Rob R. wrote:No need for that sort of thing with a Coal Gun. The output is fixed, and there is no timer. The boiler simply maintains a set temperature and runs the fan as needed to maintain that temperature. It is impressive how fast those units go from sleeping to a roaring fire.
Aside from a few ashing parameters, the only thing you can change on a Coal Gun is the boilers internal water temperature maintenance setting. Mine is currently set to turn the fan on at 170 degrees, and shut the fan off at 180 degrees. The 10 degree differential is fixed. If the L4006 aquastat that regulates this was to be replaced with an L6006 that had a variable differential, the fixed 10 degree dif could be modulated (expanded or contracted).
The Coal Gun gravity stokes via ashing. It is a lot like a fan assisted hand fed hopper equipped boiler that shakes itself down occasionally and automatically instead of having to be manually shaken. I have 250 lbs. of coal sitting in the hopper above my fire. As ashes fall out the bottom of the fire tube (the ash grate mechanism simply shaves them off the bottom of the fire tube via a knife edge that moves back and forth), fresh coal falls by gravity alone from the hopper into the fire tube. Nothing is hindering this fall. No flaps or cut-offs separate or isolate the coal in the hopper from the fire tube.