Jotul F3 Won't Maintain Heat

[John P.]

Hi everyone! It's my first post here, so thanks in advance for any help you can offer. Having read through the forum a bit, you seem like some nice folks.

I have a new Jotul F3 that works great for the most part - lights easily, heats right up to 500-600 degrees pretty quickly, generates a nice secondary burn, and seems to have a great draft - very little smoke spillage when I have to open the door at the beginning or end of a burn cycle.

The problem I'm having is that it won't maintain heat once I begin to close the primary, or it will burn through wood too fast if I leave the primary open. I've followed a lot of your advice to slowly close the primary once it gets up around 500-600, but I get one of two problems - either I leave the primary pretty wide open and burn through wood quickly, or I close the primary almost all the way and the stove cools right off to sub-300 within an hour or so. For what it's worth, it will continue to burn for a long enough that I still have hot coals after an overnight burn, it just won't burn very hot.

Any idea what I'm doing wrong? For the record, I burn only hardwoods (mostly oak, maple, and ash), and they're seasoned a solid year before they hit the stove.

Thanks again for any help you can offer!

John P.
Freeport, Maine

 

[Dakotas Dad]

A solid year on many hardwoods isn't near "seasoned" Oak can be 4 years to get good and dry. usually 3. When you start closing down the air, what are the secondaries doing, and how do they react?

The F3 isn't a very large stove.. so getting a long peak temp burn in it is going to only be accomplished by getting a lot of things "right".. including the wood. And even then, well.. it's a small gas tank, so only so far between fuel ups. (to use an automotive reference)

Can you tell us a little more about your instal? size of house, basic floor plan, chimney style/type/height..

EDIT: Welcome to the forum.. read and dig, tons of info here..

 

[begreen]

Yep, sounds like partially seasoned wood. Oak needs a couple good years to dry at its core. If you have some ash or fruitwood in the shed, try burning just that. I think you will find it burns hotter and with less air.

Use this to your advantage. Getting an overnight burn out of this stove is not easy. Burn the oak for overnight fires and the ash + maple during the day.

 

[John P.]

Hey guys-

Thanks for the advice! I went out and bought a couple of packs of kiln-dried wood at the grocery store, but it was the same result: I can get the fire nice and hot and a really good secondary combustion going, but when I completely shut down the primary (slowly, over the course of 15-20 minutes), the fire slowly dies and the stove loses heat. It seems like the best result for me is to leave that primary about 20% open to maintain a consistent hot temperature, but when I do that, I only get around a 3-hour burn time.

To answer DD's question, I have a pretty large house, but I have most of it closed down in the winter, and I'm only trying to heat about 1200 - 1500 sq. ft. (I have a forced hot air furnace that's on another flue to provide auxiliary heat when needed).

I'm not sure what 'type' of chimney I have, but it's about ~20ft tall or so. Pics attached.

(broken image removed)

My main question is, am I doing something wrong, or does my stove need to be 'fixed' in some way?

Thanks again for all your help, guys!

JP

 

[mol1jb]

Man that is it pretty chimney. Next question is is that chimney lined? A lined chimney creates substantially a better draft an unlined.

 

[John P.]

Thanks! You should have seen the two guys who built that chimney - the project got delayed because one of them was in jail, and the other looked like he was recently on the losing end of a barroom brawl. Both had forearms like Popeye. It's a minor miracle it turned out so well!

To answer your question, it's just a basic terra-cotta liner in each flue, but the draft doesn't seem to be a big problem - fires light right up easily, and there's little to no smoke spillage when I open the door.

JP

 

[pen]

Why completely shut down the air?

Can you leave it open 10% or 15% or so and get a better result? I haven't closed the air control fully on my stove other than during the off season in several years....... the other times I had to close it all the way I loaded on a coal bed that was too hot.

If you need to leave it open a bit, there's no harm in that.

Nothing wrong with an unlined / uninsulated chimney other than it doesn't create as much draft as a 6 inch insulated flue would for that stove. Even being that tall, I think you just need to leave the air open a bit.

What is the diameter of the flue liner in that chimney? Is it 6 inch? 8 inch? Round? Square?

pen

 

[Swedishchef]

I can never close my stove down all the way...it always remains open 10-15% as Pen mentioned. As everyone mentioned , the stove isn't that big and getting an overnight burn will be tough.

Super nice chimney! I love the story of the builders...lol

Welcome to the forum!

Andrew

 

[Nick Mystic]

The Jotul F3 is a pretty small stove with only a 1.17 cubic foot firebox. It sounds like you are getting about as much heat as a stove this size can deliver in my opinion. I have a Jotul F 600 with a 3 cubic foot firebox and I start shutting down my primary at 300 F and cruise at 400 F for only a couple of hours before my temperature starts dropping. When you say you wait until you hit 500 - 600 F to start shutting down your primary you might be getting too hot before you start shutting things down if you want longer burns. I've noticed with my stove that with some loads it burns best only shut down to the 20% your mention as your best burning primary setting, as well. There is no rule that you need to get a complete shut down on you primary for the best burn. It sounds to me like you pretty much have things figured out. If you want better performance you might have to consider moving up to a larger stove.

 

[John P.]

Great advice/insight, guys. Thanks very much! I just want to make sure I'm maximizing my stove, which was a gift from my in-laws. If I were going to do it all over again and pay for it myself, I'd probably buy a bigger stove, but I'm certainly not complaining!

Thanks again!

John

 

[Swedishchef]

I wish I had your inlaws (nice gift!).....and all the outlets of Freeport Plan on going down there next month for a bit of shopping

Good luck!

 

[pen]

Great advice/insight, guys. Thanks very much! I just want to make sure I'm maximizing my stove, which was a gift from my in-laws. If I were going to do it all over again and pay for it myself, I'd probably buy a bigger stove, but I'm certainly not complaining!

Thanks again!

John

Yep, every BTU that sucker puts out is one less other heat sources need to provide.

Keep us posted.

 

[Davidram]

Yep, every BTU that sucker puts out is one less other heat sources need to provide.

Keep us posted.

 

[BrotherBart]

Having run an F3 for a couple of years I advise that once you get the stove top up around 400 degrees that you close the primary air 3/4 and leave it there. The sweet spot for me and every F3 owner I know. And three hours is about the run for the lil pup. Coals forward and reload time.

 

[Davidram]

Check out the cast iron top of your stove. It is only held on by gravity and can be bumped ajar when you are loading the stove. Air comes in the firebox and straight up the flue when it is not on right. The result is a cool fire. You would think the stove would smoke or the fire hard to control but all that happens is a cooler than normal stove. It happened to me last night on my series 8 Jotul. The catalytic converter kept going out and I thought I had some wet wood.

 

[begreen]

The top on the F3CB is held in place by two allen screws. Unless these screws have been loosened or removed the top should be at factory position. In this case I think BB is correct. The fire needs a bit more air. Not a lot, but try it at 3/4s closed.

 

[tsquini]

I get a good secondary burn after I build up a good bed of hot coals. With about 2" of glowing red coals I can place 2 seasoned pieces of wood have the primary set a 50% let it run for 10min. Then close the primary all the way. I only need my stove top temp around 400-450 for the secondaries to kick in.