If you're only burning coal you don't need to worry about maintaining a certain flue temp. like you do with burning wood. Soot from coal isn't flammable like creosote from wood burning but you should check the chimney frequently to see how fast/much soot accumulation you get to be sure chimney doesn't get clogged to the point where draft is affected.
I don't get that much soot in my stoves or chimney in an entire winter so it could be the quality of the soft coal, the way you're firing stove or the stove design could be reasons for excessive buildup.
tractorboy13 wrote:Thanks I have a 9" or 10" diameter cement chimney. With 9" stove pipe to the in side. I have a 9" to 8" reducer and ordered a 7"to8" I'm thinking of running 8" from the stove to the chimney.
{Copied this post from other thread}
Did you go with 8 inch?
Edit: Oh, I just looked at the photo in the other thread....I remember now that you replaced an old furnace/stove with this one. Did you have lots of soot buildup in the old stove?