Hearth brutha hooks me up; Cat probe ready to go!

[Woody Stover]

A few more weeks in, running with the cat probe, and I have to say...why didn't I do this sooner?! You're able to tell right away, or in a very short time, exactly how the burn is reacting when you make air adjustments. No more guessing when you don't have a cat glow--you can tell if the cat is burning by what the probe is telling you. As Todd mentioned, you might have 1000* on the cat probe, but it isn't glowing yet. Or the cat temp might rise or fall in response to an air adjustment you make, whereas without the probe you are just guessing if the cat's not glowing. You know it's burning though, if the probe is telling you it's well above 500, and you can verify that it is by looking at the stack, although you don't have to.
We're getting nights that drop to about freezing so I'm still loading the stove full sometimes, even though it may burn down to just a few coals left during the day. I've been generally getting the probe up to 450 or better before closing the bypass, then the probe temp will rise quickly as the cat begins to burn and I'm routing flame heat to it. Now, stove top temp may only be a little above 100 at this point and it sure is nice to have the probe to tell you what's really going on.
I'm sold on this new way of running my cat stove and I highly recommend the use of a cat probe if you want a great aid to burning. I sure won't be going back to the old way, now that I've seen how well this works!
Hey, wait a minute Todd; I think I saw an analog probe in your connector pipe in one of your pics. How come you didn't keep the digital thermometer/washer sensor, or get a shorter probe to use in the pipe of the Jotul secondary stove that you now run? 😯 Then again, I suspect that precise temps and instant feedback wouldn't be quite as important to running a secondary stove, and you may go more by what your eyes are telling you, since you can see what's going on at the tubes..

 

[Todd]

Glad it’s working so well for you. It does really help with a cat stove. I do have another Auber with a shorter probe to monitor my flue temps and it works great but I removed it this year cuz I got sick of looking at the wires and I get by just fine with the Condar Fluegard and watching the flames. With the Auber I was cutting back the air at 500 in 2 or 3 steps before final setting. With the Condar I start to adjust down the air at 400 because it’s slower to react. It will also continue to rise as I shut down the air unlike the Auber. If it doesn’t continue to rise and actually fall I know I shut it down too soon. The flames also tell me what going on as well. Once it’s settled in it runs between 400-700. If it’s below 400 I know I’ll have a little smoke out the stack.

 

[Woody Stover]

I have the washer sensor on the tee/liner connection, but I've mainly been focused on the cat probe so far. I should see more how the washer works, while I still have a little burning weather left.
It would be easy to switch back and forth between the two. Maybe I need to switch the Auber off when I change sensors, though, and not do it on the fly with the Auber still turned on...?
Where I have the washer probe, the liner is inserted into the tee there so it's in effect a double thickness. That could slow the reaction time of the sensor, over what it would be if just screwed into the tee metal only. I could put it further up on the liner, but it's heavy-duty stuff so it is pretty thick, just by itself--different than mounting on relatively thin connector pipe.
Or I could get a shorter probe sensor and go into the liner center to get the true temp of the exhaust stream...

 

[Todd]

Or you could use the washer sensor to monitor stove top temps. I think I used to slide that washer under the cast iron on the middle stone?

 

[Woody Stover]

In a couple of recent fires, I would think I had enough wood gassing, and had the cat glowing with flame heat, but when I cut the air the probe showed cat temp dropping, and cat didn't glow on its own as I thought it should be doing at that point.
At first I thought it was because I had a damp split or two, since the glass gunked slightly. But then on another couple of burns with proven dry wood, and no glass gunking, it happened again. Then I figured the cat must be getting weak. Not sure exactly how many hours are on that ceramic cat, as I've swapped back and forth between it and an older steel cat I had saved, but was getting weak.
I switched back to the old steel cat, and basically got the same results...just a bit sluggish to get it burning at first.
So I ordered a new steelie from Woodstock and it arrived today, about a week later. I've been wanting to try one of their new cats, which I understand are made in-house now. But I'm not sure if they do everything there, applying the catalyst to the steel and so on..? I may email them to get more details.
Looks like I've got a couple more burning nights coming up, with temps down to about 40, so maybe I'll pop that baby in to check it out. Of course, the new cat won't be broken in, and might be a bit more active at first. I'm not really sure how long it takes to fully break one in..??

 

[huauqui]

Woody,
Can't wait to see what you think of the in-house made cat as opposed to the older steel cat. Mine has held up well so far and still lights off pretty quick.

 

[Woody Stover]

Woody,
Can't wait to see what you think of the in-house made cat as opposed to the older steel cat. Mine has held up well so far and still lights off pretty quick.

How long have you had it in there?
I even ran some of the old diesel-foil steels, which were prone to warping, etc.

 

[Woody Stover]

I popped the new steel cat from Woodstock in a few nights back. I went off bypass at 500* and it lit right away. I didn't observe either of the burns I did, beginning to end, though.
Cat probe never got over 850, even though the cat had an 1000-1200 glow going on. When I was putting in the cat frame bolts, I must have jostled the probe a bit further away from the face of the cat. I'll pop the lid on the stove and check that before firing up this weekend, when a couple of mid-30s nights are forecast.
Here's a nice little burn from under the load, fed by ash pan housing air through the 1/4" hole in the side. I'm tellin' ya, this has gotta be the funnest stove out there to run. 🤗

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[Todd]

Yes it is a fun little stove to run. Sometimes I wish I had bought another for this cabin but with a corner install the side loading would have been a pain.

I think the proper distance of the probe from the cat is 1/4” as I recall.

 

[Woody Stover]

I think the proper distance of the probe from the cat is 1/4” as I recall.

I found that the tip of the sensor wasn't quite that close..apparently forgot to look after I put in the new cat and re-installed the heat shield! 😆 Got temps more in line with what's expected, after I fixed that. I also took off the tin foil wrapped around the sensor and put a little stainless trim coil piece into the probe hole instead--may hold it in place better, I thought.

Window is still gunking a bit--not sure if it's the two-year Cherry splits (5" half-rounds) or a couple unsplit 4-5" Red Elm rounds I tossed in. I thought that Red was testing 20% or under. Heard hissing but didn't see moisture on the ends of the Cherry that caught first after I lit the load.
I'll try them in separate loads to see if I can narrow it down. We've got several more days of cool weather to burn a few night loads.
New Woodstock cat is working nicely, glows immediately on flame heat when I've closed the bypass at about 500*, and I'd have to cut the air way lower for the cat temp to start dropping, than I did with the old cat (which was ceramic, so that could be another factor besides the age of the cat.)
This AM I looked at the cat and saw it faintly glowing, when the load was only a couple of coaled split forms left and temp was about 580 on the Auber. Those mighta been the two medium-small BL splits I had in there...maybe the center gasses longer in dense woods, I don't know.

 

[huauqui]

How long have you had it in there?
I even ran some of the old diesel-foil steels, which were prone to warping, etc.

Woody,
I put the new Woodstock-made cat in on December 21 of 2022. I have run just shy of two cords through it with great success. It is not warped and is still popping off right away on closing the bypass. I am very happy with it so far.