Expert: Bart Ogden - 5/5/2005

Question
I just had a screen porch built with a full sized outdoor brick wood burning fireplace.  It works great with a super hot fire and ZERO wind.  Once the wind blows(even a little) or the fire cools down the smoke fills the room.  The fireplace is not drawing at all.  My contractor thinks the fireplace is built correctly and he is now saying that maybe it is because the room is open.  

I need to know where I can read more about fireplaces.  Or if I can send in pictures and/or deminsions to someone for help..  I have a lot invested in this and need a solution.


Another solution my contactor came up with was a fan in the chimney to help it draw.  What is your opinion on this?  Is that a standard solution for an outdoor fireplace?  Do you have any other recommendations?

Pleas help!

Thank you,
Michael  

Answer
Hi Michael,

The main force that "runs" a fireplace is draft.  Draft is the difference in pressure between the bottom (firebox)and the top (cap).

Pressure differentials can be created several ways, but with a fireplace it's mainly the difference in temperature between the bottom and the top.

Fireplaces operate on a relatively low draft, but a relatively  high flow.

You mentioned it works good with a super hot fire and zero wind.  The super hot fire would create a temperature differential between the bottom and the top, thereby creating draft.  An outdoor fireplace is a tough beast to get working correctly because of the problem with temperatures being the same at the bottom and the top.  

What is the opening size of the fireplace and the inside diameter of the flue tile? Also, how tall is the chimney from the base of the fireplace where you build the fire to the top?  Please send this information and pictures to me at bart@homesafeks.com and I'll see if we can't work through some solutions on this. I'd also like to see a picture of the fireplace in relationship to the surroundings (house, trees, etc.)

Sincerely,
A. Bart Ogden, President
Home Safe Hearth & Chimney
Wichita, KS
Voice: 316-265-9828
Fax: 316-265-9890
www.homesafeks.com