Okay - when my stove would reach a little over 600*, I'd basically turn into a worrying ball of nervousness (going above 600* 'seems' to be higher than this stove should run at, but....no actual numbers available from the manufacturer to indicate how hot is too hot). But.....during the past few days, with temps now in the single digits at night, my draft is strong and the stove, when completely shut down (and pipe damper basically closed) the stove wants to hit a peak of ~ 625-650 stove top. It's just how my stove wants to work. No cracked stones, no pile of rubble in the morning, just a warm house and plenty of coals for reload. So, unless I see a 7 in front of my stove top temp, I'm done worrying about getting above 600*. Time to just enjoy a stove that is pumping out some serious heat. Cheers!