Newbie here: what would make our used Whitfield only run on setting 5? When set on 5 we have the damper completly open and it runs beautiful but the house is heating up to 80 degrees by 3:00am.... When we try and put it down to setting 1 the fire always goes out, do we have to have the damper all the way closed on setting 1? We have put on an OAK, a new gasket for the combustion, new auger endplate with a new bushing. Thanks all.