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We replaced the raincap on our outdoor flue with a Tee and 2 elbows (cowl) to combat downdraft but we had major downdrafts & smokeback this morning with our heater.

What have other folks who live in wind prone areas done to combat downdraft? What can we do to ameliorate this problem?

This heater is largley based on donkey's 6" dragon burner except our core is comprised of firebricks (rather than the dragon core) surrounded by perlclay insulation encased by 30g barrel surrounded by 55g barrel.
Thanks

You will probably solve your problem instantly by just putting another section of chimney on it and getting it 2' above the highest peak in the roof.

I would agree with Matt. In order for a chimney to draw properly it should extend 3 ft from the roof line and be at least 2 ft taller than anything within 10 ft. Here is a link that gives a little more detail:

thanks for your replies.

would extending the chimney like you're suggesting eliminate downdrafts / smokeback on windy days with this kind of rocket mason heater ?

we have a wood stove with a flue that is 5 feet over the ridge of the roof that is affected by downdraft on windy days so we are concerned that even with a comparable flue for this heater that the smokeback problem would persist.
our home sits just north of a wall of huge evergreens so the winds drop down from over the trees onto our home.
since the wood stove is sealed, the downdraft will be a problem mostly if it's happening when we're starting the fire but we can just close the door of the stove to prevent filling the home with smoke.

however, the downdraft causes a gush of smoke & flames to come out the feed tube. how do you stop that?
my R lung still hurts from it.

It can't work the way you have it now, so you've got to get up above the peak regardless. If the tree line is causing downdrafts, that will continue to be the case when those conditions persist. You would do well to get yourself a proper cap that can help with that. You still need to get above the peak, but it will help when the trees cause problems. Here's the two I like....

http://www.chimneycapsource.com/stormshield.htm

http://www.chimneycapsource.com/vacustack.htm

I have seen something similar to the VacuStack cap before. The one I saw was shaped more like a "V" on a swivel kinda like a weather-vane. The guy that I saw using it said it worked real well until the creosote buildup would stop it from spinning into the wind. But you should not have that problem with a RMH.

I'm surprised because with all the wind I have, I have never run into any down draft issues. A testament to my inexperience, I suppose.

I don't know what this is, but it was on some 6" pipe I salvaged from the steel yard a couple years ago. I always imagined it was for some kind of downdraft issues...

I want to extend the flue but have been tentative because we don't want to draw the attention of neighbors for potential complaints.
I live on a suburban street. I researched local codes & ordinances but couldn't get clear answers on what the ramifications would be if neighbors complained and alerted the code officials.
I anonymously emailed the county but didn't get answers and don't want to draw unwanted attention. I dont want the county to fine us for not having a permit. Could they force me to disassemble & remove it as it's not an approved heating apparatus?

How did/do you deal with this concern?

My home already had a wood stove and masonry chimney. I do not know what to tell you, it depends on your neighbors, your state, your county/city, etc. What state are you in?

WA, like you : )