New Ideal Steel Cat Temperatures

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idealheat

New Member
Sep 8, 2022
4
MN
I’m on day three of using our new IS stove and am looking for some assurance that I’m not doing it wrong. On almost every load of wood I’ve burned so far the fire gets to a point where the cat probe goes up to 1400+ or even 1500 degrees even though the air control is all the way closed. On one fire this happened when the air control had been closed for well over an hour. STT is in the 350-400 range measured to the left of the flue collar. The manual states the cat is best run between 500-1400 which is the reason for my concern. Is there a max temperature limit for the cat probe? If necessary, is there anyway to bring the cat temp down besides having the air all the way closed?
 

Pigeonman

New Member
Mar 2, 2022
5
Northern MI
This is my first year with the Woodstock Ideal. When I called Beth at Woodstock and asked her where I should place the magnetic thermometer, she told me to also place it on the top rear to the left of the flue collar which I believe you are doing, also. I am venting directly out the rear.

If I remember our discussion correctly she told me when that thermometer was in the 300-400 degree range, the flue temperature was approximately double the thermometer reading. At that time the catalyst should be engaged. Again, if I recalled correctly, she said the internal cat probe reading was insignificant . I'm sure many out there will correct me if I'm wrong.
 

Highbeam

Minister of Fire
Dec 28, 2006
20,376
Mt. Rainier Foothills, WA
Woodstock likely depends on their design being adequate to control the cat to stay within safe levels almost regardless of how you operate it. If your stt is at 400 then you’re not too hot.
 

begreen

Mooderator
Staff member
Nov 18, 2005
99,658
South Puget Sound, WA
A new cat is going to burn a bit hot. It will break in and settle down soon.
 

Woody Stover

Minister of Fire
Dec 25, 2010
13,059
Southern IN
I’m on day three of using our new IS stove and am looking for some assurance that I’m not doing it wrong. On almost every load of wood I’ve burned so far the fire gets to a point where the cat probe goes up to 1400+ or even 1500 degrees even though the air control is all the way closed. ...If necessary, is there anyway to bring the cat temp down besides having the air all the way closed?
What I've read about cats, from makers and other sources, has said don't run the cat in excess of 1600 or so for any length of time, or damage may occur...separation of the catalyst material from the substrate, etc.
The cat on the Buck 91 I used to run would go high once in a while. I was fine with 1500, though...kinda liked it in fact, since that house was hard to heat When it went high, I'd just open the bypass so it was not supplied with fuel (smoke.) Another way to control cat temp is to control the amount of smoke going to it. Experiment with top-down starts, to heat up the re-burn section of the stove quickly, yet not get too much wood gassing, where the cat will be "over-fed." On a re-load with hot coals, I would pull the coals together instead of lying all the splits on top of the coals, which got too much wood burning.
 

Woody Stover

Minister of Fire
Dec 25, 2010
13,059
Southern IN
Woodstock likely depends on their design being adequate to control the cat to stay within safe levels almost regardless of how you operate it. If your stt is at 400 then you’re not too hot.
IIRC, you've said you don't watch cat temp max, just whether the probe says "active." I don't think your BK probe shows actual temps, does it?
I know from the probe on Buck 91, when the cat gets to glowing bright orange, where you can no longer see the individual cells, just a bright glow, that rascal is pushing up toward 1600.
 

Highbeam

Minister of Fire
Dec 28, 2006
20,376
Mt. Rainier Foothills, WA
IIRC, you've said you don't watch cat temp max, just whether the probe says "active." I don't think your BK probe shows actual temps, does it?
I know from the probe on Buck 91, when the cat gets to glowing bright orange, where you can no longer see the individual cells, just a bright glow, that rascal is pushing up toward 1600.
My cat gauge shows numbers. I watch everything but I also know that the BK instructions do not prescribe actions based on cat temperature beyond the active line.

I have found no color to temperature correlation as you describe. Sometimes it glows immediately after engagement at 500 sometimes black at 1400. I don’t have the problem of the cat glowing so brightly that I can’t see the cells. Maybe that’s a buck issue?
 

Woody Stover

Minister of Fire
Dec 25, 2010
13,059
Southern IN
A new cat is going to burn a bit hot. It will break in and settle down soon.
Right; Give it a week or so and you'll probably see cat temps moderate a bit.
But I've run three different brands of cat stoves, and all of them were capable of glowing the cat brighter than I really wanted to see it. A general rule I operate under is "If you want something to last longer, run it easier."
Another way that you can slow the cat down a bit, if it's pushing toward 1600, is to run a small amount of flame on the wood. Flames will burn some of the gasses before they can reach the cat, so it won't run as hot. But adding air to get small flames, you may also get more wood burning which would release more smoke, and when you cut the air back to get a cat-only low burn you might be back in the same boat with a hot-running cat. You'll just have to experiment. As I mentioned, top-down starts might be another way to flatten the curve of smoke release at the beginning of the load, if that's when the cat is going high. Bigger splits also burn in a more controlled manner than a bunch of small ones, which ignite faster and gas more at startup.
Now, the IS tube/cat hybrid is different than the straight cat stoves I've run, so I don't have those additional insights. Obviously the tube flames are going to eat smoke, as flames on the wood do...
If you continue to max out at 1400-1500, I wouldn't be concerned.
idealheat, I hope you report back with an update on your burns and cat temps. I'd find it interesting. 😀

My cat gauge shows numbers. I watch everything but I also know that the BK instructions do not prescribe actions based on cat temperature beyond the active line.
Oh, yeah, I remember now that you finally did switch out their stock probe to one with numbers.
As for BK instructions, I'm not surprised that they don't mention high cat temps. Their general approach seems to me to be "Don't concern yourself with details, we'll run your stove for you as much as possible." They may also believe that the less people get involved with their stoves, and the less they know, the fewer questions they'll ask and the less confusion there will be. So they give you the thermostat and the numberless thermometer.
Now, Beth(?) at Woodstock also told Pigeonman "the internal cat probe reading was insignificant" but it's unclear whether they were talking about high cat temps, whether she was telling him to close the bypass based on stove top temp, not cat temp, or what..?
But I'm something of a detail guy, so I want more info (to a point.) My quest for cat info led me to articles by the combustor makers themselves, and they talk about excessive combustor temps over an extended period as a source of potential damage. I'd trust what those folks are telling me, more than I'd trust what BK is not telling me.



I have found no color to temperature correlation as you describe. Sometimes it glows immediately after engagement at 500 sometimes black at 1400. I don’t have the problem of the cat glowing so brightly that I can’t see the cells. Maybe that’s a buck issue?
Well, I did have an issue with the Buck 91 that I didn't have with the Woodstocks or the Dutchwest; With those, I could kill the flame burn and cat burn by cutting the air all the way, on the Buck I couldn't. I was in the process of adjusting the air intake covers to fit tighter, so that I could cut the air low enough to kill the burn, but my MIL moved and I never got to implement that. I'm pretty sure it woulda worked, though.
Other than that, I don't think there are any "stove maker issues" determining how brightly a cat will burn in a particular stove. If you feed a cat a lot of smoke, it's gonna glow brightly. After all, all of these ceramic cats were made by Applied Ceramics, out of the same materials, and displayed the same characteristics regardless of the stove they were in. Even the steel cat I had in the Dutchwest at one point reacted similarly...ALL of them started to glow at around 1000* and got progressively brighter, the hotter they got.
Now I guess I'll have to drill a hole in the top of the Keystone and put a probe in there to verify that the same thing is happening, thanks to your contrarian arse. 😆 The probe hole on the Fv and Keystone is in the back, and the probe needed is so long that the cat temp can't transmit all the way back to the dial. Or I guess I could feed a digital probe lead through that hole.. OK, I'm a little off track here, sorry.. 😏
Regardless, I never saw a cat that wasn't glowing at 1400 degrees, as you are claiming yours does (n't.) I'd in fact be willing to put down a substantial wager that, besides you, the number of others that would report ever having seen a 1400* cat that wasn't glowing, would be exactly zero people. The only way I can see that kind of a reading happening is if your cat probe is faulty.
As to your other claim of never to have never seen your cat glowing brightly enough to where the cells become indistinct, or disappear...not sure what your deal is on that one. Wet wood? Seems to me that in BK threads over the years, I've seen some mighty bright cat pics posted, where it just looks like a very bright orange mass with no distinguishing features. I'm obviously not gonna go find them now; I'm an old man and my remaining time grows short. 😏
 

Todd

Minister of Fire
Nov 19, 2005
9,937
NW Wisconsin
Woody,
I thought I talked you into a digital thermocouple probe years ago? No need to drill a hole into your soapstone lol😂
 

Woody Stover

Minister of Fire
Dec 25, 2010
13,059
Southern IN
Woody,
I thought I talked you into a digital thermocouple probe years ago? No need to drill a hole into your soapstone lol😂
You no doubt did. My curiosity is growing, so I'll have to get that done this winter..
I like the idea of having the analog meter on the stove top, but I'd be able to see a digital readout from my post in front of the desktop comp display. 😏
 
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