I run on high 24/7. 8" should be the peak flame height. I can't seem to get in the range o 4 - 8 any longer. It's more like 4 - 10 or 12 and my feed gate is closed almost all the way. I don't want to close any more to guarantee good starts. With my stove being in the basement I set the tstat, (which is also in basement), to give a comfortable temperature on the 1st floor, this seems to work well. Maybe a small fan blowing into the area where the tstat is will help it cycle better.