Note: No ashing can occur unless both the fan motor is running and the Anthrastat switch has closed.
Note: The volume of fresh coal added on top of the fire is equal to volume of ash displaced from bottom of the fire.
Note: AA's can and do have puff backs if not properly adjusted.
For the AHS this becomes:
No ashing can occur unless both the fan motor is running and the temperature of the ash grate is 10 degrees below the setpoint for the LC.
The volume of fresh coal added on top of the fire is equal to volume of ash displaced from bottom of the fire.
AHS's can and do have puff backs if not properly adjusted.
The lower the setpoint on the LC (the temp selected for ashing initiation), the higher the fire resides within the tube.
And likewise the higher the setpoint on the LC, the lower the fire resides within the tube.
The proper settings for the LC in all cases being highly dependent upon the ash content of the coal.
Perhaps the problem is compounded for the AHS by the manual insisting that the LC setpoint be maintained at (from memory here) between 140 degrees and 120 degrees. This narrow range of temperature setpoint options may not be sufficient to cover all of the various coals available.
NOTE: Before AHS settled on the Love Control (LC), I believe they used a similar Fuji supplied temperature control, but that probably changes little here. And before that they used a timer to initiate ashing. The timer counted time only while the fan was running. After so many minutes of fan operation (cumulative over multiple fan on/off cycles) you got so many minutes of ashing, with the times being user selectable.