Production Woodstock IS

The flaking thins the steel and makes it warp more. I never thought about it like that- makes sense. I never had much flaking for some reason.

 

You are probably running the stove a bit harder (Boys!) than most of us and that will cut way down on the radiator scaling. Does not seem to make sense but really, it does: running the stove low- to- medium results in very little to no flame in the firebox with the wood smoldering. Lots of smoke is lots of fuel for the catalyst and it will run very hot, making the radiator very hot and also making it scale. Running the stove a bit harder will result in some secondary flames, which burn a lot of the smoke while still inside the firebox, leaving less smoke (fuel) for the cat., which in turn will run cooler- in most cases that I have seen, a LOT cooler. So, stove being pushed a little harder results in more fire, more heat but that extra coming out of the secondary burn in the firebox rather than a pure cat. burn. This is the 'hybrid' part of these hybrid stoves: they fall out of cat- only burn and kick over to a combination of secondary burn, cat burn stove with the bulk of the heat produced by the secondary burn, just like any modern non- cat stove.

Brian

 

Leave it to Brian to understand and explain things sooo well.. Unhdsm live in Bradford that region always needs more heat and less snow!!

 

Very true. I don't tend to run marathon reloads. I burn exclusively in 10-12 hour cycles- plus having run one for a year that I was supposed to try and break- I have confidence to run it closer to the recommended limits.

 

So a little shorter of heat than I thought when I actually got a look at the data. Looks like I got about 7 hours with the STT above 300F which took me to 04:00, so I would have liked to carry that a little longer. Stove held >200F for almost 15 hours, which took it to mid-afternoon. At 14.75 hours, you can see me come down and bump the air control wide open, which bounced the temp up for another ~2 hours. At 16.75 hours, I opened the door, knocked the ashes off the coals, and mounded the coals up and got about another hour out of it before I turned the logger off.

Each box on the chart is 1 hour wide by 100F tall.

 

Was that a full load? What type of wood. What was draft setting at for most of the burn?

I'm just curious.

 

I was just running on the very edge of cat only mode. Where you get a couple of poofs and a few seconds of flame. I happened to be near the stove and I swear I saw a puff of smoke come out the back of the stove. Grabbed a laser and waited. Sure enough after the next poof and flames you could see the path of the laser for 3 to 4 seconds. I saw the smoke too. Just a tiny bit. I'm wondering if I should be concerned.

I can also smell the slightest smoke smell in the house. Very slight but it's there

 

As full as I could stuff the thing, but our average length is 15" and we're loaded N-S so we're missing 3" times the entire face area of the firebox worth of wood. In other words, you could stuff more into it if you had better optimized wood. It was 80% ash and 20% cherry. Dried about 18-20 months. It's all reading 16-18% when I check it. The stove was played with several times in maybe the first hour and then left alone at 1 small notch under the first big notch for the rest of the run until I whacked it full open this afternoon. During the burn, it showed free-floating secondaries the whole time and never went fully dark until it burned down to coals-only.

 

Could you possibly load an EW log acrossed the back of the stove as you are putting the NS tiers? And alternate left side, right side on those EW logs? I explained that kind of confusing I know!! But do you get my draft or I mean drift?

 

I ran the stove exactly the same last night and had the same burn times. I was a little lazy filling it and used some odd shaped pieces so I only got it about 85% full.

 

Looks like a nice, pretty even burn to me. A thought: notice when you opened the draft the stove top did not increase in temp. but the flue temp. did? The stove did not produce any more heat (that ended up in your house) but it did produce a hotter and larger volume of flue gasses- that means a drop in efficiency.

The other thought is that your graph shows exactly what Hollywood, myself and a few others are after regarding efficiency. The goal is to get the ratio between the flue temps and the stove top temps more beneficial to you, meaning lowering flue temps. and raising stove top temps. The mods we have done to our stoves have done exactly this: the two temps. are very close for the entire burn and that means more of the heat that the stove has produced stays in the house. I only mention this because some people have asked if it is necessary to modify these stoves and if it is worth it to modify them at all, and your graph is a perfect snapshot of the changes one can have with a couple of 'tweaks'.

Now that you have filled the stove, it looks like your earlier problems of the stove stalling and smoldering have gone away. These stoves really do not work well with small loads of wood. What you have there looks perfect though with not a hint of stalling at any time and yet a nice, long burn.

Brian

 

Yeah I've thought about that. The problem is that I didn't make any splits thin enough to actually fit into that space. Right now, I don't need the extra heat badly enough to bother re-splitting a bunch of wood.

Yeah whacking the draft back open wasn't to get more heat out of it, it was to ensure the massive amount of coals in the bottom of the firebox burned down to something manageable by the time I needed to reload.

Are you referring to the lip a the back of the cat radiator/shield and the tiny hole in the ash pan door?

The downside is that the Ohio winter has a lot of time I'm not going to be able to burn this high though. But yes, under 30F outside and a stuffed full firebox makes the stove easier to run!

 

Yep, these stoves (and I think most modern, top / front draft stoves) generate a lot of coals and are slow to burn them down. That is where a bit of air introduced under the grate really helps.

And yes, the three mods. that seemed to have made the most difference are 1) blocking off part of the path at the back of the radiator, 2) introducing a small amount of air under the grate and closing the draft control a bit to compensate and 3) installing a flue damper and actually closing it when setting the stove for the long burn.

Opening up the two small holes in the front / bottom of the firebox may work instead of introducing air below the grate also- it would be easier, work on stoves that do not have the ash pan and do not have a grate, and probably not generate so much negativity overall.

Brian

 

Just remember more wood doesn't have to mean higher temps, it can mean longer burn time at the same heat level. If you had secondaries going most of the time in that burn you just graphed, and you were only 1 notch below the first big one, you had plenty of room you could have lowered the heat output still and got a longer burn. I'm trying to find my data but I can't at the moment, but I believe with a straight up load of ash I was somewhere in the 22-24hr burn time with a full cat and no secondaries burn last year. With my key damper installed I'm curious to try some more of these long burn tests, but right now I'm still burning mostly spruce and uglies and such.

 

Do you have any mods on your stove?

 

freeburn Not other than the key damper I mentioned I just installed a few days ago.

 

Nice. I'm trying to figure out how to get those long and slow burns. So far I can string it out to 14-16 hrs but I pretty much leave it on 1/4 open. Seems to be the best compromise between clean glass and hybrid burn.

 

Well for the record I tried overnight to pack er full of ash and go for a long burn, but it didn't go as well as I hoped. There was a bit to much hot coals in there, and the load really wanted to burn hot. Even with somewhat mild temps around 40 or so I had it backed down to about 2 notches open and the CAT still was hitting ~1200F and stovetop at 500. That was with the key damper in the closed position. I let it roll with that high cat burn thinking I'd still get good burn time since I had no secondaries at all (at least while I was up and checking), but when I woke up the next morning the CAT was at 400, stovetop down to 250, and a firebox still half full... not sure if it was fully into the coaling stage yet or if it had just smoldered out - I didn't open the door and prod but I turned it up and got it glowing again. While it did come back alive a bit and keep on rolling it wasn't worth much heat. But it was mild in the 40's and kept my house warm enough around 70 so I let it burn down until I reloaded at 21 hrs, but I could have reloaded several hours sooner.

14-16 hrs is still great, that is where most of my burns land, since 14 hrs is my door to door time for work and I usually give myself an hour or so to get the stove going and settled. Anything more than that does take a bit of tinkering keeping the stove down low as well as getting it packed full and tight. Type of wood and dryness a big factor too of course, I'm limited to ash for hardwoods but ecobricks greatly extend the time like by 2x or so. I suspect some really good dry dense hardwoods would also burn much longer than ash, like hedge, hickory, black locust, etc. I used to burn mostly bl, wish I still had some to try. Ash is good though, don't get me wrong. Mines also cut for my last stove and often I can't fill the stove with it since it leaves gaps, but the eco bricks work well to fill in the gaps when I want to mix em in.

 

I tried the same thing with the key damper and noticed the same drop in temp on the Cat side of things. With my chimney and setup, my stove runs best without the key damper closed and adjusted via the draft.

 

I am having similar results & am still trying to figure things out. If I dial it back for a cat only burn (damper closed, draft set between 2-5 ticks), I wake up in the AM to find lower stove top temps than I would like & more big chunks of coals than I would like. I keep tinkering and am sure I'll figure it out eventually.

Bottom line, it's still meeting my demands & I love the stove. I'm just trying to figure out a good balance between long burns and useable heat output.