Picture perfect secondary burn, but always with smoke

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mike01

New Member
Jan 4, 2012
16
Catskills Mountains, NY
Hi all,

I'm new to the forum and I've lurked in the last few days and read a lot. This is a great source of information.

I have a new Regency F2400 medium and I have a few concerns. I'm not quite sure I'm doing this right and I'm hoping you can help me.

Here is what's going on:

I can load east-west or north south and get beautiful swirling flames above the wood, what I'm assuming is secondary burn. These swirling flames start at about 400-500F stove top in about 10-15 minutes if building on a coal bed and then I throttle down the air control to 75%, then a few minutes later to 50%, and a few minutes later to 25%. The swirls stay for a bit less than an hour then begin to die unless I open the air control a bit, and then a bit more, etc. If I pack the stove I can keep the swirls burning for about 4 hours if I keep slowly opening the air until I end up at 75% again. Is this normal? People talk about secondary burn lasting for hours...does that mean they can do it without opening the air control as I do? If so, what am I doing wrong?

My other problem is that no matter how perfect the secondary swirling flames look, I always get some smoke. Usually it's whitish and dissipates very quickly, but it's always there. I've seen the youtube videos where there is no smoke at all but I've only been able to do that once. It was during the day, it wasn't too cold and I let the stove get very hot, like 700F hot, before throttling it down. This ate up my wood though and the burn did not last too long after that.

I am in NY, at 1850ft elevation, it has been very cold lately, ranging from 8F to 30F.

Any advice?
 
If I want heat and need to chew through wood I do the same as you described by opening the air back up. If I don't need the heat, I leave the air left at 20% or so and just let it ride. Those picture perfect secondaries don't need to last forever. Many videos on the topic were made specifically to showcase them rather than to show what regular, everyday burns are like. In other words, every fire doesn't need to be like that for things to still work effeciently.

Sure the "smoke" you are seeing isn't steam?

Welcome to the site!

pen
 
Thank you, good to be here.

How can I tell the difference between smoke and steam? Sometimes this smoke of mine is not pure white, other times it is.

So the secondary burn dying after an hour or so without opening the air control back up is normal?
 
It's going to depend on your fuel source and how well it's seasoned, how large the splits are, the way the wood is loaded in the stove, how long you let the wood char first before turning it down, etc, etc.

When your secondary flames die out, are there still flames in the stove coming off of the wood itself?

Usually, stuff exiting the chimney that dissipates quickly is steam. The way my prevailing winds go, usually my exhaust comes towards the area i'd be doing work outside if I'm out there. If I have smoke coming from the chimney I can smell it 100 feet away. If it's steam exiting, I won't notice that same acrid smell.

pen
 
mike01 said:
How can I tell the difference between smoke and steam? Sometimes this smoke of mine is not pure white, other times it is.
Click to expand...

If it rises and then dissipates in twenty feet or so it is steam. Smoke will want to sink and also it does not dissipate that quickly. Usually ends up as soot on your neighbor's car.
 
I think you're doing fine. Four hours of strong secondary flames sounds like a pretty good burn, and adjusting the air settings is the right way to optimize your fire. I agree with others that you could leave the air setting a little lower and get less heat but use less wood, but there is nothing wrong with the way you're burning. Any time you burn wood (or anything else) you create some water vapor by combining hydrogen in the wood with oxygen from the air to make H2O. Depending on the relative humidity of the atmosphere the water vapor may be more or less visible at the chimney. I wouldn't worry about it.
 
Okay, maybe it's steam then! It does dissipate very quickly and it does go up. I feel better now. :)

pen said:
When your secondary flames die out, are there still flames in the stove coming off of the wood itself?
Click to expand...

No, most of the time when they are going there is no flame from the wood itself, and if they die out the wood just glows red.

When you say depends on, etc., how long of a secondary burn should I be getting if my wood is perfect?

Also, from watching instructional videos on youtube it seems like the shut the air down all the way as soon as they get secondary combustion. If I do that my fire dies. Is that normal? What's up with the vids then?

Thanks to everyone for the help, I really appreciate it.
 
Gotta remember in the vids the folks are generally showing off.

The way the stove will burn will change or depend on how large a diameter your splits are, if there are all splits in there or rounds too, what kind of wood it is, how you loaded them, how seasoned they are, how much air can get between them, etc, etc. Your comment about having most of your wood eaten up to get the stove up to 700 makes me wonder if some variable w/ your wood is less than perfect, however, from what you describe it can't be too far off.

I think in all if you are staying warm and the chimney doesn't show signs of creosote buildup, that you are doing it right. Maybe try experimenting w/ different sized splits, different ways of loading, some man-made wood, some known well seasoned wood, etc, etc, to see if you can find that magic combination.

pen
 
Ok, I hear a lot about how the burn will depend on how big the splits are, etc.

Is there any information (or can you provide any) about HOW the size, age, etc. of the splits affects the burn? Do smaller splits create a longer secondary burn or vice versa?

As for what kind of wood I'm burning, I don't know. Where we live now used to be a vacation home and a couple of years ago we ordered a truck load of wood, and there was wood stacked under the deck before even that, being rained on and snowed on. I now have half of it covered in a tarp and I have an 8' wood rack on the deck and a 2' wood rack in the house, so I take the wood from under the deck, split if necessary, stack it on the deck rack, then take it inside if needed. Most seems dry and sounds hollow, but I have no idea what kind of wood it is. I ordered a moisture meter off of Amazon so at least I will know how wet it is.
 
This is stuff that most people just enjoy playing around with. Wood burning is as much an art as a science. Last year I used pretty huge splits, this year I'm playing around w/ smaller ones and different ways of loading.

So long as you aren't getting excessive creosote build-up, it doesn't hurt to play. I think the moisture meter will be a good tool for you. I have gone years w/out and just picked up the "general" moisture meter from amazon. I'm very happy with it and hte readings on some of my wood have really surpised me and have given me new things to play around with.

pen
 
I guess I will play around also.

When you burn for heat in the winter, do you always stuff your firebox to capacity or close to capacity?
 
Only when I have to. Even w/ a 30-50% load and good dry fuel, I can generally relight from coals 8-10-12 hours later so long as I keep a good deep ash bed in there. If I can heat this place on a 1/2 load, then that's what I do. Putting more wood in would just extend how long I can go between reloads and give me a hotter stove top for a while when first filled. Not every stove will go that long on a partial load, so it will vary. For me to load it to the gills it generally needs to be in the teens for day time highs or else I'll be gone from the house for an extended period (up to 24 hours).

pen
 
Forget that those tubes are up there. There doesn't need to be rolling flames at the tubes for them to be doing their job. No smoke, good wood, proper stove temps and a warm house are the things that really matter. ;-)
 
Jags said:
Forget that those tubes are up there. There doesn't need to be rolling flames at the tubes for them to be doing their job. No smoke, good wood, proper stove temps and a warm house are the things that really matter. ;-)
Click to expand...

True dat.

But it is COOL when all those holes look like the gas jets on my Ducane. lol
 
Thanks everyone. I actually had a smokeles/steamless fire today with some lovely swirly secondary flames.

It seems to me that if I want to get the most out of the wood (so efficiency being more important than burn time) I should never close my air control more than half way, because then the swirly flames eventually die down or reduce dramatically in size and that should mean, in theory, that much of the smoke is not being burned. Does that sound right?
 
I'm interested to hear what you find when you get that moisture meter. I'm thinking either your wood is not quite as dry as it should be yet, or else your draft isn't that strong.

You should be able to drop down to at least 25% air and still have good secondaries if the wood and draft are good.

What's your chimney like?

BTW, so long as you aren't billowing smoke there is no problem with you operating the stove as you are describing. I'm just surprised that you are having this happen if you turn the air down less than 1/2. Just being thorough.

pen
 
I got the meter, it sounds like the same General meter you have, also from Amazon (30 bucks). I tested the wood that's in my log rack in the house. Most is 10% or less (6% was not an uncommon reading), some is low teens, two logs were teens but had a spot where it was 30% or more, those spots were also squishy so either they were touching the ground or they rotted and are retaining moisture in those spots. But that's just two logs out of many and the wet spots are small.

As I said, it's really old wood.

My draft is strong, or so I think. I can start a fire easily, always on the first try, and when I close my door almost all the way the flames take off like they are being sucked up the chimney by a vacuum cleaner.

To be clear, if I turn down the air slowly I can get secondary burn at less than 25%, sometimes I can even get it if I shut it down fully, but it doesn't last very long. Always less than an hour, sometimes less than half (if I shut it all the way). I don't know why I can sometimes shut it down and sometimes not. I guess maybe it depends on the wood.
 
Man, that is some dry wood if those measurements were taken on a freshly split face. I've been pleased w/ that moisture meter so far.

By the sounds of it I think you have your t's crossed and i's dotted. Maybe playing around w/ how the wood is loaded in the stove may be next.

Well done.

pen
 
How fresh does freshly split have to be? Those were split about a week ago. I'll try next time I split one for an immediate reading.

I heard somewhere that wood can be too dry...is that true?
 
If it were seasoning outside or under other normal circumstances, I don't see it getting too dry. Wood can be made dry enough that it wouldn't burn as efficiently as it should. I've read debates about what percentage that tipping point takes place at, but I'd say you'd pretty much have to work at it to get wood there.

I have burned some oak 2x4 lumber scraps that had been in a dry barn / garage for close to 50 years. They didn't do anything out of the ordinary.

pen
 
Here's something interesting. I filled the firebox a little more than halfway and I am getting the same heat output as a full box and perfect secondary flames with the air fully closed. I wonder how long it will last.
 
Another thing...I'm not convinced that puffy white stuff that rises and dissipates is steam. The reason is that if I increase combustion it goes away (yes I finally managed to get rid of my "smoke"! :) ) and if I turn down the air it comes back. If it was steam, wouldn't there be more of it if I turn up the heat?

It behaves exactly as you guys described...it rises and quickly dissipates. But why does it go away when I raise the flames?
 
hehe, I'd still bet a 6 pack that it's steam.

I get the same thing. Lots of water produced when wood is burned.

I think a greater volume of air getting up the chimney w/ the air open more, the moisture from combustion can dilute in that larger amount of air and then isn't visible as "fog" when it condenses in the cold air since it's spread out more to start with.

How'd that burn end up w/ using less air.

If you want, set this thing so that you can see the steam or smoke in question, then shut the air fully and take some aluminum foil and block the air ports. Basically, you are forcing this thing to turn into a smokey mess. Go out side and start taking the visual in and wander around so that you can smell the difference as well. The neighbors will think you are crazy as hell, but hopefully you'd be able to see a difference.

One more thing, even in a worst case scenario and it were a touch of smoke, so long as the chimney can keep the temps about about 220 on the way up and out you shouldn't have much creosote to worry about. So, I saw keep an eye on the chimney and if that's staying in good condition, then things are just fine.

pen
 
You can have picture perfect secondaries, and a great burn and still have smoke is there is some leakage around the baffle that allows some of the unburnt gases to sneak up the flue without going past the tubes.
 
With my stove I generally have to leave the primary air control at least partially open to maintain a good fire. If the fire is going well I can shut down completely and still get nice secondary flames at the top of the firebox, but this doesn't last long. It might last 15 minutes, maybe half an hour, maybe longer, but it typically isn't going to work for any longer than that. In order to keep a fire going without watching and adjusting all the time I have to keep the primary open 25% or more.

I think if you can get secondary flames for four hours you're doing great. Better than I can do most of the time, although you might have a larger stove than my 1.6 cubic ft firebox. My firewood is in good shape and it sounds like yours is too. I doubt the wood is actually below 10% moisture content inside a split because you live in NY state. If you lived in AZ maybe it would be that low, but outside in the east I think 10% is about as low as wood will get and plenty dry for burning. A fresh split stored inside for a few days in the winter could definitely be drier on the outer layers than in typical of the inside of the split.

If my stove and flue are both hot I can sometimes get a really good burn with a half load of wood the way you described. usually I load the stove more than half so that I will get a longer time between reloading. i generally burn the stove close to full heat output, but in my house the heat is part wood stove and part electric baseboard heat. The more heat I get from the wood the less electric I need so I can have the stove burning fully without overheating the part of the house where the stove sits if the temperature is below about 40F outside. Thats is good because I don't think my non-cat stove is well suited to low burning.
 
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