Large stove how low

I have been reading this forum for several weeks now, my wife posted about the Harman XL Hearth Hero which we purchased ( $400 with a ton of coal ) figured how could I go wrong.

Anyway like most guys the small stove is cool and all but I have been wondering about the larger ones ( think harman sf-250 or harman mark 3 ), and my question is this how low can you burn these,ie can I fully load the stove with an established bed of coals and dampen down the air intake to result in say 10K-15K btu of output and still have the fire keep burning???

If I'm understanding your question, you are asking if you can keep a full, large stove burning at a low temperatures & the answer is absolutely, providing that your stove is air tight or close to it. Unlike wood, a coal fire's heat is not totally dependent on the amount of coal you have burning but rather by the amount of air you provide it. (assuming at least a minimum amount of coal in a deep bed of course) A leaky stove does not give you this control, but a good tight one does. I burn my Harman TLC2000 regularly at (stick on) thermometer temps of 120*-140* with ease when it is not real cold out.
At these low temps you'll burn allot less coal & have to service the appliance less often. Keep in mind that when you are burning very low fires, you also will have less chimney draft & are really working at the edge of your appliances working envelope. It's easy to lose a fire like this, but experience helps allot.(also one of these helps http://www.4thegrill.com/mavet73.html It remotely alarms if your stove gets to hot or gets to cold)

Thats exactly what I wanted to know, I am sure the smaller stove we have will heat our house fine but the firebox is real small for burning wood ( which we have plenty of ) so I was looking at getting a larger stove at some point next year. I just don't want to be in the position of having to run something like a harman sf-250 at a miniumun of 30k btu on coal for warmer days, for wood I have no concerns about its size.

I have read where some people reduce the size of the firebox, and didn't understand why if they can adjust the air intake for a lower burn rate.

The problem with burning too cool a fire is what Richard mentioned,, the draft in the chimney gets pretty weak with so little heat leaving the stove.. So if the draft gets too weak, you will lose the fire.. it is a balancing act.

Reducing the size of the firebox allows a smaller but hotter, more vigorous fire to be burnt which keeps the draft more regular.. If you have a really tall chimney often the draft is not a problem..

Greg L.

I doin't have time to do a search right now, but last winter there was a thread devoted to just this topic. I think it was titled "How low can you go??""...or something like that.... & members reported some amazingly low stack temps in warmer weather.
As I said, & as Greg explained, with such a weak draft from your chimney, these low temp fires can be tricky to maintain & require a pretty air-tight stove, but we do them all the time!
Good luck!