Help with Jotul - burn tube -- UPDATE --

Not familiar with your stove but that baffle should be flush with the back of the stove. Something is out of wack, Do you have a manual? Should have instructions on how to take out the baffle, maybe take everything out and back in?

I am not familiar with the inner workings of the 118. If you can remove the top of stove, then lift entire reburn unit up and out(may have to be pushed up from underneath). There will be a gasket along the edge on the underside that you need to be careful with. If it anything like the two Jotuls I have( and it may not be) then you can drop the unit back in squarely and it should line up provided it is not warped and it would take a whole lot of heat to warp the cast iron/ss unit. Mine have seen really high temps with no warpage.

The burn tubes on the non-cat stoves are made of stainless steel and not cast iron. They are supposed to look rusty, more tarnished really, but not flaking apart. These tubes tend to glow red on a hot fire and will take more abuse than cast iron.

I have an old 118 so I'm not sure I can be of any help too you? I'm not sure what the new plumbing on the Blackbears looks like up top? Mine has a baffle plate that can only fit in two ways. The correct way or 180 degrees off (up side down). I have the notches that the baffles fit into on the sides though. If it's only 1/8th of an inch off you could take a small file and extend the notch a bit? If the stove is still under warrentee then by all means have the dealer replace it. By the way, what length of burn times do you get out of yours? Good Luck

PS: Sorry after reading the post and the 2nd link I can see that the new ones are nothing like mine. No tubes involved just the baffle plate on my old 118.

I've muscled those tubes and that baffle in and out of that stove a few times. It's pretty easy to get the problem you're talking about, even with an unwarped baffle. Everything is so doggone tight up there, the only way I was able to get the placement correct was to actually unbolt the top of the stove. Fun fun.

I am the earlier poster that BeGreen referred to. As it happened, I got another stove (that's another story in itself) and never entirely finished my troubleshooting. However I can explain my efforts so far.

First, let me say that Corie's praise of the design (can't find this post now, but in as I recall it he talks of discussing the design in detail with the original engineer) seems to be to be unjustified. The original 118 was so beautifully uncomplicated & reliable; retrofitting it to be EPA compliant should have been tested under field conditions for several years before bringing it to market, as it has a couple of major failings in my experience.

First, don't remove the backplate unless there is some clear necessity. The two lengthwise secondary air tubes are held in place by one nut each, easily loosened from the rear without disturbing the backplate itself. All three tubes can then be removed for examination. I did this twice; the first time there was no significant change upon reassembly in the misalignment. The second time I was more careful in inspecting the tubes - holding them up to a straightedge & discovering that each had a warp, presumably from heat.

It appears critical that the short tube be perfectly straight - or even perhaps with a slight bow towards the rear. They are not bendable with bare hands, but in an arbor press I was able to straighten the short tube with a little trial & error. This time things went together better, but not quite good enough. I was on the verge of trying a reverse bend when another stove arrived, and this project got sidelined.

Corie is may well be right that the top needs to come off to get everything back in place - and that I take to be a serious design failure, as with the force of stuffing that last log in, and the occasional fire that gets away, it seems inevitable that these will get out of alignment sooner or later. Stoopid! In particular the three points of attachment that the short tube has creates a triangle, which as we know from high school geometry produces a rigid structure. Have any one of these three points become dislocated in the slightest, and the tube will refuse to seat properly.

It is my suspicion that a great many (most? all?) black bear owners are suffering from this problem, but are not observant enough to have identified the exact problem, or for some other reason don't see fit to complain to their dealer. ( In my case, the dealer has gone out of the business, so he was no help.) I think that the problem is inherent in the design, which as I said earlier smacks of insufficient field testing.

That's all I have time for now. Perhaps more later.

Steve Clay-Young

Jeff

I have more to report - I just haven't been able to find the time to post it yet. Will try to make time soon.

Steve

Jeff

I've been to a nearby dealer's showroom a couple of times to look closely at a new Black Bear, and make comparisons to mine. As it happened, one of these times a Jotul rep was there, and although I wasn't able to talk to him directly, my problem was relayed to him, and the advise came back that it probably would be necessary to remove the top of the stove to get the tubes back in place. This is approximately what Corie reported. Needless to say, it is very annoying, at the least, to have to go to this extent to solve a problem that shouldn't have happened in the first place.

My analysis at this point suggests that the real culprit may not be the tubes themselves, but the fact that the baffle plate is very poorly retained in front by a couple of stainless clips. As soon as these clips loosen, which probably happens the first time you have a log stuck most of the way in and apply even a little force to get it home. Since the baffle slopes downward toward the back, it is very easy to find yourself in this bind.

So, coming back to the clips, it is somewhat of a mystery how they are supposed to work. I have stared at those in my stove, and in the new stove at the dealers. Their purpose must be to retain the front of the baffle, and certainly something has to do this, as otherwise the baffle can rise at the front something like 3/8' to 1/2". And of course, it that happens, the crosswise air tube can easily become dislodged and/or distorted. In my stove, these clips were flapping around doing nothing soon after I got the stove, but before the air tube problem manifested itself.

In summary - for this post anyway - my tentative conclusion is that the design of the baffle-retaining clips is very poor, and in short order the baffle becomes free to rise at least a small distance at the front. This movement allows the air tubes to lose their proper position, and from there things just get worse. I don't think that the baffle itself has necessarily become distorted, nor do I think that replacing it will do any good, as long as the clips that are supposed to keep it in place do not do their job. Perhaps, if working with the top removed, it might be clear how the clips were intended to be positioned, but as I said, from studying a new stove as well as my failed one, this is a mystery.

Let's see if the photo of a new stove I have attempted to attach comes thru. If so, you can see the clip at the front, and if you look closely, also the cast nubbin in the center engaging a hole in the top of the center air tube. Also, at the very back can be seen the bolt that retains the lengthwise tube.

Hope this clarifies my efforts to date. Ideally, Corie will chime in now, as he has done a complete disassembly, and, IIRC, was in contact with the designer of the stove. Corie, can you explain how these clips are supposed to provide positive retention of the baffle? If it is a mystery to you, could you ask the designer? As near as I can tell, the malfunctioning of these clips sets off a chain of events that leads to the air tubes becoming disconnected. In the extreme case, the crosswise tube can fall out altogether - this has actually happened to a friend of mine.

As I mentioned before, it is my belief that many if not most Black Bear owners must have this problem to some degree, but not be paving enough attention to notice it, of if they do, do not report it to their dealer. The friend that I mentioned who had the crosswise tube fall out onto the floor has said nothing to his dealer. Go figure.

Phew, all for now.

Steve

jeffee said:

My goal is to not have this problem happen again unless ten years have gone by give or take -- which seems like a more reasonable wear and tear period (?)..

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Jeff

That is awfully liberal of you. My mother-in-law has the predecessor model (pre-epa) that after 25 years looks & functions as well as when it was new. We are paying good money for these "improved" stoves, I don't see why we shouldn't get long service from them.

Steve

Jeff

Even if removing the top allows resetting the tubes, it is certainly no real answer to why the tubes are prone to becoming misaligned/disconnected in the first place, and offers no guarantee that this will not recur.

To summarize my theory, the top baffle is the lock that holds the tubes in alignment. If the baffle has more movement than the small amount necessary for thermal expansion, the crosswise tube in particular gains freedom to lose position. There are strong upward forces applied to the baffle, due to its downward slope toward the rear, creating a long tapering firebox that inevitably causes a jam when loading for overnight. Stainless steel clips of mysterious design are intended to retain the baffle at the front, but they apparently do not do their job for long, setting the stage for this chain of events.

Therefore, my belief is that the clips must be redesigned and new & improved ones supplied to all Black Bear owners, lest this problem arise repeatedly.

Perhaps you could PM Corie and draw him into this discussion, as he has had communication with the Jotul designer, and could take this theory to him directly. As near as I can tell, dealers & the importer are clueless.

Steve

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

jeffee said:

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

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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