Just to add to what I said in the other thread:
My particular set up has a 23' external masonry chimney on the east end of the house so keeping it warm and drafting is a constant challenge.
I run the a barometric damper because the house faces south and I am near the water so I get an occasional breeze that will pull hard on the stove and that's the type of thing that messes up burn times.
Right now, it's 57* outside and 74* inside burning nut coal at 3/4 turn open. I haven't touched the shaker handle in nearly 24 hours but I did through a couple shovels in around midnight last night before bed. I really ought to drag my lazy butt down stairs to tend it and turn the air back a bit because it's going to be warm today.
How often are you shaking the ash? I found that was one thing that really shortened my burn times. I wasn't letting that layer of ash to build up where it would just sit and idle.
I admit that with pea, you have to tend it a little more or it will choke itself out but with nut, let it go longer than what you had been doing.
I burn stove coal if it's really cold and the gaps in between those pieces are so big, it's almost impossible to choke it out with ash.
Another thing I do is to take the ash pan out when I'm running. I only put it in there if I'm going to shake the ash. The area below the fire is equivalent to your lungs. It's how you take in air. And if your lungs are half full of crap, how well do YOU operate?
Plus, I don't like the idea of the pan acting like a baffle right behind the intake. I know it operates with the pan in there, but with this chimney, I need an unobstructed air path to keep things moving.