Woodstock Absolute Steel - How to burn hot?

When I use those bricks in, I've been arranging them so they're loosely connected, leaning against one another with lots of room for air between them. They definitely light up easily, and they help get my marginal firewood going too. If there's any downside I've seen, it's that they burn down to dense ash rather than the airy coals that firewood produces.

I'm still planning to pick up some really dry firewood this weekend to eliminate fuel issues, but right now, I'm working with what I've got.

 

I've got it covered on top now, so it shouldn't be getting any wetter from the elements. I don't have anywhere inside to put it right now. Might not be an issue once the weather cools down for good, and hopefully I can get some more seasoned wood by next winter.

 

Good point, brother!
I've never burned them in the stove, just in a fire pit once. And they did not burn well at all. They just layed there and smoldered while my good firewood burned around them. I thought it was odd.

 

That's exactly what they did in my stove. They lit off well, but the ash built up on them and choked the fire out of them. Then they just smoldered.

 

I'm totally confused. Bypass open? Looks closed.

 

When I've run 6 or 7 of them by themselves, they light up easily and then run the cat steadily until they're completely reduced to ash. The only downside is that the seem to result in a large volume of ash as percentage of their starting volume (maybe because they're so dense to begin with), and 6 or 7 only keeps the cat lit for 2-3 hours.

There's lots of room to fit more in the firebox, but I've been wary of putting too many in because of the warnings they come with not to load more than a few at a time because they burn so hot. I wonder if that's more of a concern for smaller fireboxes or roaring fires in non-cat secondary burn stoves, rather than smoldering cat fires. Seems like I could pack the stove half full, let them burn until the stove is up to temp, then cut the air and let it ride for quite a while.

 

Open in my first pic, smoke bypassing the cat (see handle running WNW to ESE).

In a later pic the bypass is horizontal, closed, smoke going thru cat.

 

If there is an issue with compressed wood bricks it is over firing not a slow burn.

I have an IS and not an AS, but it sounds like your problems are draft related. Either the chimney or negative pressure in the house. An OAK with a line to the outside will fix the pressure issue and it also heats more efficiently since you are not sending house air up the chimney and drawing in cold outside air (into the house) to replace it.

With the Lewis/Fiber fuel bricks, I can shove them in packed as tight as I want and they will still burn well. If you really load it up though and don’t have a flue damper, be careful as they can off gas enough to send the cat super hot (1600+) and push the STT’s in the hottest spots well past 700. I load well below max and or dial back the draft with a damper to keep them under control.

Pound for pound the bricks have the same or less ash than my sticks, but you can fit around twice as many pounds of fuel in the stove since they are so dense.

 

My thoughts - (probably not worth much). Wood and draft. This is my 5th year burning and 3rd with an IS. Also been simultaneously working on that 3-year plan for wood. 1st two years with the IS I’d get long burn times but rarely those famious 500-600 degree SS temps! This year I have the benefit of longer seasoned wood and... BAM - if I’m not careful it’s a full blown China Syndrome in my stove room!

 

I've been slowly increasing the number of bricks I put in (but nowhere near packed), with good results so far, except that it's a fairly short cat burn (2-3 hours tops, more if I add a couple big splits on top). I think packing it pretty full might work well, as long as I can keep them from overfiring.

When you load up heavy with the bricks, do you leave gaps for air between them or arrange them into a larger contiguous block? And do you get them all engaged in the fire before turning down the damper/engaging the cat, or light from one end and let it slowly burn across them during the catalytic burn stage?

I've been using no more than 8 bricks at a time, spread loosely through the firebox, so they all get fully engaged, and once the stove warms up enough, I close the bypass, turn down the damper, and there's plenty of gasses released to fuel the cat for a short time. I'm thinking with more bricks, tightly packed, and maybe not all fully burning at the start, I could extend the burn time without overfiring.

 

My tests with bricks were documented in the fiber fuel thread. I will try to link below. The max loads were 2 and a half bags for a total of 80 lbs worth of bricks. This is a TON of fuel to put in an IS and it would run well over 24 hours on that load.

I did not take any special precautions for air flow, really just piled them in with minimal but not zero space. With a smaller burn, I just use one 32 lb bag and open in or near the stove and dump. These stoves seem to work best with a top down fire if it is a cold start, especially with the bricks. Light up the top and let the growing flame warm the secondary plate and the cat before all of the bricks get hot and start gassing/smoking. The bricks don’t need a lot of flame, and often, if I dial it back it only has secondaries or goes completely black for a while. They still burn down completely to a fine ash.

Fiber Fuel Wood Bricks (Lewis)

 

Thanks, that's great to know! I've got a pallet of fiber fuel (and another one of canawick bricks), so I'll check out that fiber thread for more info.

 

So I have admittedly not read every line of every post in here, but I do understand the key issue that FeelingTheBurn and Marshel54 are describing, and that is, firstly, the window gets all sooty black on initial startup and is very difficult to get to burn off. Secondly, getting really hot fires seems difficult getting temps significantly beyond the 400STT that FTB describe. Even though low temp long burns seem to work well.

I have had an AS stove in my downstairs family room which is really a secondary stove for me. The main stove is a Fireview in the 1st floor living area of a cape style home with a cathedral ceiling on one side and a loft upstairs, 2nd floor is the main bedroom. So that AS is a top exhaust AS with one 90' flue pipe into the chimney which is a 8 inch fireclay terracotta flue liner. I have 2 flues in the chimney, 1 for the oil burner, the other for the woodstoves. Both stoves are on the same flue. I've had it this way since I built the house in '79 and that was approved code back then. The only stipulation was you couldn't mix multiple fuels per flue. I had two previous stoves down stairs prior to the AS I have now. The first was a CAT based CDW and the second was a VC Resolute. Both always worked fine and never had a problem with the draft.

So when I was field testing the AS the initial issue I had was no matter what I did that glass window got major dirty immediately on cold start up, and then did not clean up well at all, although I was never really looking to run "blast furnace" like fires there. My typical burn cycle is almost always CAT based. ie get it up to temp, engage cat, gradually move draft towards 1 in a couple of 15 to 20 minute steps. Woodstock's response to my issue with the window was that I'm not supposed to run more than one stove per flue and that was most likely the issue. So I didn't get the Field Test Stove till late in the February, so most of my testing wasn't at really cold temps/strong drafts, so I figured that it was probably just a poor draft. I'm on a 3 year wood plan so none of what oak I burn is anything under 24 months aged.

So I then return the FT stove and pick up my new product level stove, and there were a few small changes the WA had made. Also during deinstallation and then installation of the new one I found I did have an air leak in the 90 degree flue pipe as it was one of those hardware store adjustable ones, (I think they suck) so with the new install I had a really good one I bought from WS while I was there.

So, all installed and a new year of burning the product level stove, and pretty much the same thing with the glass. I think these AS stoves have a pretty restrictive airflow that slows down the air as it passes through the stove, secondary plates/path then up into the Cat and reverse direction again to exit to the rear. On cold start ups I keep the door crack an inch until I see that the wood is fully engaged, and STT may be as high as 500+F before I close the door and then let it rip again for a bit to make certain the wood is fully engaged, before I finally engage the cat. I engage the cat while I'm wide open. abd kit it rip that way for a good 15 20 minutes until I finally bring the stove down to lower settings. Usually for me, I bring it down to 1 and I expect to go into CAT burn mode and I expect the secondary's will stop. But I have been surprised sometimes on cold nights when I come downstairs to take a P (at my age it's part of the mackage man) and check on the stove.. it'll be sitting there with a pretty good load of wood, no wood flames but with a both CAT burn and secondary burns all going at once. With a setting of 1 or so on the draft lever.

What I have seen is that I don't worry the glass so much anymore and it seems to clean itself up pretty much over a few days of burning.

I don't think the AS and IS necessarily behave the same. You may get a better airflow through the IS, I don't know.. but I'd be hesitant to say they're apples to apples comparison as I've never seen to much moaning about the IS glass. Up until this year there haven't really been that many AS owners so I haven't had a lot to compare with, but I don't think there's anything wrong with your chimney draft, or your wood. I think it's just the nature of this stove. After all, WS is on the path of the cleanest burning stove they can get, and I think that was the design priority over any nice clean glass or other ambiance like features. They do a kick-azz job of giving us lots of choices of bling and colors and and designs, so it's not that they don't care, it's just how the stove works.

I'd suggest get your wood blazin before you engage the cat, run it wide open if you want to get those STTs up there and enjoy the heat. Oh the other issue with the IS is because they put the pretty bling on the top surface of the stove there really isn't any ideal place for a thermometer. So it's really tough to get a decent STT reading on this stove without a CAT probe.

Just my 2 cents... sorry for the long windedness.

 

What you have described is almost exactly what I was experiencing and how I operate my AS after trying many approaches. Sometimes I engage the CAT at around 300* but have found the stove likes it when the SST is around 500*. SST is centered to the right of the discharge. Top discharge. Engage the CAT and then wait 10 to 15 minutes before throttling the incoming air in a couple of increments eventually arriving at about 1.5. Overnight burn is a little lower.

Glass smoking over was an initially problem, but now with hot fire the glass will clean it's self.

I did not think that it was my wood like many were blaming it on. Shoulder season wood was manly Ash with one summer's worth of season on it. Some of the stacks had 2 summer's worth. I am into a portion of my "good" wood now. Two years inside stored with prevailing winds hitting it. 30% Ash, 10 percent Oak, 10% beech, 30% Honey Locus and 20% unknown. When I brought this stack up the highest mm reading I found was 20.1%. Most reading low to mid 19%. Yes it was with a fresh split. I just pick 4 random pieces out of the wood that I had brought in the other day, split it and took readings. Highest was 20% and lowest 17.7%. Most readings were in the low 19s to upper 18s.

The colder it gets the more I like the AS. The people on here pretty much were under the opinion that the AS would drive me out. Heating a 2 story 1600 sq. ft. old farm house with the up stairs closed off.
The AS doesn't hold up to my non EPA stove of a few years ago. That stove would have me stripping to my skivvies, but was a thirsty son of a gun. It did not have a gourmet taste for the wood. Didn't care what you threw in it, but did dirty up the chimney bad.

Thanks for your input. I am feeling a lot better about my purchase.

Edited to add: Most of the Woodstock owners that I am close to from here own ISs or Fireviews. I was happy when you said they are different beasts.

 

OldHippie - thanks for the detailed response! I've wondered if there might be differences in how the AS runs compared to the IS too. Smaller firebox, lower emissions, maybe tighter air intake?

Perhaps due to colder temps the past few days, and also some experimentation, I've had an easier time getting higher temps. Keeping the door cracked until stovepipe and STT temp reach about 400 has been key, especially with my less seasoned firewood. With a good sized load of dry bricks, I can close door once both are over 300, but it takes a lot longer to get up to 400+, even with the bypass open and the air at 4. With a full load, once those temps are above 400, I can get them to keep rising to 500+, and that seems to clean up the glass a bit. Of course it usually gets pretty dirty again after I engage the cat and the temp drifts back down...

My current challenges are figuring out how to get a long burn with the cat engaged and end up with less coal when the cat drops below its burning temperature. I have a catalyst probe installed now, but I rarely see the cat temp rise after engaging it. Typically it will hold steady near whatever temp I engage it at for a couple hours and then slowly drift down. Usually it drops below the catalytic range while there's still a lot of unburnt chunks left (a combination of glowing red coals and large black chunks of charcoal. Once I hit this point, its basically impossible to resume a catalytic burn, though I can open the bypass and air all the way and keep a steady mild heat (perfect for the daytime, actually) with occasional stirring of the coals.

I suspect one of the following is happening when I burn with my under-seasoned firewood:

• If I spend a lot of time in bypass mode trying to get the temperature up high at the start, I waste a lot of the combustible gasses up the chimney while the moisture is driven off, leaving less available to extend the catalytic burn.
• If I engage the catalyst earlier, the moisture that's still being driven out keeps the stove and catalyst from getting as hot as it could otherwise, requiring more air and burning through the gasses faster to keep the catalyst hot enough.

I tried a large load of just very low moisture fiber fuel bricks last night, and I was able to go to bed with the air at 0.5, cat temp around 750, and steady secondaries coming out the air holes in the front and back top of the chamber. When I got up this morning, the house was plenty warm still, but the STT and stovepipe temps had dropped to about 150 and the catalyst to around 300, despite large blocks of lightly glowing bricks remaining. It took me most of the day today to burn those down with the bypass open, air at 4, and occasional raking/stirring.

I'll have to repeat this experiment during the day sometime so I can see exactly when the temp starts to fall.

 

You had me at black gunk... Sounds like wet wood

 

I only burn lodge pole, and I haven't let the fire die since september. I have found that the SST, needs to be 350 or higher to shut way down. My fuel doesn't register often on the MM.
I do have good draft, and my sweet spot is set at .75 on the absolute steel. I burned one load of too wet fir (22 MC), and will never do so again. Even split small.

 

If it burns better at lower outside temperatures, that screams draft issues. The colder outside temps are giving you a wider temp difference and therefore more draft.

Also, the IS has (can have) the same black glass issues as the AS. You can operate to avoid it, or ignore it.