Does my catalyst need to be replaced?

[N.E.K. - D.D.S.]

One of my stoves is a Jotul 3TDIC-2.

It was beat up by the previous owner(s).... overfired, warped baffles, etc. I did not know better at the time. Still, it is a nice looking little stove and perfect for the difficult space (in front of small old fireplace). I put some new parts in, did some repairs, gaskets, resealed the joints, etc. My wife loves this stove, more than our Woodstock Fireview, so that says something. It is perfect in shoulder seasons with relatively quick starts, and limited output. When it is brutally cold we burn both this one and the Woodstock.

One would assume that an old and abused stove would need a catalyst replacement. Last year they were unavailable, so I vacuumed and blew all the dust out of the catalyst, soaked it in vinegar, and gave it a good rinse. I don't have anything previous to compare it to, but the stove (and catalyst) just WORKS. The stove has good draw with the catalyst disengaged. Once it is hot, with catalyst engaged, it is a smooth and controlled fire. I am not getting great burn times, but it is a tiny stove. I am not getting much buildup in the stove pipe or chimney.

Is there any reason to change the catalyst? I don't know if it is functioning, or if redirecting the exhaust is just acting sort of like a damper, turning the really strong draw into something more appropriate. it is actually an 8" liner (I think) reduced down to 6 inch a little way above the stove.

The catalysts used to be 80 bucks, but now that they are back in stock it is closer to 200.

I have no idea how many hours are on it.

 

[begreen]

Do you see smoke out of the chimney when the cat is engaged? If so, it probably needs replacement. If not, then no, but it wouldn't hurt to have a replacement on hand.

Is this the cat?

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[stoveliker]

To better gauge that, explain to someone how to engage the cat. Have both have a cellphone. Make a fire, turn it down. Go outside, look at what's coming out of the chimney. Then call the person inside and ask to (dis-)engage the cat. Observe any change in what comes out of the chimney.

 

[N.E.K. - D.D.S.]

Do you see smoke out of the chimney when the cat is engaged? If so, it probably needs replacement. If not, then no, but it wouldn't hurt to have a replacement on hand.

Is this the cat?

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Midwest Hearth MH-20C replacement combustors are a high-quality choice for your catalytic wood burning stove.Replacing your old combustor will help you improve your stove's efficiency, saving you money and producing less pollution. split Catalytic Combustor FAQ Catalytic Combustor Warranty...

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My cat is a CC-552 (I think). The one you posted looks similar, but I think it is not the exact model.

There is smoke when starting up (obviously) but once the fire gets going, it is pretty clean, and remains so even when the catalyst is engaged.

I wonder if they wear out as far as catalytic action.... or if it is just them becoming dirty or broken.

To better gauge that, explain to someone how to engage the cat. Have both have a cellphone. Make a fire, turn it down. Go outside, look at what's coming out of the chimney. Then call the person inside and ask to (dis-)engage the cat. Observe any change in what comes out of the chimney.

Hmmm. My wife is crabby enough even without this task. However, I shall try it next time. Right now I fired up the Woodstock Fireview and the thing is blowing me out of the house.

The small Jotul would have been the appropriate one for this fall day. I was juts curious to test the upgrades I made on the Fireview.

 

[N.E.K. - D.D.S.]

And by the way... CAN these catalysts be cleaned effectively?
Some people say that all the precious metals get scraped off and the things are then useless.

In my experience in chemistry, the catalysts never got used up. In fact, that was part of the definition of a catalyst. It was part of the reaction.... it was needed to make it happen.... but it never was consumed. So I find it strange that these things burn out at all. it would only make sense if it was from physical degradation (crumbling) or getting plugged up with gunk where the smoke passes through.

 

[stoveliker]

They should not be cleaned mechanically as you do remove the nanoparticles of metals then.

Some people use a vinegar wash, i.e a chemical cleaning. This is because catalysts do not get used indeed but might get covered, or poisoned. That is not "burned up", it's due to a process that does not meet the needs of the catalyst (in supplying poison, or not meeting temperature requirements).


They can be damaged by thermal shock; there is a coating on the substrate that holds the active metal particles. Thermal shock can start crumbling this coating.


Finally, the lifetime of a cat likely (imo) has to do with the temperature budget and amount of inappropriate feedstock (the poisoning agents). Temperature: eventually the particles will coagulate by atomic diffusion, leaving less active surface accessible to the gases. And given that even clean cordwood contains all elements of the periodic table, one inevitably slowly poisons a catalyst.

There will likely be other factors playing a (possibly larger) role too - this is my understanding (I am not a chemist but have done some basic catalytic research).

 

[N.E.K. - D.D.S.]

They should not be cleaned mechanically as you do remove the nanoparticles of metals then.

I just used vacuum and soak. I did not scrub it.

I did take your recommendation and compare the smoke with the catalyst engaged (practically no smoke) to the catalyst non engaged... which still had almost no smoke while burning hot. It is confusing. The stove is burning well. But I wonder if the catalyst is doing anything.

 

[bholler]

I just used vacuum and soak. I did not scrub it.

I did take your recommendation and compare the smoke with the catalyst engaged (practically no smoke) to the catalyst non engaged... which still had almost no smoke while burning hot. It is confusing. The stove is burning well. But I wonder if the catalyst is doing anything.

No visible smoke doesn't nessecarily mean the cat is working either. If the stove is burning hot enough you won't have visible smoke anyway

 

[stoveliker]

The visual check works best when the stove is turned down rather than hot. The cat would eat the smoke from a turned down fire.

 

[N.E.K. - D.D.S.]

No visible smoke doesn't nessecarily mean the cat is working either. If the stove is burning hot enough you won't have visible smoke anyway

Yes this is exactly what I said. No smoke either way. So I am still confused as to whether cat is functioning

The visual check works best when the stove is turned down rather than hot. The cat would eat the smoke from a turned down fire.

Hmmm yes I see. The stove works so well, it is hard to get a crappy fire out of it. I will try it early on... a bit closer to startup. I will try when there is visible smoke... and see if cat will remove it. BUT of course, the cat has to be hot enough for it to work. And by then.... the stove is burning pretty cleanly (little smoke).

I will wait for some blue sky when I can see it better too (more difficult to see smoke against grey sky).

 

[stoveliker]

Hmmm yes I see. The stove works so well, it is hard to get a crappy fire out of it. I will try it early on... a bit closer to startup. I will try when there is visible smoke... and see if cat will remove it. BUT of course, the cat has to be hot enough for it to work. And by then.... the stove is burning pretty cleanly (little smoke).

I will wait for some blue sky when I can see it better too (more difficult to see smoke against grey sky).

You would have to start with a hot enough fire to get the cat active, and then turn down the air - in my stove I can completely snuff out all the flames and be left with a smoldering heap. The cat then eats that smoke, and in doing so gets more hot (because that eating releases energy - it is in fact something similar as "burning the smoke"; that's why it's also called a combustor).

So you should NOT need a hot fire to *keep* the cat hot. You need a hot fire to make it hot enough to start being active, but turning the fire down then would provide even more "food" (smoke) for the cat, and that would make the cat hotter. I.e. it should keep itself hot.

If it does not keep itself hot after the flames are extinguished (or nearly so), then I would suspect the cat is not "good" anymore.

So I would not necessarily do it closer to start up; if the cat is on the edge of being (becoming) active, that might mess with the observations. You want to do this in a good steady state. You say "by then it's burning pretty cleanly" - but is that with the air fully (!) closed (minus the non-closable holes I presume are present in the system)?

 

[bholler]

Yes this is exactly what I said. No smoke either way. So I am still confused as to whether cat is functioning

Hmmm yes I see. The stove works so well, it is hard to get a crappy fire out of it. I will try it early on... a bit closer to startup. I will try when there is visible smoke... and see if cat will remove it. BUT of course, the cat has to be hot enough for it to work. And by then.... the stove is burning pretty cleanly (little smoke).

I will wait for some blue sky when I can see it better too (more difficult to see smoke against grey sky).

Does your stove have a spot for a cat thermometer?

 

[N.E.K. - D.D.S.]

Does your stove have a spot for a cat thermometer?

Unfortunately, no. Or I don't think so. It would require some modification and drilling through iron to potentially install one. Then I would want the hole for thermometer to be relatively sealed. Hmm.

You would have to start with a hot enough fire to get the cat active, and then turn down the air - in my stove I can completely snuff out all the flames and be left with a smoldering heap. The cat then eats that smoke, and in doing so gets more hot (because that eating releases energy - it is in fact something similar as "burning the smoke"; that's why it's also called a combustor).

So you should NOT need a hot fire to *keep* the cat hot. You need a hot fire to make it hot enough to start being active, but turning the fire down then would provide even more "food" (smoke) for the cat, and that would make the cat hotter. I.e. it should keep itself hot.

Yes I see. What about getting a good fire started.... having cat engaged.... letting it go down to hot coals (doesn't take too long) when exhaust temp (and presumably catalyst) are still hot... then loading a bunch of wood with low air flow and catalyst engaged. In a way, some purposely bad burning practices to see if the cat burns the smoke. Then I will bypass the cat and hope to see more smoke out the chimney.... which would be evidence that the cat is working.

I will try this. My wife was crabbing already with the test today. But she is the only one else in the house, so this experiment shall be her duty.

If it does not keep itself hot after the flames are extinguished (or nearly so), then I would suspect the cat is not "good" anymore.

So I would not necessarily do it closer to start up; if the cat is on the edge of being (becoming) active, that might mess with the observations. You want to do this in a good steady state. You say "by then it's burning pretty cleanly" - but is that with the air fully (!) closed (minus the non-closable holes I presume are present in the system)?

The answer is yes. Even with the air closed, this little Jotul 3TDIC-2 that everyone hates burns clean for me. I have no idea why.

 

[bholler]

What about getting a good fire started.... having cat engaged.... letting it go down to hot coals

When it's down to coals it won't be producing smoke anyway

 

[N.E.K. - D.D.S.]

When it's down to coals it won't be producing smoke anyway

But if I throw a bunch of wood on it at that point and keep the air intake closed (purposely bad practice just for the experiment) maybe I can get some smoke out of it. That should work, but if it doesn't, a piece of green or wet wood should do it!

I just want to test if the catalyst is helping anything.

 

[bholler]

But if I throw a bunch of wood on it at that point and keep the air intake closed (purposely bad practice just for the experiment) maybe I can get some smoke out of it. That should work, but if it doesn't, a piece of green or wet wood should do it!

I just want to test if the catalyst is helping anything.

Throwing a piece of green or wet wood on a hot coal bed through a hot cat is a really good way to destroy a cat.

Just start a fire get the cat up to temp then shut the air back so you see lots of smoke in the firebox. Then go outside and see if there is smoke coming out the chimney.

 

[stoveliker]

Even with the air closed, this little Jotul 3TDIC-2 that everyone hates burns clean for me. I have no idea why.

Well, I know exactly why. It has been designed to do so.

I concur with bholler. Just burn with a large load, hot. Then boom, shut the air as much as you can. That full and fully charred load will produce a ton of smoke. If you're lucky, you'll even get backpuffing

Again this would be most reliable if you work in a system that you don't open, don't change (add wood). Just a hot cat, and then produce smoke. If the cat works, it'll reduce the smoke. If no difference with the bypass, then cat didn't do a thing.

And if the tubes burn all the smoke when going from full blast to completely closed, then you don't have to worry about the cat... imo. Because it burns clean in the worst case already. (i.e. the cat is overkill then).

 

[N.E.K. - D.D.S.]

is a really good way to destroy a cat.

You are killing me.

Just start a fire get the cat up to temp then shut the air back so you see lots of smoke in the firebox. Then go outside and see if there is smoke coming out the chimney.

I will try this when I have blue sky.
Soon.
I know the other readers can't contain themselves waiting for my results, but they must exercise patience.

Well, I know exactly why. It has been designed to do so.

Yessssssssss the 3TDIC-2 is the most awesome stove in the history and future of all stoves. Long live the 3TDIC-2 !

If anybody has an inner back plate (not the common back burn plate) let me know. Or if someone wants to unload one of these pieces of junk for some parts, I need the inner back plate. Mine is warped from previous owner over-firing.

If you're lucky, you'll even get backpuffing

Now I'm getting excited.

And if the tubes burn all the smoke when going from full blast to completely closed, then you don't have to worry about the cat... imo. Because it burns clean in the worst case already. (i.e. the cat is overkill then).

I was thinking this, but did not type it because I feared discipline.

What tubes?

 

[stoveliker]

I thought it was said this was a hybrid stove. I.e. cat + (tubes).

Tubes are, well tubes in the top of the firebox that have small holes in them. The air coming out will burn the gases (smoke) there.

But maybe I'm wrong about (hybrid) this particular stove.

 

[N.E.K. - D.D.S.]

I thought it was said this was a hybrid stove. I.e. cat + (tubes).

Tubes are, well tubes in the top of the firebox that have small holes in them. The air coming out will burn the gases (smoke) there.

But maybe I'm wrong about (hybrid) this particular stove.

I think bholler and I went off on some tangent, and were speaking of hybrid stoves in general. But no, I don't think this Jotul is a hybrid. It is fairly primitive.

I would love to avoid buying a catalyst and say that my cleaning job was sufficient. I just don't know how the catalyst is (seemingly) performing so well on this stove that was completely beat to shoot by its previous owners (so many melted internal parts).

 

[stoveliker]

I thought this was the more modern one of your two stoves.
Anyway, if there is no other secondary combustion design here, then running full blast on a new load for half an hour, and then just shutting it down abruptly and as much as you can should result in a ton of smoke.

 

[N.E.K. - D.D.S.]

I thought this was the more modern one of your two stoves.
Anyway, if there is no other secondary combustion design here, then running full blast on a new load for half an hour, and then just shutting it down abruptly and as much as you can should result in a ton of smoke.

There are two "modern" stoves, which are not even all THAT modern. But at least they are catalytic. The Jotul, and the Woodstock Fireview.

I also have three antique stoves, like late 1800s and early 1900s. Two of those get very little use. One of them... the little "morning stove" in the kitchen gets some use, but only when we are in there. That stove is awesome. One of the members on this forum wanted to buy it, but I can't possibly part with it.

 

[bholler]

Mine is warped from previous owner over-firing.

Nope they all are. I have never worked on one that wasn't

 

[bholler]

completely beat to shoot by its previous owners (so many melted internal parts).

Again very common for these stoves. How long have you been using it now?

 

[N.E.K. - D.D.S.]

Again very common for these stoves. How long have you been using it now?

I think we got it only last fall... a year ago. It served pretty well in the winter (the furnace is undersized and also terrible install).

We got the Fireview last spring, so we used it only at the end of the season (with broken upper baffle, and non functional catalyst). I just now got it fixed up and converted into catalytic model.

Nope they all are. I have never worked on one that wasn't

They are all warped/melted?
I got a bunch of parts... but I can't find an inner back plate anywhere. It is preventing all the other baffles from seating properly. It decreases the size of my firebox, due top the warping.