Un-Burnt Coal, Fire Goes Out

My fire is hot for 4 hours, then everything gets really red hot, then the fire goes out. Lots of half-burnt coal. I have adjusted my drafts from wide open to closed a little. I start my fire with charcoal and when there is a red bed, I add coal to cover the coals, I then keep adding when the coal is red. I top it off before bedtime, banking it up on the sides.
I have a really old Glenwood #10 cylander stove.
Using coal from Agway.
Any ideas what I am doing wrong.
When this baby burns, it is the best most even heat I have ever seen, I just need to figure out why she goes out.
Thanks
Chris in New Hampshire

Are you dampering down too much before bed? It sounds like air starvation. A roaring fire does not just "poof" go out if all elements necessary for combustion are present. I'm not an expert on your style of stove though; maybe someone else can assist?

What do you have for a chimney? Any idea how strong the draft is?

retire2017 wrote: I start my fire with charcoal and when there is a red bed, I add coal to cover the coals, I then keep adding when the coal is red. I top it off before bedtime, banking it up on the sides.

You are not burning wood, fill it completley once you have a good fire established. Open the ash door and rev the fire up before you shake it down well before bed and refill it. Do not attempt to run it with a small load of coal, coal burns in stages. If the top layer is burning, you are at the end of the coal fire. Don't wait that long, keep it full. You may want to try mounding in the center and stay away from the sides.