#1  
Old 07-22-2009, 03:51 AM
Serf
 
Join Date: May 2009
Location: australia
Posts: 7
Default Chimney Not Drawing Enough

hi guys,

just starting to use my barrel vault oven. I have gone through the curing fires with no real issues (some small cracks). my main concern is my chimney doesn't seem to draw enough of the smoke as it spills out the front arch.

I have made my chimney just outside of the door/opening. Im thinking of cutting out a small hole (size of half a brick) at the front end of the dome just above the door and feeding it to the chimney. Im hoping this will also help my fire to breathe as it appears to be choked by the excess smoke in the dome.
If i blast the fire with a hairdryer, it burns well, but soon after i move the dryer away it dies down again..

i will try and post a few pics of my oven. i will appreciate any feedback ond or advice on my situation.

EDIT: i also have a 3ft galvanized chimney flue which is detachable and is not in the pic
Attached Thumbnails
Chimney Not Drawing Enough-oven.jpg   Chimney Not Drawing Enough-oven-003.jpg  
Reply With Quote
  #2  
Old 07-22-2009, 04:23 AM
Apprentice
 
Join Date: Feb 2009
Location: Australia
Posts: 118
Arrow Re: Chimney Not Drawing Enough

Harrison
from your picture, it is obvious that your chimney void and size is way too small for your oven size.
Look at your opening closeup and you will see that the top 1/3 of the oven opening has smoke stain on it and all that smoke is expected to go up that little chimney hole.
I have a 40" Pompeii with a a stainless void the full width of the door 24" x 15" and funnels 18" up to an 8" round flue. No smoke exits my front arch unless I use the petrol leaf blower to change it from an oven to a bast furnace.
It should be easy to correct by cutting (or using numerous masonary drill holes through the bricks) and making the chimney entrance
hole double the size.
The fact that it is just an open hole and not a funnel shape, you will still get some, all be much less, smoke out of your front arch. I would also then make a plate to reduce the void size to fit your flue diameter but I would ensure that it was at least 8" or preferably larger. The larger your oven, the larger the chimney needs to be.

Rastys
Reply With Quote
  #3  
Old 07-22-2009, 04:34 AM
CanuckJim's Avatar
Il Pizzaiolo
 
Join Date: Jan 2006
Location: Prince Albert, Ontario, Canada
Posts: 1,480
Default Re: Chimney Not Drawing Enough

Harrison,

I have a barrel vault oven as well. The method and size of opening are basically the same as what Rastys used. I get zero smoke out the front, and the chimney draws like a locomotive. Suggest you do a search of the photo gallery for vent and chimney work by members. Rastys is right on in what he recommeds. However, three feet of pipe is not enough;should be above four for the best draw. Don't go cutting holes in anything; just make the vent area larger and taper it upward to where the flue begins.

Jim
__________________
"Made are tools, and born are hands"--William Blake, 1757-1827

Last edited by CanuckJim; 07-22-2009 at 04:38 AM.
Reply With Quote
  #4  
Old 07-22-2009, 08:08 AM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default Re: Chimney Not Drawing Enough

Quote:
Im thinking of cutting out a small hole (size of half a brick) at the front end of the dome just above the door and feeding it to the chimney.
This is a really bad idea. You wouldn't have built a barrel vault oven if you didn't want to do retained heat cooking, and this vent will suck all the heat out of your oven.
__________________
My geodesic oven project:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #5  
Old 07-22-2009, 05:42 PM
Dutchoven's Avatar
Master Builder
 
Join Date: Apr 2007
Location: Mississippi
Posts: 931
Default Re: Chimney Not Drawing Enough

Absolutely don't go cutting anything. When we built the barrel vault in our back yard I made a similar mistake. The vent opening to our chimney there is about 5 inches deep by nine inches wide so it appears to be about the same area as yours. Other than that is appears that the oven is a similar shape. We get some smoke puffing out the front but mostly in the beginning of the fire. I think you could get by with increasing the height of the chimney. I do think that the detatchable thing could be creating a problem as well in the sense that without a really good seal your flue could be acting like a mixing valve sucking fresh air in at the crack and thus slowing down the flue gases on the way up.
All the best!
Dutch
__________________
"Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that's creativity. " Charles Mingus
"Build at least two brick ovens...one to make all the mistakes on and the other to be just like you dreamed of!" Dutch
Reply With Quote
  #6  
Old 07-23-2009, 12:59 AM
Serf
 
Join Date: May 2009
Location: australia
Posts: 7
Default Re: Chimney Not Drawing Enough

thanks guys.. im going to try the longer flue first.. if thats a no go then im bringing out the angle grinder and widening the chimney to the width of the oven door..

im hoping this chimney fix will also take care of the smoke buildup inside.. im already in trouble for using the mrs' hair dryer to blast the fire..
Reply With Quote
  #7  
Old 07-23-2009, 04:30 AM
Apprentice
 
Join Date: Jul 2008
Location: Norway
Posts: 120
Default Re: Chimney Not Drawing Enough

Remember that even with a higher (longer) chimney (which should help a lot) it needs to heat up before it works properly. I suggest that you prime your flue gas stack by starting a small fire just below the flue gas exit before you start your main fire in the oven.

Regards from Karl
Reply With Quote
  #8  
Old 07-23-2009, 06:56 AM
BurntFingers's Avatar
Apprentice
 
Join Date: Jun 2009
Location: Ocean County New Jersey
Posts: 137
Default Re: Chimney Not Drawing Enough

Keep it hot and make it 3X to 4X higher then it will draw like a factory.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Chimney options Yahoo-Archive Design Styles, Chimneys and Finish 3 10-01-2010 11:18 AM
Shape of a brick chimney Jochen Design Styles, Chimneys and Finish 2 06-13-2010 05:16 AM
Chimney transition Wiley Design Styles, Chimneys and Finish 5 05-20-2008 10:25 PM
Chimney / Flue Question.. johnrbek Pompeii Oven Construction 1 02-20-2007 04:07 PM
Flue Chimney Tips Alf Design Styles, Chimneys and Finish 1 08-02-2005 08:07 AM


All times are GMT -7. The time now is 01:45 PM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC