I load mine every 12 hours on a nice bed of coals, i wouldnt say there are too many, but plenty. stove top is at 275-300 after 12 hours. i let the fire get going really well with air at 1/2 closed on reload. Stove top temp doesnt climb much at all until i engage the cat. than it climbs up to the 450ish range. when i close the cat all flames go away for probably an hour or so. they than return after a bit and when i get up in the middle of the night they are dancing in the firebox lazily. slow 1, with the ash pan im guessing you dont have any ashes left over in your firebox??? i always leave a fair amount of ash in the bottom of my stove (no ashpan) to "insulate" the coal bed. This seems to really work well. If i run stove empty of all ash i dont get the longer burn times. Im going to see how long it will hold coals for relight this weekend. im guessing easily 16-20 hours with stovetop temps around 250 id say. im burning kinda junky hardwood with mixed poplar for shoulder season. I swear, this thing still burns forever even with chunks of light poplar mixed in. really is amazing! i kinda doubt you have air leak issues.