Lennox Hearth B-MNC0353VDE - Manual (Page 15)

NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE. 15
Figure 28 - Rear Vent - THREE ELBOWS
Figure 29 - Top Vent - THREE ELBOWS
H1
V
V1
H
*Ceiling
Firestop/Spacer
(SV4.5VF)
**Wall
Firestop/Spacer
(SV4.5HF)
*Ceiling
Firestop/Spacer
(SV4.5VF)
*When using Secure Flex,
use Firestop/Spacer
SF4.5VF
**When using Secure
Flex, use Firestop/Spacer
SF4.5HF
V
H1
H
V1
*Ceiling
Firestop/Spacer
(SV4.5VF)
**Wall
Firestop/Spacer
(SV4.5HF)
*When using Secure Flex,
use Firestop/Spacer
SF4.5VF
**When using Secure
Flex, use Firestop/Spacer
SF4.5HF
TABLE C
H +H
1
Maximum H Maximum V Minimum
feet feet feet
5 (1.524) 2 (0.610) 1 (0.305)
10 (3.048) 4 (1.219) 2 (0.610)
15 (4.572) 6 (1.829) 3 (0.914)
20 (6.096) 8 (2.438) 4 (1.219)
V + V1 + H + H1 = 40 feet (12.2 m) Max
H = 8 feet (2.438 meters) Max.
H + H1 = 20 feet (6.096 meters) Max.
(meters) (meters) (meters)
Example: If 20 feet of (H) horizontal vent run is needed, then
4 feet minimum of (V) vertical vent will be required.
This table shows a 1 (V) to 5 (H) ratio. For every 1 foot of (V)
vertical, you are allowed 5 feet of (H) horizontal run, up to a
maximum horizontal run of 20 feet.
TABLE D
H + H
1
Maximum V Minimum
feet feet
5 (1.524) Elbow Only
5 (1.524) 1 (0.305)
10 (3.048) 2 (0.610)
15 (4.572) 3 (0.914)
20 (6.096) 4 (1.219)
H + H
1
= 20 feet (6.096 m) Max.
V + V
1
+ H + H
1
= 40 ft. (12.192 m) Max.
(meters) (meters)
Example: If 20 feet of (H) horizontal vent run is needed, then 4 feet
minimum of (V) vertical vent will be required.
This table shows a 1 (V) to 5 (H) ratio. For every 1 foot of (V) vertical,
you are allowed 5 feet of (H) horizontal run, up to a maximum
horizontal run of 20 feet.
An elbow is acceptable as 1 foot of vertical rise except where an
elbow is the only vertical component in the system. See Figure 34.
VERTICAL VENT FIGURES/TABLES
(continued)