Jotul F55 1 hour burn time Help!

[Trunkinator]

Hello Everyone,.... HELP !!

-Jotul F55 Carrabassett 2020 with ReBurn tech non cat
-20ft flue, no damper, double wall insulated flue
-Rutland magnetic stove top thermometer

I'm new to operating a wood stove. My wife and I settled on the Jotul F55 as we have a 2000 sqft home and look to heat it throughout the cold spells of winter with this stove. I competed the break in process, very carefully and slowly. I've begun to burn (well try to anyway! ) at operating temp (500 - 600 deg F) i will admit, I have been very timid to load up the stove. I've been reading all day on these threads and i believe I've definitely found some of my mistakes, but I feel like I'm still doing some things wrong. Im burning Birch with a few Ash mixed in the lot at times. I'm still waiting for my cords of ash and oak to fully season and then i will move away from birch.

Like I said I've been very timid, and haven't been able to get the temp beyond 350 and active flames for more than an hour until tonight. I was initially loading 2 to 4 logs at a time and as they burned down, adding 1 to 2 more at a time.

After researching today, I finally grew the gonads and loaded 8 splits in at once, decent size splits, i would say i filled the stove a little more than 1/3. This was on a bed of hot coals.

I had bypass wide open for about 5 minutes until flames were full and all splits caught. Then lowered to half, and after a few minutes of rolling fire, my temp was 500 deg, re-burners in full swing, and consistent flames from the splits. At this point i closed the bypass completely.

This lasted about 45 minutes until it really started to die down, temp dropped to about 450-475, and slowly dropped from there. At an hour and a half, stove was at 400 and there were large remnants of splits, smoldering, some with very short blue flames emerging. The room has begun to cool and the temp is 300 after 2 hours, still large smoldering with small blue flames.

When the fire began to die down, i tried to open the bypass a little more but this did not seem to help.

2 hours in, after loading 8 splits, my stove top temp is 300.

Thank you in advance, i look forward to any advice, criticisms, and knowledge you are willing to share.

Regards,

Matt

 

[begreen]

If 8 splits only filled the stove 1/3 full, then the splits are on the small side and will burn quicker than 4-6 in. thick splits. Also, how were they loaded? N/S or E/W or lincoln log style with alternating layers?
The F55 does not have a bypass, it has an air control. Is that what was meant? It sounds like the fire could have used a little more air around the 90 minute mark. Keep experimenting. If you can post a picture of the next loading that would help.

 

[Trunkinator]

If 8 splits only filled the stove 1/3 full, then the splits are on the small side and will burn quicker than 4-6 in. thick splits. Also, how were they loaded? N/S or E/W or lincoln log style with alternating layers?
The F55 does not have a bypass, it has an air control. Is that what was meant? It sounds like the fire could have used a little more air around the 90 minute mark. Keep experimenting. If you can post a picture of the next loading that would help.

Hi Begreen,

I've loaded N/S in order to avoid a log rolling into the window, tried E/W before, but cannot count it as i only loaded 3 or 4 logs.

The splits im using are about 12" long and maybe 4 inches at the widest (triangular) and some half splits (a radius no greater than 3 inches)

Yes, sorry, i was calling the air control the "bypass"

I will post some pictures and video of my attempt tomorrow. I guess I'm just afraid of overfiring, the 8 splits shot the temp up to 500-515 and i closed the air control completely because the inside looked like mount vesuvius. The rutland thermometer i got from a tractor supply store either moves very very slowly and is not so accurate because it takes a while to register or it is in fact accurate and I'm just not very familiar with judging temperature. I'm considering picking up a flue thermometer, the type for which i drill a hole and insert it into the flue.

The ultimate goal is to at least have 400+ degree heat for at least 5 to 6 hours. I've read and have been told this stove can easily do that, if not exceed those expectations.

 

[begreen]

If loading N/S the splits should be 16-18" long. 12" splits would be 1/3 less filling.

 

[firefighterjake]

As others have mentioned . . . if you only loaded the firebox 1/3 full with eight splits the splits are on the smaller size and will burn up faster which means less time spent in the secondary reburning stage, less time with active flames, etc.

Your process in loading the stove and controlling the air flow seems sound, although I will even let my stove go a bit hotter even on occasion (but again, I think the process is the size of the splits).

That said, you are right in not wanting to necessary load the stove to the gills with all smaller sized wood as you will most likely skip right be the Fires of Vesuvius and go right to the Portals of Hell and could even bypass the Portal to Hell and go right to the dreaded Thermonuclear Stove Melt Down (aka the Chernobyl Effect.)

My suggestion would be to load the stove a bit fuller next time, but also use larger splits if possible.

P.S. I find that stove thermometers do move a bit more sluggishly compared to the stove pipe thermometer.

 

[Trunkinator]

As others have mentioned . . . if you only loaded the firebox 1/3 full with eight splits the splits are on the smaller size and will burn up faster which means less time spent in the secondary reburning stage, less time with active flames, etc.

Your process in loading the stove and controlling the air flow seems sound, although I will even let my stove go a bit hotter even on occasion (but again, I think the process is the size of the splits).

That said, you are right in not wanting to necessary load the stove to the gills with all smaller sized wood as you will most likely skip right be the Fires of Vesuvius and go right to the Portals of Hell and could even bypass the Portal to Hell and go right to the dreaded Thermonuclear Stove Melt Down (aka the Chernobyl Effect.)

My suggestion would be to load the stove a bit fuller next time, but also use larger splits if possible.

P.S. I find that stove thermometers do move a bit more sluggishly compared to the stove pipe thermometer.

Thanks for your insight! About an hour and i half ago or so, i raised the temp of my cold fire box to about 300 deg using some kiln dried birch splits. Once it was only hot coals and 250-275 deg, i did the following;

Started with 3 birch for embers, got hot coal bed and stove top therm at 200 deg(again this thermometer is not being friendly, I'm sure it was warmer than 200)

Put on 2 large 20% moisture ash and one medium 15% ash in middle, N/S big little big

Left Door cracked open 5 min until all splits are ablaze

Close door, air control total open for 10 min more. Stove top thermometer SLOOOOWLY climbing.... 250 now

Close air control halfway. Once flames visually settle down, close to a 1/4 open

Totally died at 20 min. opened control all the way, fire caught after a couple min,

At 28min, closed control halfway

At 43 min, close air control to 1/4, smaller lazy licking clear/blue orange tipped flames from all splits, splits are certainly charred

At 49 min fire died out. I opened the air control all the way in order to reignite the splits, with it did very quickly, and then i turned back to half throttle and been cruising since. At an hour in, still have three 70% intact splits. Temp reads 300 which has got to be BS. (I really don't like this Rutland thermometer - I'm calling it my yesterday's news thermometer )

It definitely seems like this stove will not maintain a fire with the air control closed, unless maybe i must get it up to 450-550deg so the secondaries ignite, then close it. I definitely couldn't get 400+ with 3 large splits, after this i will try with 5 good sized splits that are a bit dryer i guess.
I really need a good reliable thermometer. Any suggestions?

stove top is cast iron
Flue goes up 4ft from stove top, then 90 deg into wall.
no damper
Single wall pipe (inside the wall and chimney is all double wall)

thanks!!

 

[Trunkinator]

If loading N/S the splits should be 16-18" long. 12" splits would be 1/3 less filling.

See my reply to firefighterjake, I've tried something new definitely got bigger splits per your suggestions. I think I'm improving, certainly lots to learn. Got a much longer flame time but not a lot of heat. So maybe with more splits and more airflow i can option higher temps with prolonged heat? I feel like if i leave the air control half or more open, it causes quick burning, but I'm finding that i need the larger quantity air flow just to keep things ignited. Maybe my feeling was wrong all along about more air flow means faster burning (i mean it certainly does, but maybe this stove requires it??)

this is a science!!

Thanks much for your time and wisdom!

 

[Trunkinator]

As others have mentioned . . . if you only loaded the firebox 1/3 full with eight splits the splits are on the smaller size and will burn up faster which means less time spent in the secondary reburning stage, less time with active flames, etc.

Your process in loading the stove and controlling the air flow seems sound, although I will even let my stove go a bit hotter even on occasion (but again, I think the process is the size of the splits).

That said, you are right in not wanting to necessary load the stove to the gills with all smaller sized wood as you will most likely skip right be the Fires of Vesuvius and go right to the Portals of Hell and could even bypass the Portal to Hell and go right to the dreaded Thermonuclear Stove Melt Down (aka the Chernobyl Effect.)

My suggestion would be to load the stove a bit fuller next time, but also use larger splits if possible.

P.S. I find that stove thermometers do move a bit more sluggishly compared to the stove pipe thermometer.

At 1 hour 15min, , air control still halfway, only one split had flames, red coals beneath the other two splits, about 60% intact, and stovetop temp guage still only reading 300...

do i need to spike the stove up to temp (500-600deg) then start dropping the air control? I feel like anytime i drop it below 75% open, within an hour, it dies almost totally aaargh this is frustrating!

 

[moresnow]

How exactly are you measuring moisture content?

 

[Trunkinator]

How exactly are you measuring moisture content?

I have a General brand 2 pin moisture meter. I've also tried the dish soap method. I tested the dish soap on my killn dried <5% birch and blew crazy bubbles. Once tried on the ash, i got only a few bubbles, which told me the meter is relatively accurate. Sticking the prongs deep in the end with the grain and in the side of the splits against the grain, yielded results within 2%.

 

[begreen]

I have a General brand 2 pin moisture meter. I've also tried the dish soap method. I tested the dish soap on my killn dried <5% birch and blew crazy bubbles. Once tried on the ash, i got only a few bubbles, which told me the meter is relatively accurate. Sticking the prongs deep in the end with the grain and in the side of the splits against the grain, yielded results within 2%.

Neither of those two locations will provide an accurate reading. It's what is inside the log that is important. The wood must be resplit so that the reading can be taken on the freshly exposed wood in the middle of the split, preferably with the wood at room temperature.

Take a picture of the stove with the door open right after reloading so that we can see what you are seeing.

 

[Trunkinator]

Neither of those two locations will provide an accurate reading. It's what is inside the log that is important. The wood must be resplit so that the reading can be taken on the freshly exposed wood in the middle of the split, preferably with the wood at room temperature.

So if i take one of the larger splits, split it, and check the moisture within, can i reliably count on that to speak for the remainder of the splits (within reason) as long as they were seasoned together?

 

[begreen]

Sort of, but not if there are varying species in the stack or if the wood sat on a lot in a big pile for a time. Wood that sits on the ground for a while is likely to be wetter. Often you can feel this by weight. The damp split will be heavier.

 

[Trunkinator]

Sort of, but not if there are varying species in the stack or if the wood sat on a lot in a big pile for a time. Wood that sits on the ground for a while is likely to be wetter. Often you can feel this by weight. The damp split will be heavier.

This is from an ash tree i fell on my property. I fell, cut and split in the same weekend, and I had it stacked on pallets of the ground from may to september, and oc till now it's been in my wood crib (elevated 1ft off the ground and covered with a tin roof, all sides open to cross breeze

 

[moresnow]

re split and check a random selection of your splits after they have been allowed to get up to room temp. Let us know what you come up with.

 

[Trunkinator]

re split and check a random selection of your splits after they have been allowed to get up to room temp. Let us know what you come up with.

Roughly a 6" diameter split, about 15" in length
12.1% on ends
23% in center

This is after being split, checking center this is in the end before

 

[begreen]

So, it's a bit high in moisture still, but probably burnable, if a bit balky. It would be better to be in the 17% range in the middle. The end grain reading is irrelevant.

 

[moresnow]

Now you know the actual M/C. 20% M/C or preferably less is generally considered properly seasoned and ready to burn correctly in todays modern stove designs. As hard as it may be to believe it's really amazing how much better your burn characteristics will be with drier fuel.

 

[Trunkinator]

So, it's a bit high in moisture still, but probably burnable, if a bit balky. It would be better to be in the 17% range in the middle. The end grain reading is irrelevant.

I've had those 3 splits in for almost 3 hours now and it's still burning! Not a ton of heat, stove top says 350, but this is the longest burn I've had yet (i mean burn time with actual flames) and there is still at least 50% of each split left. There are almost transparent flames throughout. Now I'm getting encouraged! However, I'm still going to beat around the idea that this thermometer is junk. How can the stove top possibly only be 350deg!? I refuse to believe this thing is accurate...

 

[Trunkinator]

Now you know the actual M/C. 20% M/C or preferably less is generally considered properly seasoned and ready to burn correctly in todays modern stove designs. As hard as it may be to believe it's really amazing how much better your burn characteristics will be with drier fuel.

See my reply to Begreen. Thank you so much for your info. I feel like step by step I'm making progress. I've learned so much from this forum. Love it

 

[begreen]

Stove top thermometers

Condar stove top thermometers magnetically attach to the surface of your stove and help optimise stove's performance by showing best temperature range.

www.condar.com

 

[firefighterjake]

Random thoughts . . .

I burn both birch (white, yellow and gray) and ash . . . I find in general white birch (the most common birch I burn) is fair in terms of BTUs when compared to other wood (i.e. maple, beech, apple, oak, etc.) Perhaps more importantly it seems as if birch takes longer to season. What I mean to say is if I have two splits of roughly the same type of wood, cut, split and stacked around the same time and in the same manner, in general it seems as though the birch isn't quite as good as the other hardwood I am comparing it against. Now make no mistake. I love birch as well . . . my wife likes the fact that it comes with its own "kindling" with the papery bark, but when the winter winds are howling and I have a choice I tend to go to my better woods.

I think some members here are thinking what I was starting to think as I read your latest thread . . . your wood may be less than optimal. It's not that it is a wet, sopping mess that will creosote your chimney, but rather it will take longer to get more heat and will not burn as well. Let me give you an example. In Year One (2008) I was burning a lot of elm (mostly standing dead elm without bark) and to be frank I thought I was doing pretty well . . . and in hindsight I think I was doing OK with all things considering as the wood was maybe seasoned for a few months at best. I was also using busted up pallets to help bring the temps up. My chimney was pretty clean and I stayed warm.

In Year Two I began burning wood left over from the previous year . . . and immediately had a Come To Jesus moment when I realized how much of a difference a few more months made in terms of the fuel. Now I was able to burn longer, could shut down the air control further without suffocating the fire and had much more heat . . . not to mention that I no longer had to use pallets or dimensional lumber scraps to help bring the fire up to temp . . . and the secondaries . . . holy moley . . . before I would have some lazy flames or "fireworks" . . . but now I had the Portal to Hell opening up in my Jotul.

If you are unable to get a longer burn than what you have described AND are not getting the heat output AND have to constantly open up the air because the fire keeps dying I really think it may be less than optimally seasoned wood. Again . . . do not despair. If this is the case it is still possible to improve the situation, stay warm and burn safely . . . but it may require a few changes such as using some pallet wood or wood scraps (2 x 4 pieces for example) on a start up to build up the temp in the stove (and effectively drive any remaining moisture out of the wood) before you start to dial down the air . . . and when you do dial down the air I would do it pretty much as you describe. Let the temps go up to 500-600 before you start to dial down the air and then do so in quarter mark increments . . . first taking it down to 3/4 and letting it burn there for 10 minutes or so to make sure the fire is still raging and then take it down to the halfway mark, pausing for another 10 or 15 minutes and then taking it down to the quarter mark. If you are lucky you may eventually be able to close it down "all the way" . . . and hopefully somewhere around the quarter mark you will see some strong secondary action and hopefully a much longer, hotter burn.

Good luck.

P.S. I am a bit partial to Condar themometers. I have one on my stove and a probe style for my double wall pipe and the stove model seems relatively accurate when I check it with a digital laser thermometer.

 

[Trunkinator]

Hello again,

Random thoughts . . .
I burn both birch (white, yellow and gray) and ash . . . I find in general white birch (the most common birch I burn) is fair in terms of BTUs when compared to other wood (i.e. maple, beech, apple, oak, etc.) Perhaps more importantly it seems as if birch takes longer to season. What I mean to say is if I have two splits of roughly the same type of wood, cut, split and stacked around the same time and in the same manner, in general it seems as though the birch isn't quite as good as the other hardwood I am comparing it against. Now make no mistake. I love birch as well . . . my wife likes the fact that it comes with its own "kindling" with the papery bark, but when the winter winds are howling and I have a choice I tend to go to my better woods.

I think some members here are thinking what I was starting to think as I read your latest thread . . . your wood may be less than optimal. It's not that it is a wet, sopping mess that will creosote your chimney, but rather it will take longer to get more heat and will not burn as well. Let me give you an example. In Year One (2008) I was burning a lot of elm (mostly standing dead elm without bark) and to be frank I thought I was doing pretty well . . . and in hindsight I think I was doing OK with all things considering as the wood was maybe seasoned for a few months at best. I was also using busted up pallets to help bring the temps up. My chimney was pretty clean and I stayed warm.

In Year Two I began burning wood left over from the previous year . . . and immediately had a Come To Jesus moment when I realized how much of a difference a few more months made in terms of the fuel. Now I was able to burn longer, could shut down the air control further without suffocating the fire and had much more heat . . . not to mention that I no longer had to use pallets or dimensional lumber scraps to help bring the fire up to temp . . . and the secondaries . . . holy moley . . . before I would have some lazy flames or "fireworks" . . . but now I had the Portal to Hell opening up in my Jotul.

If you are unable to get a longer burn than what you have described AND are not getting the heat output AND have to constantly open up the air because the fire keeps dying I really think it may be less than optimally seasoned wood. Again . . . do not despair. If this is the case it is still possible to improve the situation, stay warm and burn safely . . . but it may require a few changes such as using some pallet wood or wood scraps (2 x 4 pieces for example) on a start up to build up the temp in the stove (and effectively drive any remaining moisture out of the wood) before you start to dial down the air . . . and when you do dial down the air I would do it pretty much as you describe. Let the temps go up to 500-600 before you start to dial down the air and then do so in quarter mark increments . . . first taking it down to 3/4 and letting it burn there for 10 minutes or so to make sure the fire is still raging and then take it down to the halfway mark, pausing for another 10 or 15 minutes and then taking it down to the quarter mark. If you are lucky you may eventually be able to close it down "all the way" . . . and hopefully somewhere around the quarter mark you will see some strong secondary action and hopefully a much longer, hotter burn.

Good luck.

P.S. I am a bit partial to Condar themometers. I have one on my stove and a probe style for my double wall pipe and the stove model seems relatively accurate when I check it with a digital laser thermometer.

Thank you again so much for your time and input.

I was just reading a thread and saw you mentioned closing off a portion of the opening on the bottom of your stove where the secondaries air enters. my F55 seems to turn into mount vesuvious on steroids if i put a 2/3 load in, at 500deg stove top i have secondaries that last about 20 minutes, and then the stove dies down to big chunks of charred splits after another 45 min. So from lighting the top-down wood stack to red coals is about 3 hours maximum. I'm seriously considering closing off that secondary port with some high temp tape.
Do you suppose this will increase my burn time? In addition, i must ensure my wood is fully and properly seasoned.

i also noticed that there is a steel bar that slides back and forth under the dog house controlling air inflow. I noticed if i close completely, there is still gaps letting air in (two windows, and the bar has two windows, and when slid back and forth, the windows open/close but the one remains about a half inch open and the other about 1/4" open. Does this sound normal? Shouldn't it totally close?

thanks!!

 

[Trunkinator]

Stove top thermometers

Condar stove top thermometers magnetically attach to the surface of your stove and help optimise stove's performance by showing best temperature range.

www.condar.com

I've got a stovetop and a single wall flue thermometer in the Mail from condar. Please see my reply to firefighterjake. I noticed today that the air control bar, even if I'm fully closed position, has a half inch gap in one window and a 1/4" gap in the other, allowing what IMHO is still a ton of air flow to the fire even if lever is totally "closed". Does this sound normal? Thanks!

 

[firefighterjake]

Hello again,
Thank you again so much for your time and input.

I was just reading a thread and saw you mentioned closing off a portion of the opening on the bottom of your stove where the secondaries air enters. my F55 seems to turn into mount vesuvious on steroids if i put a 2/3 load in, at 500deg stove top i have secondaries that last about 20 minutes, and then the stove dies down to big chunks of charred splits after another 45 min. So from lighting the top-down wood stack to red coals is about 3 hours maximum. I'm seriously considering closing off that secondary port with some high temp tape.
Do you suppose this will increase my burn time? In addition, i must ensure my wood is fully and properly seasoned. Yes . . . it most likely would affect the draft. I would exercise caution in doing so. I do know a few folks here have used magnets as a permanent-temporary fix, another person fabricated a sliding mechanism to cut back on the air. I personally would not add tape as it may affect fire behavior when first lighting the fire. The nice thing about the aluminum foil I use on the raging fires is the suction from the draft keeps it in place until the fire and draft die down . . . at which point the aluminum foil naturally falls on to the hearth.

i also noticed that there is a steel bar that slides back and forth under the dog house controlling air inflow. I noticed if i close completely, there is still gaps letting air in (two windows, and the bar has two windows, and when slid back and forth, the windows open/close but the one remains about a half inch open and the other about 1/4" open. Does this sound normal? Shouldn't it totally close? Different stove from my Oslo . . . but I will say these modern stoves are designed to always allow some incoming air. Perhaps asking another user with the same stove to take a picture of their air control or checking out the same model in a showroom would let you know if your stove's air control is good or needs to be adjusted.

thanks!!