Seems to be a wide range of temps being run..... So just curiouse what temps do you run up to (on a full load before cutting back) and where are you measureing? I have been trying to run about 400 on cooktop which gives me about 250 on stack.... stove tends to do whatever it wants that way. last 2 days try to get stack to 400 then cut back tends to work better... cooktop is about 550 or so from a low start. I also notice that primary air open I get lower top and higher stack temps...not sure why?
