Absolute Steel beta testing... my first cat

[LocustBurner]

Yeah I've owned quite a few stoves in my life, and if the Absolute is anything like my Progress, what a relief it is to not have to keep the door open to light or restart and always be able to start simply by adding a few sticks without starters etc. and sitting, blowing, adding...They really are amazing stoves. I'm so glad they are marketing an affordable model with some flair.

Woodstock is on the cutting edge of stove design. This smaller stove will be a great addition to their lineup.

 

[LocustBurner]

Yeah I've owned quite a few stoves in my life, and if the Absolute is anything like my Progress, what a relief it is to not have to keep the door open to light or restart.
They really are amazing stoves. I'm so glad they are marketing an affordable model with some flair.

Wish this smaller model had been available last year.

 

[OhioBurner©]

That is an interesting point that I hadn't thought too much about but I always had to crack open the door to get a new load going in every single stove I had before, even a 300+ reload would need just a bit of door cracked open. But the ISH seems to work best when you keep the door shut actually. Even when it's down to just a couple handfull of coals, as long as your starting with some small stuff on em and not smothered it lights off faster with the door shut. With the door cracked open it tends to blow out the fire. It is a nice feature and no smoke in the house. Could be my strong draft too, as I recall smoke spillage being an issue with some but a non-issue here and I usually leave the automatic smoke flap locked up and out of the way.

 

[branchburner]

My experience so far is that on just a few coals, the fire comes back to life and up to temp far more quickly with the door cracked for just a bit after reloading, especially the splits in the rear of the firebox.

I have also noticed that a little ways into the burn, if the bypass is closed and the air has been cut back, I can sort of turbocharge the fire by re-opening the bypass and cracking the door for just a few seconds. So if the stove has been slowly creeping up to 400f with little flame in the firebox, this quick introduction of air will fill the firebox with flames that do not really subside even after the bypass is re-closed and the air stepped down. The stove temps then seem to rise more quickly than they had been. It's like shifting the burn from cat mode into burn-tube mode... does this make sense?

 

[begreen]

Wish this smaller model had been available last year.

At 2.45 cu ft this is a medium-large stove. It's not a lot smaller than the Progress, only .4 cu ft.. If less firepower is desired the Fireview and Keystone are smaller.

 

[branchburner]

So I've noticed the very different nature of a low cat burn, where there is little or no flame in the firebox, and of a high burn, where top of the firebox is filled with rolling secondaries. The low-flame burn seems to give higher stove top temps, not surprisingly as the cat is working hard (temps right above the cat over 500f). But the high-flame burn puts out a lot more of a blast of heat, as the front and sides of the stove get much hotter (pushing 650f, while top is only in the 400f range). The sides don't get much over 450-500f when in cat-only burns.

So far, my experience is that to maintain a low burn, the air must be shut down pretty far and pretty early in the burn. I mentioned in the above post that a little boost of air will shift the burn into high gear, but then I can't really shift it back into low... the secondaries seem self-sustaining once they get cranking, even with air setting at zero.

If the fire gets too hot and lively early on in the burn, it seems the rolling secondaries kick in and then stay kicked in... shutting the air all the way back at that point will not take the fire down to a slow, low-flame or no-flame burn of lower heat output. In effect, the option of "dialing down" the stove is lost if not opted for early on in the burn. (This is not a really complaint , BTW... n this high-burn stage, the stove puts out a tremendous amount of heat at relatively low flue temps.)

I suspect this also has something to do with the increased draft seen under colder outdoor conditions, as even with air setting all the way down, when it's cold out I seem to have a harder time getting a real low-output burn with a similar load of wood. Almost as if the stove automatically adjusts to the outdoor temps in its ability to put out heat, where cooler outdoor temps mean more secondary flames in the firebox and less time in cat-only mode.

Wondering if that is the nature of just this stove (or of the way I'm running it) or of these hybrids in general. Seems like maybe a cat-only stove can be dialed down more easily than in a stove where rather than just a cat there is burn-tube technology also at work.

 

[blades]

So I've noticed the very different nature of a low cat burn, where there is little or no flame in the firebox, and of a high burn, where top of the firebox is filled with rolling secondaries. The low-flame burn seems to give higher stove top temps, not surprisingly as the cat is working hard (temps right above the cat over 500f). But the high-flame burn puts out a lot more of a blast of heat, as the front and sides of the stove get much hotter (pushing 650f, while top is only in the 400f range). The sides don't get much over 450-500f when in cat-only burns.

So far, my experience is that to maintain a low burn, the air must be shut down pretty far and pretty early in the burn. I mentioned in the above post that a little boost of air will shift the burn into high gear, but then I can't really shift it back into low... the secondaries seem self-sustaining once they get cranking, even with air setting at zero.

If the fire gets too hot and lively early on in the burn, it seems the rolling secondaries kick in and then stay kicked in... shutting the air all the way back at that point will not take the fire down to a slow, low-flame or no-flame burn of lower heat output. In effect, the option of "dialing down" the stove is lost if not opted for early on in the burn. (This is not a really complaint , BTW... n this high-burn stage, the stove puts out a tremendous amount of heat at relatively low flue temps.)

I suspect this also has something to do with the increased draft seen under colder outdoor conditions, as even with air setting all the way down, when it's cold out I seem to have a harder time getting a real low-output burn with a similar load of wood. Almost as if the stove automatically adjusts to the outdoor temps in its ability to put out heat, where cooler outdoor temps mean more secondary flames in the firebox and less time in cat-only mode.

Wondering if that is the nature of just this stove (or of the way I'm running it) or of these hybrids in general. Seems like maybe a cat-only stove can be dialed down more easily than in a stove where rather than just a cat there is burn-tube technology also at work.

likely the higher draft due to the colder outside temps coming into play - might just require a key damper on your set up to smooth things out.

 

[OhioBurner©]

Yes very similar to my experience with the Ideal Steel Hybrid. It seems if packed full and let go into a high burn it is a lot of 'momentum' to stop and I've dialed it down to minimum and still it wants to burn secondaries for a while. Usually if left alone for a couple hours the secondaries will fizzle out but it takes some time. Wind seems to be the biggest factor for me - even if the initial burn wasn't too high and I was in a full cat burn, if the wind is really gusting it will often light off the secondaries intermittently. I need to put in a key damper myself.

 

[huauqui]

Sounds like the stove needs a way to shut down the air just a bit more. Maybe that will be coming down the road. I love this stove in the plain box configuration and from all the reviews, so far, it seems it would make a wonderful supplemental heater for our upstairs on those really cold spells.

 

[Rearscreen]

Wondering why The Absolute is less efficient than the other 2 hybrid models. Seems like they may be running backwards towards their R2Z. Just wondering...

 

[LDay]

Wondering why The Absolute is less efficient than the other 2 hybrid models. Seems like they may be running backwards towards their R2Z. Just wondering...

Hi Rearscreen,

I forwarded your statement along with this thread to Tom, since he's spent the most amount of time both in our lab and with the Absolute Steel during the EPA testing. Below is his response and explanation.

"The short answer is that we developed the Absolute Steel Hybrid and carried out our R&D testing using cordwood. We requested permission from the EPA in mid-November to conduct emissions testing with cordwood, and we reserved lab time for early January in anticipation. When the EPA hadn’t responded, we made the decision to move forward and test with cribs, with no changes to the stove.

Cordwood testing would have yielded slightly higher results for both efficiency and emissions. Based on our testing and the independent lab results the comparison between cordwood and cribs would look roughly like this:

Estimated Cordwood: 80% efficiency and 1.0 g/hr emissions
Actual Cribwood: 77% actual tested efficiency, and 0.5 g/hr emissions

In either case, our common goal for the Absolute Steel Hybrid and our R2Z quest is the lowering of emissions. The low EPA emission results were a definitive step towards our R2Z goal.

The EPA eventually approved our request to test with cordwood, but only after our EPA cribwood testing had begun, and with some caveats that would have further delayed the testing. To add to the delays, the test lab had not done any cordwood testing, so they needed time to come up to speed (when you are paying for each test, you don’t necessarily want to pay to be a guinea pig). We were the first stove manufacturer to request approval for cordwood testing, and as far as we know, the only one approved to date.

Now that we have cordwood testing approval, we may still go ahead and do the EPA test again with cordwood. We think the cordwood results would be quite impressive and on target with our initial estimate (1 gm/h and 80% OHE, maybe better), and we want to prove real world emission can be very low, and real world efficiency very high. Stay tuned… "

-Tom Morrissey