Installation
900960-00C, 06/2019
Innovative Hearth Products
DRT3500-C Series Direct-Vent Gas Fireplaces
37
Vertical or Horizontal Venting Using Secure Flex
®
Kits and Components
When Secure Flex
®
kits are used in a rear flue, horizontal termination installation, at least 1 ft of vertical rise is required.
Secure Flex venting kits and components may be used in any other vent installation where rigid Secure Vent
®
(SV4.5)
direct-vent components can be used. All restrictions, clearances and allowances pertaining to rigid vent also apply to
flexible vent. Do NOT modify Secure Flex kits . Also, do NOT join separate sections of flex vent together. Secure Flex
kits can be installed on the end of a Secure Vent (SV4.5) rigid vent run, provided that doing so does not violate any
of the venting length, height, routing, horizontal to vertical ratio requirements, or clearance considerations detailed in
this manual. When combined, a rigid vent should not be installed between two flexible vents.
Secure Flex kits come with an included adaptor that can be installed on the fireplace collar or the inclined channel
end of the last Secure Vent (SV4.5) vent section in a rigid system in the exact same fashion as any other Secure Vent
section. Align the dimpled end of the adaptor over the previously installed section or fireplace collar, adjusting the
radial alignment until the four locking dimples of the adaptor are aligned with the inlets of the four incline channels of
the last vent section or collar. Push on the adaptor until it is fully engaged, then twist the adaptor clockwise running
the dimples down and along the incline channels until they seat at the end of the channels.
Figure 27 - Flexible Vent Adaptor
Figure 28 - Flexible Vent
Apply ONLY MIL-PAC BLACK
HIGH TEMPERATURE
SEALANT (P/N 10K81) to
the outside surface of both
collars of the adaptor (fill the
grooves of the outer collar to
be covered by the flexible pipe)
and slide the flexible vent over
the inner and outer adaptor
collars
NOTE: Outer vent pipe is pulled away
to show inner vent pipe details.
Adaptor (SV4.5RF)
Attach adaptor to vent collar or Secure Vent sections
1-3/4” (44 mm) flexible
vent and adaptor inner
collar overlap
Securing screws
in three (3) places
through perforation
and into the pipe
Gear clamps
Flexible vent
Flexible vent section
5” (127 mm)
radius minimum
Shown here: 36” Flex Connector Kit
(H7748)
36” of flex with two adaptors for
mating two rigid sections of vent
together.
1. Install the Inner Flex Pipe.
a. Install the small gear clamp loosely around the inner flexible vent, then push it back out of the way.
b. Apply a bead of Mill-Pac Black (700 °F) high temperature sealant (P/N 10K81) to the inner adaptor collar,
approximately 1/2” from the end.
c. Pull and extend the inner flexible vent.
d. Slide the inner flex vent over the adaptor collar at least 1-3/4”.
NOTE: Ensure the flex vent is free from damage or tears.
e. Slide the gear clamp down and tighten it fully to secure the flexible vent to the adaptor inner collar
approximately 3/4” from the end of the flex.
f. Install three (3) sheet metal screws 120° apart through the flexible vent and into the adaptor collar just below
the gear clamp to provide additional security to the connection.
2. Install the outer Flex Pipe.
a. Install the large gear clamp loosely around the outer flexible vent pipe, then push it back out of the way.
b. Apply a bead of Mill-Pac Black (700 °F) high temperature sealant (P/N 10K81) to the outer adaptor collar.
Cover to the grooves of the collar that extend approximately 1” from the end and to the flat surface,
approximately 1 3/8” from the end.
c. Pull and extend the outer flexible vent.
d. Slide the outer flexible vent over the adaptor collar. Ensure the flexible vent completely engages the adaptor collar
1-3/4” from the end, and that it is free from damage or tears.
e. Slide the gear clamp down and tighten it fully to secure the flexible vent to the adaptor outer collar
approximately 3/4” from the end of the flexible vent.
1-3/4” (44 mm) flexible
vent and adaptor outer
collar overlap
Securing screws
in three (3) places
through perforation
and into the pipe
