Help with Jotul - burn tube -- UPDATE --

[begreen]

Some wood species coal a lot and some don't. When there's a big coal bed, try putting just one or two medium splits on top of the coals. The fire won't run away, but it will get hot and will burn down the coal bed with it.

 

[jeffee]

Jeff

Interesting that the baffle has been modified to retain the center tube better, but from your description it doesn't sound like anything has been done to address the tendency of the baffle clips to loosen & allow the baffle to rise at the front. Because the firebox tapers toward the rear, it seems inevitable that any user will have the experience of that last log for the overnight burn getting jammed part-way in. Since it is probably flaming at this time, withdrawing it is not really workable, so forcing it in is the only viable option. This force presses upward on the baffle, and so tends to separate the air tubes.

Have you never had this problem? Hard to see how you could have avoided it.

Steve

Steve, I'm not sure if I've had that problem, although I can't rule out the possibility that this is the sort of thing that may have caused this problem originally. I use 16" firewood, which obviously makes it much easier to avoid this. Also, it is not out of question that Jotul has redesigned the clips - I wouldn't know, and indeed it seems difficult to really get this kind of information; I say this because, as I mentioned in a previous post, my dealer said that he asked someone from Jotul about my problem, and the fact that Jotul has changed the design of the baffle (in a way that would seem to prevent the 'swiveling' out of alignment of that center tube) was not discussed with me, so I'm assuming that the Jotul rep. didn't know about it and didn't find out about it. At this point I don't know if the baffle pressing upward would be of any consequence -- unless that center tube didn't align itself into the notches in both the side tubes - and if that happened, then I would be stumped as to why it would fit upon installation but not after some time -- maybe expansion of parts due to prolonged heat cycles? In any case because of the second nub or knob, the connection between the baffle and center tube is much better now. Agreed that the clips you refer to are not very useful -- but personally, especially after talking with the service person, I think that one could take out those clips and even the center tube and the stove would run the same -- although no I'm not going the try that!

 

[jeffee]

As I said previously, I am very happy with the stove.

Jeff

Aside from the air tube problem that you have focused on, have you not had the excessive coaling problem? Other posters on this forum have reported this, and it has annoyed me greatly. Basically, the stove creates such a large quantity of coals that they take up too much room in the firebox, and before long have to be burnt down before reloading. However, the coals alone don't put out that much heat, even with the draft wide open, so the stove cools down until there is space for another load of wood. On the other hand, if wood is loaded on top of too many coals, the fire tends to run away, such that closing down both the primary & secondary air is not enough to bring it under control.

I would like to believe this is due to something unique to my installation, but there are posts here describing this same behavior, & my local friend has the same issue.

So, it is interesting to see that you are "very happy" with the stove. Truly, you don't have this coaling problem? How much area are you heating? You must have a small, very well insulated home.

Steve

No, I haven't had either problem you describe -- excessive coaling or 'run away' fires. Sure, when it gets extremely cold I have to work the stove hard, and it is at these times, when I'm trying to raise my house temperature in the morning or after coming home, that I wish the stove were bigger! I want to cycle it quickly for 2 or 3 burn cycles, and when the stove top gets below say 500 degrees, it won't raise my house temperature. I really need it to be between 500 and 600 to do that -- again I'm talking about extremely cold/windy conditions, lets say wind chill below zero. So, sometimes in these circumstances I have to rake the coals forward and wait say half an hour give or take, before I can break them up enough to fit another load in. As far as run away fire, do you mean that if you put a load of wood on a thick bed of hot coals that you have difficulty containing the stove top temperatures from going over 550 or 600? If this is what you mean, then no, I have not had that problem. As I think I stated in a previous post, I'm not sure that I could get the stove top over say 650 if I tried (which I wouldn't obviously).

My house is 850 or 900 square feet; But, it's a log home - no insulation on the walls. So, figure about R-6 for the walls. Also, many gigantic windows! Also, a slightly windy location! When I originally sized the stove with the dealer, he suggested that the Black Bear might heat me out my house. Ha! Nope. If anything, I could have gone bigger; But I think I made the right choice. It works! Thanks, hearth.com community!

 

[stecy]

I use 16" firewood...

Jeff

Well, that explains a lot. I was using 23" wood, and although the sales lit claims that the capacity is 24", in my experience 22" would be about right. In any case, if you are using such short wood, then it is unlikely indeed that you would run into the problems caused by the long slow rearward taper of the firebox that vexed me so much.

I have to wonder, however, why you would want to use only 2/3 of the capacity of the stove, especially if you could use more heat output. Perhaps you had a large amount of wood sized for a previous stove?

Steve

 

[gpcollen1]

I use 16" firewood...

Jeff

Well, that explains a lot. I was using 23" wood, and although the sales lit claims that the capacity is 24", in my experience 22" would be about right. In any case, if you are using such short wood, then it is unlikely indeed that you would run into the problems caused by the long slow rearward taper of the firebox that vexed me so much.

I have to wonder, however, why you would want to use only 2/3 of the capacity of the stove, especially if you could use more heat output. Perhaps you had a large amount of wood sized for a previous stove?

Steve

If your stove is just a bit over-sized, you generally do not need to take advantage of every cubic inch of the firebox. If you are a hair under-sized, every bit would count. Depends on what you need really.

 

[stecy]

Some wood species coal a lot and some don't. When there's a big coal bed, try putting just one or two medium splits on top of the coals. The fire won't run away, but it will get hot and will burn down the coal bed with it.

Thanks, BeGreen

I burn mixed hardwood, dried at least one year, and often two. Then I have two wood racks in the house, drawn from alternately, so that the wood spends at least a week in the room with the stove before being burnt - don't often have a sizzler. The mix is maple, ash, birch, cherry mostly, with occasionally some oak or hickory. Any of those sound like coalers?

Although your advise about managing a big coal bed makes sense, I've done that, and the heat output is diminished, although greater than with the coals alone. When you are trying to raise the house temperature on a cold morning, you want a 600 degree surface temp, not 400. Not just me, but anybody would want to be able to feed to maintain a constant temp, not have to cycle down every hour or two to reduce coal build-up, don't you think?

I've been burning wood for over 30 years, in at least 6 different stoves, and never had a coal problem like this before. However, that doesn't rule out operator error, but what I possibly could be doing to cause it eludes me. Any more ideas?

 

[begreen]

It sounds like the coals are not getting enough air. Is the stove burning evenly now? Were you able to get the secondary air issue taken care of?

 

[firefighterjake]

About the only time I have a real issue with excessive coaling in my Oslo is when myself or my wife is stoking the fire too often and not allowing the coals to burn down a bit . . . usually more of a problem when it's sub-zero and windy and we need a lot of heat. Normally once a fire has been established I just let the fire burn down to coals and then load 'er up again . . . the ambient temp in the room doesn't really drop.

 

[stecy]

Normally once a fire has been established I just let the fire burn down to coals and then load 'er up again . . . the ambient temp in the room doesn't really drop.

Well, if the temp in the room doesn't drop, then the lower heat output of the stove while burning up the excess coals wouldn't matter that much. In my case - a poorly insulated victorian home - the room temp drops quickly when the stove output lowers, so I don't have much leeway.

 

[stecy]

It sounds like the coals are not getting enough air. Is the stove burning evenly now? Were you able to get the secondary air issue taken care of?

No, the secondary air issue has not been resolved. The dealer from whom I bought it has gone out of business, and none of the other dealers around here want to pick up the slack, so - unlike Jeff - I'm on my own. At this point, it is mainly an issue of getting the stove functioning so I can sell it - it has been replaced.

Do you remember the poster last year who was not pleased with the performance of his Morso 3610 in combination with his masonry chimney? Well, I drove out to Syracuse & took it off his hands this past fall. Although it does have a tendency to release some smoke when the door is open, it has overall been a BIG improvement over the Jotul. Perhaps the black bear was just too small for my poorly insulated situation.

 

[firefighterjake]

Normally once a fire has been established I just let the fire burn down to coals and then load 'er up again . . . the ambient temp in the room doesn't really drop.

Well, if the temp in the room doesn't drop, then the lower heat output of the stove while burning up the excess coals wouldn't matter that much. In my case - a poorly insulated victorian home - the room temp drops quickly when the stove output lowers, so I don't have much leeway.

Ahhh . . . makes sense now. One of the best bits of advice I ever got here early on was folks' recommendations to newbies looking for heating advice was to first and foremost spend the money on buttoning up and insulating a house . . . even before buying a woodstove . . . advice I took to heart as I did some more insulating this past Summer/Fall.

I can see your problem now though . . . without good insulation I imagine the room temp might drop as the stove's heat output also drops.

 

[jeffee]

Steve, out of curiosity, what is the square footage of your house?

 

[begreen]

It sounds like the coals are not getting enough air. Is the stove burning evenly now? Were you able to get the secondary air issue taken care of?

No, the secondary air issue has not been resolved. The dealer from whom I bought it has gone out of business, and none of the other dealers around here want to pick up the slack, so - unlike Jeff - I'm on my own. At this point, it is mainly an issue of getting the stove functioning so I can sell it - it has been replaced.

Do you remember the poster last year who was not pleased with the performance of his Morso 3610 in combination with his masonry chimney? Well, I drove out to Syracuse & took it off his hands this past fall. Although it does have a tendency to release some smoke when the door is open, it has overall been a BIG improvement over the Jotul. Perhaps the black bear was just too small for my poorly insulated situation.

This could also be a situation of poor draft on the flue. If the draft is poor there might not be enough air feeding the fire. The Morso spilling a little smoke could also be an indication of this. Can you describe the flue system from stove to chimney cap?

Regardless, this summer invest in insulation + caulking and sealing. It will be the best investment you can make.

 

[stecy]

This could also be a situation of poor draft on the flue. If the draft is poor there might not be enough air feeding the fire. The Morso spilling a little smoke could also be an indication of this. Can you describe the flue system from stove to chimney cap?

Regardless, this summer invest in insulation + caulking and sealing. It will be the best investment you can make.

Funny that you should suspect too little draft - when I first complained to the Jotul dealer, he told me I had too much draft, and to install a damper! Here are the specs for the Mosro installation: 6" single wall pipe 30" up to an elbow, then 15" horiz into a 6" metalbestos base tee, then 18' straight up to the cap, with all but the last section within the house. All brand new 6" metalbestos about 6 years ago. The Jotul installation had slightly more single wall pipe, otherwise the same.

Considering that the former owner found the Morso sluggish as well as unbearably smoky, I haven't worried much about spilling a little smoke, as it is a great heater and not remotely sluggish in my installation. The smoke discharge can be managed by always opening the draft full some minutes before reloading, but I find it easier to tolerate a little smoke than go thru that drill.

Regrettably, proper insulation has to wait a while longer, as this place is a fixer-upper, with a lot of structural, electrical & plumbing work required before insulating, which is the final step. In the meantime, I just accept that most of the house, beyond the room that the stove is in, won't be all that comfortable. I burn 3-4 cords a season, and wear long johns & a sweater indoors.

To give the floor area of my house would be deceptive, as I am not expecting it to all be warm until the insulation work can be done. Basically this is a live-in construction site/money pit.

Don't see how any of this could explain what seems to me to be flaws inherent in the design of the Jotul, but I would love to be proven wrong.

 

[begreen]

Steve, just to be sure I have this visualized correctly, is the last section that's outdoors the 18' of pipe + tee?

 

[stecy]

Steve, just to be sure I have this visualized correctly, is the last section that's outdoors the 18' of pipe + tee?

What I meant is that the top 3' section of pipe passes thru the roof, just below the ridge. The tee and the other 15' of pipe are all within the building, more or less in the center.

 

[begreen]

Got it, I thought that might be it. It should draft decently then as long as it is not in a negative pressure zone and the horizontal section is heading uphill. The two 90's reduce draft a bit. Overall, I could see this performing more like a 14' flue. A loose cleanout cap can further reduce draft. Was the Jotul connected rear vent or top?

 

[stecy]

A loose cleanout cap can further reduce draft. Was the Jotul connected rear vent or top?

Clean-out cap is snug now, but might not always have been.

The Jotul was used in the top vent mode.