F400 still wants to overfire at night

Revturbo977 · Dec 8, 2014

i started a thread a while ago about how my f400 wants to take off at night . Still can't seem to find out what the issue is or what I'm doing wrong. It did it again last night . I burned the coals down and raked them forward. Filled the box full of wood and left the damper open for about 5-10 minutes. Wood did not catch, but I closed it off completely and went to bed. Woke up to use that bathroom around 1130 and it was going nuts. Was a very bright yellow secondary burn and the stovetop was at 650. Kept going to 750 and started to slow down. I sat for about 20 minutes watching it till it calmed down and dropped below 700.

Now I did some testing to see it the stove is leaking air and I can't find it. I filled the box during the day one Sunday so I can watch it and left it with the damper closed. Never lit, 4-5 hours went by and the wood smoldered out. It was about 40 out . Last night it was below 20 out so I suspect it was still pulling hard. What am I doing wrong during this process ? How small of a coal bed should I have and how much wood can I really put in this thing? When I loaded it last night temps were at 250 . I'm so baffled about this

tarzan · Dec 8, 2014

I struggled with this issue for a while myself.

Part of it is likely a better draft because of the colder temps at night. The other part, the part you can control, is not letting the wood get burning good and off gassing some before you shut it down for bed.

You want to see a calm fire when you leave the room for bed so you shut the draft sooner than normal. Eventually though, it will catch and all that wood that's been smoldering will start off gassing at once.

Try running the stove more like you would during the day, and then give it about 15 minutes to settle in after you shut it down to your normal draft setting and before going to bed.

fishinpa · Dec 8, 2014

I really don't know your stove, but have a friend with a similar Jotul. , Checking out his stove one day I noticed I could see flames in the fire box from the external corners when it was burning. Then I realized that all 4 sides of his fire box are separate panels.

I did some basic research and although he was doing basic maintenance, cleaning chimney, replacing door gaskets, etc, that he was neglecting to re-cement the inside corners of the fire box. ALSO: If your stove opens from the top (as my friends does) there are gaskets to inspect and possibly replace there too!

Revturbo977, I just pulled the manual for your stove and it appears you fire box is 4 separate panels also so this is why I am mentioning it.

As I said, I really do not know your stove, but that may give you a temporary direction to investigate until someone that knows your stove may have a more definitive answer for you.

Best of luck getting to the bottom of this.

Revturbo977 · Dec 8, 2014

tarzan said:
I struggled with this issue for a while myself.

Part of it is likely a better draft because of the colder temps at night. The other part, the part you can control, is not letting the wood get burning good and off gassing some before you shut it down for bed.

You want to see a calm fire when you leave the room for bed so you shut the draft sooner than normal. Eventually though, it will catch and all that wood that's been smoldering will start off gassing at once.

Try running the stove more like you would during the day, and then give it about 15 minutes to settle in after you shut it down to your normal draft setting and before going to bed.

95% of the time the wood doesnt even catch before i push the damper all the way closed. somestimes would take a half hour to start burning with the damper open. if i understand this correctly, even smoldering with no flame, the wood is heating up and eventually off gasses and ignites?

Revturbo977 · Dec 8, 2014

fishinpa said:
I really don't know your stove, but have a friend with a similar Jotul. , Checking out his stove one day I noticed I could see flames in the fire box from the external corners when it was burning. Then I realized that all 4 sides of his fire box are separate panels.

I did some basic research and although he was doing basic maintenance, cleaning chimney, replacing door gaskets, etc, that he was neglecting to re-cement the inside corners of the fire box. ALSO: If your stove opens from the top (as my friends does) there are gaskets to inspect and possibly replace there too!

Revturbo977, I just pulled the manual for your stove and it appears you fire box is 4 separate panels also so this is why I am mentioning it.

As I said, I really do not know your stove, but that may give you a temporary direction to investigate until someone that knows your stove may have a more definitive answer for you.

Best of luck getting to the bottom of this.

ive never taken the stove apart because its brand new. bought it new in july. it could be leaking from the factory?

Warm_in_NH · Dec 8, 2014

Revturbo977 said:
95% of the time the wood doesnt even catch before i push the damper all the way closed. somestimes would take a half hour to start burning with the damper open. if i understand this correctly, even smoldering with no flame, the wood is heating up and eventually off gasses and ignites?

Let it catch w the air open. Otherwise you're essentially filling the fire box with excessive fuel (gas) then throwing a match into it. (Ever see the movie back draft? )

Once it's burning cut the air back slowly, maintain a flame but work on getting the flame from the bottom of the wood to the top where the secondaries are. Takes me up to an hour some days from fresh load to fully cut air supply, other times it's a 25 min process. Depends a lot on wood moisture, coal bed, and draft.

If it's a new stove I'm thinking it's probably a learn curve for you and you probably have less than ideal wood.

tarzan · Dec 8, 2014

Revturbo977 said:
95% of the time the wood doesnt even catch before i push the damper all the way closed. somestimes would take a half hour to start burning with the damper open. if i understand this correctly, even smoldering with no flame, the wood is heating up and eventually off gasses and ignites?

Basicly correct. An EPA approved stove has a good amount of secondary air that will get in no matter how far you shut the primary. This design is to prevent a smoldering fire so if you shut it down before it gets caught up eventually it will catch up on its own and with wood that's been smoldering a while this could become a gates of hell type fire in short order.

You always want to let the fire catch good while shutting the draft in two or even three steps. You should never shut the draft on a fire that's not established. Try leaving the draft wide open till about 300*F to 350*F, then shut it down to about half until it reaches around 450*F, then the last step. Shutting the draft to your normal operating setting. This could be from fully closed to open about an inch depending on your stove, primary air control design, heating needs, weather , length of pipe and other factor, lol. Made it sound complicated but it really isn't. Once you start shutting it down in steps you will quickly find that sweet spot.

An air leak can not be totally ruled out but based on your description of events I would rather think wet wood and not letting the fire get properly established

claydogg84 · Dec 8, 2014

You shouldn't be shutting the air down without any flame. By doing that you're just throwing tons of smoke up the chimney. Shut the air down in stages, 2 or 3. Once I have a good fire going in the box, I'll knock it down a little over half. 7-10 minutes later I drop it down to about 1/4 open where I leave it for the night. If the flames go out, you need to start over. To see how hot it's getting overnight you can put a piece of aluminum foil on the temp gauge. I'm running the Oslo.

Revturbo977 · Dec 8, 2014

this is starting to make sense. basically when i wake up i find a violent secondary burn that is not controllable. my wood is far from perfect so it takes forever for it to light with the coals raked forward. i thought letting it light was causing this problem but it seems its the other way around. so with all this fuel in the stove, i need to let it catch and burn to a temp before closing the damper down.

Revturbo977 · Dec 8, 2014

claydogg84 said:
You shouldn't be shutting the air down without any flame. By doing that you're just throwing tons of smoke up the chimney. Shut the air down in stages, 2 or 3. Once I have a good fire going in the box, I'll knock it down a little over half. 7-10 minutes later I drop it down to about 1/4 open where I leave it for the night. If the flames go out, you need to start over. To see how hot it's getting overnight you can put a piece of aluminum foil on the temp gauge. I'm running the Oslo.

someone suggested i turn the air all the way off right away, i guess i misunderstood him. it is very hard for me to keep a full box of wood burning with just setting the damper and walking away . i can do this with 1 or 2 pieces but a full box seems to be all over the place and i need to really watch it. sometimes it burns fine, or gets too hot, or just goes out. i guess my wood is the culprit of this .

i feel like im beating the snot out of this stove. all this smoke and then over fire once in a while is killing it

fishinpa · Dec 8, 2014

Revturbo977 said:
ive never taken the stove apart because its brand new. bought it new in july. it could be leaking from the factory?

I'm sorry, I mis-interpreted your post opening "i started a thread a while ago about how my f400 " as this not being a brand new stove. Just use my reply as a prompting to stay on top of maintenance then.

Revturbo977 · Dec 8, 2014

fishinpa said:
I'm sorry, I mis-interpreted your post opening "i started a thread a while ago about how my f400 " as this not being a brand new stove. Just use my reply as a prompting to stay on top of maintenance then.

thank you for your research

claydogg84 · Dec 8, 2014

Revturbo977 said:
someone suggested i turn the air all the way off right away, i guess i misunderstood him. it is very hard for me to keep a full box of wood burning with just setting the damper and walking away . i can do this with 1 or 2 pieces but a full box seems to be all over the place and i need to really watch it. sometimes it burns fine, or gets too hot, or just goes out. i guess my wood is the culprit of this .

i feel like im beating the snot out of this stove. all this smoke and then over fire once in a while is killing it

Depending on whether I have time to babysit the stove sometimes I rake the coals forward, sometimes I don't. I leave the door cracked to get it up around 400, then shut the door. It will creep up to around 500 and that's when I'll start to knock the air down in stages. I can't shut mine down all the way because it doesn't burn correctly.

Revturbo977 · Dec 8, 2014

i feel like raking the coals forward takes much longer to re light. but putting wood directly on the coals makes it take off too fast. when i rake the coals forward there is still 1-2 of the splits in direct contact with the coals. is this correct or should my coal bed be smaller?

when im burning when im home, i just put in a split every hour and a half of so and dont rake them forward, ill rake them out but put the split right on the coals

BigCountryNY · Dec 8, 2014

Revturbo977 said:
i feel like raking the coals forward takes much longer to re light. but putting wood directly on the coals makes it take off too fast. when i rake the coals forward there is still 1-2 of the splits in direct contact with the coals. is this correct or should my coal bed be smaller?

when im burning when im home, i just put in a split every hour and a half of so and dont rake them forward, ill rake them out but put the split right on the coals

Sounds like your wood is the biggest hurdle in your battle of the new stove. You definitely want to have the wood catch and be completely charred before you start closing down the air control. When I load up, I rake the coals forward and put a large split in the back of the stove. I put a smaller split on top of the coals (which are now like another split - just already hot) and build up from there. I leave my door cracked open for a bit or just slightly pull it open for a few minutes until the flames are such that the secondaries ignite well. At that point, I close the door and it's off to the races. We had 18F here this morning, so when I loaded up and got her going the secondaries were like a flame thrower down the front of the glass as the draft was pulling hard. They were doing battle with the primaries as the wood was outgassing - so much that it would rattle the air control on my insert. I started closing down around 450F and had it full closed just over 500F. The flames were nice and lazy and cruising along at 625 all in about 12 min. from reload. My wood isn't perfect either, it's ~ 22% MC, mostly red oak and birch. But it's my first season in our house since we moved to NY and it's the best I've got. This is also my first EPA stove, so it's been a bit of a learning curve for me too - but you'll get it figured out. Just be safe and I'd probably have a look at your stove pipe or liner when you get a chance as you likely have some creosote build-up from the way you had been running it previously.

Revturbo977 · Dec 8, 2014

ya im sure the pipe is nasty right now. my glass gets black every night but then is cleaned from the crazy burn i encounter. i hope my stove is ok from all of this . how much can these things handle? my wife and i talked that we wont run the stove unmanned until we get it figured out. i guess we have been doing it all wrong.

Revturbo977 · Dec 8, 2014

this stove needs a full box, filled to the brim with wood to make it over night. do i need to treat this differently from what everyone explained to me on setting up my overnight burn with that much wood?

Stretch · Dec 8, 2014

Good Morning!

I'm running an F400 up in Maine in a 1200sf+/- house. I've had mine run away once, when
I first moved in last winter. I had it filled full of biobricks with the damper wide open, and it just
took off. I ended up removing a couple of flaming bricks from the stove and throwing them out into
the snow to calm things down. Exciting stuff......

I've been burning fires for about 6 or 8 weeks so far this season and I think I've
mostly cracked the code on how to run this rig. The stove seems to prefer a
full load or close to it, and mine cruises with a stack temp (on the single-walled
pipe) of 300-350F, and a stove surface temp of 600-650F. This seems to
be what it likes - if I choke it down more, I get a smoldering fire.

Get the stove running quickly and hot. My record to operating temp (275-300F stack;
500-600F stovetop) is 8 minutes now, but it usually takes15-20 mins. Then I let things burn until
everything visible is fully engaged, and start backing the damper off about 1/4 at a time.
This will stabilize the stovetop temp at the aforementioned 600-650F, and the stack
temp will rise to 320-350F. Keep closing the damper 1/4 at a time until it's about 20-25%
open. That seems to stabilize everything at max economical cruise, and I'm pretty sure I'm
not making much creosote at that point. My firewood, like most people's, is not perfect
this year. I keep a couple of days' supply next to the stove to dry and warm to room temps.

My problem now is how to get it to run overnight without the fire dying and smoldering. It won't
do 8 hours on a full load, unless it smolders a bit. With my wood not quite as dry as I'd prefer, I
don't want to spend the evening making creosote.

-Stretch

Revturbo977 · Dec 8, 2014

seems like your wood is better then mine. with a full load and the coals raked forward it takes me 20-30 min with the damper all the way open to engulf all of the wood. maybe even longer. i feel like a larger coal bed will help but then hurt me once the wood starts to out gas.

at what temp are you filling your box?

Stretch · Dec 8, 2014

My stove is sometimes a bear to get back to temp when I reload. It seems to be the worst
when I let the stovetop temp fall below about 300F. Then it takes 20-30-40 mins to get back to
temp, just like yours does. Unless, of course, I QUICKLY lay some kindling on the coals and
then add wood, but then I've the issue of a puff of smoke in the house. Reloads between a stovetop
temp of 300-400F seem to work best, but I really don't want to sit up for 30 mins every night
while the stove comes back up to temp.

A big coal bed helps with reignition, that's true, but for some reason it seems to impede
the air flow. I'm still working on that problem. Making sure the stove interior doesn't cool
too much before a reload seems to help a lot. I don't always get it right! LOL! A little bit of
kindling seems to help A LOT with getting reloads ignited quickly, but I hate to use all of
my kindling that way. Maybe some smaller splits on the bottom of the reload for quick
ignition and better airflow, although one gives up some volume to air that could otherwise
be used for wood, thus reducing long-term burn time, while shortening the window needed
for full ignition of the reload.

I've read that some folks use short pieces north/south as the first layer of a reload, and then stack
east/west on top. I'll have to try that, but it means hacking splits in half with the chopsaw. Maybe
next year I'll cut the logs with 1/3 of the wood short for north/south loads. The north/south arrangement
on the bottom layer DEFINITELY helps with cold starts, so it stands to reason it oughta help with
restarts. But we're also giving up some wood volume for air volume/circulation to get things
started. This may be a compromise I have to live with. Dunno yet......

Revturbo977 · Dec 8, 2014

i agree this thing loves air to get the wood lit. i always chop the coals out from under a few logs to get the air moving better. im going to experiment more the next few days and really give it a try to make this thing run right,

begreen · Dec 8, 2014

Revturbo977 said:
95% of the time the wood doesnt even catch before i push the damper all the way closed. somestimes would take a half hour to start burning with the damper open. if i understand this correctly, even smoldering with no flame, the wood is heating up and eventually off gasses and ignites?

That is the first problem. You should not be turning down the air until the wood has started to flame. This is causing a seriously smoldering fire which defeats the purpose of the stove. Also, by turning the air down too early you risk a serious puffback when the smoke finally does ignite.

What size are your splits? If they are spindly they are going to burn up quickly. Try loading larger splits and use smaller ones to fill in the gaps. Don't load lincoln log or criss-cross style. Instead, after raking the coals forward, put two small, short splits, parallel to the sides, in the middle about 4" apart with the coals in between them. Then load up the stove with wood, E/W, with larger splits on the bottom, resting on those two sleeper splits. This will allow air to get under the wood for a quicker start. Leave the door slightly ajar until the wood ignites, then close, but leave the air wide open. Start closing down the air as the wood gets fully involved with flame.

Note that 650-700F is not an uncommon peak temp with this stove when fed dry wood and smaller splits.

Revturbo977 · Dec 8, 2014

begreen said:
That is the first problem. You should not be turning down the air until the wood has started to flame. This is causing a seriously smoldering fire which defeats the purpose of the stove. Also, by turning the air down too early you risk a serious puffback when the smoke finally does ignite.

What size are your splits? If they are spindly they are going to burn up quickly. Try loading larger splits and use smaller ones to fill in the gaps. Don't load lincoln log or criss-cross style. Instead, after raking the coals forward, put two small, short splits, parallel to the sides, in the middle about 4" apart with the coals in between them. Then load up the stove with wood, E/W, with larger splits on the bottom, resting on those two sleeper splits. This will allow air to get under the wood for a quicker start. Leave the door slightly ajar until the wood ignites, then close, but leave the air wide open. Start closing down the air as the wood gets fully involved with flame.

Note that 650-700F is not an uncommon peak temp with this stove when fed dry wood and smaller splits.

i had everything backwards i guess. i dont know why i thought i should shut it down like that. my splits are all over and ive been saving the bigger ones for over night . i will have to cut my splits to get them to fit north/south.
the stove hit 750 last night. i know it went much higher 2 other times. i hope there isnt damage

Warm_in_NH · Dec 8, 2014

Wet wood is a bear to deal with too. Most "normal" practices go out the window when you're burning high moisture content wood. Also, if you burn dry wood like you do wet, you'll have a borderline over fire.

If the wood is really hissing and pouring water out of the ends, split small try feeding it like a campfire until you get a good bed of coals going, a log here and there, too much wet wood, not enough coals, you'll smother the fire.

If you're really in doubt if it's you or the stove, go spend 10 bucks on a couple bundles of kiln dried wood at the box stores and try a night of burning that, it should be a whole different experience.

claydogg84 · Dec 8, 2014

Revturbo977 said:
i had everything backwards i guess. i dont know why i thought i should shut it down like that. my splits are all over and ive been saving the bigger ones for over night . i will have to cut my splits to get them to fit north/south.
the stove hit 750 last night. i know it went much higher 2 other times. i hope there isnt damage

I think the 800 mark is where it can become an issue. How long have you been running the stove the incorrect way? Just wondering if you may want to get on the roof and atleast take a peak down the chimney.

F400 still wants to overfire at night

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