Low flue temps?

[Graelb]

Hi again Graelb. I was hoping some of the more experienced users would jump in and try to help here, but here's my take on things. It sounds like you have a good flue/chimney system, and that you've got more than adequate length to give your flue system a good draw. As far as a general start up procedure would go (forget about the flue damper for now), I was taught that you should put in enough wood to sustain a good burn. Perhaps just adding that 1 split of madrone isn't enough to keep things going for a very long time. I'd recommend that you try loading 3 splits on the bottom layer, and then a 2nd layer with another 2 splits, and pack them together nice and snug. That would give you a nice base for a long burn. So after the wood takes off, the wood is nicely charred and the fire is very lively and really starting to fill the box, you would damp down the primary air intake say around 25% closed. That will usually slow down the fire so that the flames are slow and lazy, but not going out or smoldering; if that happens you need to quickly open the primary air up a little. So once you turn it down this first time to 25% closed you leave it and watch while it slowly starts to build back up, maybe for 5 or 10 minutes. After the fire has built back up again, and it is vigorous and lively, and the temps are climbing (I monitor my flue temps and use that as my guide) then you would go and turn down the primary air again to say ~50% closed; again, the flames should get slow and lazy, and you can sit back and watch it until it builds back up again (maybe watching the flue temps and when you see them starting to climb fast) then you go over and turn it down another 25% so that your primary air inlet is now closed ~75%.... So here you go and sit back down again and wait for the fire to build back up, BUT, this is probably your last (or close to last) adjustment, and when the fire is building back up again (and the flue temps are starting to climb again) you head over and adjust it, but probably not all the way closed; this last adjustment is where you're hoping to make some very small slight adjustments to slow the blaze down slightly, but not so much that it's going to go out. I used to figure closing it to around 90% or so, so the flames are slow and lazy, the secondary's are lighting off and putting on a nice show, and your keeping your flue temps down a bit, although not too low... I wouldn't worry so much about keeping the stove top down below 600 F.... You can probably run the stove pretty safely with the stove top touching up to between 700 and 750 F at the start of your fire (and your flue temp will be slightly less than that, so maybe around 600 or 650 F). Once the fire has been burning for an hour or so they will begin to slowly drop again.... But my main point is that you don't have to be a slave to the numbers... you really have to learn how your stove burns and then try to work within it's habits... And here's where it's nice to have the Flue Damper; if you find that you've got the primary air inlet almost completely shut down, but the fire is still growing hotter and hotter (and probably the flue temps are going up as well) then you can start turning down the damper incrementally, just like you were doing with the primary air: shut it down a bit until the flames get slow and lazy, and then just watch to see if they start building back up.... if they do, damp it down a bit more, and keep watching it. Eventually you're going to hit the sweet spot where you've found that the fire is staying at a nice comfortable rate that you can live with... This is how I would approach your learning curve with your stove. I wouldn't just keep using 1 or 2 sticks, because it just ain't gonna be sustainable... you've got to feed the stove the way it was meant to be fed. Now that doesn't necessarily mean stuffing it to the gills, but 4 or 5 splits is kind of where the stove would need to start to live to its fullest potential, to attain its ultimate function as a hot blooded heating machine! It will be happy, and you will be happy. I think this would be a nice safe way for you to approach your next stage of experimentation with the stove of yours... even though I understand the difficulty of running a stove without the proper mechanisms needed to adjust the air inlet and whatnot....

Good luck brother!.

Good lord that's the best write up I've had so far. Thank you so much chuck!

I really appreciate your help. I'll give that a shot tonight, and hopefully in a few days I'll have this thing purring like a kitten.



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[Graelb]

Hi again Graelb. I was hoping some of the more experienced users would jump in and try to help here, but here's my take on things. It sounds like you have a good flue/chimney system, and that you've got more than adequate length to give your flue system a good draw. As far as a general start up procedure would go (forget about the flue damper for now), I was taught that you should put in enough wood to sustain a good burn. Perhaps just adding that 1 split of madrone isn't enough to keep things going for a very long time. I'd recommend that you try loading 3 splits on the bottom layer, and then a 2nd layer with another 2 splits, and pack them together nice and snug. That would give you a nice base for a long burn. So after the wood takes off, the wood is nicely charred and the fire is very lively and really starting to fill the box, you would damp down the primary air intake say around 25% closed. That will usually slow down the fire so that the flames are slow and lazy, but not going out or smoldering; if that happens you need to quickly open the primary air up a little. So once you turn it down this first time to 25% closed you leave it and watch while it slowly starts to build back up, maybe for 5 or 10 minutes. After the fire has built back up again, and it is vigorous and lively, and the temps are climbing (I monitor my flue temps and use that as my guide) then you would go and turn down the primary air again to say ~50% closed; again, the flames should get slow and lazy, and you can sit back and watch it until it builds back up again (maybe watching the flue temps and when you see them starting to climb fast) then you go over and turn it down another 25% so that your primary air inlet is now closed ~75%.... So here you go and sit back down again and wait for the fire to build back up, BUT, this is probably your last (or close to last) adjustment, and when the fire is building back up again (and the flue temps are starting to climb again) you head over and adjust it, but probably not all the way closed; this last adjustment is where you're hoping to make some very small slight adjustments to slow the blaze down slightly, but not so much that it's going to go out. I used to figure closing it to around 90% or so, so the flames are slow and lazy, the secondary's are lighting off and putting on a nice show, and your keeping your flue temps down a bit, although not too low... I wouldn't worry so much about keeping the stove top down below 600 F.... You can probably run the stove pretty safely with the stove top touching up to between 700 and 750 F at the start of your fire (and your flue temp will be slightly less than that, so maybe around 600 or 650 F). Once the fire has been burning for an hour or so they will begin to slowly drop again.... But my main point is that you don't have to be a slave to the numbers... you really have to learn how your stove burns and then try to work within it's habits... And here's where it's nice to have the Flue Damper; if you find that you've got the primary air inlet almost completely shut down, but the fire is still growing hotter and hotter (and probably the flue temps are going up as well) then you can start turning down the damper incrementally, just like you were doing with the primary air: shut it down a bit until the flames get slow and lazy, and then just watch to see if they start building back up.... if they do, damp it down a bit more, and keep watching it. Eventually you're going to hit the sweet spot where you've found that the fire is staying at a nice comfortable rate that you can live with... This is how I would approach your learning curve with your stove. I wouldn't just keep using 1 or 2 sticks, because it just ain't gonna be sustainable... you've got to feed the stove the way it was meant to be fed. Now that doesn't necessarily mean stuffing it to the gills, but 4 or 5 splits is kind of where the stove would need to start to live to its fullest potential, to attain its ultimate function as a hot blooded heating machine! It will be happy, and you will be happy. I think this would be a nice safe way for you to approach your next stage of experimentation with the stove of yours... even though I understand the difficulty of running a stove without the proper mechanisms needed to adjust the air inlet and whatnot....

Good luck brother!.

So the bigger danger is in making sure the flue is a reasonable temperature, not so much the stove temp, provided the stove temp is reasonable?

I set up a webcam to watch the stove since I'm not usually in that room, and I can see the fire and the flue temp. If the flue temp is steady, is that reasonable to assume the stove temp is steady as a rule? I haven't quite figured out the stove vs flue temp correlations yet

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[Chuck the Canuck]

So the bigger danger is in making sure the flue is a reasonable temperature, not so much the stove temp, provided the stove temp is reasonable?

I set up a webcam to watch the stove since I'm not usually in that room, and I can see the fire and the flue temp. If the flue temp is steady, is that reasonable to assume the stove temp is steady as a rule? I haven't quite figured out the stove vs flue temp correlations yet

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Yes, you've got it. As a general rule you will probably find that the flue temp runs maybe 50 - 100 F lower than the stove top temp. But that's not always the case, as many times when I first start running the fire my flue temps are pretty close to the same as my stove top temps, although the flue temps start dropping slowly after you get into the burn for awhile. And finally, yes, I monitor my stove's burn by watching the flue temps, as it gives me a very good picture of how things are going overall.

Good luck brother! And ask anything your not sure about, as there's lots of people here to help...

 

[Graelb]

Yes, you've got it. As a general rule you will probably find that the flue temp runs maybe 50 - 100 F lower than the stove top temp. But that's not always the case, as many times when I first start running the fire my flue temps are pretty close to the same as my stove top temps, although the flue temps start dropping slowly after you get into the burn for awhile. And finally, yes, I monitor my stove's burn by watching the flue temps, as it gives me a very good picture of how things are going overall.

Good luck brother! And ask anything your not sure about, as there's lots of people here to help...

Thanks again chuck!

A few more questions you may be able to answer!

Is this what you'd call nice and charred? This is about ten minutes into the burn from cold.



How much ash do you leave in the bottom before emptying it?

And when you reload the stove, do you start the whole process over again, or start from somewhere in the middle? Last night I got it going, then added a big split right in the center, and it almost snuffed the fire out, with all air open it probably took a good half hour to get going at good speed again.

You've been so helpful. Like I said I really appreciate the help. It's nice to know I'll get to a point (hopefully soon) where I can start to enjoy this thing more than worrying about it[emoji16]

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[Chuck the Canuck]

Thanks again chuck!

A few more questions you may be able to answer!

Is this what you'd call nice and charred? This is about ten minutes into the burn from cold.

View attachment 194588

How much ash do you leave in the bottom before emptying it?

And when you reload the stove, do you start the whole process over again, or start from somewhere in the middle? Last night I got it going, then added a big split right in the center, and it almost snuffed the fire out, with all air open it probably took a good half hour to get going at good speed again.

You've been so helpful. Like I said I really appreciate the help. It's nice to know I'll get to a point (hopefully soon) where I can start to enjoy this thing more than worrying about it[emoji16]

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Hi again. Yes, the picture you posted gives a good indication of the wood being well charred, that and the timing of the burn (about 10 minutes in) seems spot on... so that would be a good starting point for slowly beginning to shut down the primary air as I outlined earlier.

Reloading the stove presents different issues, especially if you're reloading on a nice hot bed of coals. That would be when you might need to start turning down the primary air a little bit faster, especially if the fire is really taking off and going gang-busters. On the other hand, sometimes you have to wait for the fire to really pick up the pace (as you had to wait last night). In this case you need to be patient and wait for the fire to really take hold and start burning vigorously before you can dare to turn down the primary air: too fast on that and you'll find that you're snuffing out your fire rather than slowing it down to a lazy rolling flame... You'll pick up the idea as you keep going forward.

And finally with the ashes.... well I'm never in a big huge rush to empty the ashes, and I can get by emptying the ashes about once every week or two. For sure you want to have a nice bed of ashes in the bottom of your stove, maybe a good inch and a half, or two inches, but things get interesting when you're trying to clean out ashes while moving over nice big juicy red-hot coals. I usually try to move the coals over to one side and get a good hefty shovel load or two of mostly ashes emptied into my metal ash bin; then I move the coals over to the other side of the stove and go in for another couple of big shovel loads. I find that when emptying ashes like this I end up with an inch or so of ashes, topped off with another couple inches of blazing red hot coals... And don't forget to use a nice sealed ash can that you can remove to the outdoors, preferably placed on a non-combustible surface, so they can cool off for a few days....

I think you're definitely heading in the right direction Graelb. However, you've got a pretty serious challenge to learn how best to burn in that stove of yours, being as it ain't got any rods, or mechanisms, to turn down and adjust your primary air... well, that's just taking things to a whole different level. But you seem to be the man that can do it Do you find that you need to use the flue damper all the time, like whenever you have a burn going? If that was the case, I'd probably follow the procedure I outlined yesterday, except that I'd adjust the primary air pretty fast to where you want it to end up, and then start adjusting the flue damper incrementally the way I outlined yesterday. I really like the set up you have for monitoring your stove top temps with the digital read out and thermocouple.... I have the same sort of set up (digital readout and thermocouple) but I use it to monitor my flue temps, and that's what I use to watch the burn and figure out when it's time to turn down the air (whether primary, or with the flue damper).... Anyways, keep on burning because practise makes perfect, and you'll certainly get there eventually; I'd say you're well on your way to getting there already.....

Cheers