New stove question

[MontanaSam]

Recently saw a True North stove installed in a small house without a damper on the chimney pipe. Is this common? Every single stove I've ever used/seen has had a damper on the chimney.

Installing a Super 27 soon and am now very curious about this. Do I need a damper with these newer, super efficient stoves??

 

[DougA]

Most installations of new stoves do not need a damper. Only in cases where you have too much draft would you need one.

 

[Fastdonzi]

Modern wood stoves have Dampers built in.. Rarely ever in the pipe....

 

[Grisu]

Yes, it is common to not have one with a modern stove while with the "classic" stoves that sent ~60% of their heat up the chimney it was common to have one.

You should not need one for the Super unless your flue will be really tall and may easily overdraft. You can still put one in as insurance e. g. in case of a runaway fire but you will rarely if ever use it.

 

[bholler]

Modern wood stoves have Dampers built in.. Rarely ever in the pipe....

Not really most new stoves dont have dampers unless it is a bypass damper. They are pretty much all controlled by controlling the incoming air not the exhaust

 

[jeff_t]

How tall will your pipe be?

I've found the 27 to be a very easy breather, and that's with a 13' chimney. Much taller and I would have to think about adding a damper.

 

[Fastdonzi]

Oh, the only two ive had (both Bucks) one had an actual Damper, the other (new 91) has Damper/Bypass thing Lol.. but after much reading I see it is rare to install a damper in the pipe...

 

[MontanaSam]

The pipe will run up about 25'...... 18' of which inside the house envelope. Damper needed?

What say you on outside air intake? The house is very tight...new construction, spray foam insulation, etc. Thinking about an inlet from under the stove and running it out the basement wall, any thoughts?

 

[bholler]

I say yes to oak and not to the damper untill you see if you need it. It is much easier to clean especially if it is straight up with out a damper. You can always add one later

 

[Grisu]

And should you have too much draft I would first try to close the air supply of the boost air ("doghouse") before adding the damper. That made my fires more controllable with the air control.

 

[Huntindog1]

The Damper is nice to have for those oh sh*t moments.

 

[brad wilton]

I have in all 31 feet of pipe no draft problems on mine.try it and see if you need one first

 

[Starstuff]

And should you have too much draft I would first try to close the air supply of the boost air ("doghouse") before adding the damper. That made my fires more controllable with the air control.

Digging up this relatively old thread because I'm planning to do the same thing as you, Grisu: block off the boost air. My Super insert has a very strong draft and I feel like too much heat is going up the pipe even when primary is as low as it will go.

A few things lead me to believe it's overdrafting:

1) Even after diligently staggering off the primary air and getting stove to cruising, there are plenty of primary flames (orange) in addition to the blue secondaries.
2) I'll usually get very active secondary flames coming out of the boost air ports, especially with big loads.
3) I've read so much about the desirable "slow motion" secondary flames, but I've rarely seen them. Secondary flames on mine seem to be very active and quickly go right up the top
4) I don't even have the room air cover (on bottom of stove) removed and it still has no problems.
5) I feel like burn times should be longer and more even. I don't think I've ever really gotten 8-10 hours that this stove is supposed to be capable of, but at the same time, I'm not sure how people measure a "burn." 6 hours after a full load and there will just be small to medium coals left.

I'm wondering if the room air vent just feeds the secondaries, or does that also feed the primaries? Anyone know?

 

[cookin2night]

Not really most new stoves dont have dampers unless it is a bypass damper. They are pretty much all controlled by controlling the incoming air not the exhaust

That acts as a damper.

 

[begreen]

The way I understand it a damper is on the exhaust side. It would be added to the connector pipe if not built into the stove. The incoming air is regulated with an air control. It gets confusing to call the air intake control a damper.

 

[bholler]

That acts as a damper.

No not really it adjusts the air coming in a damper is in the smoke stream not ahead of it

 

[cookin2night]

No not really it adjusts the air coming in a damper is in the smoke stream not ahead of it

Doesn't it limit the air going out?

 

[FionaD]

Digging up this relatively old thread because I'm planning to do the same thing as you, Grisu: block off the boost air. My Super insert has a very strong draft and I feel like too much heat is going up the pipe even when primary is as low as it will go.

My jotul F3 has all those symptoms you have listed too, Starstuff. This very mild and windless shoulder season, here in Scotland, has confirmed it for me....In these milder temps and still air I have seen (at long last!) the slow, waving flames I have always heard people talk about but never experienced myself. My burn times are also twice as long. I am anticipating the usual overdraft behaviour you have described as soon as the temps drop and there are winds of any kind.

I tried attaching a magnet to the secondary air intake in the back (is that what people mean by the doghouse??) but I can't say it has worked very well for me - it seemed to just undermine the performance of the secondaries. It also made the primary air intake make even more of an annoying whistling sound than it normally does when it's fully closed off, I guess becuase the stove is trying to draw more air in from the front if it can't get it from the back. Perhaps I covered up too much of the secondary intake; I plan to experiment again this winter, when the right conditions present theselves... won't be long I'm sure!

I'd love to hear how you get on with solving your own issue, becuase I've got to the stage where I will be fitting a damper soon, if blocking some of the secondary intake continues to have no great effect.

 

[beatlefan]

Fiona and Starstuff, are your doors sealing tight? You might try the "dollar bill test."

 

[FionaD]

Doesn't it limit the air going out?

I guess a damper does limit the air going OUT, but the air intake doesn't get called a damper becuase it regulates the air going IN

 

[FionaD]

Fiona and Starstuff, are your doors sealing tight? You might try the "dollar bill test."

I have tried it.. Both with a dollar bill as well as a British pound I can pull the bill out at the very top of the door, but with a little effort - and when I asked here about this a year or so ago I was advised it was probably OK, as long as it didn't come out too easily. I've also gasketted the living daylights out of the stove in the spring (turned out that gaskets were missing, that should have been there, all round the secondary burn plate). That improved things a lot, maybe it will turn out to be enough come the colder weather, I hope so.

But I know for sure that I have a strong draft up the chimney, it was an issue even when I still had an open fire and the chimney sweep would always comment on it. I swear last winter some of those gales almost pulled splits up the flue!

The problem is made more complex by the fact that my stove burns unevenly - way more excitable on the right side than the left. Always has done. A few other folk with F3s have the exact same issue - there are several threads here about it... But this means that, really, I only want to reduce the burn on one side of my stove - the side opposite the secondary intake.

 

[beatlefan]

I have tried it.. Both with a dollar bill as well as a British pound I can pull the bill out at the very top of the door, but with a little effort - and when I asked here about this a year or so ago I was advised it was probably OK, as long as it didn't come out too easily. I've also gasketted the living daylights out of the stove in the spring (turned out that gaskets were missing, that should have been there, all round the secondary burn plate). That improved things a lot, maybe it will turn out to be enough come the colder weather, I hope so.

But I know for sure that I have a strong draft up the chimney, it was an issue even when I still had an open fire and the chimney sweep would always comment on it. I swear last winter some of those gales almost pulled splits up the flue!

The problem is made more complex by the fact that my stove burns unevenly - way more excitable on the right side than the left. Always has done. A few other folk with F3s have the exact same issue - there are several threads here about it... But this means that, really, I only want to reduce the burn on one side of my stove - the side opposite the secondary intake.

A door gasket might help. My stove ran like a flame thrower when the gasket got old. I couldn't get to secondary burn unless I put an extra push on the latch to make the door seal a little tighter.

 

[FionaD]

Aye,you're right... It sure makes sense to fit a new door gasket before putting in a damper

 

[Starstuff]

Fiona and Starstuff, are your doors sealing tight? You might try the "dollar bill test."

Definitely not the door. I've done the dollar bill test and it is tight as can be. The latch on the PEs make it very easy to tighten the seal.

 

[Starstuff]

My jotul F3 has all those symptoms you have listed too, Starstuff. This very mild and windless shoulder season, here in Scotland, has confirmed it for me....In these milder temps and still air I have seen (at long last!) the slow, waving flames I have always heard people talk about but never experienced myself. My burn times are also twice as long. I am anticipating the usual overdraft behaviour you have described as soon as the temps drop and there are winds of any kind.

I tried attaching a magnet to the secondary air intake in the back (is that what people mean by the doghouse??) but I can't say it has worked very well for me - it seemed to just undermine the performance of the secondaries. It also made the primary air intake make even more of an annoying whistling sound than it normally does when it's fully closed off, I guess becuase the stove is trying to draw more air in from the front if it can't get it from the back. Perhaps I covered up too much of the secondary intake; I plan to experiment again this winter, when the right conditions present theselves... won't be long I'm sure!

I'd love to hear how you get on with solving your own issue, becuase I've got to the stage where I will be fitting a damper soon, if blocking some of the secondary intake continues to have no great effect.

This morning, I blocked the boost air port using a piece of spare rope gasket I had. I am only familiar with my PE stove, so I do not know if your Jotul also has a boost air channel. The "doghouse" that Grisu referred to is a piece of drilled corner steel, which acts as a manifold for the boost air channel. It is positioned directly under the door of the Super.

Admittedly, I have not been burning optimum wood (mostly pine and punky-but-dry oak), so these are preliminary observations, but here's what I've noticed so far with the boost air blocked:

Pros:
1) draft is definitely reduced but still very strong, especially when primary air is engaged more than halfway open.
2) Secondaries seem to start lighting off much sooner with the primary still open, but it takes longer to get stove up to normal cruising temperature (500 for my stove, measured in the front center just above the door.)
3) With primary air completely shut off, I get a true secondaries-only burn with downward jets and nice lazy dancing flames.

Cons:
1)Stove has a much harder time staying in cruise mode with primary air cut all the way down--in fact, it appears to be impossible. It seems like everything is going fine and then all of a sudden it starts dying down and then secondaries just go off and then it smolders. I have to open primary air back up and get the flames up again and getting the gases released again. This happens regardless of the size of the wood or the temperature of the stove. The only way to keep the stove cruising all the way until all the off gasses have been burned is to leave the primary air open a bit, which defeats the purpose of blocking off the boost air. I even took off the cover for inside air, which did not seem to make any difference.
2) Burn times do not seem much improved, but I've yet to try a full load of hardwood.

So far, it appears that the boost air is absolutely necessary for the secondary combustion to sustain itself through a full burn cycle. I'm not sure if Grisu--or anyone else who has plugged their boost air hole--is able to run his stove with primary air completely shut down, so I would love for him to chime in here. I'll continue experimenting with fuel and load size (Tomorrow, I'll try stuffing it with nice big 16% dry ash splits), but I'm a little disappointed that closing the boost has affected the secondaries so dramatically.