We replaced a Jotul Castine with a Hearthstone Heritage and used the same six inch flue double walled pipe. The length from stove to rain cap is 24 ft. We did not have a damper control with the Jotul and are wondering if installing one with the Heritage is a good thing to do. Stove temps are about 425 dampered down but the flue pipe seems to be much warmer [hotter] than with the Jotul. Input?...thak you.