SteelCat vs. Ceramic - My verdict

[Ashful]

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]

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.

I can not say much about creosote in the cat other than above but will add that we have never seen any creosote on the cat; only a very light fly ash which easily brushes off.

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. The steel do light off quicker when new but as they age it will take a little bit longer but certainly not enough to be a problem. One thing we do is to wait until our stove top is near 250 degrees (with steel) rather than the 200 claimed. We also want our flue thermometer to read at least 400 degrees. On the ceramic, we for sure waited for 250 and the flue at 450 or 500. Also the steel cats can be cleaned with a vinegar/distilled water solution and that really restores them nicely.

 

[chance135]

I actually have a love/hate relationship with the steel cat in my Fireview. I purchased the stove in 2008 when they were shipped with ceramic cats. I had no problem getting it to light off so long as the stove top was about 250 and the pipe was around 450-500, just like Backwoods mentioned. Gobs of heat came off that cat. 625 stovetop temps were common. Unfortunately it literally fell apart after only two years ( 8 cords) of use and was replaced with the 1st gen steel cat. The steel cat lights off about the same but I have to keep my draft open to 1.5 for the first 20 minutes or it will stall. I also don't see nearly as high temps with this cat (475 mostly) with short bursts up to 525 that only last 30 minutes or so. Although I don't own a moisture meter, my wood is most likely better now than in 2008-2009 ( I have been lurking this forum for quite some time). If I had a choice I would gladly go back to ceramic and just replace it every three years.

 

[Backwoods Savage]

Welcome to the forum Chance.

I'm surprised at your stove top temperatures. With both the ceramic and steel, we have no problem getting our stove top well over 600 and have done it with as little as 3 splits. With more than 3 it is easy to get it up near the 700 degree mark. But like you, we do tend to leave the draft around 1.5 for maybe closer to 10 minutes and sometimes not that long. Sometimes if the fire is well established we go right to the .75 which is our more normal setting. Perhaps it is your wood that does not allow your stove to get that high of a temperature?

 

[homebrewz]

I've used both the ceramic and steel cat in my VC Defiant Encore 0028. With a ceramic catalyst, I had problems with thermal shock, but I was also new to burning an EPA stove, let alone one with a catalyst. I switched to steel which lit off at lower temps, but I did have problems with it clogging from the smaller passageways. I can't add much to the debate, but one thing I noticed with steel is that the metal folds will deform with time. The problem with that is, while the metal folds are flexible, the precious catalytic material they are coated with is not.. which can lead to it flaking off. Something that didn't happen with the ceramic cat.

The steel one is just about done, so looking at a new one soon.

 

[chance135]

Thanks for the welcome Backwoods. It could very well be my wood as I have not been able to get on the three year plan yet My wood in 2 year c/s/s mix of oak, beech, and maple. I know oak could really use another year so I split all of it small, about 4 inches. I was getting higher temps though with the ceramic cat and wood dried in the same manner. The one nice thing about the steel cat is that I no longer have run away cat temps like I occasionally had with the ceramic cat. The steel cat has been very consistent.

 

[Ashful]

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.

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.

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.

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

 

[Ashful]

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.

 

[HotCoals]

I'm happy with my ceramic cat so far. 4th season on it. Light off temp has moved up some but still pegs my gauge when in cruise.

 

[TX-L]

From my experiences, ceramic all the way. My BK came with a ceramic, still have no problems whatsoever. My mom's Princess came equipped with steel, she developed problems with it (problems staying in the active zone, not enough heat output from the stove, and cat passage clogging) during it's second season, so I bought a ceramic from the dealer, installed it, and it works perfectly. This was absolutely not a wood quality issue. When the day comes where I have to get a replacement, it will be a ceramic version.

 

[jharkin]

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.

Guilty.

And I had the same experience with Condar... When I contacted them about switching steel back to ceramic they offered to do it no questions asked, even cross shipped me a new one.

I have had all the problems you did except for the clogging. The first steel I struggled with I had stalls at startup, significant smoke when in the 800-1100F probe temp region, and occasional runaways to 1800+. It also warped badly.

Now I assumed the warping and smoke problems where just because it degraded over time due to my newbie abuse, and got a new one this year. Well only 3 months use on the new one (about 1 cord), and the problems persisted, but my wood and burning habits have improved significantly with experience vs the last one. I have also freshly rebuilt the stove so the refractory box, thermostats, gasket seals -everything is perfect. This time I started having the mid cycle stalls where it could be happily cruising at 1200F + probe temps for 2-3 hours and then just randomly drop to 800 and start belching like a smoke dragon for no rhyme or reason.

This is burning 2 and 3 year C/S/S and top covered wood that's mostly under 20%, some under 15%. All tested on a resplit. It doesn't hiss, lights very easy, easily reaches 500-600 stovetop temps, glass stays fairly clean.. it really is not the wood in my case.

Pop the ceramic in, and bam. No more billowing smoke when under 1100, and so far no mid cycle stalls. Its too early to tell but I feel like its holding temps longer as well.

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.

This actually is a case where the VC and Jotul designs differ (Jotul possibly the better idea). In the VC, the smoke enters the rear chamber through an iron hood just below the bypass, then immediately enters the refractory box and makes a 180 degree u-turn to flow down through the catalyst. then at the bottom of the refractory exits and makes another 180 to go up the back of the stove and out.

The cat element is only a couple inches from that inlet hood, so if we are not careful it is quite possible to get flame impingement with the VC design. It might be part of the reason they can be prone to over-fire when not operated very carefully.

 

[Todd]

I also prefer the ceramic cat over steel. After burning both I found the ceramic burned hotter for longer and also clog up less.

I know Woodstock and Sud Chemie have worked on making the steels better and have a new and improved model out this year so it will be interesting to see how it performs the next couple years.

 

[3fordasho]

Pretty much identical experience - Ceramic cat performs better but would only get about 2.5 years and then fall apart. First one might have been my wood, but not the second and third. Steel cats now, stove doesn't get as hot or stay hot as long. Much easier to stall the steel cat. On a cold start (no established or minimal coal bed) once the wood in the front of the stove is burned the cat will stall and the wood in the back just smolders and I'm seeing smoke out the stack. That rarely happened with the ceramic cat. The steel cat in my Progress Hybrid likes to plug with fly ash in about 3-4 weeks of full time use, for some reason the one in the Fireview does not - same wood.

I actually have a love/hate relationship with the steel cat in my Fireview. I purchased the stove in 2008 when they were shipped with ceramic cats. I had no problem getting it to light off so long as the stove top was about 250 and the pipe was around 450-500, just like Backwoods mentioned. Gobs of heat came off that cat. 625 stovetop temps were common. Unfortunately it literally fell apart after only two years ( 8 cords) of use and was replaced with the 1st gen steel cat. The steel cat lights off about the same but I have to keep my draft open to 1.5 for the first 20 minutes or it will stall. I also don't see nearly as high temps with this cat (475 mostly) with short bursts up to 525 that only last 30 minutes or so. Although I don't own a moisture meter, my wood is most likely better now than in 2008-2009 ( I have been lurking this forum for quite some time). If I had a choice I would gladly go back to ceramic and just replace it every three years.

 

[rideau]

There is no ceramic cat for the PH, so cannot try it here. Ceramic cat with the Fireview lasted five years. Had an early steel cat with the PH, which was replaced. Then the replacement warped. Replaced. Have that same design steel cat now. awaiting the newer design. Only problem I have had is total surface clogging of the input side of the cat, stopping draft completely, about every three weeks or so. Have to remove the cat and brush it off. Did so yesterday, stovetop at 200 and some active coals. No problem...took only minutes.

I think the old ceramic cats didn't clog because of the much bigger openings and the much bigger screen openings. However, I have to believe that all the fly ash accumulating on the steel cat is going up the flue on the ceramic cat....I brush off about 1/2 to 1 cu inch of very fine fly ash from the cat and screen every three weeks or

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?

 

[Ashful]

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?

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.

 

[jharkin]

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.

I would definately agree with you Joful, even my first newbie year burning wood close to 30% moisture I never clogged the cat with creo. Once its burning well I dont see how tar could deposit in that 1500 degree environment. This being a symptom of an already damaged catalyst that just isnt fully active is far more plausible.


Granted, that first year I had a TON of creo in the firebox itself, and a fair amount up the flue probably all from the bypass periods on reload, but never anything in the cat chamber itself.

 

[Backwoods Savage]

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.

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.

 

[Ashful]

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.

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.

 

[Backwoods Savage]

Joful, on our stove the cat does not have a separate air supply. I also do not think turning the draft down will harm the cat in any way. I do know they are really struggling to come up with new cat designs and it is good to see them continually trying to improve. I do think the newer cats are better but only time will tell on the long range use of them. On our stove the new ones come with their own frame so there is no switching of the frame at all. They are also very light in weight. The early results have been very good so far.

Also, we do not have a hybrid stove yet. In the Woodstock line that is the Progress and the new stove which hopefully will be introduced next summer.

 

[Highbeam]

The woodstocks must not be set up to allow the user to close the draft very far. Dennis is unable to stall his cat, as he says the cat just gets hotter with draft set to zero. Well, a tighter stove does allow cat snuffage and I can stall the BK cat with a too low draft setting. When that happens, or even at very low settings, I will get a noticable amount of tar on the glass and firebox but I have never had anything set up on the cat itself, not even fly ash. All cells are still clear with zero maintenance.

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?

 

[HotCoals]

I think what happened in Jotuls case is the cat crapped the bed as he said because of welds or whatever.
After the cat dies or is real close to death it won't light off very good or not at all. When a cat is in that bad of shape you lose draft at low burn and the cat is what grabbed the creo first apparently. But it's my opinion that a hot cat does help pull a draft. I say that because if the cat is not feed well enough with gas's it will stall..then it seems everything just sets there because the draft also died.

 

[chance135]

I know I can stall the cat in my Fireview by cranking the air down to below 1 ( <25%) unless it is very cold out, then I need more heat anyway so my stove pretty much always runs at about 1 on the draft control. With the ceramic cat I could lower the draft to almost the zero mark. That's when I would get high stove top temps but the rest of the stove was relatively cool. Next warm up we get I may try a distiller water/ vinegar bath to try and breath new life into the steel cat.

 

[Ashful]

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?

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.

 

[Todd]

You can stall a WS cat, just depends on how you load the stove and run it. The air supply for the cat on the Fireview and Keystone/Palladian is on the air wash plate above the glass. There are holes drilled across it that suck some of the air wash to the cat.

 

[fox9988]

I got my KS in Sept '12. Never had a single cat stall until about Dec '13. Then I couldn't keep it from stalling. That was a first gen SS, so far the new second gen SS is hyperactive and awesome....we shall see.....