Lennox MPD Series User Manual

17
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT PLUS
®
DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • INSTALLATION INSTRUCTIONS
Figure 28: Rear Vent—ONE 90-DEGREE ELBOW
Figure 27: Top Vent—STRAIGHT
Figure 29: Top Vent—TWO 90-DEGREE ELBOWS
VERTICAL VENT FIGURES/TABLES
Note: Secure Vent
®
(rigid vent pipe) is
shown in the fi gures; Secure Flex
®
(fl exible
vent pipe) may also be used.
Note: It is very important that the horizontal/
inclined run be maintained in a straight
(no dips), slightly elevated plane. The
recommended incline is approximately 1/4 in.
per foot (20 mm per meter) horizontal, in a
direction away from the fi replace. The rise per
foot run ratios that are smaller are acceptable
all the way down to at or near level.
Note: SV4.5VF (Secure Vent), SF4.5VF
(Secure Flex
®
) fi restop/spacer must be
used anytime vent pipe passes through
a combustible fl oor or ceiling. SV4.5HF
(Secure Vent), SF4.5HF (Secure Flex
®
)
fi restop/spacer must be used anytime vent
pipe passes through a combustible wall.
Note: Two 45 degree elbows may be used in
place of one 90 degree elbow. The same rise
to run ratios, as shown in the venting fi gures
for 90 elbows, must be followed if 45 degree
elbows are used.
Note: An elbow is acceptable as 1 foot of
vertical rise, except where an elbow is the
only vertical component in the system. (See
Figure 36 on Page 21).
A Vent Restrictor, as shown in
Figure 17 on Page 13, must be used in
this application.
This table shows a 1 (V) to 2 (H) ratio.
For every 1 foot of (V) vertical, you are
allowed 2 feet of (H) horizontal run, up
to a maximum horizontal run of 8 feet.
Example: If 8 feet of (H) horizontal
vent run is needed, then 4 feet
minimum (V) vertical vent will
be required.
TABLE A
H Maximum V Minimum
feet feet
2 (0.610) 1 (0.305)
4 (1.219) 2 (0.610)
6 (1.829) 3 (0.914)
8 (2.438) 4 (1.219)
V + H = 40 feet (12.2 meters) Max.
H = 8 feet (2.4 meters) Max.
Ratio V to H ratio is 1:2
(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 36.
Note: Install the U-shaped vent restrictor
in any vent run with more than 8 ft of
vertical rise (See Page 13).
TABLE B
H Maximum
V Minimum
feet
(meters)
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)
V + V
1
+ H = 40 feet (12.2 m) Max.
H = 20 feet (6.096 meters) Max.
(meters)
WARNING
Under no circumstances, may separate sections of concentric fl exible vent
pipe be joined together.
Max. 40 ft
(12.2 m)
*When using
Secure Flex, use
Ceiling Firestop/
Spacer SF4.5VF.
Ceiling
Firestop/
Spacer
SV4.5VF*
V
H
Ceiling
Firestop/Spacer
SV4.5VF*
*When using Secure Flex, use
Ceiling Firestop/Spacer SF4.5VF
H
V
V1
Ceiling
Firestop/Spacer
SV4.5VF*
Wall
Firestop/Spacer
SV4.5HF**
*When using Secure Flex, use
Ceiling Firestop/Spacer SF4.5VF.
**When using Secure Flex, use
Wall Firestop/Spacer SF4.5HF.
Note: Install the U-shaped vent restrictor in
any vent run with more than 8 ft of vertical
rise (See Page 13).

Lennox MPD Series Specifications

General

Brand	Lennox
Model	MPD Series
Category	Indoor Fireplace
Language	English