Need Woodstock AS help, at wits end.

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stoveliker

Minister of Fire
Nov 17, 2019
4,353
Long Island NY
Nobody has ever tested my draft. I would say it’s not poor draft, but if anything I’ve worried about overdraft. Actually the backpuffing seems better if I engage a key damper. But then again, I like blew up that one time.
Liner is closed off at clean out.

This is a bit of a summary, strategy, and my own interpretations to make the case a bit clear, as it is not completely clear to me what are single instances of something happening ("that one time") and what is a consistent feature.

You have a consistent issue with warping pieces and backpuffing. I do not know whether the circumstances have systematically been addressed.


To nail down the cause of a complex system that misbehaves, one needs to be very systematic. Eliminate causes one at a time, honing in on the issue.

This does not always lead to a clear answer, but in my experience it is the course most likely to lead to an answer.

Hence, first look at the fuel (experience tells us many problems are due to fuel). Please measure the moisture content.

If that is not an issue (we don't know yet), experience tells us user behavior or flue system are more often the issue than the stove itself (if from a known, trusted brand).

So second is to look at draft, if at all possible. You are working on that with the kind help of someone here. Good. (Do see if you can keep in touch with him about how precisely to do this - we want the data to be as good as possible.)
Though 25 ft after an 1.5 ft rise, some horizontal piece, and two 90 degree elbows should not be overdrafting imo. Could be a bit on the high side of the recommended range, but the elbows and horizontal section, as well as the bit short first vertical rise, will kill some draft of the "too much. 25 ft".
However, counter the above "not likely a problem", is the observation that you consistently end up with warped pieces.

With user behavior I mean in this case the "don't close the air too fast, but in small steps spaced out in time". Closing too fast could be instigated by too high draft too (it roars, one gets scared and closes the air - too rigorous). The result of that is that a lot of fuel is outgassing (it's hot enough to produce smoke/gases), and after closing the air there are not enough flames to consume most of that, resulting in a build-up of gaseous fuel that if the mix is right occasionally explodes. Given that the stove is not a tight container, it's not like a bomb, but it'll spew smoke out of the air inlet(s), anywhere else with low pressure tolerances, and pushes it up the flue. That is backpuffing.
As bholler said, backpuffing is more common with poor draft (because the other way to describe it is that there is not enough oxygen coming in to burn the gases - because it's not being sucked in due to low draft in a poor draft case). Therefore measuring draft is before this.

Regarding the observation that the OAK made the stove run hotter, that suggests to me you may have "high" draft and a tight home. The home dampens the air flow, but with the OAK that damping is not present, and thus it runs hotter. (An open window would do the same.)

In any case, I suggest you do measure the moisture on a (room temperature) piece that you freshly split. It's important to know for the issue you have, but also for burning cleanly (and thus safely) - and for the heat output (you don't want to be using the heat to boil unnecessary water out of your system). It's good to do this as soon as possible.


Summing up the observations:
The OAK=hotter, warped metal suggest high draft to me. The backpuffing could then be fuel wetness and/or too quick closing of the air.

I'm sure there are others who may disagree and who may be more knowledgeable, but this is how I see it.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
That's why I asked if the wood moisture was tested. The only time I have had to deal with backpuffing on a proper flue setup is when I was burning wood that I thought was dry and it wasn't.
Same here I have only seen it with wood that isn't dry enough or poor draft.
 

Chris1927

Member
Feb 15, 2016
96
Massachusetts
Yeah. So I just drafted an email to Woodstock. And in doing so, when I was reading the manual, and looking at the Woodstock thermometer” overburning is above 700. My stove has NEVER burned that high. The highest I e seen the STT is 625 and that’s when it was broken and I didn’t realize it yet.
So to me, I shouldn’t have had all this warping.
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
Yeah. So I just drafted an email to Woodstock. And in doing so, when I was reading the manual, and looking at the Woodstock thermometer” overburning is above 700. My stove has NEVER burned that high. The highest I e seen the STT is 625 and that’s when it was broken and I didn’t realize it yet.
So to me, I shouldn’t have had all this warping.
Agreed.
 

Chris1927

Member
Feb 15, 2016
96
Massachusetts
I guess I’m not smart enough to use this stove. I reconnected the OAK. The last couple of days, I have been burning it like I used to burn it. On a reload, I wait for the pipe temp to reach 250, then I keep the air 3/4 open until it gets to 400 STT, then shut the air to final setting, and I’ve got better results. STT peaks at about 500 or just above and when the stove comes out of not seeing any visible flame, when the gasses ignite, it’s much better. Sometimes the sudden ignition of gasses is mildly strong, sometimes not strong at all. The worry that I have is this is how I used to burn it and it’s resulted in being broken twice and the secondary burn grate warped.

Woodstock has been telling me (multiple times over the past year now) to, on a reload, as long as the STT is 250, engage the cat, and you can shut the air right down. But when I do this, I’ve eventually gotten STT’s of 600 sometimes and strong backpuffing. Is it that the cat wasn’t even working, that I overloaded the cat? I don’t know, but I still worry about the warping and that secondary burn grate, when I think about it, does bother me.
The OAK though, really does make a huge difference. Not using conditioned air from the house. My house is 3200 square feet. Open concept, open lofted to upstairs. It was 15 degrees this morning and 32 now. Not a completely full load of wood. 69-75 in the house right now.
 
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Bobbob

Member
Jan 13, 2022
42
Transfer PA
That is not the stoves fault, in general.

In almost all cases it's how it is connected, humidity, wind, chimney, home tightness, fuel (not being manufactured as gasoline is; even pellets are variable...).

Yes there are poorly designed (and untested or insufficiently tested, so the requirements from the above list for proper, safe, or clean operation are not known) stoves. But th far majority of what we can buy has been designed ok.

That is very different from a car where fuel is much more regulated, and operation does not depend on tightness of an enclosure, local wind and weather parameters, fuel variability (because that's rather standard and uniform), user installed tail pipe length etc.

We can get where you want to be. But having the government dictate precisely how much your door may leak, that you've should take 2.5 bricks off of your chimney, and you can only burn 1 ft sections of 2*4 at 8 pct humidity, stacked in this geometry (see figure provided to you by law).

I surmise that none of us want that amount of govt interference in our lives.
We are slowly getting it (government interference) wether we like it or not. Maybe not so slowly...
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
We are slowly getting it (government interference) wether we like it or not. Maybe not so slowly...
How much do you know about the owner's passion to develop a zero-emissions wood stove or close to it? This is a quest for them, their stoves often exceed govt. requirements by a healthy margin. It's possible that not every stove is going to end up a home run. In this case, the secondary turbulator design may be a bit frail. IMO, the stove should not be destroying itself at these operating temps, but sometimes there are problems that don't show up in the lab.
 
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Chris1927

Member
Feb 15, 2016
96
Massachusetts
Well, I know the owner probably doesn’t care for me, cause I’ve had so much trouble and had so many complaints/questions. I also know that he used to be a teacher, he agreed to run the company for a short time because the company wasn’t doing well, and then he ended up taking it over for good and becoming the owner. I also know that he occasionally drives a box truck and rides around with a dog.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
He is well respected in the stove industry and has come up with some excellent designs that demonstrate that very clean burning stoves are possible and for the most part practical.
 

snobuilder

Feeling the Heat
Dec 16, 2021
431
WI
We are slowly getting it (government interference) wether we like it or not. Maybe not so slowly...
But on the bright side, at least he has Oak to burn.
I am surprised it isn't putting out more heat though. Everytime I get oak to burn, I feel blessed.
 

snobuilder

Feeling the Heat
Dec 16, 2021
431
WI
He is well respected in the stove industry and has come up with some excellent designs that demonstrate that very clean burning stoves are possible and for the most part practical.
I converted my non epa stove into a clean burning heat monster and Im a efgin dumbass with a torch and a welder. How hard can burning wood for heat be?..... oh wait,.... I forgot who decided to get involved.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,441
central pa
I converted my non epa stove into a clean burning heat monster and Im a efgin dumbass with a torch and a welder. How hard can burning wood for heat be?..... oh wait,.... I forgot who decided to get involved.
But no one has any idea how effective your modifications are. Or how durable they will be.

Oh and did you come up with the idea for air tubes and baffles yourself? No you got that idea because the EPA implemented emissions requirements leading to companies developing that technology which you copied.

Burning wood is not hard or complicated at all. Even burning properly in a modern stove is not complicated either. Installing it properly and getting it setup properly can be a bit more challenging in some situations. But unless you do that part correctly you will be fighting to make things work right afterwards.


I don't know what the issue with this stove is yet at all. But I would be willing to bet it is either draft or lack of air supply. Or some combination of the two.
 

snobuilder

Feeling the Heat
Dec 16, 2021
431
WI
But no one has any idea how effective your modifications are. Or how durable they will be.

Oh and did you come up with the idea for air tubes and baffles yourself? No you got that idea because the EPA implemented emissions requirements leading to companies developing that technology which you copied.

Burning wood is not hard or complicated at all. Even burning properly in a modern stove is not complicated either. Installing it properly and getting it setup properly can be a bit more challenging in some situations. But unless you do that part correctly you will be fighting to make things work right afterwards.


I don't know what the issue with this stove is yet at all. But I would be willing to bet it is either draft or lack of air supply. Or some combination of the two.
My stove proves it's effectiveness everyday, yet I am constantly reading here how the EPA instigated stoves are not in many cases.

I didn't build anything complicated in my development. ,and I don't need to come here and ask why my stove doesn't perform easily for me.

Secondary burn systems were around before the EPA existed
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
People generally come to forums for information on what to buy, or with problems. A few come to brag and boast. This is the same with cars, stoves, or chain saws. In this thread, which is rapidly getting hijacked, we have the first known problem with this stove. It hardly represents intervention by any outside agency and at this point is a singular issue. The design may be flawed or perhaps this particular setup is fussier. No homebuilt stove mod gets the exposure to the myriad varying conditions a stove sold nationwide gets. If you have success, great, but keep it to your thread, please.
 
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Chris1927

Member
Feb 15, 2016
96
Massachusetts
Please help. I have had this AS since October of 2016. If it isn’t one thing, it’s another. And I just can’t seem to figure it out. I just can’t seem to figure out if it’s the stove, if it’s my tight house, if it’s the chimney, or if it’s all of the above.

Let me back up a little. Before the AS, I had a Vermont Castings 1975? It worked just fine for years. I would always burn it open for about 40 minutes before closing the damper. And then one day, I closed the damper and a few minutes later, it blew up. Smoke came exploding out the top, and even the clean out door blew open. I didn’t understand then what happened, but I’m guessing now it was related to a tight house, that the fire smoldered and then caught some air, and boom! I never burned that stove again.

I bought the AS. Up until this year, I ran it on an 8 inch round clay flue all the way up (about 25 feet). Before this year I added a preinsulated 6 inch liner and a direct air intake or OAK (outside air kit).

The stove has warped/broken twice between the firebox and the area that houses the cat. I brought it to Woodstock the first time and they fixed it. The second time I made them get it, fix it, and bring it back. Also, within the first year or two, the secondary burn grate warped bad. Woodstock said it’s designed to flex and that has never been fixed.

Before I lined the chimney, I would get condensation really bad dripping in the chimney on a cold start. It would drip back into the house at the thimble until I built a dam with refractory cement. And there was evidence of it dripping out the clean out door. I also to this day get a lot of condensation inside the ash pan.

I’ve tested my wood many times. I freshly split it and test it and have used two different moisture meters. The wood definatley measures less than 20% moisture content before bringing it in. I store it in the basement. The wood in the basement reads more like below 15%.

I just got a new cat in January. Chimney cleaned in late January.

This whole year, I’ve been worried/paranoid of burning the stove too hot. I’ve tried to keep it below 550 STT. Don’t want it to break again. Woodstock tells me, on a reload, to engage the cat pretty much right away as long as the STT is 250. They also say I can close the air right down immediately to get a long burn. I tried it that way for a long time. What happens is, completely dirty glass, then the pipe temp eventually rises up to 350 or so and the STT eventually rises up to 550 or so and it feels like an out of control fire. I’ve actually heard the secondaries roaring as they’re rolling at the top front of the firebox.

I’ve tried disconnecting and reconnecting the direct air intake. That really doesn’t seem to me to make much of a difference.

So lately, I’ve burned it like I used to burn it. On a reload I may close the bypass before the pipe gets to 250, but I wait til the fire is reengaged, and I keep the air 3/4 open for quite a while and gradually close the air in increments but now I’m keeping the air more open for a final setting than I did before. And the STT is more like 450, maybe 500 and the pipe is like 250 to 300.

But now, (actually I’ve been battling this for a while) I’m getting strong backpuffing or sudden ignition of secondaries and I can’t seem to solve this. If I leave the air open so I always see flames, then I’m good. If the fire dies out so there’s no visible flames, then eventually I get backpuffing. It seems like when the fire dies out/no visible flames, the pipe temp gradually rises and seems like pressure builds up inside the stove, so that I can actually feel that the air control is harder to move.

When I’ve engaged a pipe damper, the fire has actually come out of a “black box” or no visible flames gently. I’ve also battled clogging up the cat a lot this year when I’ve closed down the stove too much.

Can anyone make any sense of this? I emailed Woodstock weeks ago, actually asking if they would swap out the stove or buy it back for a reduced price. But they did not respond. I don’t feel like I will be getting any more help from them. I wish I had a simple non cat stove with just an air control. But then again, maybe it’s my house or my chimney.

The reason I wonder about draft is that the first time the stove warped, the guy who loaded the stove onto my truck when I picked it up from repair said that sometimes it can warp like this if there’s an overdraft. I have no way to measure draft.
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
Has anything developed or changed since the last thread on this topic?

 

clancey

Minister of Fire
Feb 26, 2021
2,330
Colorado
With all your hard work I would get another stove and save all your wonderful parts for I have a feeling of dread here with no experience and only burned a wood stove about 6 times but the point I would make is you would never feel secure about this stove and you seem knowledgeable and whats that saying--you can't beat a dead horse or something and I think that would apply here..Save the parts and chalk up you labor...old mrs clancey
 

snobuilder

Feeling the Heat
Dec 16, 2021
431
WI
With all your hard work I would get another stove and save all your wonderful parts for I have a feeling of dread here with no experience and only burned a wood stove about 6 times but the point I would make is you would never feel secure about this stove and you seem knowledgeable and whats that saying--you can't beat a dead horse or something and I think that would apply here..Save the parts and chalk up you labor...old mrs clancey
Are you speaking to the Post starter because it would be a shame for him to have to scrap his expensive EPA inspired CAT stove and sell the parts,....but maybe cutting his losses are a smart move.

Meanwhile my stove mods are performing flawlessly which is great because the heating season has been extended here in the midwest. Low 30's and teens at night for the next 4 days .. Past 5 days the stove been fully stoked as well. Those early March 60's were just an annual tease.

But seriously, I hope the OP has gotten to a point where his stove investment is paying him back with a controlled safe and confident feel while burning.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
There's no point in running two threads and having to repeat everything already posted. I will merge the threads but will use this title as it's more explicit. You have my sympathy. It's not like you haven't tried everything suggested. At some point, it may be better to sell the stove and cut your losses.
 
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Chris1927

Member
Feb 15, 2016
96
Massachusetts
I think trying to sell the stove and cut my losses is where I am going to end up. It’s just a hard result to accept/settle on.
I guess if I could sell it for enough to break even or close enough where I could get a Drolet or something, I would be happy in the end.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
93,156
South Puget Sound, WA
I think that is what I would do in your shoes. You've given it a good try, but it's time to reduce hassles and frustration and get back to enjoying wood heat.