castine…400…runaway temp.

Hi guys and gals,
I have a jotul castine 400 i bought about ten years ago,
I try to keep the stove at 500-700 deg. Once or twice it spiked to 900,when i had some very dry red oak, when it spiked i shut the air off till i got it back down to a reasonable temp.
I noticed last year the air valve was much more to the closed position than ever, and temps were running high, i thought it was because the wood was almost 2 yrs. old.
well this year,i ran it with cherry wood seasoned 12 mon. and it was still way too hot.
I have replaced the door gasket,pan gasket and glass gasket,the stove had its usual 5" of banked embers and two pieces of wood,temp got to 700, and i closed the air off completely,the temp made it up to 900!!
seems to be sucking air from underneath, (i can see the yellow hot spot of the embers).
anyone know how i can check for warped plates on this? Is this a common thing with the 400? did i ruin the stove the times i went to 900 deg? i have tried to use a flame and smoke to see if it is sucking air from the sides and don't see anything obvious..please someone help me out.
Thanks to all who have helped me in the past!!

aaron1 said:

You need to do more diagnostics before burning it in my opinion. that is way too hot! over 700 and firefighterjake says (according to Joutul) you are doing bad things to the stove. there has to be a leak, ashpan?, slider mechanism leaking in too much primary air behind "dog house"? it never did this before? has anything changed in your draft that you did?

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first off thanks for reply, the ash pan has a gasket rope type and i replaced it the door shuts firmly. and the slider mechanism i am not sure, i think its just a slide and when closed it should be shut,not allowing air to pass through…i i dont think there is a way for that to fail. dog house? i don't know what that is…and the draft has no changes…its a forever flex stainless liner in a chimney,worked great for 10 yrs. i just knocked all the ash down from the last logs and the temp went down to 400,it seem when i have multiple logs loosely stacked i get the runaway effect.

begreen said:

As you have noted, the F400CB is a willing heater. A 5" bed of coals needs to be burned down. Try burning down the coal bed a lot more by opening up the air for ~30 min. before reloading. Rake the coals to the front of the stove first. And try stacking the reload tighter with large splits and smaller splits filling the gaps.

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well,for sure if i don't bank the coals,this won't happen,but….i had been doing it for so long and never had an issue before,i like to bank,then turn it down to 300,that way if i go to bed at 11pm, i still have a 100 degree stove at 7 am.
Then at that point add a handful of loose wood and presto,
Also,i did not notice any loud or abnormal sounds when this happened.

aaron1 said:

one other thought i had is that you might have had some fire in your liner that increased draft? is that possible? was there a huge draft sound when you went so hot?

maybe begreen is spot on. if you are using dry, nice wood, you could shoot up in temp really fast loading onto a really hot, thick coal bed. my temps can shoot up really hot on my F500 if I load it with small splits of really dry wood.

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Thanks for reply guys,and no, no loud sounds.
Im not sure if i did even burn a hole in the liner,that this would cause and draft increase would it?…ehhh what ever,i hope i can figure this out before i damage it….if i haven't already,
I was a mechanic for years and we would check for warped cylinder heads with a straight edge,i have no idea if this can be done with a wood stove.
I have been able to maintain a 500 since last pm… there seems to be a threshold that once i cross the stove just runs with it,and for sure like you said,its when i have a full bed..never before though,
before if i closed the air off it would snuff it out in 2 min…now i have to open the door,rake it down,let cool to 400 and then close the door and crack the air and keep and eye on it…..kinda like a sneaky dog.

webby3650 said:

Have you done a "dollar bill"test? (close a bill in the doors and see if it pulls out easily) I think you are leaking air through the ashpan. Are you sure that there is no ash built up behind the pan? I see this alot, ash will get packed in everytime the pan is removed and replaced. The door might still latch, but not seal properly.

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Yes i have done the dollar test,tight as a bulls butt.
i have noticed the ash build up behind the can,i just checked it and cleaned the ash from behind the can,i was keeping it more forward,i see if that helped. thanks.
and cape cod?? mass? i see you are from indiana. thanks

begreen said:

The other question I dread to ask is do you frequently use the ash pan door to start the fire? If the answer is yes, you need to shut down the stove, clean out all ash and inspect for cracks in the interior base around the grate.

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Oh God, yes i do use the ash pan to start the fire,it keeps up a killer draft, BUT i only do this when its first stared,and to restart…..i never let it run for more than a minute,just till the fire licks up on the wood.
Do you know something about this???
Now i have a sick feeling, how could this destroy or …well yeah, destroy that plate if i do this at a low temp fire?
Albeit,that is the area where the coals seem to be fed even at total shut down.
what i am going to do is keep it low for now,its 12 deg outside,when it gets over freezing i will inspect as you say,thanks a ton. I would like to know how this could warp or crack that cast though.
did you hear or read something about this?
thanks begreen.

begreen said:

The other question I dread to ask is do you frequently use the ash pan door to start the fire? If the answer is yes, you need to shut down the stove, clean out all ash and inspect for cracks in the interior base around the grate.

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i think i just read an explanation on how this can crack on wise heat.com…. well looks like i have to check that area,thank you so much,i will fill you in of my findings!!
you all rock!! this forum is too cool! ttyl.
chris.

adrpga498 said:

I think you just answered your own question. How many and what size would you define as multiple logs.

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as many as i could fit. If i have room for two 18" logs ill pack them in,but see this is all a NEW problem,it never happened before,i could pack it full or loose with dry wood and never had an issue
till late last year…….i"ll figure it out i guess, its been cold here for the past week and i haven't shut it down.
Just have to keep the temp under 500 and shut air to low, i noticed i do have suction into the ash door,using the flame method,
the door shuts tightly,on the hinge side,the latch side is sucking air,i think maybe ui used too much furnace cement in some areas,and its keeping the door from shutting properly….
thanks everyone!

begreen said:

Remove the ash pan and check the ash pan box for ash build up in back. Buildup can push the ashpan forward a little and prevent the ashpan door from closing tightly. Use a flashlight as this can be hard to spot and take a poker to scrape and remove with an ash vacuum.

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yes sir, i did that a few days ago,there was allot of ash,and it was pushing can foreward,
but not the problem…damn thing pegged over 900 yesterday!, its cooled now I'm join to redo the pan gasket.
I'll let you know. thanks.

begreen said:

Remove the ash pan and check the ash pan box for ash build up in back. Buildup can push the ashpan forward a little and prevent the ashpan door from closing tightly. Use a flashlight as this can be hard to spot and take a poker to scrape and remove with an ash vacuum.

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well, kept running hot,i noticed that there is a hot spot,in the ashes,dead center and it looks like too much air coming in from below,i let it cool off 100%
I have just inspected the bottom,sides and cannot for the life of me find any cracks.I had also used the flame test again,i did get some air sucking in from the bottom left side.
doesn't seem like it would be enough air to cause the runaway effect,it's not even in the same area.
I cannot find a manual or any info on resealing or diagnosing problems for this stove.
I am a great auto mechanic,welder carpenter,etc…anyone know where i can buy a book to service this stove myself?
Do people pay to have a stove resealed?…i'd hate to reseal this whole thing and find out i had a warped plate, hence the repair manual search.
thanks begreen

HotCoals said:

Can you plug the ash drop from inside the stove to see if the problem goes away?

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never thought of that…..i will try it, what if it goes away? that tells me what?, that the leak is in the bottom plate? or below the ash drop,right?

HotCoals said:

Can you plug the ash drop from inside the stove to see if the problem goes away?

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actually I'm not sure i can do that, doesn't the primary air come through the bottom of that grate?/ash drop?

HotCoals said:

I have no idea but I would not think so. Maybe some better informed people with that stove will know.

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well i have some 1/4" plate that will cover that grate nicely…I'm going to try it and see.
Thanks Hotcoals! you have all been a great help with good ideas! ill let ya know!

HotCoals said:

I have no idea but I would not think so. Maybe some better informed people with that stove will know.

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hey there i went down and took a look see i can't block that grate,the air comes in the front near the air lever and then between the two plates,and up through the grate…i did see where some of the cement has cracked away,and it is discolored,i tried to seal it up…we will see. thnx