Lennox Hearth MPD-35 Series Indoor Fireplace User Manual


 
14
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
40 feet
(12.2 meters)
Maximum
*Ceiling
Firestop/Spacer
(SV4.5VF)
*
When using
Secure Flex, use
Firestop/Spacer
SF4.5VF
Figure 26
- Top Vent - STRAIGHT
VERTICAL VENT FIGURES/TABLES
Note: It is very important that the horizontal/
inclined run be maintained in a straight (no
dips) and recommended to be in a slightly
elevated plane, in a direction away from the
fireplace of 1/4" rise per foot (20 mm per
meter) which is ideal, though 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) firestop/spacer must be used anytime vent
pipe passes through a combustible floor or
ceiling. SV4.5HF (Secure Vent), SF4.5HF (Se-
cure Flex)firestop/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 figures 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 35 on page 18 ).
Note: Secure Vent (rigid vent pipe) is shown
in the figures; Secure Flex (flexible vent pipe)
may also be used.
Example: If 8 feet of (H) horizontal
vent run is needed, then 4 feet mini-
mum (V) vertical vent will be required.
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 20 feet of (H) horizontal
vent run is needed, then 4 feet mini-
mum 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) hori-
zontal run, up to a maximum hori-
zontal 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 35.
A Vent Restrictor, as shown in Figure 14 on
Page 10, must be used in this application.
V
H
*
Ceiling
Firestop/Spacer
(SV4.5VF)
*
When using Secure Flex,
use Firestop/Spacer
SF4.5VF
H
V
V1
*Ceiling
Firestop/Spacer
(SV4.5VF)
**Wall
Firestop/Spacer
(SV4.5HF)
**When using Secure
Flex, use Firestop/Spacer
SF4.5HF
*When using Secure Flex,
use Firestop/Spacer
SF4.5VF
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)
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 FLEXIBLE VENT PIPE BE JOINED TOGETHER.
Figure 27
-
Rear Vent - ONE 90 DEGREE ELBOW
Figure 28
-
Top Vent - TWO 90 DEGREE ELBOWS