Jotul Firelight 12

begreen, you might remember one night when my cat temp hit 2200F. On that day, my stove was glowing in exactly the same two spots where this one shows some paint issues. In my case, there was no permanent paint damage.

Is the floor grate bowed up, or is that just a photographic illusion? That would be one sure sign of overfiring.

The rest of the stove looks pretty nice. I don't see any crack in the inner back burn plate (small plate on back wall with sunburst design), and that's the most common thing to fail on these stoves, but I guess there's a chance it was replaced. I replaced them in each of my stoves, since each were cracked when I bought the stoves.

My issues with the F12's were all around the combustors, so I'd get a look at this one, before making any verdict. This is why I eventually sold mine, as I got tired of burning up combustors and damaging too-expensive combustor chambers ($1000 rebuild, each time). I'm not sure why this kept happening to me, but I believe it may be due to combustor size, and my desire to run full loads of high-BTU hardwoods. Note that the combustor cross-section in this stove is only 28 sq.in., about half that of any modern cat stove of similar size. The thing that causes me to doubt whether combustor cross section is entirely to blame is that I don't know how Jotul produced this stove for ten years, with me being the only person to come to that conclusion.

Remove the single bolt at the top of that inner back burn plate, lift it out, and remove the small cover (just slip fit) over the cat chamber. Slide the cat out, and let's get some pics of what's going on in there!

arakt1 said:

You guys are right about the grate...definitely bowed. Supposedly this stove was only fired 5 times according to the owner...he was not there when I picked it up. I got it out of his house which was up for sale in the NC mountains...$1.2mil price tag. Maybe he had no clue how to run this stove...I did find aluminum foil in it when I cleaned it out. I paid $400...should I be worried about dumping lots of money into it? I probably should have never sold my Fisher Mama Bear. I'll take some picks with the back plate off and see what you guys think. Should I replace the "bowed" grate or just leave it? Thanks for the help on this.

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The bowed grate is not going to cause you any problems, in itself. It's just a sign that stove was severely overfired. The curling paint on either side of the cat chamber is another sign that maye it got scary hot (think glowing stove).

Me? I'd re-sell it for $400 and look for another stove. If you like the looks of the Jotul Firelight (they are superbly beautiful), I'd look for a Firelight 600. I lost all confidence in the Firelight 12's, after my last winter with them, but others here used them for years without issues.

Looks like the left rear vertical seam may be missing some cement? Would that make it burn too hot? That's where a stove with a welded plate-steel box is good....no seam leaks.

Ashful said:

The bowed grate is not going to cause you any problems, in itself. It's just a sign that stove was severely overfired. The curling paint on either side of the cat chamber is another sign that maye it got scary hot (think glowing stove).
I'd re-sell it for $400 and look for another stove. If you like the looks of the Jotul Firelight (they are superbly beautiful), I'd look for a Firelight 600. I lost all confidence in the Firelight 12's, after my last winter with them, but others here used them for years without issues.

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Yeah, I might bail out as well. If so, I wouldn't get another Fisher...get an EPA stove, mid-'90s or newer, which will save you a ton of wood over an old smoke-blower. There are many good stoves out there. It will take some reading here to get up to speed, but the heating season's about over so you have time. If you don't have DRY wood yet, either start splitting and stacking some fast-drying woods now, such as soft Maple, Black Cherry or Ash....any medium-weight wood, really, or cut small, dead trees with the bark gone. Or if you are going to buy, try to find some wood that has been split and stacked for a while already. Try to avoid Oak unless you can let it sit split and stacked for a couple of years, since it is slow-drying.
You need dry wood for the new stoves to heat well...wet wood kills the re-burn of the smoke, which kills heat output.

Woody has it right. I don't know the efficiency of a Mama Bear, but I see typical efficiency numbers of 40% to 50% for pre-EPA stoves. A quick bit of math, assuming operation near LHV, and 45% efficiency for the pre-EPA stove:

It will take approximately 3.25 cords in a non-cat EPA stove, to provide the same amount of heat as 3.00 cords in a catalytic EPA stove. A fairly small difference.

But, it will take 5.75 cords in a pre-EPA stove, to provide the same heat as the catalytic stove. Yikes! I don't want to split nearly double the wood I have to, and load twice as often, when better tech is available.

There may be a way. The trouble I had with my F12's is that they were literally eating catalytic combustors. I tried ceramic cat's from Condar, which seemed to hold up to the temperatures my F12's generated, but the expanding gasket that Condar uses between the ceramic element and the steel can of the cat would cause the soft refractory catalytic chamber on the F12 to break. That chamber with combustor cover costs $525, so that's a no-go. Next I switched to the Condar SteelCat, which completely self-destructed. Their SteelCat would deform under these high temperatures, which would constrict the air passages, and cause clogging. After burning thru four SteelCats in two years, I switched to the Applied Ceramics ceramic cats, and found the cans on those fell apart at the high temperatures (2000F) that the combustors ran in my F12's.

Having been thru just about every cat on the market that fit these stoves, I made the decision to sell my small collection of three Firelight 12's, but I had to get thru one more season. So, I bought some old OEM combustors on ebay, and these seemed to hold up okay. I'm not sure if it's just because they were mostly depleted, and therefore didn't run as hot, or if they're actually of different construction than the Condar and Applied Ceramics cats of today. Unfortunately, finding OEM combustors for a 30 year old stove, which Jotul hasn't built in at least 20 years, is getting near impossible.

So, my suggestion to you would be to buy some old OEM combustors, and try running those. Even if they're depleted, they'll operate like a non-cat at any combustor temperature above 1000F, and like a smoke dragon at lower burn rates. You'll get by, I guess.

I think that gutting it would leave it unsafe and unusable. Likewise on leaving it in bypass, you'll ruin your chimney. What's the condition of the combustor in yours? Why not just run it as intended?

If it's fried, I'd just run it without the cat installed, but still close bypass after fire gets going. Then it will run like a Fisher!

By the way, cat = combustor. Same thing.

Yes, and your damper key fits that screw. Remove single bolt at top of burn plate, and lift it out. Behind that, you'll find a fragile refractory cover. Remove cover, and you'll be looking at edge of catalytic combustor. Gently slide it out towards you, and see if it's deformed, cracked, or plugged.

Why don't you just try and run it like it's meant to and see how it does. Ashfull was heating a mansion with his so your results may differ from his.

I've seen worse, like at the end of the last two seasons in my Firelight 12's!

Your chamber looks good, which is great, as that's the only expensive part on this stove. The combustor is obviously shot, but see if you can slide it out of the chamber without damaging the edges of the chamber.

That little cover that was over the combustor is cheap ($70), as is the combustor ($160). The other little piece just sits on the floor in front of the chamber, behind the burn plate.