I dont have that stove, but are you sure there is no doghouse opening? When i first started using my stove, i thought the air only came in through the top of the glass as well. Someone mentioned a doghouse air opening, some call it zipper. I have two 3/16" holes pointed right at the middle bottom of the bed. I found them, and have been experimenting ever since, plugging one with a bolt etc... The doghouse opening can really kill your burn times, especially with a string drafting chimney. Its basically a plasma cutter pointed right at the heart of the burn. it only gets worse when you close down the primary as the air has to come from somewhere.