Kuuma stove pipe keeps lighting on fire

[MN~Nice]

Hi I am new to this forum but I need advise.

I bought a house last year which came with a wonderful add-on wood furnace setup. The unit is a Kuuma 1.

After a few months I lit a fire and before I knew it I had a gnarly chimney fire. So after that I installed a seamless single wall chimney liner and a new stove pipe. It's drafted way better. I read the stove manual front to back and hooked it back up per the recommendations with a key damper in the stove pipe, only 1 90 elbow into the chimney, etc.

Now the crazy part is I have great wood I know pine isn't ideal but it's all I've got right now and it's bone dry. Flue temps run 400 to 450 consistently. But when I go to restoke the fire it's nothing but a few coals and when I open the smoke bypass slide the flue pipe thermometer temp instantly maxes out and sparks are in the chimney.

I can't figure it out it's like my stove pipe starts on fire and I'm worried it will lead to another fire. Any thoughts or anyone experience this before?

 

[Tar12]

STOP burning! Its not normal! Did you have the chimney cleaned prior to the first time you ever used it? If not you have no way of knowing if they burned properly in the is Kuuma. Have you checked your wood with a moisture meter? You can't just look at it and say ...yep...thats good. The Kuuma people have a presence here and will hopefully see and be along to help you out more than i can.

 

[MN~Nice]

STOP burning! Its not normal! Did you have the chimney cleaned prior to the first time you ever used it? If not you have no way of knowing if they burned properly in the is Kuuma. Have you checked your wood with a moisture meter? You can't just look at it and say ...yep...thats good. The Kuuma people have a presence here and will hopefully see and be along to help you out more than i can.

I had the old chimney flue cleaned thoroughly still residual glaze but not much. I installed a new liner though and stove pipe too. Just cleaned out both a couple weeks ago and it's still doing it, just can't figure out why. I post pictures of my setup

 

[brenndatomu]

A Kuuma 1 huh?! Wow, I never even heard of them until a few months ago, now here you are and have one, live and in captivity...got any pics? I bet there aren't two other people on Hearth (other than the manufacturer) that know what these are. (but I could be wrong too)
The best people to answer any specific questions on it would be the manufacturer @lampmfg ...or you could call them at 1-800-358-2049...talk to the owner Daryl...he can tell you all about it I'm sure.
For everybody else, as I understand it, the Kuuma 1 is an early version of the current Kuuma VF200 add on furnace. I think it is smaller and was totally manually operated...very much unlike the current computer controlled Kuuma furnaces.

To answer your questions...you are having chimney fires due to creosote buildup. Creosote comes from 2 things, cutting the air back too far/too fast which smolders the fire, and/or burning wet wood. You said you have dry wood, are you positive? How long has it been cut/split/stacked? Do you have a moisture meter? I'm betting your wood is not as dry as you think (internally) and this is your issue.
The other thing is to run the air a little further open, you want to run the flue temp (internally) above 250* (and likely higher) for at least the first 2-3 hours after loading. (after that the creosote causing ingredients are pretty well burnt off) Get a probe type flue thermometer to monitor the flue temps.
Also you need to clean your flue often until you get this straightened out...maybe even weekly.
If there was no creosote, there would be no flue/chimney fire.
Kinda crazy reading about a Kuuma having chimneys fires since the modern ones are known for being the cleanest burning furnaces out there...the VF100 is currently the only forced air wood fired furnace in the world certified to the EPAs 2020 specs.

 

[JRHAWK9]

Depending on where in MN they live, they could be down the road from the manufacturer in Tower, MN. I can't imagine they sold too many of these units too far removed from where they were made in Tower, what, 30+ years ago maybe...?? Damn, we need pics

 

[brenndatomu]

Well, I know of at least one that made it down to Ohio.
I dunno when they quit making them...I found 'em on a "price list" dated 2001.
(broken link removed to http://www.rangenet.com/kuuma/heater.html)

 

[JRHAWK9]

Holy crap. I think I gotzed over charged!

 

[BrotherBart]

Folks, let's get back to the problem here. As much chimney cleaning and replacement as has been done it ain't the pipe. That pine is popcorn fart dry and going nuclear.

 

[MN~Nice]

A Kuuma 1 huh?! Wow, I never even heard of them until a few months ago, now here you are and have one, live and in captivity...got any pics? I bet there aren't two other people on Hearth (other than the manufacturer) that know what these are. (but I could be wrong too)
The best people to answer any specific questions on it would be the manufacturer @lampmfg ...or

A Kuuma 1 huh?! Wow, I never even heard of them until a few months ago, now here you are and have one, live and in captivity...got any pics? I bet there aren't two other people on Hearth (other than the manufacturer) that know what these are. (but I could be wrong too)
The best people to answer any specific questions on it would be the manufacturer @lampmfg ...or you could call them at 1-800-358-2049...talk to the owner Daryl...he can tell you all about it I'm sure.
For everybody else, as I understand it, the Kuuma 1 is an early version of the current Kuuma VF200 add on furnace. I think it is smaller and was totally manually operated...very much unlike the current computer controlled Kuuma furnaces.

To answer your questions...you are having chimney fires due to creosote buildup. Creosote comes from 2 things, cutting the air back too far/too fast which smolders the fire, and/or burning wet wood. You said you have dry wood, are you positive? How long has it been cut/split/stacked? Do you have a moisture meter? I'm betting your wood is not as dry as you think (internally) and this is your issue.
The other thing is to run the air a little further open, you want to run the flue temp (internally) above 250* (and likely higher) for at least the first 2-3 hours after loading. (after that the creosote causing ingredients are pretty well burnt off) Get a probe type flue thermometer to monitor the flue temps.
Also you need to clean your flue often until you get this straightened out...maybe even weekly.
If there was no creosote, there would be no flue/chimney fire.
Kinda crazy reading about a Kuuma having chimneys fires since the modern ones are known for being the cleanest burning furnaces out there...the VF100 is currently the only forced air wood fired furnace in the world certified to the EPAs 2020 specs.

you could call them at 1-800-358-2049...talk to the owner Daryl...he can tell you all about it I'm sure.
For everybody else, as I understand it, the Kuuma 1 is an early version of the current Kuuma VF200 add on furnace. I think it is smaller and was totally manually operated...very much unlike the current computer controlled Kuuma furnaces.

To answer your questions...you are having chimney fires due to creosote buildup. Creosote comes from 2 things, cutting the air back too far/too fast which smolders the fire, and/or burning wet wood. You said you have dry wood, are you positive? How long has it been cut/split/stacked? Do you have a moisture meter? I'm betting your wood is not as dry as you think (internally) and this is your issue.
The other thing is to run the air a little further open, you want to run the flue temp (internally) above 250* (and likely higher) for at least the first 2-3 hours after loading. (after that the creosote causing ingredients are pretty well burnt off) Get a probe type flue thermometer to monitor the flue temps.
Also you need to clean your flue often until you get this straightened out...maybe even weekly.
If there was no creosote, there would be no flue/chimney fire.
Kinda crazy reading about a Kuuma having chimneys fires since the modern ones are known for being the cleanest burning furnaces out there...the VF100 is currently the only forced air wood fired furnace in the world certified to the EPAs 2020 specs.

 

[MN~Nice]

As far as creosote. There really isn't any in the stove pipe or the chimney liner. It's almost like the stove pipe is acting like one of those secondary burners you see in newer stoves

 

[brenndatomu]

That pine is popcorn fart dry and going nuclear.

How can that happen when its down to coals?

when I go to restoke the fire it's nothing but a few coals and when I open the smoke bypass slide the flue pipe thermometer temp instantly maxes out and sparks are in the chimney

There's gotta be buildup...clean steel don't burn and coals can't go nuclear...at least not that I have ever heard of or seen. About the closest thing I've seen may have been Mulberry coals giving me a spark shower upon opening the door...

As far as creosote. There really isn't any in the stove pipe or the chimney liner. It's almost like the stove pipe is acting like one of those secondary burners you see in newer stoves

Man, I dunno...have you ever called Kuuma?
What kind of flue temps are you seeing when this happens?
Where are you seeing the sparks, out the top of the chimney?

 

[brenndatomu]

Thanks for the pics...never actually seen one before.
So looking at the pics, your stove pipe doesn't look like it has been overly hot...

 

[MN~Nice]

Luckily I've become paranoid and watch it like a hawk for about 20 minutes every time I load it up. When it does take off I cut air off and it starts to cool down.

When I am loaded up and running my stove probe reads between 400 and 450 on avg. when it gets down to around 250 I know it's just coals and it's time to load it up again. But if I take too much time putting wood in the temps on the thermometer skyrocket until I shut the whole stove down. It only happens when I open the smoke bypass tho. If it's open along with the door and that thermometer reads 300 it takes off on me even if there is only a minimal amount of coal in the firebox.

 

[Tar12]

Luckily I've become paranoid and watch it like a hawk for about 20 minutes every time I load it up. When it does take off I cut air off and it starts to cool down.

When I am loaded up and running my stove probe reads between 400 and 450 on avg. when it gets down to around 250 I know it's just coals and it's time to load it up again. But if I take too much time putting wood in the temps on the thermometer skyrocket until I shut the whole stove down. It only happens when I open the smoke bypass tho. If it's open along with the door and that thermometer reads 300 it takes off on me even if there is only a minimal amount of coal in the firebox.

Brother Bart is correct....any time you load super dry wood on a bed of coals its gong to fire right off...pine is probably the best for this....load faster!

 

[blacktail]

What do you mean by "sparks are in the chimney"? Sparks from your coals are being sucked up the chimney? Sparks are shooting out the top of the chimney?

 

[brenndatomu]

I think I may have misunderstood whats going on here...of course the title leads one to believe this is a chimney fire issue.
Are you saying the stove just goes crazy with flames right after a reload on hot coals? Or the stovepipe/chimney is burning?

 

[kennyp2339]

I'm confused my the op description also, Is he stating that when he loads with the by-pass open it looks like the flames get sucked up the chimney? Or is he stating that after loading he goes outside and see's sparks / flames coming out of the chimney stack.
If it's the 1st I would say its normal, keep a chimney pipe thermometer on the single wall and only be worried after the temps get past the 700 deg mark.

 

[sportbikerider78]

Pine can snap and crack like a son of a gun.

 

[MN~Nice]

I'm confused my the op description also, Is he stating that when he loads with the by-pass open it looks like the flames get sucked up the chimney? Or is he stating that after loading he goes outside and see's sparks / flames coming out of the chimney stack.
If it's the 1st I would say its normal, keep a chimney pipe thermometer on the single wall and only be worried after the temps get past the 700 deg mark.

The fire doesn't have to be burning at all for it to happen. Even if I have coals in the firebox it still happens. To clarify I mean the stove pipe temps skyrocket and I cut the air out to choke it off. This is when I use a mirror and flashlight to look up chimney to verify I don't have fire transfer into the chimney liner. What I usually see is a small clump of smoldering embers where the stove pipe attaches to chimney liner.

I'm just trying to figure out if my stove pipe is the cause or is my furnace damaged in some way that might cause this kind of stuff.

 

[kennyp2339]

The fire doesn't have to be burning at all for it to happen. Even if I have coals in the firebox it still happens. To clarify I mean the stove pipe temps skyrocket and I cut the air out to choke it off. This is when I use a mirror and flashlight to look up chimney to verify I don't have fire transfer into the chimney liner. What I usually see is a small clump of smoldering embers where the stove pipe attaches to chimney liner.

I'm just trying to figure out if my stove pipe is the cause or is my furnace damaged in some way that might cause this kind of stuff.

Is the stove pipe entering to deep past the thimble in the chimney?

 

[Marshy]

So to recap @MN~Nice, upon reloading the stove on a small bed of coals the wood will catch fire and flames and sparks are pulled out of the firebox and into the chimney connector pipe. Your concern is possible chimney fire from the flames and sparks from the firebox during refueling. Your concern is based on a previous chimney fire that you experienced before. Since then, the chimney was cleaned and a new liner and connector pipe was installed.

Since the new liner and connector pipe has been installed you are (or are not) getting creosote buildup in the newly lined chimney?

If you are not getting any residue buildup in the new liner I see no problem with how it is operating. I would expect the flue temp to spike while reloading the stove. As the fire is catching and pulling flame and sparks up the flue connector your flue temp is bound to go up. As someone mentioned, as long as you're only reaching 700-800 flue temp momentarily I don't believe there is a concern, especially if the flue is clean and no creosote.

 

[Marshy]

The fire doesn't have to be burning at all for it to happen. Even if I have coals in the firebox it still happens. To clarify I mean the stove pipe temps skyrocket and I cut the air out to choke it off. This is when I use a mirror and flashlight to look up chimney to verify I don't have fire transfer into the chimney liner. What I usually see is a small clump of smoldering embers where the stove pipe attaches to chimney liner.

I'm just trying to figure out if my stove pipe is the cause or is my furnace damaged in some way that might cause this kind of stuff.

Sounds like excessive draft or lack of air inlet control. Does the stove have an internal baffle to deflect flame and sparks from directly entering the single wall connector pipe?

 

[ratsrepus]

Ive had two wood furnaces in my home, first was a Fire Chief, the 2nd was a Charmaster. They were both chimney clogging turds. Thats the nature of the beast. The Kuma is probably the most expensive forced air furnace you can buy, but I think they are all creosote makers. I also got tired of tossing 5 cords a season in mine.

 

[Mnpellet]

The fire doesn't have to be burning at all for it to happen. Even if I have coals in the firebox it still happens. To clarify I mean the stove pipe temps skyrocket and I cut the air out to choke it off. This is when I use a mirror and flashlight to look up chimney to verify I don't have fire transfer into the chimney liner. What I usually see is a small clump of smoldering embers where the stove pipe attaches to chimney liner.

I'm just trying to figure out if my stove pipe is the cause or is my furnace damaged in some way that might cause this kind of stuff.

Just curious how your looking up the chimney if it’s attached to a liner.

 

[ratsrepus]

Another big problem at least with the two I had, was if you lost power and the blower couldn't run, they will go nuclear on you. No air between the burn box and the outer cabinet.