For those interested, I had a small victory last night with the Jotul Oslo and got a 8.5 hr burn. I have not tried to push this in past and would typically get 3-5 hours burn time. I personally measure this time from the time I load up the stove to the time where the coals have burned down to a point where I know I could continue the burn by throwing more wood on (stove top corner was at 200 degrees at the end of the burn). Below is what I did different to get this burn time. This was based on bits and pieces of info I picked up here of course (Thanks). 1) I loaded the stove on a good bed of coals - approx 2-3" thick and red before pushing a good portion of them to the front. 2) I loaded a good 5" diameter round of birch to the back of the stove and then loaded three to four oak splits that were approx 3x4" on top and on the side of this round. I did keep it about 5" from the glass and about 2" below the burn tubes. I finally tucked a couple shorter pieces of wood at the end of the round and splits to fill the space on the end of the stove. I basically loaded it more than I normally would without stuffing the firebox full to the gills. 3) I then opened the primary air for about 20 minutes to get good flame in the stove and get the corner stove top temp to approx 450 degrees, then cut air to 50% for 15 min and then down to approx 20%. Hard to exactly say where I had the air at the end due to the "premadonna" air control lever and "slop" in it. I had a pretty good strong secondary burn coming from the back tube at the end of the air adjustment. The secondaries would occasionally dance down the face of the glass. This was all started at 10:00pm last night and at 6:30am this morn, the coals were looking good and strong and ready for another burn. I let the fire go out due to not having time to get one going before work. The glass on the stove had a slight dust on it with a little more brown along the lower edge of the door. This tells me I did not soot up the system.
Abbreviated version ==> fill the stove up good and plenty on a good bed of coals. Get the fire going good, but not too long and then cut the air back.
Abbreviated version ==> fill the stove up good and plenty on a good bed of coals. Get the fire going good, but not too long and then cut the air back.