Flue has trouble drawing when it's windy.

[lwood]

Here is a pic of my flue. The light is not good but you can see the cap. Maybe I will take another pic this afternoon.

[brickie in oz]

I tried to enhance the picture in Photoshop but couldnt, a wider pic with the roof in it too please.

[lwood]

A few more pics, even got out the telephoto. Still no light. on pic 023 you can see a faint line of the top of the flue under the cap. It looks to me, if I put a vertical guard (a peice of sheet-metal) on the windward side btw the cap and the top of the flue, it might help. Also raise the cap up...but how much?

[brickie in oz]

The pics are all still to dark to really tell, but pic 1 shows that the flue is too low to the adjacent roof.

As a rule of thumb you need to be at least above the measurements in the pic.

[brickie in oz]

Originally Posted by lwood

Also raise the cap up...but how much?

As much as you can, if you have a really big cap the rain wont get in and the wind will blow the smoke away, assuming you are above the down draft zone in the pic.

[lwood]

Okay, been thinking about making it to the top of the ridge.

[brickie in oz]

Cool, keep us informed.

[mickyD]

Gulf,

Tried your method of heating the flue before start up, only took about 30 seconds with a few pieces of scrunched up newspaper then started the main fire. There was no smoke coming out the front at all during start up. There was no wind that day though. Can’t wait to try it on a windy day.

Cheers,

Mick

[Gulf]

Mick,
I thought of something else that might help. My experience with preheating chimneys is with fireplaces and it does work. In a fireplace you are preheating directly above the kindling which you are going to light. With an oven (which I have no experience to date) the interior arch is lower than the apex of the oven. On a very windy day after lighting the kindling in the oven you might want to return to the flu and keep a flame there a few more seconds until the oven fills up and starts wafting out of the interior arch. It should follow the draft created by the preheated air. That should do it.

I just remembered another time when this method failed me miserably, though:

Most chimneys that I was familiar with growing up did not have caps or spark arrestors. Every spring you were supposed to send the most expendable male child up on the roof to place an asbestos shingle (another story) and a couple of bricks to keep it in place. For some reason my dad always sent me Every fall that same child (if he did not slide off of the tin roof in the spring) was supposed to venture back up there and remove the shingle.

If for some unexplained reason the child (who forgot to place the asbestos shingle on the chimney in the spring told dad “yes sir” when asked “did you uncap the chimney?”,) was not exactly truthful: There might be a chance that chimney sweeps (the avian kind) could nest up in that chimney over the summer.

Damn, those things can create a down draft that no amount of preheating can overcome

[mickyD]

Hey Gulf, great story. Thanks for the advice. I’ll give that a go as well although the fire up the flue trick seems to be working a treat.

Cheers,

Mick