Draft and Cold Weather

[Huntindog1]

I think everyone is seeing an increase in draw from their flues during these frigid weather periods.

Makes it harder to control the stove.

Isnt it the difference in temps that determine how much draw a flue has.

The stove is hot and outside its colder so more draw of the flue.

Temperature difference works with heat transfer also as how much heat transfer that's going on like between the stove top and the room or object or the air in the room.

Makes me think of voltage as its a measurement of potential difference.
So the more potential difference (voltage) the more current flows in the electrical circuit.

Ok I will quit rambling now.

 

[Seasoned Oak]

Stove seems to burn hotter in this weather. Just in time.

 

[CenterTree]

Yeah, and also the WIND seems to increase the draft as it zips across the top of the flue.
Unless that's just my imagination.

 

[branchburner]

With my air control at the same setting as usual, in this weather I am sometimes seeing flue temps as much as 50f higher than usual while the stove is cruising. So while my heat output is up, so is my heat loss... one of the things that frustrates me with a downdraft stove, because I think it is more prone to give heat up the flue than other EPA stoves might be.

 

[Seasoned Oak]

With my air control at the same setting as usual, in this weather I am sometimes seeing flue temps as much as 50f higher than usual while the stove is cruising. So while my heat output is up, so is my heat loss... one of the things that frustrates me with a downdraft stove, because I think it is more prone to give heat up the flue than other EPA stoves might be.

I get the most heat out of my downdraft harman. Seem like twice as much with the same size firebox. also the harman seems to burn the wood to a fine ash as opposed to lots of charcoal left over in the englander. Both stoves produce a hot flue pipe.

 

[branchburner]

Both stoves produce a hot flue pipe.

What do you see for flue temps with the two stoves?

I can only measure about a foot up (higher than that is up the chimney), and my single wall is running nearly 300f external right now, stove top cruising at about 500f with 1/4 air. That flue temp seems high to me, relative to what others report.

 

[saskwoodburner]

Yeah, and also the WIND seems to increase the draft as it zips across the top of the flue.
Unless that's just my imagination.

My little stove just gets up and goes with the cold weather. Funny you mention wind and increasing draft, as it seems to affect my draft depending which way it's coming from. Winds from the north and west are neutral, neither helping nor hurting regardless of outside temp. From the east the stove seems to be fighting it when the temperatures outside are warmer (flames flutter, going up, and washing back onto the logs). Winds from the south seem to help or turbo charge the stove. Still fairly new to this, could be a coincidence I suppose.

 

[realstihl]

My little stove just gets up and goes with the cold weather. Funny you mention wind and increasing draft, as it seems to affect my draft depending which way it's coming from. Winds from the north and west are neutral, neither helping nor hurting regardless of outside temp. From the east the stove seems to be fighting it when the temperatures outside are warmer (flames flutter, going up, and washing back onto the logs). Winds from the south seem to help or turbo charge the stove. Still fairly new to this, could be a coincidence I suppose.

Mine does the same thing except turbo charge is when the wind is NW.

 

[Wood Duck]

My draft is a lot better in cold weather than in less cold weather, and it makes my stove easier to adjust. I have to change the usual air settings for cold weather, but the better draft gives me a wider range of air settings - I get more air with the draft open and can still shut it down with the draft closed.

 

[begreen]

With 20 ft of flue on the T6 it performs well even with temps in the teens. I suspect that the harder control cases will also have tall stacks. Up to 25 ft or so should behave quite well.

 

[Seasoned Oak]

What do you see for flue temps with the two stoves?

I can only measure about a foot up (higher than that is up the chimney), and my single wall is running nearly 300f external right now, stove top cruising at about 500f with 1/4 air. That flue temp seems high to me, relative to what others report.

Sounds about right, both stoves in that range. It seems the downdraft harman radiates heat from the sides and back as well as the top and front ,were the englander mostly just the top and front. ANd its easier to pack the harman as its a top loader,with the englander your always mindful of hitting the burn tubes and damaging the fibre board on top.

 

[Seasoned Oak]

I like the fact that the flue is hot. I have an outside masonry chimney and i need to keep the flue hot so creosote dont form.

 

[shoot-straight]

i have mega-draft. 25' + of lined, insulated masoned chimney on a hilltop with nothing to block the wind. this is compounded when its cold and blowing like it is now. i dont even get an 8 hr burn from my bk on a med setting and thats WITH a pipe damper partially closed. i forgot to close the damper the other day and i came home from work to an almost empty firebox.

the idea of a barometric damper is good, especially for people like me, but they have too many downsides and their use is not approved to code in most areas.

 

[begreen]

Wind can present problems. On our old setup I had to close off the key damper completely to get good results.

What type of chimney pipe do you have? The cap style can help in windy areas. Selkirk's is pretty good. There is also the Vacu-Stack cap that is designed for high-wind problems, but that is more to stop wind-driven blowback.

 

[shoot-straight]

Wind can present problems. On our old setup I had to close off the key damper completely to get good results.

What type of chimney pipe do you have? The cap style can help in windy areas. Selkirk's is pretty good. There is also the Vacu-Stack cap that is designed for high-wind problems, but that is more to stop wind-driven blowback.

i assume you are asking me... no idea, its square with mesh on sides and SS top with 4 bolts to tighten. i googled "draft reducing cap" and couldnt find anything.

 

[begreen]

http://www.chimneycaps.com/

 

[F4jock]

I think everyone is seeing an increase in draw from their flues during these frigid weather periods.

Makes it harder to control the stove.

Isnt it the difference in temps that determine how much draw a flue has.

The stove is hot and outside its colder so more draw of the flue.

Temperature difference works with heat transfer also as how much heat transfer that's going on like between the stove top and the room or object or the air in the room.

Makes me think of voltage as its a measurement of potential difference.
So the more potential difference (voltage) the more current flows in the electrical circuit.

Ok I will quit rambling now.

Actually no. My Harman controls itself. Very windy and no problems at all.

 

[NinjaTech]

Over the last few weeks we have been averaging right about freezing, and it always runs about .10-.11 last night and tonight are going to be a lot colder. It was 8 out when i woke up this morning and it was running quite a bit more draft. Its pretty neat to see. The wind does have a pretty big effect, if its windy and gusty out the needle will jump all over like crazy. Its going to be 0 tomorrow morning, i'm curious to see what its pulling then.

 

[saskwoodburner]

Over the last few weeks we have been averaging right about freezing, and it always runs about .10-.11 last night and tonight are going to be a lot colder. It was 8 out when i woke up this morning and it was running quite a bit more draft. Its pretty neat to see. The wind does have a pretty big effect, if its windy and gusty out the needle will jump all over like crazy. Its going to be 0 tomorrow morning, i'm curious to see what its pulling then.

What may I ask is this device?

 

[NinjaTech]

Industrial vacuum gauge i hooked up as a draft gauge.

 

[shoot-straight]

http://www.chimneycaps.com/

everything i see is for down draft problems or increasing draft issues. i have neither. they have lots of caps though. the site is poorly organized.

 

[saskwoodburner]

Industrial vacuum gauge i hooked up as a draft gauge.

Well that's pretty neat NinjaTech.

 

[NinjaTech]

Well that's pretty neat NinjaTech.

If your curious, here is some pictures of how its installed, you can find those gauges on ebay for a decent price. They are magnehelic vacuum gauges, for a wood stove you will want to look for one thats about 0-.25 inches of water. Its pretty much the most sensitive one they make, if you have a longer pipe you may want to go 0-.5 so you don't peak out a .25. (mine is about 14 feet) Here are some pictures of how i installed it though if anyone wants to do something similar. They are not really designed for wood stoves so you gotta kinda get creative in hooking it up.

 

[saskwoodburner]

I think I'll look into that in the future.

 

[Slevys95]

Wind can present problems. On our old setup I had to close off the key damper completely to get good results.

What type of chimney pipe do you have? The cap style can help in windy areas. Selkirk's is pretty good. There is also the Vacu-Stack cap that is designed for high-wind problems, but that is more to stop wind-driven blowback.