Jotul F400 Burn Control

[CastineBurner]

Hello All,

Brand new to the forum, not new to woodburning. Recently upgraded my Quadrafire voyager insert to a Jotul F400 to get away from the blower and enable longer burns/easier ash removal. The F400 is a used stove I bought for $1K that I believe is in good shape. Stove is rear exit setup into a SS liner all the way up a 2 story exterior masonry chimney.

I am struggling to control the stove with these symptoms:

I struggle to get the stove going at startup unless opening the ashpan door
Once the stove is going it is sluggish to gain temp up to 350F
I start to gradually close air as the stove warms and at the point I get steady secondaries I typically move the air all the way left (closed); still hear roaring of air into the firebox
When I have a full load in, this sometimes "runs away" and I get 600F+ on the side of the top plate and 750F+ in the center of top plate at which point I use alum foil to cover the intake. Then I get a BEAUTIFUL SLOW SECONDARY FLAME.

Is this (600F+ on the side & 750+ center) a concern or operating as intended? I know the air control works because when the draft isnt so strong, shifting left will smother the fire quickly.

Thanks for the help.

 

[Todd]

Careful using the ash pan for starts, it could cause damage if you forget to close. Try a top down start. This method helps warm the flue faster. A new stove will take some trial and error til you get the hang of it. Once going good try turning down the air sooner. Sometimes non cats have a point of no return and seem a little uncontrollable if you get them ripping too much before turning down.

 

[dmansen]

Hi, I'm also new here and am using an F400 for the first time. It came with the house. I was running into overfiring problems due to the draft being more open than I thought (tee pipe was open on the bottom...uh oh). Since I fixed that I have much greater control over temp, no issue starting with 4-5 pieces of kindling with the door shut / damper all the way open. I run it with the damper open til about 450-500 then I start lowering to 1/2 and then 1/4. Once I start closing the stove doesn't get hotter the way it did before I fixed the draft issues.

Apologies for obvious question - how dry is the wood?

 

[EbS-P]

I have run one on two story chimney lined 6”. And one on a single story lined and insulated 15’. The blowtorch secondaries are a constant feature on the two story to the point they almost blow themselves out. I never thought it was over firing.

Slow sluggish startup then an uncontrollable fire. Seems a bit odd.

600 top corners is normal high output. I don’t get concerned until the center goes past 850. Make sure your IR thermometer is good for temps pst 750. My first one wasn’t.

 

[CastineBurner]

Thanks all for the replies.

Been using top down starts from cold, the ash pan door is mainly used when starting from coals when she burns down too low. Noted about being careful with the ash door; I know this can lead to trouble but without it she smolders for a long time before ignition.

Wood is 2yr old split and covered red oak. There’s probably a few splits that aren’t as dry as the others but the meter reads them all at under 20% at a fresh split.

Starting to think I may just have some air leakage through either door gasket despite dollar bill test looking ok. My burn time is 4-5 hrs fully closed down and I think they should be longer w a full load of oak. Only symptom that doesn’t line up is the slow starts.

 

[EbS-P]

Thanks all for the replies.

Been using top down starts from cold, the ash pan door is mainly used when starting from coals when she burns down too low. Noted about being careful with the ash door; I know this can lead to trouble but without it she smolders for a long time before ignition.

Wood is 2yr old split and covered red oak. There’s probably a few splits that aren’t as dry as the others but the meter reads them all at under 20% at a fresh split.

Starting to think I may just have some air leakage through either door gasket despite dollar bill test looking ok. My burn time is 4-5 hrs fully closed down and I think they should be longer w a full load of oak. Only symptom that doesn’t line up is the slow starts.

Try a torch or hair dryer( you might not want the goat dryer as it will blow the fly ash around) to warm up the flue. Before lighting. Think if you get a good hot fire going for a good bit the close air all the way then use the tinfoil you can see where there are leaks if any. The flames dance down to the leak.

 

[CastineBurner]

Video of burn after adding foil as it was getting to hot for my comfort. Stove top 600+ on each side, 750+ center. Any other castine owners get a burn like this fully shut down w foil over the inlet? This load was some smaller diameter splits but I’d like to have enough control to feel good about cranking it down and walking away…

 

[EbS-P]

Does it always have more flame on the left side. Black around the bottom glass is that always there? Have you checked the glass gasket? When it’s cool place a hand on each side of the glass and see if you can move the glass any up or down left or right. Then check your clips. All 4. Mine came with pieces of gasket between the clip and the glass up top.

Secondaries looked a little lazy.

I think you are going to find an air leak somewhere. That’s just more flame down low than I have seen with the air control full closed.

 

[Todd]

When you reload on top of a good coal bed do you rake those coals all forward or spread them around evenly? For a longer more controlled burn try raking coals forward pack a large Oak split in back against the bricks then pack the rest in tight as you can. This should give you a somewhat front to back burn and leave some coals in the back the next morning.

 

[CastineBurner]

When you reload on top of a good coal bed do you rake those coals all forward or spread them around evenly? For a longer more controlled burn try raking coals forward pack a large Oak split in back against the bricks then pack the rest in tight as you can. This should give you a somewhat front to back burn and leave some coals in the back the next morning.

Will give this a shot. Usually I just place on top of what’s there to try and load quick and close it up. What temp at the end of the burn cycle do others load the f400 at? I let it get to 250-300. Is this longer/lower than other ppl let it go? Maybe that is the root of my reload slowness?

 

[Todd]

With my F45 the stove top is around 150-200 when I reload after 8-12 hours.

 

[dmansen]

I replaced my glass gasket yesterday and am now noticing similar behavior to yours. Startup is fine, smoky for a bit but then gets hot. Once it's there, if I've filled the firebox, I have a hard time keeping it under 600F stove top side temp. I reload at 250 and am getting 5-6 hour burn times. Dollar bill test was better in some places than others - I suspect I still have a leak somewhere. The ash door gasket also hasn't been replaced and looks old. That will be my next step. Let us know if you have any success.

 

[begreen]

Our F400 new had a leaky glass gasket. It was improperly seated. I had to redo that early on, but no issues after that. 650º on the stovetop was pretty normal and at times when pushed for heat it was over 700º.

Make sure the ashpan gasket is sealing well. Sometimes ash can build up and get impacted behind the ash pan. This can push the ashpan forward and prevent the door from closing tightly.

 

[CastineBurner]

When you reload on top of a good coal bed do you rake those coals all forward or spread them around evenly? For a longer more controlled burn try raking coals forward pack a large Oak split in back against the bricks then pack the rest in tight as you can. This should give you a somewhat front to back burn and leave some coals in the back the next morning.

Been warm in pa so I hadn’t been burning 24/7 like I was. Let the stove cool and gave it a good cleaning. Looked over seams and cleaned bits of ash and charcoal out of the gasket… nothing too bad. Did a top down start being generous w the kindling and it took off wonderfully. Went 4 hrs + and reloaded. Did the coals to the front method and woke up (6.5 hrs) to more coals than before but still relatively sparse. Startup went a little slow I think due to relatively cool stove and few coals. Probably need to be less stingy w the kindling. 3.5 hrs later I’m probably going to let it burn out but VAST improvement from before. Thanks for the help @Todd ! Will keep at the front to back reload method. This seems to be the best way to have controlled extended fires. Need to refine some to keep glass from getting black and also maximize burn times but I think I’m on the right track.

 

[CastineBurner]

Getting some exercise w the front to back burns and they continue to make a world of difference. Longer more controlled burns(can hit 6hrs). For anyone out there having an issue w overburns on a reburn stove I would definitely exhaust this option before trying other things. When loading on a non-raked bed of coals, I think the whole firebox offgasses at once which is too much. This causes glass to blacken and the stove runs away (these symptoms were counterintuitive to me before but now make sense). The front to back limits the material off gassing to the front portion of the firebox and mitigates this.

Saw some posts about side to side burns. Given the lack of depth in the castine and the fact the firebox is relatively wide, I plan to play around w that next. Maybe even longer burns? Hoping for 7+ hrs to get through the night without a reload.

Thanks guys for all the help. Hope this can benefit anyone else learning on a f400 castine.

 

[CastineBurner]

Anyone who has a F400 castine, please chime in… what are your center stovetop temps (above the baffle) vs your side stove top temps (where jotul recommends you put your thermometer)? My stove can get to 750 in the center and not over 600 on the side of the top plate.

 

[bigealta]

Not sure what my top is at full on fire. its 420F right now on a dieing fire with no real flames but large coaling chunks.

My f400 stove runs much more in control than the above posters.

 

[EbS-P]

Center is always 100-150 degrees hotter than the sides. The hotter the fire the greater the difference.

Generally I don’t go higher than 550 on sides of the top. Did have one “event” where the center was 900 the sides were 720. Don’t do that.

 

[begreen]

I always left the thermometer where recommended and ran the stove accordingly. There were a couple of forays up to 700º, but mostly the high temp was closer to 650.

 

[bigealta]

I'm at 500F Top middle with this just cruising fire. Laser Spot reader for temp.
(10 minutes later) 520F now Top middle and 450-470FTop sides.

 

[bigealta]

Ran about 600F Top middle and 525F Top sides with a medium fire today.