Questions on Running a Jotul F3 After First Month

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CutterComp

Member
Oct 27, 2018
6
Bechtelsville, PA
Installed a Jotul F3 CB about one month ago and although I would generally say it's going well, I do have a few questions.

First some background info that would be helpful. We're in southeast PA, in a 200 year old stone farmhouse built into the hillside (ground level in the rear is level with the second floor). There are three floors, connected by winding staircases. No significant additions to the original house, which is 20' deep and 24' wide, so 480 sq ft per floor. It previously had replacement windows installed, but otherwise the house is anything but tight. The house has walk-in fireplaces on the first and second floors that share a common internal chimney structure with individual original plaster lined flues. The first floor fireplace is actually offset to the front of the gable end of the house, while the second floor fireplace is about centered in the gable wall. Hence, the flue for the first floor fireplace has a gentle curve to it so it can join the center chimney. I would estimate the length of the first floor fireplace flue to be 25-30 ft.

When we bought the house in 2014, there was no stove installed in either fireplace but both had just been relined with 6" flexible stainless liners and a new chimney cap by the previous owners. These liners are not insulated. The original flues are roughly 18" square, now with the 6" liner running up them. Our first winter we heated the first and second floors with the oil/hot water boiler but kept the temps only about 60*. Since then, we've only heated the first floor, still at 60*. The second floor gets some heat coming up through the floors and stairway (door kept closed)... and generally sits at 54*. The third floor where the bedrooms are located has electric baseboards which we don't use except for my son's bedroom occasionally. So it gets quite cold up there... I've seen 39*. So you can imagine it's generally pretty cold in the house during the winter trying to keep the oil bills down... yet still pretty expensive. Worst of both worlds, haha.

So that sets the stage for buying a wood stove. We have about 6 wooded acres, more tulip poplar than anything, but also fair amounts of red oak and ash (which of course are all dying). A few years ago I built a nice woodshed and filled it with split cherry, oak, and ash in prep for buying a stove but didn't actually have the opportunity to buy a stove until a month ago.

The stove was new in 1999, but has been disused since 2011. It is in very nice, clean condition. Using the dollar bill trick, the door and ash pan gaskets are tight. I had the top off the stove to clean it and that gasket is also tight. I have not checked the gasket between the ashpan and stove body and I read that can be troublesome. There is a telescoping, black, single wall stove pipe from the 'T' at the rear of the stove going up about 5 feet to join the flexible stainless liner at the block off plate at the top of the fireplace. We've been using it as our only heat source for a month... once it reaches a 400*F cruise, it will keep the first floor at about 65-66*F which is better than we've ever lived! I'm planning to buy an Ecofan too, so that should help. I'd say we've been averaging outside daytime temps in the 40s and nighttime temps in the upper 20s.

Questions:
1) Looking for advice on whether or not I could benefit from installing a stove pipe damper to aid burn times. First, I know this is a small stove... still wondering if I should I upgrade to an F400/500 in the future. Being a small stove, you can't put much wood in it at one time. But if I get 3 hours burn time out of two thick 18" pieces of dry oak or ash, that's a better than typical burn. Yes, this is with the startup damper and primary damper fully closed. If I go to bed at midnight with the stove freshly loaded and cruising nicely at 350-400*F on the stovetop thermometer, by 3:30AM, it's either fully dead or so little embers remain that it takes 30+ minutes to get going again. In that scenario, I often find the thermometer reading 150-200*F. Thus in an 8 hour night, I have to get up twice for 30 minutes to keep the stove going. Would a stove pipe damper help? If so, where's the best place to put it and how should I use it to my advantage?

2) As I mentioned in Question 1, I usually put no more than 2 thick pieces of 18" oak or ash in at one time when going for maximum burn. The reason is that if I add a third piece, it has to go on top of the first two and this makes it within a few inches of the top of the firebox. In this scenario, I find the stove goes into an uncontrollable burn. If it was previously cruising steadily at 400*F and I add a third piece too close to the top of the firebox, it will jump to 600*+ even with the dampers fully closed. I've been very careful with this, by either leaving the door open for a bit till the wood burns down or trying to quickly remove the third piece... otherwise the stove would probably go beyond 600*F. Have other people found this to be true with their F3? Perhaps having the wood too close to the roof of the firebox negatively affects how airflow is designed ?

3) How often should I be getting the flue liner cleaned? I understand this depends on many variables but I'm totally new to this with no point of reference. Monthly? Once per season?

4) When I run the stove fully damped for the longest burn times at night, I assume those are the times when I'm adding the most creosote to the inside of the liner. I guess this is unavoidable but I also worry adding a stove pipe damper could make this even worse. Thoughts?

5) We haven't burned full time for the last month, I'd estimate it totals 2 weeks of continuous burning. My woodshed holds just shy of 2 cords of wood. In that two weeks, we've used nearly a quarter of that, so half a cord. Again I have no frame of reference here, but will say I'd hoped it would last longer. Does that seem normal-ish?

Thanks!

Stove1.jpeg Stove2.jpeg
 

EbS-P

Minister of Fire
Jan 19, 2019
1,714
SE North Carolina
So I have the F400 it’s been the next size up in th jotul line. I’ve never run an F3. But I’ll give you some thoughts.

1 and 2

probably anything over 25 adding damper might help. How are you measuring temps (did I miss it sorry) Anything less than 700 is fine. Short excursions to 850 are probably ok don’t make it a regular thing. I run my stove top at the hottest part at 700 regularly. I pack it full but not touching baffle. Adding damper 18” up the single wall pipe where it can easily be accessible. It won’t need constant adjustments. Extra windy extra cold. Extra warm days. Ect

Opening the door may cool the top but it burns the wood faster so when you close the door again it is burning at a rate faster than it could have with the door open. what I do is add a small piece of kindling first load full and packed tight less air circulation means a slower burn. close the door open air full for 10 minutes then close the air down to desired burn rate. Just experiment. I like my Auber at200 temp alarm. It’s worth the money.

The ash pan body gasket id be looking for flames coming up through ash grate holes where coals burned faster in that area.


3) if your wood is truly dry and you are burning hot I’d sweep to check after one cord. If it looks fine the. End of the season. Bottom up with a soot eater would be how I would do yours.

4
yes, but again dry wood helps. Insulating you liner would help and make your 200 plus year old chimney meet code. I suggest you just put that on a list of items to do or have done. Especially if adding a damper.

5
I can burn 5 cu ft a day. So that doesn’t seem unreasonable a cord a month. You are going to need more wood. Poplar dries fast. (Burns fast too). Same with pine. I burn both not the best wood for the coldest nights but it’s heat. If I want to keep my house holding temp over night I need to load at 10:30 and again at 2:30am.

Love the look of the hearth. Love the idea of an old home. Would not like to take care of it. Consider adding a mini split. Any time it’s 30 or warmer just run it. That’s a lot of hours Nov -March. The F3 is not going to heat the whole house but as you have shown it’s nice. I would be looking for a bigger stove as time and money allow.

Get a damper. Sweep in December. Get an accurate thermometer. Run it hotter, And more wood.

Hope that help.
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,333
South Puget Sound, WA
Yes a stovepipe damper won't hurt, but it is not going to make a huge difference for heat. Old stone houses suck up heat like a sponge. I had the F3CB on a short 12' flue and the best times were 4-5hrs., but it was only putting out good heat for 2-3 hrs. Sold it after a year and went to the F400. That was better, though in very cold weather I had to stoke it frequently to keep the house heated well. Also room temp swings were an issue. We didn't need a radiant stove for our house. Now we have a 3 cu ft convective stove that works a lot better at heating the house well. I would be looking at 3 cu ft stoves for this location and I would go for a convective heater with a blower.

PS: Is there a blockoff plate in the damper area of the fireplace? Has it been verified that there is no wood in the interior of the chimney or fireplace? There was in Ashful's stone house.
 

CutterComp

Member
Oct 27, 2018
6
Bechtelsville, PA
1 and 2

probably anything over 25 adding damper might help. How are you measuring temps (did I miss it sorry) Anything less than 700 is fine. Short excursions to 850 are probably ok don’t make it a regular thing. I run my stove top at the hottest part at 700 regularly. I pack it full but not touching baffle. Adding damper 18” up the single wall pipe where it can easily be accessible. It won’t need constant adjustments. Extra windy extra cold. Extra warm days. Ect

Opening the door may cool the top but it burns the wood faster so when you close the door again it is burning at a rate faster than it could have with the door open. what I do is add a small piece of kindling first load full and packed tight less air circulation means a slower burn. close the door open air full for 10 minutes then close the air down to desired burn rate. Just experiment. I like my Auber at200 temp alarm. It’s worth the money.

The ash pan body gasket id be looking for flames coming up through ash grate holes where coals burned faster in that area.


3) if your wood is truly dry and you are burning hot I’d sweep to check after one cord. If it looks fine the. End of the season. Bottom up with a soot eater would be how I would do yours.

4
yes, but again dry wood helps. Insulating you liner would help and make your 200 plus year old chimney meet code. I suggest you just put that on a list of items to do or have done. Especially if adding a damper.

5
I can burn 5 cu ft a day. So that doesn’t seem unreasonable a cord a month. You are going to need more wood. Poplar dries fast. (Burns fast too). Same with pine. I burn both not the best wood for the coldest nights but it’s heat. If I want to keep my house holding temp over night I need to load at 10:30 and again at 2:30am.

Love the look of the hearth. Love the idea of an old home. Would not like to take care of it. Consider adding a mini split. Any time it’s 30 or warmer just run it. That’s a lot of hours Nov -March. The F3 is not going to heat the whole house but as you have shown it’s nice. I would be looking for a bigger stove as time and money allow.

Get a damper. Sweep in December. Get an accurate thermometer. Run it hotter, And more wood.

Hope that help.

Thanks for the very helpful response. I'm checking temps just with a magnetic stovetop thermometer. You can probably see it if you look closely at the second picture I posted. I didn't realize 700F was acceptable, but good to know I can take it up there and be safe. I just looked up the Auber AT200, didn't know they existed, very slick. Will look into a Soot Eater too, never heard of it. On that topic, I know very little up sweeping flues, I was afraid I was going to have to go on the roof to do it.... or pay someone.

Showing more ignorance here, but I didn't realize the liner had to be insulated in my situation to meet code. Again, it was installed by the previous owners. I wonder what it would cost to have it insulated? I know they sell pre-insulated liners, I wonder if that would be cheaper than trying to remove, line, reinstall my existing liner.

Agreed, gonna need more wood for the winter.... need to buy a splitter. Borrowed one last time.
Yes a stovepipe damper won't hurt, but it is not going to make a huge difference for heat. Old stone houses suck up heat like a sponge. I had the F3CB on a short 12' flue and the best times were 4-5hrs., but it was only putting out good heat for 2-3 hrs. Sold it after a year and went to the F400. That was better, though in very cold weather I had to stoke it frequently to keep the house heated well. Also room temp swings were an issue. We didn't need a radiant stove for our house. Now we have a 3 cu ft convective stove that works a lot better at heating the house well. I would be looking at 3 cu ft stoves for this location and I would go for a convective heater with a blower.

PS: Is there a blockoff plate in the damper area of the fireplace? Has it been verified that there is no wood in the interior of the chimney or fireplace? There was in Ashful's stone house.

Thanks begreen. Is a 12' or 30' flue generally better for burn time? Interesting points about the convective vs radiant stoves... I'll have to research the topic.

There is a blockoff in the damper area of the fireplace. Two actually. There is a very old, rusty one, I'd say 3/16" plate with a hole torched in the middle of it for the stainless liner. Then when they installed the liner, they added a very poorly fitting thin sheet metal plate below the original with a clamping stainless collar around the flue where it passes through. No insulation of any kind around the perimeter of the block off plates and there are quite a few gaps where the stonework is uneven. I did remove the sheetmetal plate when I installed the stove hoping to see up the chimney but found the 3/16" block off above it which is bolted and partially plastered into place and I didn't want to remove it. The best I could do was look up through the gap between the flue liner and plate with a flashlight. I did see there were two 4x4" sized piece of wood that cross the chimney passage about 2 feet above the block off plate on either side of the liner, maybe spaced 8" from it. Both were already mostly burned up from years ago... no idea what their original purpose was. But they terminate in stonework. Beyond them, I could not see any wood, but hard to see accurately and again, the flue curves up the left as it finds the center of the house. Knowing how the house is built, where the joists and summer beams tie into the stonework on the gable ends, I don't believe there is any wood in close proximity to the flue liner but that's just my educated guess. I suppose the only way to know would be to send a camera down the chimney with the cap removed at the top?
 

EbS-P

Minister of Fire
Jan 19, 2019
1,714
SE North Carolina
Thanks for the very helpful response. I'm checking temps just with a magnetic stovetop thermometer. You can probably see it if you look closely at the second picture I posted. I didn't realize 700F was acceptable, but good to know I can take it up there and be safe. I just looked up the Auber AT200, didn't know they existed, very slick. Will look into a Soot Eater too, never heard of it. On that topic, I know very little up sweeping flues, I was afraid I was going to have to go on the roof to do it.... or pay someone.

Showing more ignorance here, but I didn't realize the liner had to be insulated in my situation to meet code. Again, it was installed by the previous owners. I wonder what it would cost to have it insulated? I know they sell pre-insulated liners, I wonder if that would be cheaper than trying to remove, line, reinstall my existing liner.

Agreed, gonna need more wood for the winter.... need to buy a splitter. Borrowed one last time.


Thanks begreen. Is a 12' or 30' flue generally better for burn time? Interesting points about the convective vs radiant stoves... I'll have to research the topic.

There is a blockoff in the damper area of the fireplace. Two actually. There is a very old, rusty one, I'd say 3/16" plate with a hole torched in the middle of it for the stainless liner. Then when they installed the liner, they added a very poorly fitting thin sheet metal plate below the original with a clamping stainless collar around the flue where it passes through. No insulation of any kind around the perimeter of the block off plates and there are quite a few gaps where the stonework is uneven. I did remove the sheetmetal plate when I installed the stove hoping to see up the chimney but found the 3/16" block off above it which is bolted and partially plastered into place and I didn't want to remove it. The best I could do was look up through the gap between the flue liner and plate with a flashlight. I did see there were two 4x4" sized piece of wood that cross the chimney passage about 2 feet above the block off plate on either side of the liner, maybe spaced 8" from it. Both were already mostly burned up from years ago... no idea what their original purpose was. But they terminate in stonework. Beyond them, I could not see any wood, but hard to see accurately and again, the flue curves up the left as it finds the center of the house. Knowing how the house is built, where the joists and summer beams tie into the stonework on the gable ends, I don't believe there is any wood in close proximity to the flue liner but that's just my educated guess. I suppose the only way to know would be to send a camera down the chimney with the cap removed at the top?
Insulation wrap is 375$ for 25’. Probably cheaper to pull and insulate what you have rather than replace.

As for the block off plate the more you can seal the more heat stays In The house. You can use mineral wool to insulate I use tin foil to seal big gaps.

I don’t have a splitter. I use a fiskars x27 and maul. I’m pretty fast work 30 minutes at a time 3-5 days a week and I can split and stack a cord in less than 4 weeks. Average wood should dry for 2 years once split.
 
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EbS-P

Minister of Fire
Jan 19, 2019
1,714
SE North Carolina
I use a blower on the floor behind my stove to help move heat out of the fireplace you might consider that. I have it set up just to blow up the back of the stove.
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,333
South Puget Sound, WA
The F3CB breathes pretty easily to work on a 12' flue system. A 30' flue would be like attaching a vacuum cleaner on the stove pipe. On a 30' flue most of the heat is being sucked out of the stove and up the liner. That's a lot of wasted heat. It will need a damper, and maybe two. A flue thermometer will illustrated this clearly. Without a damper you will see that the liner temp is quite hot. After the damper has been installed and closed you should note a significant drop in temperature on the liner. Our F3CB typically ran about 550-650 on the stove top, but in colder weather I took it up to 700º occasionally, albeit with a shorter burntime by doing so.

I'm not surprised by the wood showing up in the chimney. There may be more further up. Seems like stone house builders didn't have a lot of concern about this, but it illustrates the need for the insulated liner.
 

gfirob

Member
Dec 7, 2014
24
Rochester, Vt
We have a Jotul F3 in a 100 year old Vermont wooden house, with the wood stove in the living room and good air circulation around to the the dining room and kitchen (no dead ends). It is about a 2,000 square foot, 3 bedroom house, with a small bedroom on the third floor with an electric heater for its occasional use.

We burn about four to five cords a year, including a smaller wood stove in a finished carriage barn, mostly oak, maple and birch, dry. We also have an oil boiler, which we use when needed, but we try to avoid using it if we can.

When packed at midnight, this stove will deliver burning coals in the morning, just enough to start a fire, but now we usually just let it burn down from the evening’s last fire and light a new one in the morning, the temperature in the living room having dropped about 10 or 12 degrees by then. The house has new windows, a foamed basement and is insulated, pretty tight.

That stove is fine for a house of this size. We have no damper, the straight pipe goes out of the top of the stove straight up to an elbow into an asbestos right angle joint into the chimney. We have a ceiling fan in the living room which helps quite a bit. The stove sits out in the living room two feet or so from the wall in the back, so it is radiating in all directions

We get the chimney cleaned every year (I have experienced a chimney fire in an earlier house and I don’t want to repeat it) but the chimney guy tells me every year that there is not much build up from this stove. In Vermont wood heat is pretty common and the chimney guys are experienced and helpful (not my experience in Virginia).

Winters are cold here, often in the teens, so buttoning up the house is really important, good windows, doors, and no leaks if possible.

After seven years of using it, I like the Jotul quite a bit, and it has no problem heating the whole house, the upstairs bedrooms being about 10 degrees colder than the down stairs which is good for sleeping.
 

Geoff C

Burning Hunk
Oct 29, 2011
138
PA
Cutter and gfirob, I would try and find a used F500 or even F600

Loading at midnight and not having coals…. 2000sq ft in Vermont. 200 year olds farm house.


A bigger stove would make a world of difference.
 
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CutterComp

Member
Oct 27, 2018
6
Bechtelsville, PA
We have a Jotul F3 in a 100 year old Vermont wooden house, with the wood stove in the living room and good air circulation around to the the dining room and kitchen (no dead ends). It is about a 2,000 square foot, 3 bedroom house, with a small bedroom on the third floor with an electric heater for its occasional use.

We burn about four to five cords a year, including a smaller wood stove in a finished carriage barn, mostly oak, maple and birch, dry. We also have an oil boiler, which we use when needed, but we try to avoid using it if we can.

When packed at midnight, this stove will deliver burning coals in the morning, just enough to start a fire, but now we usually just let it burn down from the evening’s last fire and light a new one in the morning, the temperature in the living room having dropped about 10 or 12 degrees by then. The house has new windows, a foamed basement and is insulated, pretty tight.

That stove is fine for a house of this size. We have no damper, the straight pipe goes out of the top of the stove straight up to an elbow into an asbestos right angle joint into the chimney. We have a ceiling fan in the living room which helps quite a bit. The stove sits out in the living room two feet or so from the wall in the back, so it is radiating in all directions

We get the chimney cleaned every year (I have experienced a chimney fire in an earlier house and I don’t want to repeat it) but the chimney guy tells me every year that there is not much build up from this stove. In Vermont wood heat is pretty common and the chimney guys are experienced and helpful (not my experience in Virginia).

Winters are cold here, often in the teens, so buttoning up the house is really important, good windows, doors, and no leaks if possible.

After seven years of using it, I like the Jotul quite a bit, and it has no problem heating the whole house, the upstairs bedrooms being about 10 degrees colder than the down stairs which is good for sleeping.

Great info, thanks. When you say you can load at midnight and have hot coals in the morning, what time is that? Last night I was elated because I packed it with red oak at midnight and had enough hot coals at 4am to start another log. And it was warm outside last night, which helped. Probably my longest burn to date.