The dryer flex duct is about 6" long and goes straight from the dryer to the wall connect. The vent piping is clean. Over the past three years this dryer was installed in two different houses where the dryer vents to the roof of the house vice out the side of the house. There is 1 90 and 1 45 degree bend in the piping. The dryer is only 4 years old. Could the length of the exhaust causing back pressure over heated or over worked the overload protector and made it weak? Should I replace it?