Put a load on the boiler and make the stoker run for 30 minutes...the fire should be roughly the same size as the grates. If it is smaller, decrease the air slightly (0.5 or so) and do another test burn. If you observe burning coal on the burner ring (cast iron ring around the top of the grates), increase the air slightly and go from there.
As for "getting old fast", setting up a new stoker with an unknown coal source is trial and error.
Last edited by Rob R.
on Tue Jan 22, 2013 3:21 pm, edited 1 time in total.