# Installation Instructions

13

Recommended Vent Length

A 3

1

⁄

4

" x 10" (8.3 x 25.4 cm) rectangular or 6" (15.2 cm) round

vent should be used.

The total length of the vent system including straight vent,

elbow(s), transitions and wall or roof caps must not exceed

the equivalent of 140 ft (42.7 m) for either type of vent. See

the “Recommended Standard Fittings” section for equivalent

lengths.

For best performance, use no more than three 90° elbows.

To calculate the length of the system you need, add the

equivalent lengths of each vent piece used in the system.

See the following examples:

3

1

⁄

4

" x 10" (8.3 x 25.4 cm) vent system = 73 ft (22.2 m)

total

6" (15.2 cm) vent system = 73 ft (22.2 m) total

If the existing vent is round, a rectangular to round transition

piece must be used. In addition, a rectangular 3" (7.6 cm)

extension vent between the damper assembly and rectangular to

round transition piece must be installed to keep the damper from

sticking.

A B

C

6 ft (1.8 m)

2 ft

(0.6 m)

A. One 3

1

⁄

4

" x 10" (8.3 x 25.4 cm) 90° elbow = 25 ft (7.6 m)

B. One wall cap = 40 ft (12.2 m)

C. 2 ft (0.6 m) + 6 ft (1.8 m) straight = 8 ft (2.4 m)

A B

C D

6 ft (1.8 m)

2 ft

(0.6 m)

A. Two 90° elbows = 20 ft (6.1 m)

B. One wall cap = 40 ft (12.2 m)

C. One rectangular-to-round transition piece = 5 ft (1.5 m)

D. 2 ft (0.6 m) + 6 ft (1.8 m) straight = 8 ft (2.4 m)