LsFarm wrote:Now: this may be the real problem: you have a lot of sections in that ornate stove, and each section is sealed to the next, making a stack of iron cylinders, all sealed together at the joints.. a coal stove MUST have no air leaks letting the precious chimney draft leak into the stove except up through the coal bed.. I'm betting that you have a small leak here and there, around this door, this window, this plate, and the sum total of all the leaks is letting in too much air above the fire.
So what happens is that when the really hot fire starts to decline, there isn't enough draft pulling air through the bed of coals to maintain a hot fire, and the chimney cools some, further reducing the draft, and eventually the fire goes out. When you have a fresh fire with a clean grate, the airflow is less restricted, so you get enough air through the fire for awhile.
I think you may be right about this. Last night, I fed and 'watched' the fire closely, and shook down ash when the grates allowed. Most times, with a strong fire, I could hear the underfire draft pulling through the ashbox door.
I did NOT close the ashbox draft competely last night, and the fire was still going fine when I went to bed.
So either the grate clogged in the night or the overall draft pulling through the coal bed is just not adequate when the fire begins to taper off and the chimney cools.
It has always (of course) been just fine for a wood fire, and I've learned you could (judiciously) introduce secondary air anywhere on a stove you thought it useful. I've plugged one secondary draft, and I close the main secondary control on the fuel loading door when I'm done with wood and hoping to burn off the coal.
There are, I know, some (minor) additional leaks above the stove's main fire chamber and in at least one joint in the chimney. And yes, you're right the stove as a whole may be more than a little porous at the various joints.
I'm trying still another tack tonight, but likely won't load the coal bed deep.
I guess the only remaining question in my mind with respect to my half a**ed approach is whether - given sufficent temp and draft
- I should be able to expect even a small, shallow load of coal to burn completely?
That would surely help to know.