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Figure 26
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Figure 27
Example: A 20-ft horizontal vent run (H + H
1
)
would require 4.5 ft min. vertical vent (V + V
1
).
Vertical Termination System with Offset Vertical Venting using Three 90-Degree Elbows
Vertical Termination System with Offset Vertical Venting using Two 90-Degree Elbows
H max. V + V
1
min.
feet (meters) feet (meters)
10 (3.1) 2.5 (0.762)
15 (4.65) 3.5 (1.06)
20 (6.2) 4.5 (1.37)
V + V
1
+ H = 40 ft (12.4 m) max.
V + V
1
= 11 ft (3.3 m) min.
Example: A 20-ft horizontal vent run (H + H
1
)
would require 4.5 ft min. vertical vent (V + V
1
).
LENNOX HEARTH PRODUCTS • MONTEBELLO
®
SEE-THROUGH DIRECT-VENT GAS FIREPLACES (LSM40ST-N / LSM40ST-P) • INSTALLATION INSTRUCTIONS
V
H
1
H
V
1
Vertical
Firestop/Spacer
(SV8BF)
Horizontal Firestop/Spacer
(SV8HF4)
H
V
V
1
Vertical Firestop/Spacer
(SV8BF)
*
*Install the provided Vent Restrictor (see Page 14).
*Install the provided Vent Restrictor (see Page 14).
*
VERTICAL TERMINATION SYSTEM
FIGURES AND TABLES
Secure Vent™ rigid vent pipe and termination
components are shown in the figures.
Note: Two 45-degree elbows may be used
in place of one 90-degree elbow. If using
45-degree elbows, follow the same rise-to-
run ratios as shown for 90-degree elbows.
H + H
1
max. V + V
1
min.
feet (meters) feet (meters)
10 (3.1) 2.5 (0.762)
15 (4.65) 3.5 (1.06)
20 (6.2) 4.5 (1.37)
H + H
1
= 20 ft (6.2 m) max.
V + V
1
= 11 ft (3.3 m) min.
V + V
1
+ H + H
1
= 40 ft (12.4 m) max.
NOTICE:
Secure Vent Vertical Firestop/Spacer
(SV8BF) must be used anywhere vent
pipe passes through a combustible
floor or ceiling. Secure Vent Horizontal
Firestop/Spacer (SV8HF4) must be used
anywhere vent pipe passes through a
combustible wall.
It is important to install horizontal runs
on a steady, (i.e., no “dips”), slightly
positive incline of approximately 1/4
inch rise-per-foot (20 millimeters
rise-per-meter) horizontal, in a direc-
tion away from the fireplace. (Slightly
smaller rise-per-foot run ratios are
acceptable.) Use a carpenter’s level to
measure from a constant surface, and
adjust support straps as necessary.
Ceiling
Firestop/Spacer
(SV8BF)
60 ft (18.3 m) max.
6 ft (1.83 m) min.
Vertical Termination System
with Straight Vertical Venting
Figure 25
*Install the provided Vent Restrictor
(see Page 14).
*