Okay, What is a Safe % M/C of wood for a Cat Stove???

[Fastdonzi]

I have searched and found where Sub 15% is Primo but also where 25% was Good too... Today I was splitting and for the heck of it took a year old Oak split and measured, the out side was 11% , I split it again and the inner was 23%, Is 23% Okay to burn in a Cat stove?? I have some fresh splits that are high 20's to 30%.... What Is Tolerable for a Cat stove??

 

[bholler]

15% to 20% you can get by a little over 20% but not much. And under 15% it is possible for it to off gas to quickly and overwhelm the cat. Most places if you are air drying you are not going to get the wood to dry 13% to 14% is the lowest most of us are going to get unless you are in the desert.

 

[begreen]

20% or below is the goal.

 

[webby3650]

By the time winter rolls around in East Tennessee, it just might be 20% mc.

 

[BKVP]

Not all cat stoves have equal combustion designs. Bholler is dead on about air/gas ratios and possible delayed ignitions.

All wood stove users, catalyst equipped and non catalyst equipped should burn wood that ranges between 15-22%...not because of their combustion design but because they all burn cleaner. Mix drier wood with higher mc fuels (above 18%, but lower than 22%) and with proper draft you should be able to mitigate over gassing in both combustion designs.

Remember the first step in combustion is to deal with moisture in the fuel load. Operating any stove at a higher temperature will help better deal with the mc of the load. Then after an hour or so....turn it down and cruise.

 

[JA600L]

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[Ashful]

All wood stove users, catalyst equipped and non catalyst equipped should burn wood that ranges between 15-22%...not because of their combustion design but because they all burn cleaner. Mix drier wood with higher mc fuels (above 18%, but lower than 22%) and with proper draft you should be able to mitigate over gassing in both combustion designs.

Tell us more about this "over gassing", BKVP. In my first year (or maybe two), I had a lot of trouble with my first Jotul Firelight 12 (3 cu.ft. cat stove) back-puffing. I never had that trouble in later years, and wood MC % may have been a primary variable in this. The cat on these stoves has about half the cross-section of a BK, per unit firebox volume.

In terms of delayed ignition, I found that 22% was roughly the threshold. I could not burn above that, and get reliable cat light-off. This is measuring on a freshly split face, of course.

 

[Fastdonzi]

I should be Good, We get about 90* almost every day and all my wood is covered in a 24' x 30' open sided shelter with a clear roof, So it doesn't ever get rained on. Then I have about 1 cord in one of those Solar Kilns where the inside top temp gets high 120's* and has fans that pull the hot air down through the wood. that's where I store my highest mc% wood. I'm not years ahead on wood cause the Old Buck 27000 consumed it all Lol.....

 

[Poindexter]

OP, I find right about 22% per electronic gizmo to be the absolute top end for my stove, but drier is better...

BKVP, last season in my Ashford 30 I ran spruce at 12% MC and birch at 16% MC no problem - but for most of the season, say Thanksgiving to Valentine's Day give or take I was running the stove at wide open throttle, three/three on the dial, as hot as possible.

Is "too dry" wood more likely to be a problem at part throttle settings? Pretty sure the manual for my A30 suggests wood at 13% MC, just saying.

 

[fire_man]

I burn some 4+ year bone dry wood and I have to be careful about the delayed ignition thing. I had a couple really violent backpuffs when the stove was loaded 1/2 way but no problem when fully loaded.

 

[BKVP]

Over gassing can occur when the air to fuel ratio is out of whack. Load a stove up with sub 10% mc content of fuel, run the stove on a maximum burn rate and then cut back on the air. Creating an extremely rich fuel mixture and there after the hot gasses come into contact with combustor....pop. Much like the old days of stepping on the gas pedal in a hot engine and then have the car backfire. Not fun when the next step is to replace the power valves in the carb.

Of course the caveat here is the effect that draft will have on the above scenario. Marginal draft could limit the pulling on fresh air into the stove and exacerbate the problem.

Incidentally, my friends at other stove companies have seen the same issue transpire in non catalyst equipped stoves.

ADEC in Alaska had some studies done of burning dry manufactured pressed log burned, then logging the results. The same test was repeated, but a portion of the load was wood that was 18+ mc. Can you guess which burned cleaner?

Poindexter you are excluded from this test as you know the answer!!

 

[Woody Stover]

I had a lot of trouble with my first Jotul Firelight 12 (3 cu.ft. cat stove) back-puffing. I never had that trouble in later years, and wood MC % may have been a primary variable in this.

Marginal draft could limit the pulling on fresh air into the stove and exacerbate the problem.

When that cat is blazin' away I would think you're gonna get better draft on a given air setting than when the cat has stalled on wet wood and not putting as much heat up the flue...

year old Oak split and measured, the out side was 11% , I split it again and the inner was 23%, Is 23% Okay to burn in a Cat stove??

If that Oak was dead wood when cut, it may just be able to get below 20% by this fall. How big are the splits, and are your stacks single-row in a windy spot? I had the feeling a couple of times that the 91 wasn't lighting off as quickly, when I had some soft Maple that I suspected wasn't quite dry. I never measured the MC though, and that was before I replaced some gaskets and got better air control on the stove. Plus I was never there all day to see how it did later in the burn, so I don't really know how wet of wood I coulda gotten away with in that stove. I think if you can get to 18%, it's pretty much guaranteed that any cat stove will run great.

 

[Fastdonzi]

They are fairly Big, Like 5"- 6" on the wide Bark side. I may split all the bigger ones down again. and yes they are in a single row under a clear roof with no walls and no chance of getting wet (unless we get the Horizontal Rain again)

 

[begreen]

It sounds like it's on the threshold of being ok. You've done the right thing. It may be burnable by November if you burn it a bit hot. If you do burn it keep an eye on the chimney for creosote accumulation. You may need to clean monthly depending on the moisture content at that point and volume of wood burned.

 

[Fastdonzi]

I will, I cleaned it when I did the stove swap last week. once we are burning again I'll keep an eye on the cap, It gives me a good indication of the pipe at that level. All my accumulation happens right at/on the cap and about the top 5" of pipe. I guess cause that's the only place being cooled by air and causing the gasses to condensate in to that very light but thick black ash/resin/creosote/junk block.. Pipe looks good and I switched to a Poly Brush instead of my Metal Brush..

 

[Poindexter]

OP, I do remember running some tests last winter with my new stove. Most of my woodpile was around 14-16% MC. I did collect enough pieces to run a box load @20% MC. It burnt OK, but it wasn't that great.

BKVP has posted a couple times that 22%MC or less is OK. I can't argue with that, he is posting for/as BK when he posts. However, 16% burns noticeably enough better that I haven't intentionally burnt 20+% ever since. I am blessed with a sizable woodpile, when I find heavier pieces in my wood shed that are probably up over 16% I put them back on the seasoning rack for another summer in the sun and a second chance at their ultimate destiny next year.

Sorry it took me a couple days to remember that.

I would hazard a guess that your oak splits at 11% outside and 23% inside probably ~average~ under 22%MC total, and therefore usable. However, you will want to run the stove wide open for about an hour when you load that stuff, see this thread and pp 50-51 of current BK performance thread for airborne fuel v- cat performance discussion.

My local BK stove dealer has been preaching "16% per electronic gizmo" for as many years as I have known of them - they are the ones who get the service calls. I suspect if you can get your average MC down to 16% you will be happy with your stove for many many years.

 

[JA600L]

OP, I do remember running some tests last winter with my new stove. Most of my woodpile was around 14-16% MC. I did collect enough pieces to run a box load @20% MC. It burnt OK, but it wasn't that great.

BKVP has posted a couple times that 22%MC or less is OK. I can't argue with that, he is posting for/as BK when he posts. However, 16% burns noticeably enough better that I haven't intentionally burnt 20+% ever since. I am blessed with a sizable woodpile, when I find heavier pieces in my wood shed that are probably up over 16% I put them back on the seasoning rack for another summer in the sun and a second chance at their ultimate destiny next year.

Sorry it took me a couple days to remember that.

I would hazard a guess that your oak splits at 11% outside and 23% inside probably ~average~ under 22%MC total, and therefore usable. However, you will want to run the stove wide open for about an hour when you load that stuff, see this thread and pp 50-51 of current BK performance thread for airborne fuel v- cat performance discussion.

My local BK stove dealer has been preaching "16% per electronic gizmo" for as many years as I have known of them - they are the ones who get the service calls. I suspect if you can get your average MC down to 16% you will be happy with your stove for many many years.

This is interesting information. I suppose the goal has always been to get to 20% moisture, but you are saying 16% is the sweet spot.

At 16% moisture are you getting any longer burn times, less coaling, and ash? I'm sure you are able to close the bypass and shut the stove down much sooner.

 

[Poindexter]

This is interesting information. I suppose the goal has always been to get to 20% moisture, but you are saying 16% is the sweet spot.

At 16% moisture are you getting any longer burn times, less coaling, and ash? I'm sure you are able to close the bypass and shut the stove down much sooner.

I don't really know how to answer that I guess. I started with the new Ashford 30 August 27, 2014. Yup, I have a short summer up here. I was burning 16% pretty much day in and day following the threads on here daily. As above, my local BK dealer has been saying "16-16-16" for years. On here I was reading "20-20-20" in thread after thread. Somewhere in there BKVP posted on here that 22% was dry enough. I was curious enough to try it.

I drove around to the places I delivered cord wood over the summer of 2014, found some rounds I had delivered green in May of 2014 that were still rounds, but stacked up out of the snow. I bought some of that wood back from the customer, split it open and came up with a stove load at 20% average MC after spending some time on it. My garage is +55dF and essentially zero humidity ...

 

[Poindexter]

Sorry, interupted. Anyway, i put a bunch of time into coming up with a boxload of 20%MC splits, loaded them up on a good bed of hot coals and I was really really disappointed.

You know how sometimes your campfire is going along great and you toss another piece on there and it was just too wet and you want to pull that one piece back off and throw it in the river so you can put a drier stick in there and get back to making smores?

It was like that, only maybe not quite that bad - but I was running a whole darn box full of it. It just didn't burn "good" at 20%MC compared to what i was accustomed to at 16%. And I had a bunch of spruce last year at 12%MC that was split really small and dried on the sunny side of my seasoning rack. 12%, no BS, lots of sap left in it, gosh that stuff was great. The difference between 12% and 16%MC is not that big though compared to slowing the stove down by throwing 20% in there instead of 16. Try some 16% if you're used to burning 20%. You'll probably notice the difference right away.

 

[Ashful]

I started with the new Ashford 30 August 27, 2014.

I have trouble remembering my anniversary, or my kids' birthdays, and you remember the date you started burning your Ashford?

 

[begreen]

I remember the month and year that I started burning in the T6, and not much else.

 

[BKVP]

22% works but it is not optimal. If you have 50lbs made up in 5 pieces at 22%, it will not burn as well as 50lbs made up of 10 pieces. The added surface area exposed to combustion allows the load to burn hotter than the aforementioned load.

 

[Poindexter]

August 27, 2014 my wife was cold. It was the day I started saving money on the oil bill with the Ashford, and I saved a LOT of money on the oil bill, close to $4000 over the 14/15 burning season. I remember (and wrote down) the date so that this year and later years when we are making plans or discussing how big the wood pile should be I can point out we run the stove from (about) August 27 to May 15. My burn season is 8.5 months, and yes honey, the woodpile does take up a lot of space in the back yard.

Honestly I think cord wood at 20%MC is crap, but I got lots of 16% to burn instead and YMMV.

I'll issue the Poindexter challenge, part II. .
.
My original was over on a BBQ forum. I personally prefer the flavor of BBQing over hardwood lump charcoal instead of briquettes. Lump is more expensive, but I found doing back to back cooks of the same recipe changing only the charcoal I (and my family) have a very noticeable preference for hardwood lump.

So here is the Poindexter challenge part II. Once you get your 20% wood for the coming season in the shed, pull out just enough to do a hot reload on your stove (Ashful will need double of course) and put it somewhere inside the heated envelope of your house until December 26. You just go ahead on and burn that 20% crap from whenever it gets cold all the way through Christmas day and do a hot reload the morning of Boxing day with the really dry stuff down in your furnace room. Dec 26 falls on a Saturday in 2015, I'll be sure to stop by here and look for a new thread...

EDIT: Do be sure your stash is 12% or wetter before you toss it in the stove so BKVP doesn't have a coronary.

 

[Babaganoosh]

I want to burn sometime this millennium. When mine averages 20 I'm burning! 16%? Ain't nobody got time for dat!

 

[Ashful]

I want to burn sometime this millennium. When mine averages 20 I'm burning! 16%? Ain't nobody got time for dat!

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