Installation
900738-00 04/2017
Innovative Hearth Products
MHD35 Series Direct-Vent Gas Fireplaces
33
Table 20 - Venting Components Required for Various Exterior Wall Thicknesses, when using Typical Termination Kits
Vent Components Required
Exterior Wall Thickness
Termination Kit Only
6 to 9-1/4” (152 to 235 mm)
Termination Kit and 6” Vent Section (SV4.5L6)
10-3/4 to 14” (273 to 356 mm)
Termination Kit and 12” Vent Section (SV4.5L12)
16-3/4 to 20” (426 to 508 mm)
Termination Kit and Telescopic Section (SV4.5L12)
11-3/4 to 20” (299 to 508 mm)
Horizontal Vent Figures/Tables
NOTE:
Secure Vent
®
rigid vent pipe and terminal are shown in the fi gures. Secure Flex
®
fl exible vent pipe and
terminal may also be used.
NOTE:
Two (2) 45° elbows may be used in place of one (1) 90° elbow. The same rise to run ratios, as shown in the
venting fi gures for 90° elbows, must be followed if 45° elbows are used.
NOTE:
Maintain the horizontal/inclined run in a straight (no dips), slightly elevated plane. The recommended incline
is approximately 1/4” per 1 ft (20 mm per 1 m) horizontal, in a direction away from the fi replace. Smaller rise per
foot run ratios are acceptable all the way to at or near level. Use a carpenter’s level to measure from a constant
surface and adjust the support straps as necessary.
NOTE:
SV4.5VF (Secure Vent), SF4.5VF (Secure Flex) fi restop/spacer must be used any time vent pipe passes
through a combustible fl oor or ceiling. SV4.5HF (Secure Vent), SF4.5HF (Secure Flex) fi restop/spacer must be used
any time vent pipe passes through a combustible wall.
WARNING
Do not join separate sections of concentric fl exible vent together.
Table 21 - Rear Vent—No Elbows
See
Table 20
as an aid in venting component selection for a
particular range of exterior wall thicknesses.
Note: “H” is horizontal distance from rear of unit to outer wall
surface
Note:
When venting Rear Horizontal with slip collar and
termination only, install base vent restrictor with the
breakwway portion raised. On 33” Models, use the 3” base
at 6’ instead of the 2 1/2” breakaway.
**
When using
Secure Flex
, use
Wall Firestop/Spacer
SF4.5HF
.
When using Secure Flex
®
, use
wall fi restop/spacer SF4.5HF, and
install venting with a minimum of
12” rise.
H = 21” (533 mm) maximum
27-1/2”
(699 mm) to outside
of termination
Table 22 - Top Vent—One 90° Elbow, Elbow Connection at Fireplace
H Maximum
V Minimum
Wall
fi restop/
spacer
SV4.5HF *
When using Secure Flex
®
, use
wall fi restop/spacer SF4.5HF.
*
H
V
feet
meters
feet
meters
3
0.91
Elbow only
Install the U-shaped vent restrictor in any vent run with more
than 4 ft of vertical rise. See
Page 21
for more information.
See
Table 20
as an aid in venting component selection for a
particular range of exterior wall thicknesses.
NOTE: Only in top vent where elbow is connected at fi replace collar
is it allowed to count elbow as 1 ft. vertical (V) rise.
