Direct connect into a chimney: good or bad?

[mban112]

Recently, a friend of mine gave me a Dutchwest 264 wood burning stove that he pulled out of one of his rentals. The stove seems to be in fine shape. We want to put this stove in my fireplace and send the venting up through the chimney.

I know there are a variety of ways to do this and that the best way is to have a lined pipe run the entire length of the chimney; however, money is tight. I also know that I can directly vent this stove through the flue with the right type of pipe.

Are there big disadvantages to running a pipe up to the clay tile and not all the way up, assuming I seal off the flue properly and that the chimney is in okay shape?

I've read about possible back puffing. Is that all?

Are there any glaring safety issues that everyone knows but me?

I'd like to get the stove as far back into the fireplace as possible. The vent on this stove goes out the back. Can I just put a 90 degree bend right after the boot and then run pipe right up from there or do a I need a T joint?

Any help would be greatly appreciated.

I live in Kansas City. Winter's are about a 7 out of 10 as far as long cold stretches where I might be using the stove.

 

[BrotherBart]

The two big issues are sufficient draft and chimney cleaning. With the direct connect opening into the larger hard to heat up flue tiles establishing a good draft is going to be difficult at best based on what size tile flue you have. And the cold tiles are going to be a creosote factory because they will always be cooler than a liner during stove operation.

The other thing is with a full liner you can brush the crud down into the stove firebox during chimney cleaning and be done pretty quickly. With a direct connect you are going to have to move the stove out of the fireplace and take out the direct connect pipe each time to do it right. Thereby creating a lot of work and risking not getting good connections and sealing every time you do it. It is a pain in the butt.

 

[mban112]

How is a direct connect different than the same mechanics of a regular fireplace? By that I mean, does a regular fireplace--no wood stove or anything--suffer from the same drawbacks as a direct connect (i.e. take forever to heat the tile and create draft), or is there something different about a normal fireplace that heats the chimney faster than a direct connect? That is, will a normal fireplace create a draft faster or at the same rate as a direct connect?

I'm just trying to gauge the acceptability scale. We've had a normal fireplace for years and it isn't great, but it's doable. If a direct connect functions (in terms of draft creation) the same way as a normal fireplace, I might be able to tolerate the less than stellar performance. However, if a direct connect is worse at creating draft than a normal fireplace I might need to reconsider my options.

 

[BrotherBart]

A fireplace has this huge hole in the front with all the air it wants. A wood stove has to have the combustion air pulled through a much smaller opening and requires a stronger draft to accomplish it. You can make a direct connect work if you want to. It just isn't worth the couple of hundred bucks you "save" doing it.

What size are the flue tiles in that chimney and are you sure they are in perfect condition?

 

[Todd]

How is a direct connect different than the same mechanics of a regular fireplace? By that I mean, does a regular fireplace--no wood stove or anything--suffer from the same drawbacks as a direct connect (i.e. take forever to heat the tile and create draft), or is there something different about a normal fireplace that heats the chimney faster than a direct connect? That is, will a normal fireplace create a draft faster or at the same rate as a direct connect?

I'm just trying to gauge the acceptability scale. We've had a normal fireplace for years and it isn't great, but it's doable. If a direct connect functions (in terms of draft creation) the same way as a normal fireplace, I might be able to tolerate the less than stellar performance. However, if a direct connect is worse at creating draft than a normal fireplace I might need to reconsider my options.

The difference is a fireplace throws 90% or more of it's heat up the chimney, so you get a strong draft. A wood stove is much more efficient and has less heat going up the chimney. A direct connect may work fine as long as your chimney diameter is the same size as your stove exhaust collar.

 

[mban112]

I haven't measured anything out yet. Everything should be in great condition because the chimney was rebuilt 10 years ago and the previous owners never used the fireplace after it was built. It's only had one year of light to moderate fire use.

How much do you think is a reasonable price range, assuming everything's straight forward, to have a sweep install a pipe all the way up. One dude was estimation $1000, which seemed rather high, but I don't know.

 

[mban112]

seriously? a sale? That sucks. I was hoping it could be done for under or close to $1000 something.

 

[branchburner]

seriously? a sale? That sucks. I was hoping it could be done for under or close to $1000 something.

Depending on the length you need, 20' or 25' or 30', an uninsulated liner itself may run as little as $400, then the install. Get another quote. Try to measure your flue dimensions first and post them.

 

[woodgeek]

I went the direct connect route myself, but if I was planning on burning 24/7 OR had an EPA stove, I would go for a full, insulated liner.

My goal was to have 'recreational' WE/evening fires to burn through 2-3 cords worth of dead/down trees on my lot, over the space of a few seasons. As the house I bought had a preexisting good condition, 30 yo stove in a slammer install, I needed to either dump the stove and revert to an open fireplace or upgrade the venting. I went the latter route to retain some heating value, more as an 'emergency backup' than as a major supplement. An 8" direct connect and boot ran me $350, and the install was easy for me to do.

If I decide to join the ranks of 24/7 burners, I will happily shell out the $4k for a nice EPA insert or hearth stove and a professionally installed, insulated liner. For all the reasons the others will tell you. At current energy costs, however, with a busy job that would force me to buy CSD wood, I can't justify the $4k cost financially or as recreation. In a few years that might change....

 

[mban112]

That is actually the same situation I am in. Not 24/7...yet. Maybe in a season of two we might upgrade. Did your direct connect come right out of a 90 degree elbow or did you T it off? Have you had any troubles with back puffing or anything?

 

[heatwise]

years ago we put in our buck model 20 inside the fireplace back in as far as it would go. a section of pipe went up about 6 feet into the chimney and a block off plate was used . we also didnt have the funds that year to do it all the way to the top. we were extremely pleased with the performance. the following year we removed the block off plate and had the stainless insulated flex pipe ran to the top, theyre was a big difference in draft. we could slow down the air intake to the stove and it definately made a big difference.i wanted the blockoff plate removed to try the ecofans, and we got a steaming dragon on the top as well . pete

 

[heatwise]

the liner made the stove draw much better.i also like the fact i can see the pipe connections as well . pete

 

[BrotherBart]

many 6" round flues are piped into 8" square chmnis & work fine & even bigger than 8x8 chimnis....

No they don't.

 

[begreen]

8x8 flues on fireplaces are somewhat rare. If the chimney is exterior and short, it may draw like poop.

 

[Stevebass4]

many 6" round flues are piped into 8" square chmnis & work fine & even bigger than 8x8 chimnis....

No they don't.

mine does :shrug: it works just fine

heats 1300 sq feet no problem - and my manual even shows a direct connect (albeit it's from 1993)

 

[mban112]

firestarter,

your fireplace in your picture looks almost identical to mine. Did you have concern about the clearances for that mantle (on the sides especially) ? My mantle is just like that, and the stove is similar in dimensions. You've given me hope.

 

[BrotherBart]

Take a look here at the manuals for installing and operating your stove. The first document, pages 1-12 contains installation and clearance requirements including for a mantle.

https://www.hearth.com/econtent/index.php/wiki/Dutchwest_CDW_Documents

 

[mban112]

my question is, what's a sidewall? is that the mantle wall or the actual wall? According to the manual the clearance for the small trim is less than for the "sidewall." I don't understand that. Wouldn't the thin trim pieces be more combustible than the thick sidewall pieces. I ask, because according to the manual (if the sidewall is in fact the mantle wall) I don't have enough clearance. But if the sidewall is something else, then I'm great.

 

[woodgeek]

mban, my stove had a inconvenient top rectangular opening with the same area as a 8" circle. You're on your own on the config. As for draft, the DC starts easy, pulls pretty hard and hasn't ever puffed or reversed. I've got a tall inside chimney--YMMV. I burn dry wood, hot, and don't starve it for air.

Part of my decision was that I didn't think my vintage of stove was designed for a 25' SS liner--would it overdraft? I (obviously) can't say, but would be interested in the opinions of the better informed--anyone ever put a liner on a smoke dragon and have too much draft?

 

[BrotherBart]

--anyone ever put a liner on a smoke dragon and have too much draft?

I sure did. I lined the chimney for my 21 year old insert. The first time I fired it off it was great to have such fantastic draft. What I didn't know was that there was a crack in the firebox hidden by the baffle. The stove came up burning nice, I eased down the primary air and the stove temp kept climbing. Long story short it pegged the stove top thermo at 1,000 degrees and the flue collar turned cherry red. I grabbed the infrared thermo and it registered a stove top temp of 1,200 before it started back down with everything shut down. The next day I plugged the crack with furnace cement and lit it off again and the same thing happened all over again.

The next week I pulled my old favorite stove of my life and replaced it.

 

[woodgeek]

thanks BB--I suppose all's well that ends well.

 

[branchburner]

Nice link, thanks! I guess "optimal" draft for most stoves exists not as one ideal situation, but as an acceptable range to fall within.

Makes me think a control for secondary air on my stove would be nice, especially in updraft mode. Even with primary air shut the stove can get hot enough in building a coal bed that I need to close the bypass to slow it down, but it's still not really ready to burn smoke, so I need to babysit the stove. I start to think I have a leak or something, the stove is drafting too well. But the leak is the secondary air opening!

Once I am in a good secondary-burn mode, though, the air supply seems fine for stove top temps - they run steady for long burns. I can't help but feel the burn times could be longer (and still smoke free) if the air supply and/or draft could be adjusted.

Maybe someday it will be "legal" to have a thermostatically controlled secondary air supply for non-cats. Kind of like the original VC airtights, except you would never shut air out completely. It would just be reduced a little more than standard, under certain conditions, to help optimize cruising temps and burn times, and reduce risks of overfiring. And then a little more secondary air if and when the stove calls for it.

Maybe that's called a furnace.

 

[branchburner]

manual & barometric dampers control the draft as does a MAGIC HEAT

Gulland article mentions some pros and cons with both damper types... it appears he overlooked MAGIC HEAT altogether. I thought this guy knew his stuff. What gives?

 

[branchburner]

I'm mixing your posts from different threads here, GOTB, but in "big or small splits" you mentioned excessive outgassing via smaller splits will not have enough combustion air which will result in unburnt gasses. That makes me think smaller splits would do better (efficiency-wise) in a stove that has excessive draft and/or excessive secondary combustion air. And something like an airtight VC would do much better with big splits. Seems counter-intuitive, as I always think the small stuff would burn too fast with more air, and would do best with low air.

Sawdust, huh? Now those are small splits. What's the best way to burn sawdust - with a lot of air?

 

[drdoct]

You could try a direct connect if your chimney isn't too awfully big. I've got the smallest flue pipe and mine worked with ok results or so I thought before I got a new insert with a fully lined chimney. A flex liner really isn't that expensive and it's a breeze to put in yourself. Shoot, you could do it quickly and it took me less than an hour to drop mine. I made a blockoff plate with mine, but you don't even really have to do that. I think if you do a DC then you may be ok with your stove. If you get the liner you'll love it and want to be a full time burner. That's what happened to me.