Some things that I think I think... or, "Smoke in the Attic" (edit - pix added)

[edthedawg]

With apologies to Peter King and his exceptional MMQB articles on SI.com, after a month or so of burning, and some really, really cold mornings the last couple days, here are a bunch of things that I think I think about burning in our Heritage...

I think the wet wood hinders me getting up to a high surface temperature to start. OK I know this one. Kindling and firestarters seem fine, and it's genuinely not hard to build good big flames quickly, but there's a lot of hissing, it takes an hour to really hear the airflow whooshing into the feed on the back, and we're just never getting over 400F on the Heritage stovetop (top center front stone). After burning for a few hours, getting a good coal bed, then reloading w/ 3 new splits and letting those char and get well into a strong burn, with the primary backed down to only about 1/2" open (note: there's about 3.5" total travel from wide-open to full-closed), and the damper pulled down a bit, we're STILL stuck capping out at 400. Poking, prodding, rearranging - all are good for short bursts of nice lazy secondaries, but those pass and there just seems like a perpetually fast draw out of the stove, no matter what we try - like we're putting too much heat straight up the 35-foot SS liner, and not enough is being trapped in the box. If I leave the side door cracked open for a few minutes on the reload and get a really strong charring flame going in the box, the flue (metal temp on single-wall) gets to as high as 450, but shortly after shutting the door and then subsequent backdowns on the primary, that metal temp seems to hover in the 220-260 range. The glass on the door will max out around 600F while coaling down that 2nd big load, and that's usually focused in one spot (the spot moves depending on the arrangement of the splits) This is defying what little combustion and thermodynamics classwork I can still remember from college... At some point in the burn, doesn't the initial presence of moisture and/or lack of seasoning stop being such an issue?

I think my pullchain damper at the top of the flue is completely crusted into place w/ creosote by now, and I'm strongly at risk of snapping the cord, or the lever, or otherwise irreparably damaging it. In the 2 yrs since it was installed without burning, it always worked nicely - we could feel a definitive *pop* as it came down shut, spring tension was predictable, etc. Now it feels like it's hanging up, stretching out, bending, stuck - i dunno what - but it worries me. And it seems like we've got little to no control over actually dampering the flue now. I've about resigned myself to putting a manual damper plate directly off the back of the stove - between the rear outlet and the tee. That should give me some improved measure of control, despite the fact that it'll still have 35 feet of liner draft pulling on it. But I think (hope?) that won't be a huge problem since it's a fairly similar way lots of other systems are set up.

I think even if we stop burning our wood and transition to BioBricks exclusively, I wouldn't be able to greatly improve the situation, given the draft pulling on this thing.

I think no matter what, if I'm going to burn w/ the wood I have, that pullchain damper doesn't stand a chance of surviving even one season. But with the second damper down low, and a massive bluestone cap overhead, then maybe I just don't care. We primarily installed it to keep warm air from going up, and to keep sleet out, back before we ever thought of woodburning...

I think I have no clue why the unfinished attic space is routinely filling with a smoky smell. Ok more than a smell - I can see the room filled w/ hazy smoke. And we store a lot of stuff in this room - it's about one half of the attic space. The chimney itself isn't more than "a little warm" to the touch, so I'm not really worried that I have any house timbers smoldering - I'm quite certain it's a combination of ample ridge-venting + lack of wind. I'm genuinely unconvinced that adding an OAK will fix this problem, but it's certainly possible I've got a stack effect and/or suction/draw happening. We're in the midst of some massive construction putting in two new bathrooms, so there is the unique circumstance of having a large, wide-open channel in place from the peak of the roofline @ the chimney, ALL the way down to the dirt floor of the fieldstone-walled basement. So maybe that is something I need to consider. But - on the likely chance that closing up the floors & walls, and adding the OAK utterly fails to change the situation, I'm going to be dumbfounded on developing a way to avoid in-flow thru every orifice in that attic (i.e. soffit vents & ridge vents being the primary issues, then the bath vent hood)

I think I need to talk to a chimney sweep about getting the top of the chimney liner checked out. With two turns high up in the attic area, me pulling the tee cleanout cap down behind the stove, dumping it out, and peering up there w/ a mirror & flashlight just isn't going to tell me what's going on up high. But would the Biggest Problems be happening up there? or down low? I have no aspirations to climb 30+ feet up onto a 9-pitch roof in November to look at it myself...

I think I've rambled enough - I can't wait to read your thoughts! If I haven't said it before, I'll say it now - thank you ALL for your input, insight, creativity, and knowledge! Guess I'm just an overthinking engineer trying to keep the family warm while reducing our oil consumption (hmmm, new sig line...)

 

[Highbeam]

You're right, ditch that goofy top mounted damper. Add one to the stove collar where it belongs.

You shouldn't have smoke in the attic. Your flue temperatures are too low which results in cold smoke not wanting to rise away. This problem is made worse by the top damper I think. I don't know why your flue temps are low but your long liner means that the normal minimum temp of 250 in the flue is not enough. I expect you to run a flue temp up near 800 when you're getting serious.

Now a serious question. Is your liner topped with a chimney cap? Is that cap equipped with a screen? These screens are the devil and judging by the gummed up damper and cold smoke problems, wet wood, I would bet that the screen is clogged. You'll never get much heat with a plugged screen. I removed mine and have been very happy with the performance improvements/lack of required maintenance.

I get my heritage, with like 13 feet of chimney, up past 300 during the first half hour of wide open throttle. 400 is easy within the hour, and the stove when packed full and damper shut just cruises along at 450 until it runs out of fuel. The half inch open setting is what I use when I want the stove to run up to 500+. I wish they put marks on the draft control.

 

[tradergordo]

Stop burning wet wood. Burn hot. There won't be any smoke to go into your ridge vents. All problems solved.

As for where in your chimney/flue will creosote buildup accumulate the most? Its right where the chimney exits the house - the sudden change in temperature at that point is where most buildup will occur - according to what I've read. And yea, I agree with the previous comment about chimney cap screens - they should be removed unless required by local zoning.

 

[karri0n]

I agree with Highbeam. Get that damper off of there, and check the cap. You've certainly got gunk all over the cap, especially if you have a screen. You shouldn't have any smoke at all, never mind smoke in the attic. You won't if you have some dry wood. I can't see that the problems you are describing could possibly be from too much draft. It sounds like you have too little draft, or too little air going in. I believe 90% of your problems are based on the fact that you're burning the wet wood. I had an entire cord(won't be buying from that guy again) of partially seasoned oak, and I can attest to you that, NO, there really isn't a point in the burn where the water doesn't matter. I know that's counter-intuitive, but it seems to me that the moisture in the wood is just very stubborn and refuses to boil out in a timely manner. In a pinch, we tried drying our wood in the oven at 500 degrees for several hours. That seemed to help a bit. Highly impractical, but at least you aren't going to completely destroy your entire heating system.

Your idea of getting a professional out for an inspection is also a necessity at this point. You are at signifigant risk for carbon monoxide poisoning, and causing permanent damage to your chimney and possibly your stove.

 

[edthedawg]

thanks all for the helpful suggestions. Running home right now - will look and share more later. Two quick items:

1 - the bluestone cap sits up on 6 pillars about 18" high. No screens involved anywhere. I have an older post where I showed a pic of the house - you can see the chimney clearly.

2 - I'm going to burn SmartLogs tonight and see what differences there are.

oh and...

3 - I'm calling a chimney sweep the minute I get home.

ok and...

4 - I'm installing more CO detectors - both in the attic and on the 2nd floor.

 

[karri0n]

I mean no offense from this post.

Noticing your signature, I see that you are an engineer. You share the same plight as I do. Being an IT professional, and a bit of a science nerd, I tend to do tons of research, and attempt to figure out problems mathematically and scientifically. I'd imagine this is exactly what you do, being an engineer. I always find it funny that, after all our learning, research, math, and science, folks like you and I tend to lack that which the guy who grew up on his daddy's farm and went to a one room schoolhouse has an overabundance of: COMMON SENSE! We'll sit and ponder on a problem for hours, then when someone with little to no expertise on what we happen to be doing says "why don't you try plugging it in first?", we have the biggest epiphany of our lives. We can even see the evidence of this in our posts here. We're talking about making fire. This has been going on for millions of years, and ancient man had no complex knowledge of combustion or thermodynamics, yet they somehow figured out the big secret:

water + wood= no fire, and no fire=no heat

on a side note, I'm reminded of another colloquialism: "it's not rocket science". The funny thing about this is, rocket science is basically the very same rudimentary process that has been going on for millions of years: making fire. Maybe those rocket scientists need to go talk to a farmer?


All in jest, please don't take offense to this

 

[Highbeam]

Hehe.... licensed professional engineer here too.

 

[fossil]

I'm an engineer. Seems to me that means I know a whole lot about a little bit of stuff, and not necessarily much at all about everything else. Always learning, though. Rick

 

[branchburner]

I'm curious about how your ss liner terminates - you have a top-sealing damper, so I'm assuming that damper somehow fits over the pre-existing tile flue and your ss liner ends somewhere just below the top of the chimney? Please clarify if I'm picturing this wrong, and I don't know exactly what kind of damper you have, but the top-sealing damper that I have on my fireplace flue would not be at all workable on my woodstove flue with ss liner. Just trying to picture the setup (not that it will make wet wood burn any better).

 

[edthedawg]

You're all right - it ain't rocket science and I willingly admit I'm overthinking things. But at the same time, this is the way I'm gonna understand and process...

Tonight's activities:

Got home at 5pm, having last touched the fire around 7:30am. found a couple good sized coals to rebuild on. took 1/4 of a SuperCedar, a wad of shredded cardboard packing, and 3 SmartLogs, all of which were broken in half (not my doing - the box came w/ the logs almost all snapped apart inside). A little bellowing and we had large happy ignition. fire quickly grew, had excellent secondaries, burned smoke-free, etc...

We left just before 6 for dinner, got back home around 7:30, and there was just ashy coal piles, still glowing red. opened up the side door, loaded 2 more fragmented SmartLogs in, and they quickly regrew. Really never got above 400F, no matter where the primary was set, even up at the "this should be making things hot" setting of just 1/2" open. Mostly wanted to hover around 350. All primary adjustments were made in small steps over a long period of time. I threw another log on awhile after the first two, and then it was probably 9:30 when i decided those had burned down enough that i needed to reload with something. But w/ only 3 more SmartLogs in the house, I opted instead to load up w/ some of the oak that's been sitting stacked up next to the stove for a couple days. It caught quickly and fired up, but was noticeably more smoky @ the chimney. It also runs in the 300 neighborhood.

I grabbed a bunch of vids and pix, but not sure how relevant it all is. The secondaries were very pronounced on the first set of SmartLogs.

I did take another look at the chain damper, but only after loading the wood. I found I could pull it down to "shut", and since the chain is right above the intake, I could really hear the change at the air intake. It never stopped but i hesitate still to leave it "full closed". Didn't seem to really effect things too much tho the few times i did pull it "shut". One quirk is that this thing holds in place by catching chain loops on some metal fingers. Chain is about 3/8" to 1/2" per link, so no fine tuning... Seems, from the pitch of the intake whoosh, that the system either wants to run full bore, or slow to a crawl.

So I think if I can still hear the air pulling hard into the intake, and we have no smoke pouring back into the room, then things SHOULDN'T be that unsafe from a draft perspective, eh? Stove doesn't appear to have any sealing issues. It's definitely drawing hard.

OK I think I just fell asleep for 2 hours on the couch here. Gonna post now, go to sleep, read what I posted in the morning and make further additions / clarifications. There's supposed to be a huge part about calling my installer friend, and how he's coming on Black Friday to install a damper + clean the liner. Did I put that part in? I meant to. Goin' sleepies nowsknxzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz...............

 

[karri0n]

Hope you make out well. Your installer should be able to give you some good tips and figure out just what's going on here.

 

[edthedawg]

I'd like to think my installer could help a lot but I know better. He's a friend with extensive masonry wallbuilding and sheetmetalworking experience, but as for true experience with optimizing woodstove installs in old houses... let's just say I think we're both riding similar learning curves.

One recommendation he made was to use one of those little flue-cleaner sticks in an upcoming fire. Not that they clean by themselves, but that they make it easier to clean once used. I inherently distrust any "fix it quick - just pour this stuff in" type of "remedy" (think: AMSoil) so if ppl here have thoughts, I will largely go along with that.

Some other random, quick-hit thoughts (again, apologies to Peter King):

If I genuinely have wet, unseasoned wood to blame as my sole problem, then why...

- is my glass almost completely clean? Despite my stovetop hovering in the 320-380 range most of the time, I only have one narrow little crust of black on the very left edge of the window.

- is the amount of smoke I output from my chimney nowhere near the amount of smoke other neighbors put out? (holy cow I wish I had a vid camera to snap a couple houses I drove by in E. Htfd this am!)

- do I almost never have issues with getting a good strong "looking" fire started? The wood clinks instead of thuds, the bark generally falls right off, it has some checking on the ends... and while it doesn't burst into flames, and does its fair share of hissing and popping, we CAN get a good "looking" flame going without losing it, having it roil down to dull coals, etc... Maybe this is just indicative of the "seasoned" vs. 'wet" phenomena...


Anyways - can't think of much else at the morning. Bathroom plumbing, electrical, and framing are taking over my brain again - stove will occupy back-burner status for the next few days. I did notice last night that the 3rd or 4th time I loaded (around midnight - probably the first filled-box wood-packing after the SmartLog burns), despite the stovetop still insisting it was only 360, I was "feeling" the heat a bit more by then...

It was also 16 degrees this morning, so it's highly conceivable that any "feelings" of warm or cold are a bit skewed seasonally...

 

[Backwoods Savage]

And for gosh sakes Ed, quit trying to burn that wood you have on hand right now. Find something dry to burn. And if that oak you have is red oak, it needs 2 years to properly season.

btw, this all comes from someone with an Injun ear and yes, I am an old farm kid, and yes, I did go to a one room school But I ain't no rocket scientist...

 

[edthedawg]

My old electrician now works full time in wood-fired boilers (Mainline Heating), and actually just took over the stock from the hearth shop where we bought our stove (Alternative Heating). And apparently he is the area distributor for BioBricks. Gonna call right after this next meeting...

 

[LLigetfa]

IMHO those top mount dampers have a purpose and suit their purpose very well but they are not the best to regulate flow. They should be either open or shut and were originally intended for open fireplaces. If you're burning wet wood, you have to keep your flue temp up. There are three ways to keep the temp up. Reduced flue diameter increases the velocity so the gasses leave before they cool. Improved insulation so the heat doesn't escape out the sides. Increase the temperature and or volume of flow.

As others have said, stop burning wet wood.

 

[karri0n]

After your report of the wood quality and the clean glass, I'm at a loss. I will just go back to my original solution of try talking to a sweep. your smoke in the attic is really scary. Where there's smoke, there's CO.

 

[edthedawg]

The chimney is massive but central to the house, and this is the center flue. And it's twisty. So we didn't bother insulating when the liner went in. We can discuss it again now. I wouldn't want to go smaller than the current 6" flue liner. I'll get details of the top of the chimney and how the liner ties in next week when he's here to clean the liner, fix or remove the top damper, and install the bottom damper.

 

[edthedawg]

Where there's smoke, there's CO.

I put a new (and expensive) CO detector in the finished space of the attic last night.

 

[LLigetfa]

The chimney is massive but central to the house, and this is the center flue. And it's twisty. So we didn't bother insulating when the liner went in. We can discuss it again now. I wouldn't want to go smaller than the current 6" flue liner. I'll get details of the top of the chimney and how the liner ties in next week when he's here to clean the liner, fix or remove the top damper, and install the bottom damper.

OK, had I known those details, I could have saved a few keystrokes. Central chimney, unless there is a large unheated attic, should not lose too much heat out the sides. 6" is as small as I would go. Twisty might mean an insulated liner is out of the question.

It sounds more and more to be a wood quality problem and/or you are trying to squeeze too much heat out, not leaving enough for proper flue maintenance.

 

[edthedawg]

Insulated liner = no way in heck.

Pouring in an insulating medium (i.e. vermiculite) around the existing liner = many bags of expensive maybe-goodness. That's really the big stopper - no way to predict the cost is justified in any way...

Attic is technically unheated - as in, there's no radiators up there. But it stays at least 60 up there year round, with heat rising up thru the house and all. Chimney sticks up fairly far past the top of the ridge however... will post pix to refresh everyone's memories.

 

[edthedawg]

OK I should have posted these in the original send... Here are pix of the original chimney (prior to any repairs), a blurry view showing the cap we had built, a view showing the chimney inside the attic, and a view of the single wall pipe & tee behind the stove as they look today.

Possibly in that order.

Hope this helps clarify things.

 

[edthedawg]

And I'm clogging my own thread but I just remembered - I keep meaning to provide one detail that I expect is completely meaningless but wanted to vet here: the hearth is not perfectly level. it slopes ever so slightly from back to front due to the house settling. Just enough that the front door will swing open if unlatched.

I can't imagine there's any combustion physics or smoke-shelf positioning that would be THAT sensitive as to throw performance way off whack due to this - just wanted to mention it. And if Adios Pantalones decides to give me a "OMFG what were you thinking???" over this one, I'd be honored :ahhh:

 

[Jags]

And if Adios Pantalones decides to give me a "OMFG what were you thinking???" over this one, I'd be honored :ahhh:

He, he, he..now thats funny.

Hey Ed - Its your wood (hissing and popping) and that top mount damper. Fix those 2 and you will be back to "happy burning land". I could be wrong, but it rarely happens. :cheese:

 

[edthedawg]

aok - see, I knew it'd be either AP or Jags %-P

And just reminded me to call the biobrick guy...

 

[edthedawg]

As expected, they're out of BioBricks... But have SmartLogs and EcoFirelogs in stock. Now to evaluate both of those...

Guy at the shop has an old smoker, but generally agreed w/ the puzzlement at not being able to get over 400F stovetop...

So this is me... waiting (im)patiently for next Friday to roll around, so I can get my new damper......... *fingerdrum* (and burning something else in the meantime)