Evil perlite, smoke filled room, what happened?

[nola mike]

So I thought I had successfully installed a wood insert into a ZC fireplace/chimney, with a 6" (inside of 9") liner. I stuffed the bottom with fiberglass insulation (a blockoff plate was very difficult given the geometry of the chimney--I tried) and poured in perlite through the top. OK, no leaks. Until I fired the stove a couple of times. Then a few pellets would fall behind the insert as the chimney heated, and would stop. Well, on the third night, the pellets kept leaking. Looks like the expanding/compressing of the chimney ground the "course" pellets into much finer stuff. Anyway, over a period of a minute or so, about 1/2 - 3/4 of the insulation leaked down behind the insert, while I had a fairly good fire going. I was peaved, but not overly concerned, as the only space was between the new insert and the walls of the old fireplace. Very soon afterwards however, smoke started billowing into the living room. I was able to remove the burning wood outside and evacuate the family (thankfully we were all sitting there when it happened), but it freaked me out. I have no idea what happened. The chimney appears intact, and is connected securely to the insert. None of the perlite made it anywhere that I would think should impact the fire. When I open the door when cold, I can feel a good draft up the chimney. Everything looked as it was on the roof. It didn't appear that there was smoke infiltration into the gap around the lining. During/immediately after the incident I went to the attic and put a hand on the outer fall of the chimney, which was just warm--nothing out of the ordinary. So today, I cleaned the perlite from around the insert and started a small fire. So far so good. Went on the roof. All well. Made a smokey fire. No problem. Made a big, hot fire. Everything was fine. I kept a watch behind the insert during this time, and didn't see any smoke at all. So. While I'm glad I can't find anything wrong, I don't like not knowing what happened. The only thing I can think of is that the rapid perlite movement caused a temp swing in the chimney that reversed the draft. But that's a WAG and I'm not at all convinced by this. The other thing is that I wasn't happy with the top of the chimney (pics attached). There is still free movement of smoke, but it seems confined, and I'm wondering if this contributed to my problem (why I didn't have a problem the other nights, and why it coincided with the perlite falling, I don't know).
1. What caused this?
2. What's my next step?
3. As far as the chimney, my choices are to either cut that red sheetmetal down 6" to leave the guard completely exposed, raise the guard 6" with some stovepipe, or...?
4. Can/should I reinsulate? I'm thinking for now, I should just put some rock wool or whatever in the top to seal the draft. The insulation was put in mainly for protection in a chimney fire--I don't think it's strictly necessary. Shoulda gone with the vermiculite, but they were sold out, and I thought the perlite would be equivalent. Also thought I had sealed the bottom pretty well. Guess not. I'm not going to remove the insert to try and reseal the bottom--the clearances were tight, and it took me hours to get it in.

 

[maxed_out]

Couple of ideas here. I dont think we are cold enough yet to get good fires rolling.

And once it gets cold try a fire without that cap on. It looks to me like you cant get a good draft but it maybe the picture.

 

[nola mike]

Couple of ideas here. I dont think we are cold enough yet to get good fires rolling.

you obviously haven't met my wife.

And once it gets cold try a fire without that cap on. It looks to me like you cant get a good draft but it maybe the picture.

I think I'm getting a good draft, and like I said this only happened once. So if I remove the cap, and all is well, I still don't know if that's the problem or not.

 

[ecocavalier02]

yes definatly get rid of that sheetmetal arnound the cap. that would definately restrict draft. thats a wall right around the frekin thing. . and you want to be real careful removing wood from the woodstove. thats very dangerous best to open windowns and shut te stove down and open the damper and let all the smoke out of the stove. did you shut the damper down really early after starting the fire? still wouldnt make sense.

 

[elmoleaf]

Ditto. Get rid of that metal enclosure around your chimney cap. Your flue exit is too obstructed.
I'd guess you had a draft reversal.

 

[Lighting Up]

You need a different cap on that top if you get any snow and you start that stove up on a cold start you won't draft. Looks like the 6 inch liner is to short but you can still cap it on the other liner. Could be the pictures but it looks like it choking the draft.
good luck
md

 

[fishingpol]

1.) Either get an extension to raise the flue liner up over the red sheet metal and install a s/s pre-fab chimney cap that is compatible with your liner system.

2.) remove the sheet metal down lower so the cap is exposed. You got a pretty good restriction of flow there. If the wind is blowing, it could force smoke back down the flue.

Just curious, is there supposed to be a cap or flange where the sheet metal goes up through the white chimney chase? Looks like a good sized gap there between the two. I am not familiar with that type of set-up, please pardon my lack of knowledge if it is fine the way it is.

 

[BrotherBart]

Is the top plate that came with that liner kit shoved down inside that metal chimney? Where is that rain you are getting tonight and all day tomorrow gonna go after it goes into the chimney and around the liner?

 

[pen]

Is the top plate that came with that liner kit shoved down inside that metal chimney? Where is that rain you are getting tonight and all day tomorrow gonna go after it goes into the chimney and around the liner?

spot on. Get that fixed! Stopped burning! Cover it up until you or someone you can find to help can do it right.

pen

 

[nola mike]

ok, maybe some more info about what's there will help. the actual original (round) chimney is inside the white chaise (which is also sheetmetal) and ends at the junction of the white/red area. at that junction is another square horizontal piece of sheetmetal that is angled to route any rainwater away from the chimney. I put a 13 x 13" plate on top of this, and the cap on top of that. water is routed the same way as before; it isn't getting into the actual chimney. i know it looks like rain goes down the square chimney, but it doesn't get anywhere, and doesn't get around the liner--if you guys were talking about something else being a problem with the weather, please lmk. the 6" liner actually extends farther out than the original, so it isn't too short. the cap fits over the blockoff plate; if i had simply extended the liner there wouldn't be anything to support the cap. i was leery about cutting the sheetmetal, just because i was trying not to modify any of the factory built stuff if possible. i think i'll just extend it with some more pipe. all that aside, would any of this cause a one time draft reversal, and how is this related, if at all, to the perlite? i thought about wind as well, but it was pretty calm when this happened.

 

[begreen]

From what I can gather, perlite is not the issue. It sounds like the bottom seal of the liner was insufficient to contain the insulation. Without specifics on how this was done, we would just be guessing about what happened, but in no way does it seem related to the smoke issue. The perlite outfall may have been coincidental. The main issue here is the exhausting of smoke from a completely shrouded flue cap. This is a problem waiting to happen. Either extend the liner to above the red steel collar and cap it there or cut down that collar. It's blocking the exit of the stove smoke.

 

[nola mike]

From what I can gather, perlite is not the issue. It sounds like the bottom seal of the liner was insufficient to contain the insulation.

yes, clearly. the thread title was a bit tongue in cheek.

in no way does it seem related to the smoke issue. The perlite outfall may have been coincidental.

that's my biggest question. i just don't get why i would have burned the stove for 40+ hours, and only had it happen within a minute of the perlite coming out. another thing, i guess, is maybe there was either a gust of wind causing the 2 events to happen simultaneously, or maybe the draft reversal caused the perlite to fall.

The main issue here is the exhausting of smoke from a completely shrouded flue cap. This is a problem waiting to happen. Either extend the liner to above the red steel collar and cap it there or cut down that collar. It's blocking the exit of the stove smoke.

yeah, that's certainly the plan before the next burn. the house is a bit remote and i didn't have access to the materials to extend, and was/am leery about doing any cutting on the original chimney. i'm just very nervous about this happening again with my family/newborn asleep and in the house.

 

[johnstra]

Could the perlite have blocked the air intake?

 

[nola mike]

Could the perlite have blocked the air intake?

no, intake's in the front.

 

[midwestcoast]

that's my biggest question. i just don't get why i would have burned the stove for 40+ hours, and only had it happen within a minute of the perlite coming out. another thing, i guess, is maybe there was either a gust of wind causing the 2 events to happen simultaneously, or maybe the draft reversal caused the perlite to fall.

Or you had low draft happening at the time, but enough to sustain the fire & resist the wind gusts. Perlite fails, flue gases are already rising slowly, now they are cooled more & rising slower, then next good gust reverses your draft. Part coincidence, part cause/effect. Probably would have happened regardless of perlite failure.

 

[tfdchief]

My SS liner/cap install was almost identical. I simply cut the fake red tile short enough to not obstruct the flue cap venting area. Right handed Aviation snips will do the trick in short order. I have a picture somewhere. If I cna find it, I will post it later.

 

[midwestcoast]

You're sure the perlite you used was proper for this use & not garden grade stuff that may have coatings, fertilizers, combustibles in it? Perlite on the firebox didn't cause the smoke? I imagine you would have noticed evidence of that when cleaning the perlite up, but just checking.

 

[begreen]

From what I can gather, perlite is not the issue. It sounds like the bottom seal of the liner was insufficient to contain the insulation.

yes, clearly. the thread title was a bit tongue in cheek.

in no way does it seem related to the smoke issue. The perlite outfall may have been coincidental.

that's my biggest question. i just don't get why i would have burned the stove for 40+ hours, and only had it happen within a minute of the perlite coming out. another thing, i guess, is maybe there was either a gust of wind causing the 2 events to happen simultaneously, or maybe the draft reversal caused the perlite to fall.

The main issue here is the exhausting of smoke from a completely shrouded flue cap. This is a problem waiting to happen. Either extend the liner to above the red steel collar and cap it there or cut down that collar. It's blocking the exit of the stove smoke.

yeah, that's certainly the plan before the next burn. the house is a bit remote and i didn't have access to the materials to extend, and was/am leery about doing any cutting on the original chimney. i'm just very nervous about this happening again with my family/newborn asleep and in the house.

From the description it's as if the liner moved, releasing the perlite and smoke. For sure check the liner connection to the stove carefully to make sure it has not pulled apart. How is the liner attached to the stove?

 

[tfdchief]

My SS liner/cap install was almost identical. I simply cut the fake red tile short enough to not obstruct the flue cap venting area. Right handed Aviation snips will do the trick in short order. I have a picture somewhere. If I can find it, I will post it later.

Ok, here is the pic of mine after I installed the SS liner and cap and cut the fake chimney tile down so it did not restrict the cap venting.

 

[branchburner]

From the description it's as if the liner moved, releasing the perlite and smoke. For sure check the liner connection to the stove carefully to make sure it has not pulled apart. How is the liner attached to the stove?

For that matter, how is it attached at the top plate?

Anyway, I think the liner connections are not related to what happened. I'm guessing the smoke was having a tough time getting out of that tight spot. Once the perlite broke loose and drained out, the empty space filled with cold air and hot smoke from topside, sucked down by the vacuum created by the falling perlite. So maybe the smoke suddenly had an easier path to follow: right down the outside of the liner, where the perlite used to be, and into the house! The path of least resistance was down and in, aided by the sudden creation of a downdraft and the partial obstruction of the normal up-and-out flow.

 

[nola mike]

From the description it's as if the liner moved, releasing the perlite and smoke. For sure check the liner connection to the stove carefully to make sure it has not pulled apart. How is the liner attached to the stove?

Yeah, i had thought initially that the chimney must have disconnected, but it hadn't. even verified it from the inside--I had sealed the inside seem with cement, which was still intact. also, as i mentioned, i burned a smokey fire the next day, looking carefully behind the insert to see if any smoke was escaping--it wasn't.

For that matter, how is it attached at the top plate?

top plate has a hose clamp around it that secures the chimney. the plate itself is just silicone'd to the original sheet metal.

Anyway, I think the liner connections are not related to what happened. I'm guessing the smoke was having a tough time getting out of that tight spot. Once the perlite broke loose and drained out, the empty space filled with cold air and hot smoke from topside, sucked down by the vacuum created by the falling perlite. So maybe the smoke suddenly had an easier path to follow: right down the outside of the liner, where the perlite used to be, and into the house! The path of least resistance was down and in, aided by the sudden creation of a downdraft and the partial obstruction of the normal up-and-out flow.

yeah, that makes sense, and was one of my theories. i think there's still some perlite in the chimney though--i was only able to recover 1/2-3/4 of the bag. i assume the rest will be along shortly. whatever the case may be, seems that it's nothing that's going to cause my house to catch fire, and will hopefully be remedied by fixing that chimney.

soooo....bearing in mind that i'm not going to remove the insert to seal that bottom gap any better, 2 questions:

1. i shouldn't have a problem with perlite behind the insert, right? it has no chance of obstructing any important air flow.
2. should i bother trying to re-insulate? i'm wondering if a portland/vermiculite slurry might do better; i could pour a bit in, let it firm up, and then fill up the rest. i'd think that this would have less chance to fall. and looking at the vermiculite, looks like even dry that shouldn't find the cracks like the perlite.

thanks for all the help guys.

 

[branchburner]

If you have some rock wool or fiberglass insulation stuffed in at the bottom really tightly, it should support a layer of a portland/vermiculite slurry. You could then fill up the rest with loose perlite or vermiculite. There shouldn't be any cracks left.

That's how I did mine, but bear in mind this hybrid insulation is not going to technically be seen as an "approved method" by any liner manufacturer.

 

[midwestcoast]

This stuff is UL listed @ $62 per 45 lb bag http://www.woodlanddirect.com/Chimney/Liner-Tools-Insulation/Chimney-Champion-Insulation-Mix-45-Bag. Free shipping on orders >$100. Will support itself when set. Is it any better than perlite & portland? Don't see how it would be.
If you can't get a strong block-plate I'd pour a bit & let it set-up before filling the chimney as wet will be much heavier than straight perlite.

 

[nola mike]

Here's the result. I added about 12" of galvanized pipe to the top. Strangely, 6" was too small and 7" too big. I ended up with the pipe kind of overlapping itself. Secured well with hose clamps, and sealed the seam with silicone. 36 hours of burning without recurrence.

 

[branchburner]

Lookin' a lot better!