I have a fireplace extraordinaire 44 elite which says it will heat roughly 3000 ft.². I’m very happy with the performance but wish that I had the option of turning the fan speed up by about 50% when I’ve got a nice fire going. It is 388 CFM but runs very quiet and I feel I could easily use 500 to 600 CFM when burning a hot fire. How can I change out the fan box for one with greater capacity?