Lennox Hearth Products MLDVTCD-35NE Installation Instructions Manual page 21

LENNOX HEARTH PRODUCTS • MERIT
HORIZONTAL VENT FIGURES / TABLES (CONTINUED)
H 1
Note - When using
Secure Flex , use
TM
Firestop/Spacer SF4.5VF.
When using Secure Flex,
use Firestop/Spacer
SF4.5HF.
Typical termination shown.
See Table 8 on Page 20 as an aid in venting
component selection for a particular range of
exterior wall thicknesses.
Figure 31
- Top Vent - TWO 90 DEGREE ELBOWS
SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS
®
Wall Firestop/Spacer
(SV4.5HF)
H
Wall Firestop/Spacer
(SV4.5HF)
Ceiling
Firestop/Spacer
(SV4.5VF)
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
H Maximum
+ H
1
feet (meter)
3 (0.914)
V 5 (1.524)
10 (3.048)
15 (4.572)
20 (6.096)
V + H + H
1
H
+ H
1
Example: If 20 feet of (H + H
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+ H
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 29.
Table E
V Minimum
feet (meter)
Elbow Only
1 (0.305)
2 (0.610)
3 (0.914)
4 (1.219)
= 40 feet (12.2 m) Max.
= 20 ft. (6.096 m) Max.
) horizontal vent run is needed,
1
) horizontal run, up
1
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