SteelCat vs. Ceramic - My verdict

I had posted a few comments earlier in the year, referring to troubles I was having with my SteelCats, namely clogging with creosote due to the very tiny passages thru the cat being constricted by deformation of the cat. Another regular here saw that post, and PM'd me about having the same troubles I was having, and that he was switching back to a traditional ceramic cat. This prompted me to finally contact Condar, and request the same. After a dozen loads of wood thru the new ceramic cats, I have some comments.

The SteelCats in each of my stoves performed beautifully for the first few months, although because I put these two stoves online with SteelCats at different times, and was dealing with going from well seasoned wood (left by previous owner) to poorly seasoned wood, and then eventually back to somewhat better seasoned wood, I failed to recognize the pattern early on. In both cases, after the first several months of burning, I began to have more trouble getting light-off, and also started having frequent problems with the cat's falling out of ignition after light off. I also noticed that I had to achieve higher and higher cat probe temperatures before my chimney gasses would show clean, something on which many SteelCat users have commented.

After about 1 year, I started having troubles with the SteelCat's in both stoves clogging, the one I burned 24/7 more-so than the one I burn only evenings & weekends. Removal and inspection indicated that both SteelCat's were deforming, such that the air passages thru the element were becoming constricted. Not surprisingly, the one showing more deformation was the one causing more trouble.

A few comments on this subject prompted another regular here to PM me that they were having most of the same troubles, and had made the decision to switch back to a traditional ceramic cat. I contacted Condar to ask about doing the same, and asked for an honest opinion on which cat their tech would use, if he were running my stove. The answer came back: Ceramic.

Thinking back thru the claimed advantages of the SteelCat's, and the characteristics of my particular stove, I have come to realize that none of the proposed advantages are applicable to a downdraft stove. The SteelCat was designed to be less susceptible to thermal shock (throwing cold wood into a stove with a hot cat), and flame impingement (over firing), and ash build-up. None of these problems affect the downdraft catalytic design, as flue gasses must flow down into a refractory chamber, and reverse direction before them flowing up thru the cat.

I switched to the Ceramic cat's and life is good again. The troubles I had been blaming on my 1-year seasoned wood (all testing 18 - 22% on my moisture meter) have completely disappeared. I was not having a wood problem... I was having a cat problem. And seeing as my prior (19-year old) ceramic cat was still in perfect mechanical shape (heavy metals were probably depleted years prior), I do not anticipate any of the same troubles as I had with the SteelCats. My cat's light off at 550F stovetop / 500 flue, go straight to 1000 - 1200F, and cruise there for most of the burn. I no longer have troubles with them falling out of ignition when I lower the air control, or clogging with creosote if they don't light off quickly enough upon closing the bypass damper.

If you're using a SteelCat, and observe any of the same problems, particularly if you run a downdraft stove (Jotul, VC, etc.), I urge you to give Ceramic a try again.

Backwoods Savage said:

Joful, no disrespect intended but if that cat plugged with creosote, it was not the fault of the cat but rather the fault of the fuel.

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Last year, when these cats were new and not yet deformed, I was putting marginal (MC 23 - 25%) fuel thru them, and had no clogs. Now this year, every cord put thru them tested 18% - 21% (occasional outlier at 22%), and NOW I'm having trouble with clogs. The trouble isn't the fuel, but the badly deformed and restricted air passages. After tapping and vacuuming it clean, I can barely find a few passages I can still see thru.

Backwoods Savage said:

On the steel vs ceramic I would say if your wood is such that you are getting creosote in the cat, my bet is that the ceramic will not last as long as it will begin to crumble and fall apart.

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We shall see! Again, all wood is 18% - 22%, which is within manufacturer guidelines.

Yikes... forgot how active a new cat can be. Delayed closing the bypass two minutes too long (was busy typing), and when I closed the bypass damper the cat shot right to 1769 F! You don't need poor wood to generate thermal cracking, when spiking temperatures like that.

When I would engage the old SteelCat at the same stovetop temp, it would go to 600F.

rideau said:

And I agree with Dennis....I cannot even imagine getting creosote on the cat....don't get it in my firebox, or my flue. That simply has to be a wet wood issue. Was the cat checked after last year?

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Again... this creo clogging is not a problem of wet wood. This wood measures around 20% MC, my glass stays clean, and the ceramic cat lights off perfectly. The steelcats did too, before they got so badly deformed. The creo clogging is caused by the fact that the cat is so badly deformed, that the air passages are almost completely closed off, and I don't get sufficient gasses moving thru it to cause light-off. Even dry wood, in a zero-draft scenario, will coat the insides of your stove with creo. Just ask the BK owners about their dirty glass.

Just as with TX-L's mum... the problem disappeared when I switched from steel back to ceramic. Same wood.

Backwoods Savage said:

So, it would be interesting to determine exactly what is causing the deformity in your catalysts. I have not seen this sort of thing so it is foreign to me. The ceramic are certainly a larger opening than the steel so it would certainly take longer to clog. Yet, in the 7 years we've run our stove I have yet to see anywhere near any clogging. Most times when I remove the cat I wonder even why I am doing it because there is so little fly ash (fine white powder) that it just doesn't seem necessary to clean anything. But, when we have it out, we clean whatever is on the cat.

Also, I do not agree about the creosote problem. If we do turn the draft down to the zero setting, the only thing that happens is that the stove top will get even hotter and will get way too high unless we give it a bit more air. For example, if the stove top reads 700 (maximum suggested by manufacturer) and the draft is at zero, moving it to the setting of 1 will cool the stove top but then the sides will become hotter. Never though will the sides or front get hotter than the stove top. That probably is mainly because the stove top temperature we measure is right above the catalyst; the hottest point.

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Hi Dennis,

I think the deformation is just the result of a poor material choice for the job. We certainly never got it anywhere near the 1800 F maximum temperature I've seen quoted, and it normally cruised 1300 - 1500 F, under normal operation. Removing it a few times over 2 seasons, I first noticed two lines forming on one side wall of the cat, which correspond to the two welds they place to keep the thing together. The next inspection revealed holes in the sides of the cat, where those welds used to be. The final inspection showed the cat sagging in the middle, as has been described by several other people on this forum and elsewhere.

Turning your stove down to zero draft will not cause a good catalyst to fail, because the catalyst has its own separate air supply. This is different than having a cat which is deformed, and physically not allowing air thru it. My analogy was simply pointing out that creosote is generated from even the most dry of wood, but that you don't see it in a properly operating stove, because it has no opportunity to condense. Plug your chimney to stop the draft, and you'll see it. Likewise, shut your air supply completely, and you'll see it on your glass. I don't know if your Hybrid can be shut nearly as tight as a BK or an old Jotul catalytic.

Highbeam said:

I see no reason to mess with anything other than a ceramic cat. Lower light off temps? Who cares? The ceramics light off just fine. Is the steel cat a solution looking for a problem?

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I think they were an attempt to solve the problems exhibited by some wood stoves, none of which happen to be problems with my particular stove (I may have other problems, but not these three):

1. Cracking due to thermal shock, when you put a cold load of wood (or wet wood which will give off cool steam) into a stove with a hot cat. This is an issue mostly for stoves that allow a portion of the exhaust gas to still pass thru the cat when the stove is in bypass.
2. Cratering due to flame impingement, which is mostly an issue with stoves having cat's mounted above the firebox, or with VC's design (see jharkin above).
3. Caking with fly ash , as the manufacturers claim, "the steel slices the fly ash." I have trouble believing this claim, but there it is.

I asked the Condar tech whether he would personally use a SteelCat or ceramic cat in my stove, and he recommended the ceramic. He said they're finding that the SteelCats just don't work very well in certain stoves, but he doesn't yet understand why.