Full Product Manual
Calculating Duct System Length 
The recommended duct system is 6" (15.2 cm) round duct with a maximum 
length of 35 ft (10.7 m). For the best performance, use no more than three 90° 
elbows. 
To calculate the length of the system you need, add the equivalent feet 
(meters) for each duct piece used in the system. 
Duct Piece  6" (15.2 cm) Round 
45° elbow  2.5 ft (0.8 m) 
90° elbow  5.0 ft (1.5 m) 
Maximum equivalent duct length is 35 ft (10.7 m). 
Example Duct System - 6" (15.2 cm) 
90˚ elbow Wall cap
6 ft (1.8 m)
3 ft
(0.93 m)
Maximum length  = 35 ft (10.7 m) 
1 - 90° elbow 
1 – wall cap 
6 ft (1.8 m) straight 
3 ft (0.9 m) straight 
= 5.0 ft (1.5 m) 
= 0.0 ft (0.0 m) 
= 6.0 ft (1.8 m) 
= 3.0 ft (0.9 m) 
System length  = 14.0 ft (4.3 m) 
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