Lennox Merit MLDVT-35NM-FB Installation Instructions Manual page 21

LENNOX HEARTH PRODUCTS • MERIT
Table 22: Top Vent—Two 90° Elbows
H + H Maximum
1
feet meters
3 0.914
5 1.524
10 3.048
15 4.572
20 6.096
V + H + H = 60 ft (18.3 m) maximum
1
H + H = 20 ft (6.096 m) maximum
1
Install the U-shaped vent restrictor in any vent run with more than 8 ft of
vertical rise (Figure 12).
Square termination (SV4.5HT-2) shown.
See Table 19 as an aid in venting component selection for a particular range of
exterior wall thicknesses.
If 20 ft of (H) horizontal vent run is needed, then 4 ft minimum of (V) vertical vent
will be required.
This table shows a 1 (V) to 5 (H) ratio. For every 1 ft of (V) vertical, you are allowed
5 ft of (H) horizontal run, up to a maximum horizontal run of 20 ft.
An elbow is acceptable as 1 foot of vertical rise except where an elbow is the only
vertical component in the system (Table 20).
Table 23: Top Vent—Three 90° Elbows
H Maximum
feet meters
5 1.524
5 1.524
10 3.048
15 4.572
20 6.096
H + H = 20 ft (6.096 m) maximum
1
V + V +H + H = 60 ft (18.3 m) maximum
1 1
Install the U-shaped vent restrictor in any vent run with more than 8 ft of
vertical rise (Figure 12).
Square termination (SV4.5HT-2) shown.
See Table 19 as an aid in venting component selection for a particular range of
exterior wall thicknesses.
If 20 ft of (H) horizontal vent run is needed, then 4 ft minimum of (V) vertical vent
will be required.
This table shows a 1 (V) to 5 (H) ratio. For every 1 ft of (V) vertical, you are allowed
5 ft of (H) horizontal run, up to a maximum horizontal run of 20 ft.
An elbow is acceptable as 1 foot of vertical rise except where an elbow is the only
vertical component in the system (Table 20).
SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
®
V Minimum
feet meters
Elbow Only
1 0.305
2 0.610
3 0.914
4 1.219
V Minimum
feet meters
Elbow Only
1 0.305
2 0.610
3 0.914
4 1.219
DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Wall Firestop/Spacer
SV4.5HF**
H 1
*When using Secure Flex, use
Ceiling Firestop/Spacer SF4.5VF.
**When using Secure Flex, use
Wall Firestop/Spacer SF4.5HF.
H 1
Wall Firestop/Spacer
SV4.5HF**
V 1
H
Wall Firestop/Spacer
SV4.5HF**
Ceiling Firestop/Spacer
SV4.5VF*
*When using Secure Flex, use
Ceiling Firestop/Spacer SF4.5VF.
**When using Secure Flex, use
Wall Firestop/Spacer SF4.5HF.
Ceiling
Firestop/Spacer
SV4.5VF*
H
Wall Firestop/Spacer
SV4.5HF**
V
V
21