Cat or no Cat?

Last night was pretty cold here on the NH/Mass border, so we had the Fireview going. The Fireview being a cat stove, here is a good example of maximizing the heat and minimizing the wood you're using.

Wood burning in the stove. No flames, just a slow burn in the stove. Minimal heat in the flue.

 

And a non cat doing the same With a bit of flame.

 

Those are two extremely different outcomes. The Fireview is burning at 650 on the stove top and a flue temp of 220. The stove pipe is essentially 1/3 of the stove top temp. The stove is heating the house and minimal heat is going up the stack.

With the reburner stove the stove top temp and the pipe are basically the same.

 

His 220 flue temp is external mine is internal. Double his to get an approximate internal which would be similar to mine. Also the reason his stove top is at 650 is because the 1000 degree cat sits right under it. I’ve burned Woodstocks before the stove top temps are misleading. You can have a 700 degree stt with no flame but you can have an overall hotter stove with a little flame in the box and a much cooler stt.

I believe flue temp is key here. The less heat up the stack with no smoke the better efficiency of the stove. Non cats seem to get a bad rap that they burn too hot, some do probably on purpose to pass the EPA test but there are some good non cats that have better control.

 

I see what you mean about the temps being taken from inside vs the surface of the pipe. The rest not so much. Have a good one.

 

Yep, a good secondary stove and/or a good cat stove can both do the same thing. Good wood and good results.

 

That is really good and slow for a noncat. Not my experience with my nc30 where the stove top temperature basically matches the internal flue gas temperature.

The stove top temperature of the cat stove isn't really a good measure of output because it is sitting right on top of a 1000-1500 degree catalyst. It's a hot spot. Where on the the noncat, stove top temperature, is more representative of output. To put into context, whether the cat stove is at full chooch or just idling, that stove top temperature won't change much. The amount of the cat stove that is at that temperature changes.

Two apparently excellent stoves and operators with that jotul and the fireview. Makes me want to try a high quality noncat.

 

Yeah after running three different cat stoves I’m pretty impressed with this Jotul’s control. It’s not quite as controllable and have as low an output as my previous cats but it’s close enough for what I need. Once settled in the internal flue temps will hang around 100 degrees less than my stove top temps. If I get below about 375 flue I start to see a little smoke. 400-600 is where the flue runs, while stove top runs 500-700 from low to medium low air settings.

 

I think the one thing that may be missing from any comparison is some kind of standard measurement of wood consumption. Given that all the other key measurements may be pretty close to equal, the amount of wood might be a key factor as well. I have very little knowledge of secondary burn stoves. I went from 25 years of a large steel smoke dragon, straight to a Cat stove. Since then I've had 3 cat stoves and in each case been impressed with them. For sure the wood consumed for the same house was about 33% or better for the Cat based stoves.

So many other factors play into the heating capability of a wood-burning stove. Wood type and seasoned, chimney/draft, climate, stove size, area heated and insulated ...the list goes on.

Find one that works for you and your family and get good at using it.

 

Call me middle of the road, but having so many of us advocating for our own stoves suggests that the quality of stoves from reputable manufacturers these days are up there in quality.
I hope it stays that way.

 

Oldhippie, as a young hippie, I'm still learning how best to operate my stove. You'll recall I converted my wood burning fireplace, which is how I've always burned, to the stove back in January.

So looking at your pics got me wondering. I thought soapstone was limited to 600*. Since your pic shows you above that, thought I'd probe to get your thoughts.... going that hot hasn't been a problem? Not worried about breaking a stone? And your cat doesn't get too hot???? And your thermometer shows 650* as overheat where my 'soapstone specific' thermometer shows 500*.

I'd love to get my stove that high, but never have (intentionally) because I thought it was bad for the stove. Can I go that hot without damage?

 

I think this is a stove-to-stove question. The Fireview I have has a fairly large protective plate on the bottom of the top Soapstone, and above the cat. This protects the soapstone from taking the extreme heat of the cat.

But I would give Hearthsone a call about that. Also, is there a way you can see the bottom(inside the stove) configuration above the cat? But even if not, call Hearthstone and get their input.

Steve aka OLDhippie!

 

I remember asking Woodstock about overfire temps and they told me to try and keep it under 700. They were more worried about the internal cast parts than the stones.

 

I've spoken to Hearthstone and they weren't worried about 600*, though they didn't give me a number nor is there one listed in the manual.

In the end, soapstone is soapstone, and if your guys' isn't breaking at 650*, guess I don't need to worry.

But to confirm... when your stove top temperature is reading 650*, your catalyst temp isn't in the "too hot" range?

 

You could probably buy 5 different thermometers and have a different schematic or painted on temp range on each of them. I have a cat stove and the thermo on mine has 700F in the "overfired" range but 650F is clearly within the "optimal" range. You're fine in my experience.
I'm going to paraphrase a response I got from Dennis a couple years back imagining I'm remembering it correctly, but made a post worrying about my stove hitting 700+ and I think he said "eh, don't make a habit of it" or something thereabouts.

Someone chime in if I'm way off.

 

I ran a solid stone hearthstone heritage for several years, it was the last generation before the catalyst model you have. That heritage manual specified 550 or maybe 600 as the max stove top temperature. You can't compare woodstocks because their soapstone is different. It's double wall construction. Two thin layers of stone with an air gap. Hearthstones, at least my heritage, was a solid 1.25" thick slab on 5 sides. The base was cast iron.

On edit, people crack hearthstones and they also melt them. The tops cave in when they get them too hot. Stone stoves are great for the guy that keeps them warm but frustrating for the guy that comes home to a cold house and stove and wants a lot of heat in a hurry. I think they can be abused in an effort to just get some output in a hurry.

 

I like your pics Oldhippie ..
I wish BDF was still with us. He drilled holes in his Woodstock Ideal steel and graphed them on charts over burn cycle.. a real smart man

he lived Jersey area and we often joked he kept his STT around 350 degrees; in cold I try to keep mine 650. So as opposite as possible.

His graphs showed firebox, cat, stovepipe and stovetop. He often achieved the STT to exhaust in the 3/1 ratio

 

I don't have a probe type thermometer that can read the cat heat inside the stove. But I can look up and see the bright orange of the cat totally deep orange in color so it's really HOT. I have to look into what Highbeam mentioned about the 2 soapstone slabs with an air gap between them. I will look into that. I have heard to soapstone slabs cracking, but never heard why. But I have this stove on 700 or near it almost every burn. That's how nicely dried wood and a cat get along with each other.

 

Yes, the PH has layers - a steel box clad in soapstone and with soapstone “firebrick “ within the firebox (but not in the cat area). The top stones sit above a cast cooktop and do indeed have an air gap. The rest of the stones have no air gap.

 

I was referring to Oldhippie 's fireview that is made with sidewalls of double wall stone construction. The lift up top may be single wall but even the glass is double pane! I'm aware that woodstock makes other stoves, even welded steel boxes, that may be different but none like hearthstone's all solid stone construction. It is pretty cool how they spline the bricks together.

I almost bought a fireview before the PH came out. The large rear clearances pushed me to the BK. Now, woodstock makes the IS and it would be nice to try. I never really liked soapstone for a stove. It looks great but the way I use it in this climate I was always waiting for it to warm up.