I have a Jotul F600 Stove. Had it for 6 years now and love it. There are 4 Flu bars inside the stove on the top with holes in them....When the stove is burning good it appears as though there are flames shooting out of the holes in the Flu bars. Kind of how my Barbecue grill looks in the summer time from the burners. Is that the smoke that is being produced and being forced back through and re-burned through those holes for a higher efficiency and effectiveness??? Usually has to be at least 500F for this to happen...Thanks....
The tubes introduce fresh superheated air that with the high temp in the top of the stove allow the smoke to burn.
And if you have the damper shut down most of the way, and those flames are rolling up top around those tubes but barely anything coming from the wood.... Your doing it all right!! Thats the sign of a nice long burn ahead..
That's the secondary air tubes doing their magic! I love watching the secondaries running, especially when the stove is good and hot and you shut the primary air waaaaay down. It's a sign that you've got good, seasoned fuel in the stove, as well.
