new user getting Absolute Steel hybrid dialed in

[BradW]

After many years of Vermont winters (and autumns and springs and stick seasons and mud seasons) warmed by a decades-old Vermont Castings Defiant Encore, we recently crossed the river and bought a WS Absolute Steel hybrid. I'm geeking out trying to figure out how much wood to use, when to add it, what air flow setting to use, when to engage the catalyst, etc. I honestly had wanted/hoped that the new stove would just blow us away, but although it's been super nice, it doesn't feel like a massive upgrade beyond our prior stove. So maybe that means the old stove was really good. Or else I'm not using the new stove effectively. Of course I've only been burning it for a month now, haven't gotten deep into winter. A few questions below. Any feedback appreciated, thanks.

1.I did not take a close look at all of the interior of the firebox before using it, but recently I noticed that there appeared to be some gaps between the top/ceiling of the box and the back wall of the box. There are three bolts connecting the top and back (right, center, left) and in between these connections the top of the box appears to be a bit bowed. See the photo. Is this normal? Perhaps this is by design to allow the metal to expand/contract as the temperature changes? I just want to ensure that combustion airflow, exhaust flow, isn't going somewhere that it shouldn't and undermining efficiency, creating any exhaust leakage risks, etc.


2. I've been successful at gradually getting the temp up into the 250-300 range on the external thermometer provided with the stove, placed on the pipe 8 inches above the stove. If I understand correctly, 250 is the threshold when I can then engage the catalyst. This usually requires that I have the air flow wide open to 4, though with enough wood in the box I've been able to drop the airflow to 3 or even close to 2 for a bit, while still keeping the thermometer at the 250 threshold. But I haven't been able to get it very much above 300, which is where it says the optimum burn is 300-600. I use hardwood that has been split and stacked under a roof outside for a year, so I don't think the wood is a huge problem. When reading about the stove, I had thought that the goal in terms of efficiency, using the catalyst and secondary combustion, was to get temp in the 300-600 range, engaging the catalyst, while also keeping the airflow really low. But I can barely get to 300-325 with the airflow wide open to 4. Maybe I just need to get used to throwing a LOT more wood into the box than I'm used to from our old, smaller, Vermont Castings stove? Is this an either-or situation, such that I can either (1) fill it with tons of wood, and keep airflow low and burn for a super long time, but the temp won't be super high, maybe not even high enough for the catalyst, or (2) I can keep the airflow wide open, run the stove at much higher temps and engage the catalyst? Or can I have it all, really low airflow, and temps well above 300?

 

[kborndale]

What kind of hardwood? If you are using oak it can take up to 3 years to get dry enough. Sounds like wet wood to me, get a moisture meter ($25 at home Depot or Amazon) take a piece of wood , grab an ax and resplit the wood and take a reading of the middle. It needs to be 20% or lower. How is your draft? How tall is your chimney? Is it class a or a masonry chimney?

 

[EbS-P]

Some questions, are you measuring surface temp of a single wall pipe with your thermometer? Is it a pipe thermometer?

Do you have a catalyst thermometer?

 

[moresnow]

Post pics of the entire setup with a description of the entire vent system.

 

[Todd]

Stove pipe temps will be lower than your stove top temps. I’m pretty sure Woodstock uses stove top temps as their guide for overfiring and operating temps.

Give them a call or shoot them an email, they are very helpful.

It’ll take some trial and error figuring out any new stove. This stove is a bit smaller than your previous but it’s much more efficient and will stretch out the BTU’s over a longer period so it may not feel like it’s producing the intense quick heat of the Defiant.

 

[BradW]

Thanks all, much appreciated, apologies for the delay. Per my moisture sensor tests of a few samples of wood, the interior of newly split pieces shows wood moisture equivalent is hovering around 14-15%.

The original home and stove used a poured-in-place liner, but that was not aging well after many years, so we recently had a steel liner installed within the poured-in-place cavity. The draft hasn't been a problem. The chimney height, I don't know an exact number, but the stove is on the ground floor of a two story home, with the chimney extending several feet above the pitch of the roof above the 2nd floor. Call it 30' give or take?

I'm using a magnetic thermometer provided by Woodstock Soapstone with the stove, placed on the pipe roughly 8" above the stove top, per the paperwork provided with the stove, which suggested the thermometer reading would be roughly half of the interior temp. No separate catalyst thermometer provided. I confess the paperwork provided with the stove seemed somewhat inconsistent, mostly suggesting to place the thermometer on the pipe, but at one point suggesting placement on the stove top (differences between paperwork accompanying the thermometer vs paperwork accompanying the stove itself).

Any thoughts on my 1st question and the photo from the original post, in terms of whether the gaps are normal between top and rear of firebox? It seems very much as if the top of the box is designed to account for expansion/contraction during use, but I don't know that for certain.

 

[moresnow]

If you are reading 14-15 on pieces you pulled out of the pile, re-split, and tested immediately on the freshly exposed face you appear good.
I'd guess the gaps you are seeing are common. Call Woodstock and confirm.
Sounds like you have adequate venting. Maybe consider a couple 45 degree elbows in place of the current 90 if you experience smoke rollout on startup and reloads.
Sooooo? How is this setup performing? Curious! Enjoy.

 

[Stovequest]

I'm pretty sure that is a stove top magnetic thermometer. At least for my ideal steel it came with both stove top and cat thermometer.

For my ideal my biggest learning curve was engaging the catalyst with correct the air for the smoke rate of what I loaded into the stove. Basically the wood could be off gassing faster than the catalyst could handle and my flames would die out and when conditions got right it would ignite up in a big puff and spill smoke into house.

Typically I engage catalyst with full air once cat thermometer show good range. And over 30 minutes step down air every 5-7 minutes to 1/4 air. And let it cruise from there.

 

[DBoon]

Hi BradW, congrats on your new stove.

I went from a tube-style afterburn stove to a catalytic stove a couple of years ago and I can tell you that wood dryness that used to be just fine for the tube-style stove was subpar for the cat stove - I needed an extra year of drying for the cat stove to really throw off the heat and perform the way it was intended. I could get it to work pretty well on 2 year dry wood, but when I stumbled on some wood in the stack that was drier, the performance was much better. This will be my last year of burning slightly sub-par wood in my cat stove as I will be caught up with 3 year dry wood starting next winter and I am really looking forward to it.

Given that you used to burn with an old Defiant Encore (a pretty forgiving stove with one-year dry wood), I would say that you need to take another look at the wood. I generally don't believe the results from the $20 moisture meters and, in general, I believe that most cheap moisture meters optimize their readings framing-type softwoods and also don't account for the temperature of the wood (colder wood can affect the readings) or the species of wood (really dense woods like hickory, oak and sugar maple can affect the readings). This thread might give you some ideas and perspectives on this topic https://www.hearth.com/talk/threads/using-a-multimeter-to-measure-wood-moisture-level.40033/ I know that I've learned a lot about this topic over the years, and the main thing I've learned is that if I stack my wood outside, covered and an in open area for three years I don't need to own a moisture meter and/or even think about moisture content of my wood.

You mentioned that you covered your wood during drying (great to do) but if it is not in an open area where it can get some good wind that will slow the drying time.

Most who have visited this forum after buying a new stove to replace a really old stove have similar issues with their new stove as the ones you described, and (mostly) after working through all the issues with installation, draft, operation, etc., the core problem is that the wood is just not dry enough. So just keep an open mind about that topic as you get used to your new stove. I can tell you when that Absolute Steel stove gets loaded with the wood it was designed to burn it will most likely put out a lot more heat than what you are describing now.