Yes, your stove is over drafting... Blame the EPA, NFPA, UL and stove Manufacturer jackwagons!

brenndatomu

Minister of Fire
Aug 21, 2013
6,051
NE Ohio
No a bd is not meant to reduce draft by reducing flue temps. It reduces draft by introducing dilution air. This weakens the vacuum. Yes currently it also reduces the flue temps because the dilution air is cool. It would be just as effective with hot air
I have experimented with room air for the BD, vs air from direct connect OAK...the damper opens less, to do the same job, when using the OAK.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,597
central pa
I have experimented with room air for the BD, vs air from direct connect OAK...the damper opens less, to do the same job, when using the OAK.
Yes I am sure cooler air does reduce draft a bit more than heated air. But using cool air presents more serious problems in most cases.
 

ABMax24

Minister of Fire
How much more? Does that small ammout of lost heat. Which honestly would only be a couple percent really justify the cost complexity and maintenance involved in adding electronically controlled damper or air intake? I don't think so at all.
Judging by that chart I posted 5-10%. But it wouldn't have to be electronic, a manual flue damper could do the same thing, no?

I do like the idea of electronic control. But fundamentally I'm opposed to barometric dampers, to me almost any other solution is better than that.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,051
NE Ohio
But using cool air presents more serious problems in most cases.
I'm sure it does...my comment was directed toward your earlier statement that "it would be just as effective with hot air"
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,597
central pa
I'm sure it does...my comment was directed toward your earlier statement that "it would be just as effective with hot air"
Ok so my statement there wasn't accurate. But heated air will still be very effective and won't cool the fluegases
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,597
central pa
Judging by that chart I posted 5-10%. But it wouldn't have to be electronic, a manual flue damper could do the same thing, no?

I do like the idea of electronic control. But fundamentally I'm opposed to barometric dampers, to me almost any other solution is better than that.
Can you show us where you got that chart? I really don't think it is referring to what you think it is referring to
 

ABMax24

Minister of Fire
Can you show us where you got that chart? I really don't think it is referring to what you think it is referring to
It's a chart for natural gas appliances, I can't find one for wood. But gives an approximate idea of heat loss in regards to stack temperature and excess combustion air.

This is very similar to the stack-loss method used to calculate wood stove efficiency.

 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,597
central pa
It's a chart for natural gas appliances, I can't find one for wood. But gives an approximate idea of heat loss in regards to stack temperature and excess combustion air.

This is very similar to the stack-loss method used to calculate wood stove efficiency.

Yeah that chart is talking about extra air in the combustion chamber for natural gas. Not at all referring to air introduced into the smoke stream
 

ABMax24

Minister of Fire
Yeah that chart is talking about extra air in the combustion chamber for natural gas. Not at all referring to air introduced into the smoke stream
Yeah I was talking about extra air in the firebox from overdraft, in particular the secondary tubes. Not extra air added to the flue.

But I see where I went wrong, I got mixed up in the mess of posts.
 

SpaceBus

Minister of Fire
Nov 18, 2018
5,453
Downeast Maine
Maybe the better thing to do would be to approach the legislature to try and legalize key dampers for installs that require it. Perhaps make the wording of the law require a certified sweep to come out and do measurements? We are already talking about a niche of a niche, so maybe it doesn't even matter.
 

john26

Feeling the Heat
Oct 27, 2008
463
Wildwood MO
would this work if you had an oak kit to install it on?
never mind draw through stove would be the same
 
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begreen

Mooderator
Staff member
Nov 18, 2005
86,564
South Puget Sound, WA
FWIW, I notice that the Jotul F500v3 manual specifically recommends adding a butterfly damper to the stovepipe if the draft is strong.
 

orlkc

Member
Nov 9, 2017
64
Eastern MA
Same with the F45 manual
I looked at the hearthstone manuals -- same. The older 8022 version talks about installing a damper if the draft measures more than 0.1" wc. I also looked at the newer EPA 2020 version (8024) and I see the same recommendation. The wording changed slightly, but not the overall message.
 

BKVP

Minister of Fire
All stove manuals should include information like this considering how many houses have over 25' chimneys.
How many? %?
 

SpaceBus

Minister of Fire
Nov 18, 2018
5,453
Downeast Maine
I'm also curious. 20'+ is pretty easy on a two story house. Our cheap little saltbox has a 24' flue so to my perspective they seem common. Most houses I've lived in have been of modest price and also two story. I know objectively that ranch style homes are common and popular, but I have no first hand experience.
 

begreen

Mooderator
Staff member
Nov 18, 2005
86,564
South Puget Sound, WA
How many? %?
It would depend on the region, maybe 50% or more in regions that wood heat? Ranch style houses seem to be a bit more common out west. FWIW, I have never lived in a one-story home except for one cold winter in a shack in New England.

In 1973, one-story homes made up 67% of new-home construction. That declined to 43% in 2006, before reversing course and rising to 46% in 2011, said Stephen Melman, director of economic services for the National Association of Home Builders, citing U.S. Census information.
 

john26

Feeling the Heat
Oct 27, 2008
463
Wildwood MO
I have a two story with two chimneys one is 29'3" the other is 19'3" 29'3" has some over drafting 19'3" is hard to establish a draft with a new fire but that may be the insert.
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,051
NE Ohio
We have one that is ~27' and one that is ~18'.
Might be interesting to do a poll thread of heights...
<15'
15-20'
20'-25'
25'-30'
30-35'
35'+
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
23,597
central pa
Now mine is either 19 or 21 feet I can't remember. My old house was about 38
 

john26

Feeling the Heat
Oct 27, 2008
463
Wildwood MO
So I experimented with my Lope freedom that runs on the 29' chimney last night. We had a few warm days here so I checked door gaskets with a dollar all was good. I then added a second fire brick above the baffles centered in the stove in line with the flu outlet blocking 9" of the smoke path. This stove has a bypass so start up was unchanged after I established a good fire (bypass closed) I started cutting back the air. I noticed the controls are touchier but the fire seemed slow down more at low burn very lazy flame down low but still good secondary's. The secondary flames seemed to linger and swirl more in the fire box more glowing on the secondary tubes. I did notice a little more soot on the window in an odd 3 circular pattern. I reloaded round 9.m. and cut the air back all the way. I reloaded at 4:30 a.m. this morning more coals than normal. a few logs intact just as coals usually they are broke down a lot more. The window seemed vary typical of over night burn some had burnt off from last night but was spread more evenly across the window.
I know this will probably void the UL listing and maybe an EPA violation punishable by death but I do think my burns did extend some maybe 1 hr? The wife says she will let the fire go until I get home "its hot in here" her I deal temp is 80F. The air was fully cut back at 5a.m. I did use a light weight pumice brick I may replace the rest of them in the baffle with pumice type.
 
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Nate R

Member
Nov 5, 2015
43
Wisconsin
Might be interesting to do a poll thread of heights...
<15'
15-20'
20'-25'
25'-30'
30-35'
35'+
I agree, that might be interesting to know how it's distributed.

How does one measure that? is it from the floor level the stove is on, or the exit height of the stove? I mean, that's a ~ 2 foot difference, but when you start talking about minimum stack height, that can matter.
 

john26

Feeling the Heat
Oct 27, 2008
463
Wildwood MO
My measurements are the actual length of the liners.
 
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brenndatomu

Minister of Fire
Aug 21, 2013
6,051
NE Ohio