I have been absolutely thrilled about the heat output of the Harman Mark II i recently acquired. I couldn't ask for anything more, and my measly ~1400sq/ft home is heated well beyond it's needs in the coldest of days (near zero one night already). The questions I have had are about partially loading the stove to lower the consumption and heat output. On days when temps outside hit around 40 or more, the stove just puts out way too much heat. With the windows open and draft down to 1/3 turn, it can still hit high 80's/90's in the home if I'm not careful. I can't turn it down any more than that without ending up with large amounts of unburnt coal and just overall poor utilization of fuel.
I tried thinking about this a few ways. Maybe i could weld up a small stainless insert to contain the coal in the middle or to one side, but still leave an arc at the bottom for shaking. For one reason or another, most of my ideas never made it off the drawing board. Without a even bed of coals, the draft wouldn't work and the coal wouldn't burn. So that's when i cam up with the lazy man's solution. I have done this for 5 days straight now without losing the fire since our big snow storm. the home has stayed between 74-77 degrees with the windows shut most of the day and my consumption has dropped to +/- 15lbs a day of nut Blaschak.
I bank the coal against the left side since it seemingly shakes down more thoroughly than the right side does. I leave a thick bed of ash on the right half and actually shovel ash from the pan back into the top, just to keep the bed 3-4 inches deep to block the draft from bypassing the coal i want to burn. I bank the left side all the way to the top of the bricks in the morning and have gotten a 14 hour run out of it so far on average. A little more care needs to be taken when reloading as to not make a mess though. The stove is staying dustier inside and i expected that, but running it this way at 2/3 turn open has yielded exactly the results i have hoped for. The coal consumption is even lower than i expected as well. https://www.dropbox.com/s/n2iyz3yh9t6ob21/2013-02-13%2012.40.48.jpg
Does anyone have any ideas or comments on this for running a stove at a very low heat output? maybe i am doing this the wrong way, but i just couldn't figure out a way to run the bed full width without wasting a load of coal on the edges. Burning this way has allowed me to use every bit of coal since i put unburnt pieces that rolled away back on the pile during reload. It is dirtier than running it normally, but the head output has been perfect. seems to only burn half way into the pile and take all day to reach and ignite the top. going to try and let it go late tonight since it was tended at 4am this morning as a test.