I installed approx. 30' of 6" flexible duct work from the basement to the second floor. The heater has more then enough power to pump out the airflow but when the heat comes on there's very little air flowing from the vent. I thought I might have crushed the tube but I checked and everything seems to be comfortably loose and free so that's not the problem.
The only thing I can notice is that the first floor duct work on the first floor register's is probably 10" and my thought is that it takes up most of the air that could or would go to the second floor. Is there a damper I could buy for the larger tubes so that the air was forced to the second floor? Or is there a boaster blower or something?