Wood Stove Installation questions - pipe / joint / tight space

[neo von retorch]

Tried to find good wood stove installation videos. So far they all focus on installing a pipe… in the wall, on the chimney, through the roof. No one focuses on attaching the pipe to the stove. Reading some forums apparently it’s not a big deal - you’re not actually all that concerned with a perfect, airtight seal. The chimney (liner) will have a draft of hot air moving upwards, drawing any air away from the stove and pipes. If there isn’t a perfect seal on the pipes, you lose a pinch of draft to air being sucked in. But in a worst case scenario (short of chimney fire) a backwards draft would let smoke into the room.

Additionally, I believe the main problems we had with the last stove were in part due to weak draft, so it might make a difference to get that good seal and have every bit of draft at my disposal.

Still my bigger concern is that the conversion pipe exiting the stove to the 6" size may be too long - have to measure everything when I’m not lying in bed doing internet research, and see if/how the pipe installation can be done.

Installing a freestanding soapstone on a 9" brick shelf where an insert once was. Steel liner is already installed from my last freestanding stove that I didn't install.

EDIT: Please see latest comment for new questions!

[lthenderson]

Yes you don't have to be air tight. I grew up in an old farmhouse heated by a wood stove. Our pipe running from the stove to the chimney was simply held together with a couple sheet metal screws at each joint. The draft was enough to keep any smoke from exiting the joints. Also, you want something easily undone so you can clean those sections of pipe each fall before you start your first fire.

[Car Jack]

The chimney should pull air/smoke from the stove.  You should have an automatic air damper on the pipe.  Might not be the right name, but it's a damper to the side of the pipe with a weight on the bottom.  If the draw is too strong from the chimney (as in a chimney fire), the damper opens, pulling ambient air in.  This thing ain't air tight.  My wood furnace pipe is held with 3 sheet metal screws around the pipe.  The other end is literally pushed into the chimney.  There is nothing sealing it.  For context, this is a relatively big fire box surrounded by air that's squirrel cage blower driven into heating ducts to heat a 2800 square foot house.  So yah.....we burn a LOT of wood.  Depending on how much work I want to do, this is maybe 2 cords minimum, to probably 5 in a season.

[neo von retorch]

I've heard differing opinions on whether you need the damper - they sell barometric ones that make sure you don't get a negative draft. The forum thread was arguing that he didn't see any difference without it, but we've had enough fires pushing smoke into living room with the previous wood stove that it's kind of tempting.

Are you saying you need it as a safety precaution in case of chimney fires?

[Linea_Norway]

If your draft is not good enough, you can install a ventilator in the top of the chimney. We have that in own house above the open fireplace, installed by the previous owner. I think it measures how much smoke there is, or how warm it is, because it adjusts it's own power and turns itself off when the fire is all gone. Our wood stove doesn't need it.

Normally the wood stove is just shoved into into the pipe.

[neo von retorch]

Yes - I can't tell if the draft (by itself) is a problem. The last stove had a rear chamber (i.e. "Everburn" by Dutchwest) but it required a pretty strong draft because there was an internal on/off damper that massively cut air flow -- all the gasses from the fire had to flow through tiny holes to the rear chamber to reburn before leaving to the flue.

My current plan is to measure the exact location of the stove and steel liner and get the right length pipe/joints to get it lined up, install... and give it a whirl! This stove is a much simpler design with no internal damper - not sure if I need one on the flue at all (but I'll check the manual which has thorough installation instructions). Basically it has a primary air control valve that is responsible entirely for airflow and thus how fast and hot the fuel burns.

[Fishindude]

The pipe between the wood stove and the ceiling or wall exit point is typically just black, single wall sheet metal stove pipe.   If you have to cut it to length, it's simply a matter of using some tin snips.   Usually best to trim off the female end and keep the good crimped male end so you don't have to re-crimp it.

Make sure you start out correctly with pipes fit together in correct fashion so that if you have a little water of creosote run down the flu it stays inside the flue and cant leak out at the joints.   Male ends down, female ends up.

[big_owl]

The pipe between the stove and the home exit point is pretty much just sheet metal with "slip" fittings that are held together by either gravity or some sheet metal screws.  There are no special seals involved. 

We installed a wood stove in our basement a few years ago.  There is about 6ft of internal sheet metal pipe to the exit point (through the basement foundation wall).  Then it transitions to double-wall insulated chimney pipe for three stories up the side of my house to about 10ft above the roof line. 

You shouldn't have any problems with drafting.  Our stove is basically a worst case scenario since there are three stories of exterior chimney pipe (we live in DC area so our winter temps are about the same as yours are).  The only time we ever have issues with reverse draft is when I'm starting the stove out from a completely cold condition and the ambient temps are low 30s or less.  And even then all I have to do is open a basement window slightly for about 5 minutes until a draft gets going in the stove and then it's fine from then on out.  With the fire going the draft is very strong and there's no way smoke is going to leak out the interior chimney joints.

[neo von retorch]

Thanks @big_owl. That covers a lot of my concerns, really. I think we have a tendency towards negative drafts in similar situations, and I wasn't educated enough (nor patient enough) to get the positive draft going, but I'm hoping I'll be ready this winter for that scenario! We have a 2 story chimney, but the liner is inside that rather than exposed outside! Under normal conditions, it should certainly draft fine.

Does it specifically have to be a basement window? I would think that my ~first floor (split-level) where the wood stove is window should be sufficient... if I wait for it a bit?

[big_owl]

Thanks @big_owl. That covers a lot of my concerns, really. I think we have a tendency towards negative drafts in similar situations, and I wasn't educated enough (nor patient enough) to get the positive draft going, but I'm hoping I'll be ready this winter for that scenario! We have a 2 story chimney, but the liner is inside that rather than exposed outside! Under normal conditions, it should certainly draft fine.

Does it specifically have to be a basement window? I would think that my ~first floor (split-level) where the wood stove is window should be sufficient... if I wait for it a bit?

When I was doing internet research prior to installing the chimney I was so stressed about the draft due to the long exterior chimney run.  Then once it was installed I was like oh that was no big deal.

I've never tried opening another window in the house because there's a basement window and sliding door literally right next to my stove (walkout basement) so I just reach over and open it as I'm in the process of lighting the stove.  I doubt it would matter much as long as my interior basement door was open to the rest of the house, since you're just looking for a source of cold/dense air to flood into the house to allow the draft to get started.  I assume if my interior basement door was closed then it would have to be a basement window opened in my case since that's where the stove is located.

[neo von retorch]

Oooh that makes much more sense then. I was like "why do you walk all the way to your basement?!"

[big_owl]

Oooh that makes much more sense then. I was like "why do you walk all the way to your basement?!"

Yup - we installed it when we finished the basement.  Pic of the actual stove installation:

https://forum.mrmoneymustache.com/share-your-badassity/from-zero-to-million-dollar-basement-(diy)/msg920425/#msg920425

[Fishindude]

My wood stove sometimes doesn't want to draft right when I'm lighting it cold.   A couple big wads of newspaper lit up first warm the flue quickly and get the draft going.

[neo von retorch]

My wood stove sometimes doesn't want to draft right when I'm lighting it cold.   A couple big wads of newspaper lit up first warm the flue quickly and get the draft going.

Yeah... we have had a few scenarios with the old stove where that wasn't enough. The smoke from the newspapers was still finding every crevice from the stove to come out into our living room. And that was with the on/off damper wide open. But I'm hopeful if I crack a window and wait a few minutes, maybe it'll draft in the right direction with that starter heat.

[neo von retorch]

Update

So I bought the manufacturer's compact flue adapter (goes from 3.5" x 7" oval to 6" round.) And it wasn't cheap.

It's ~1" in the middle, and 2" additional on either end for connecting.

But... it doesn't "fit" in the flue exit all the way. So it's adding another ~1" there.

Question 1

Is it OK to snip the adapter to get it to overlap itself inside that oval? Or maybe try to twist it to help it "crush" into the flue exit?
Visual aide - https://www.rockymountainstove.com/hearthstone-homestead-compact-flue-exit-adaptor/


So then even if the above was perfect, there's about 8" remaining including that 2" overlap. So we're in a tight spot. The chimney liner comes down but it's several inches right of center. So I've got one of those 90° adjustable corners, which spins at 3 intersections. But having to go left a bunch and down a bunch and then turn forward to meet the perpendicular stove exit... yeah it's just not quite happening. Especially in 8" of front-to-back. To better set the scene, with the flue adapter sticking out an inch extra, I was able to "connect" everything last night, but the stove was about 1.5" too far front. So that flue adapter fix would help a lot. But... realistically the flue adapter 6" going into the 90° joint pipe was not really parallel and almost certainly would've had a troublesome gap. But also I don't want the feet 0.5" off the front of my ledge if I can help it.

Question 2
Do 90° pipe joints exist with... a 4th intersection? Or do you have an alternate suggestion?

[Highbeam]

Is that galvanized duct pipe from the HVAC section! Good lord.

[neo von retorch]

Is that galvanized duct pipe from the HVAC section! Good lord.

Did you have some information you thought it would be important to share with me? I don't know how to interpret your comment.

[big_owl]

This is a weird thread - at one point you had a picture of the actual installation but it appears you deleted(?) it and the previous post has also been removed it seems? 

In any case, I remember looking at the pic of the installation and cringing a little at how many joints there seemed to be in such a short span.  Also it looked sort of weird in the picture I remember thinking that your first galvanized connection looked like it was actually *inside* the flue adapter piece which would have been poor installation but perhaps it was just the way it looked in the pic. 

I can't say for sure now that the pic appears to be gone.  I believe the ire was probably due to the use of galvanized pipe in this application - you had a post at one point mentioning the possible risks of outgassing so I'm pretty sure you already knew about that. 

Something weird is going on for me with this thread, either that or I'm hallucinating. 

[neo von retorch]

This is a weird thread - at one point you had a picture of the actual installation but it appears you deleted(?) it and the previous post has also been removed it seems? 

In any case, I remember looking at the pic of the installation and cringing a little at how many joints there seemed to be in such a short span.  Also it looked sort of weird in the picture I remember thinking that your first galvanized connection looked like it was actually *inside* the flue adapter piece which would have been poor installation but perhaps it was just the way it looked in the pic. 

I can't say for sure now that the pic appears to be gone.  I believe the ire was probably due to the use of galvanized pipe in this application - you had a post at one point mentioning the possible risks of outgassing so I'm pretty sure you already knew about that. 

Something weird is going on for me with this thread, either that or I'm hallucinating.

You're not - I was going on 36 hours without sleep and posted a reactionary post. I decided to delete that and try to extract actual "information" rather than get into an unnecessary skiff over what I consider to be, less useful commentary.

I think the joints will work, and I bought 2 black wood stove elbows to replace the galvanized pieces. I don't think I can remove the bends as they are because there simply isn't space. The stove seems to burn ideally as is, so I don't think I'm hurting for draft.

I'm not following - the flue adapter exit from the stove is larger than the manufacturer provided oval-to-round adapter, so the oval has to go inside that. There's no other way to put those pieces together. It doesn't fit as nicely as I would've liked considering it came from the same company, but unless it leaves gaps (which it doesn't appear to) it'll work. It just might impede upon the draft slightly more than it should. But I'm only going off my own very limited experience with this one stove, so maybe you can better explain what you mean?

[big_owl]

I'm just going off memory - it seemed weird to me in the picture but it was hard to tell for sure.  If everything is sealed up properly and it's installed per the manufacturer specs then it's probably ok.

[neo von retorch]

I'm just going off memory - it seemed weird to me in the picture but it was hard to tell for sure.  If everything is sealed up properly and it's installed per the manufacturer specs then it's probably ok.

Fair enough - thanks! Once I've got the black elbows in, I'll take new photos and get that fire nice and hot 😁

[big_owl]

I'm just going off memory - it seemed weird to me in the picture but it was hard to tell for sure.  If everything is sealed up properly and it's installed per the manufacturer specs then it's probably ok.

Fair enough - thanks! Once I've got the black elbows in, I'll take new photos and get that fire nice and hot 😁

Good deal, I've already done a few burns this fall and the wife and I are planning on lighting ours up tonight for Halloween and watching the original Halloween movie together in the basement home theater.  Apparently she's never seen it. And she hates scary movies so it should be fun :)

[neo von retorch]

So here's the updated installation with wood stove pipes in place. This was 8 days ago and we've had lots of successful fires since then. I've seen this pipe as hot as 460F.