Installation
900738-00 04/2017
Innovative Hearth Products
MHD35 Series Direct-Vent Gas Fireplaces
27
9. Continue installation of horizontal/inclined sections
—Continue with the installation of the straight vent
sections in horizontal/inclined run. Install support straps every 5 ft (1.52 m) along horizontal/inclined vent runs
using conventional plumber’s tape.
Rise per foot run ratios are acceptable all the way to level. For best results, maintain the horizontal/inclined run in
a straight (no dips), slightly elevated plane of approximately 1/4” per 1 ft (20 mm per 1 m).
Maintain the required clearances to combustibles
(
Page 24
)
.
10. Frame the roof opening
—Identify the location for the vent at the roof. Cut and/or frame opening
(
Table 15
)
.
Table 15 - Roof Framing Dimensions
C
D
Pitch
C
D
0/12
10-1/2” (267 mm)
10-1/2” (267 mm)
6/12
10-1/2” (267 mm)
12” (305 mm)
12/12
10-1/2” (267 mm)
17-3/4” (451 mm)
11. Install the roof fl ashing
—Extend the vent sections through the roof structure. Install the roof fl ashing over the
vent section and position such that the vent column rises vertically (use carpenters level). Nail along perimeter
to secure fl ashing or adjust roofi ng to overlap the fl ashing edges at top and sides only and trim where necessary.
Seal the top and both sides of the fl ashing with waterproof caulking.
12. Install the storm collar
—Install the storm collar, supplied with the fl ashing, over the vent/fl ashing joint
(
Figure
26
)
. Loosen the storm collar screw. Slide collar down until it meets the top of the fl ashing. Tighten the adjusting
screw. Apply non-combustible caulking or mastic around the circumference of the joint to provide a water tight
seal.
Figure 26 - Installing the Storm Collar
Figure 27 - Installing the Vertical Termination
Storm
Collar
13. Install the vertical termination
—The fi nal step involves installation of the SV4.5CGV-1 vertical termination.
Extend the vent sections to the correct height
(
Table 6, Page 12
)
. The SV4.5CGV-1 Vertical Termination
(
Figure 27
)
installs in the exact same fashion as any other Secure Vent
®
section. Align the termination over
the end of the previously installed section, adjusting the radial alignment until the four (4) locking dimples of
the termination are aligned with the inlets of the four (4) incline channels of the last vent section. Push the
termination down until it fully engages, then twist the termination clockwise running the dimples down and along
the incline channels until they seat at the end of the channels.
If the vent system extends more than 5 ft (1.5 m) above the roof fl ashing, stabilizers may be necessary.
Additional screws may be used at section joints for added stability. Guide wires or roof support assemblies may
be attached to the joint for additional support on multiple joint confi gurations.
