this thing? stove deck? on the angled part of the step? on the pipe?

*If the thermometer says 800 but the metal isn't glowing should I be worried about damage?

*Is it OK for internal metal parts to glow?

*When the temp ran up to 800* the inside of the firebox was curiously dark. There was a few glowing coals, and a lot of secondary flames but most of the wood was dark and the bricks were still blackened. Is this the way this is supposed to work? When my Montpelier gets rockin' the firebricks clean up nicely (although maybe I'm overfiring this one too but since it's an insert there's no good place for the thermometer.

*I've read a post or two that indicates that filling the firebox can cause an overfire - so how does one get a good overnight burn if you can't fill the box?

Thanks in advance. . .

 

[begreen]

You have a single-wall flue thermometer. The scales on the thermometer show 500F as overfire because if it is designed to be on the stove pipe. If it was placed on a flue and the temp read 550F, the interior flue temps could be pushing 900F. You will have to ignore those scales or better yet, get a stove top thermometer. 800F is hot and a bit high for daily burning, but metal won't start glowing until about 900F. A better temp to run the stove is more around 650F, but a spike of 700F is not uncommon. Do you have a blower on this stove? If yes, turning it on will drop the temp by about 100-150F.
http://www.condar.com/stove_top_meters.html

Tell us how you loaded the fire. Was this a cold start or did you add wood on a hot coal bed? What species wood and how much? At what temp did you start closing down the air? At what temp did you close it all the way?

It sounds like you have about 29ft of vertical pipe. The elbows will slow things down a bit, but if you find the draft is very strong, a pipe damper will give you more control.

 

[Black Jaque Janaviac]

Tell us how you loaded the fire. Was this a cold start or did you add wood on a hot coal bed? What species wood and how much? At what temp did you start closing down the air? At what temp did you close it all the way?

Loaded north-south.

Added to a hot coal bed.

Oak.

Filled the box.

At 600* I closed the air control completely. Because I could see it climbing from 550 in a matter of seconds.

At 800* I put the foil over the intakes and it began cooling.

No, I don't have a blower. I do have a fan aimed at it.

 

[Martin Strand III]

SNIP
*I've read a post or two that indicates that filling the firebox can cause an overfire - so how does one get a good overnight burn if you can't fill the box?

Thanks in advance. . .

This is coming up quite a bit lately: Learn to walk before you run.

In other words, until you know what you are doing with that stove, burn smaller
hot fires first, then increase the fuel load when you know what to expect.
Incoming air control is part of the "safe and proper" burn equation as well.
Filling the firebox without enough air will not over fire the stove. With too much air,
it will over fire.
Know the balance of air, fuel amount and fuel species to build safe hot fires.

Aye,
Marty

 

[begreen]

Tell us how you loaded the fire. Was this a cold start or did you add wood on a hot coal bed? What species wood and how much? At what temp did you start closing down the air? At what temp did you close it all the way?

Loaded north-south.

Added to a hot coal bed.

Oak.

Filled the box.

At 600* I closed the air control completely. Because I could see it climbing from 550 in a matter of seconds.

At 800* I put the foil over the intakes and it began cooling.

No, I don't have a blower. I do have a fan aimed at it.

Putting a full load of wood on a hot coal bed is going to cause it to outgas very rapidly. The massive secondaries were because the stove was burning off this wood gas. Burn the coal bed down further before reloading by raking the coals forward, placing a single small split on top and opening up the air.

Let that burn off the coals for about 30 minutes. Then after reloading, when the fire restarts, close off the air earlier at around 500 °F.

 

[maverick06]

glowing:
as I understand it, no part of the stove should glow. BUT this excludes the secondary air tubes in the top of the firebox. They can glow, some stoves its more easy than others. In mine they actually glow frequently, but nothing else is glowing, and my IR thermometer shows I am well below 800F

 

[BrotherBart]

The surest way in the world to over fire a 30-NC and ruin your underwear is to stack it to the roof N/S and leave air spaces between the splits. The air will travel the length of the splits and set them off while blowing the gases back through the channels in the splits and up and over the top. At that point the re-burn tubes join the band torching the top of that mess you piled in there and all hell breaks loose.

The man put not to stack wood higher than the firebrick in that manual for a reason. You don't gain any burn time by incinerating the whole load in two hours time.

 

[wkpoor]

The surest way in the world to over fire a 30-NC and ruin your underwear is to stack it to the roof N/S and leave air spaces between the splits. The air will travel the length of the splits and set them off while blowing the gases back through the channels in the splits and up and over the top. At that point the re-burn tubes join the band torching the top of that mess you piled in there and all hell breaks loose.

The man put not to stack wood higher than the firebrick in that manual for a reason. You don't gain any burn time by incinerating the whole load in two hours time.

Bart, I would guess that applies to most stoves and we see pics on here daily of stove packed to the gills. Unless you have a stove that is meant to be regulated way down like a BK I agree too much wood is not good.

 

[oldspark]

The man put not to stack wood higher than the firebrick in that manual for a reason. You don't gain any burn time by incinerating the whole load in two hours time.

So is true with all stoves built similar to this (such as a Summit)?

 

[Black Jaque Janaviac]

The man put not to stack wood higher than the firebrick in that manual for a reason. You don’t gain any burn time by incinerating the whole load in two hours time.

Oh. Now I see it. No higher than the firebrick it is then.

 

[BrotherBart]

I was addressing the 30-NC of the OP. PE just says "Do not load fuel to a height or in such a manner that would be
hazardous when opening the door."

Same thing applies though. Hogwildz attested to it last season relative to his Summit insert.

 

[corey21]

I think the closer the wood gets to the burn tubes the more secondary's you get.

 

[BrotherBart]

I think the closer the wood gets to the burn tubes the more secondary's you get.

Up around 800 degrees that is no blessing. And just cooks off the load with too much heat early and not enough later.

 

[oldspark]

Well like wkpoor says a ton of pictures with stoves packed to the gills on here, maybe not the best practice.

 

[begreen]

The man put not to stack wood higher than the firebrick in that manual for a reason. You don't gain any burn time by incinerating the whole load in two hours time.

So is true with all stoves built similar to this (such as a Summit)?

This is a reasonable load of cherry and one locust split in the T6. Brick height and no more. No I didn't fuss with it to pack in the very tightest amount of splits. It burned for about 7 hrs.. And yes, the EBT port is closed off. At night, I loaded locust splits E/W for a very good overnight burn.

 

[oldspark]

I know stoves vary from one set up to another but I can load my Summit up to the baffle and let it rip and still have control over it, thats why I can not relate to all these stove overfiring but I understand the problem.

 

[Wood Duck]

I agree with marty - work your way up to a full load, and in the process you'll figure out what a full load is for your stove. I think 800 degrees is a pretty normal stove top temperature for some stoves based on what I have read on this forum - at least I can say that people report that range of temperatures regularly. I have no idea what maximum temperature is appropriate for your stove.

 

[iceman]

800 on one of those stove top thermometers is anyone's guess! After 550 they can be off by as much as 200 degrees.
Get an ir ... Let your coals burn down a little more, turn the fan on and point it towards the stove... Most of us have fans so that would be in the mid 6-700ish range which would be fine.. but as someone said early .. learn your stove..

Ps. Pe says to fill it all the way to the baffle for max burn times.. that's why it has a floating baffle, to allow us to cram it with wood ..
I like it either way .. I just get a longer burn time packing it full of course

 

[Black Jaque Janaviac]

Up around 800 degrees that is no blessing.

I think 800 degrees is a pretty normal stove top temperature for some stoves based on what I have read on this forum - at least I can say that people report that range of temperatures regularly.

OK. . . so . . . 800* is NOT normal stove top temp for an Englander NC-30???

 

[oldspark]

Up around 800 degrees that is no blessing.

I think 800 degrees is a pretty normal stove top temperature for some stoves based on what I have read on this forum - at least I can say that people report that range of temperatures regularly.

OK. . . so . . . 800* is NOT normal stove top temp for an Englander NC-30???

Not for an extended time, I dont believe any of the stoves are made to run at 800, that would put your spikes up to 1000 degrees or so, metal glows at 900 and some degrees and that cant be good.

 

[iceman]

Burn tubes may glow that is fine. As long as the exterior if the stove doesn't glow.
How long were you at 800? What kind of wood was burned? How big were the splits?

 

[Black Jaque Janaviac]

How long were you at 800?

Less than 10 minutes. 5 maybe.

What kind of wood was burned?

Oak. an occasional maple split in there.

How big were the splits?

varying from 3 to 6 inches. 14 to 18 inches long.

The tubes glowed. Nothing else did. The curious thing was the inside was pretty dark. Even the coals had a dull glow. I did do exactly as Bart described as a surefire way to overfire to the gills north-south. I probably caught it in time. I've been working with it by only loading to the top of the brick. I understand the design now better. The secondary tubes are to provide oxygen to the gaseous fuels they are not supposed to provide oxygen for the combustion of the actual wood. When the wood is too close to the tubes the tubes act more like a primary air.

 

[js156]

Hello all. I have had fireplaces before but I am new to wood stoves. I had an Isle Royale installed last week. I am concerned that it is burning too fast and too hot.
I have had it for a week and it will burn 3 logs in 90 to 100 minutes starting on modestly hot coals. My chimney exhausts about 27 feet above the top of the stove after going through two 90 degree elbows on an outside wall.
If I fill the stove, it will burn amazingly hot for two and a half hours, making my 2900 sf house reach 75, and after that time the flames are gone but hot ashes left and then the house cools down. So I am sort of too hot and then too cold in a fairly brief amount of time for a stove that has a 3 cubic foot firebox. Please note that I do have the vents as closed as I can get them and that I keep the doors closed.
In the picture that I am hoping to upload I, again, have the doors completely closed and the vents as closed as I can get them and the flame is still blowing to the sides. I am wondering if I have too much draft and that is responsible for the quick fires.
The drywall behind the unit gets so hot that I cannot keep my hand on it. Today, I express ordered a infrared thermometer to check the walls temp because I am afraid of a fire. I also ordered a stove top thermometer.
Is there anyone who knows how hot is too hot for a drywall wall?
Also, I will happily accept any other insight that anyone may want to share.
Thank you!

 

[Jags]

Hello fellow IR owner, and welcome. Without temp readings it will be hard to nail this down. May I suggest starting a new thread in the hearth room. You will get more specific attention to your issue. This is an old wore out thread from 2012 that I am going to lock down at this point.