25
75D2523
MDV Series Direct Vent Gas Fireplace
flex VentIng InstallatIon
1. Flexible UL1777 listed venting may be used in any
venting application where rigid direct vent components
can be used.
all restrictions, clearances and allow-
ances that pertain to the rigid piping apply to the
flexible venting.
Flex kits may not be modified. Flex
kits may be added to the end of a vent run made of rigid
vent sections using pipe manufacturer's approved flex
to pipe adapters. This may occur only if doing so does
not violate any of the venting length, height, routing,
horizontal to vertical ratio requirements or clearance
considerations detailed in this manual.
5" x 8" flex Vent pipe
2. The flex adapter starter kit (DVFF8A/8) is used to attach
flex venting to the appliance starting collar. It includes
5" inner and 8" outer adapter rings.
Figure 36
FP1972
appliance connection
UL1777
Flex Vent
Screws
(3 places,
equidistant
just above
gear clamp)
1
C\v
" Flex-
ible Pipe
and Adapter
Outer
DVFF8A/8
Inner Adapter
Outer Adapter
Appliance
Starting
Collar
Figure 36 -
Typical Appliance Connection
FP1973
flex pipe bend
UL1777
Flex Vent
5
°
Radius
Figure 37 -
Minimum Radius for Flex Vent Section
FP1973
note
flex vent pipe spacers: refer to
manufacturer’s specifications for correct
positioning of the spacer springs to
maintain proper distance between inside
and outside pipe.
•
The inner and outer adapter rings are required to
start all flex runs.
•
Never install damaged or torn flexible venting.
•
Over tightening clamps may rip, tear, or otherwise
damage flexible venting.
•
The adapter kit does not include individual pipe sec-
tions which may be purchased separately. (UL1777
listed type venting only.)
3. Start the flexible vent as follows:
A. Installing the inner flex adapter and pipe.
Figure
38
1. Insert the long side of the 5" inner ring into
exhaust pipe, gently tap to seat into place, and
secure with screws.
2. Slide the small gear clamp over the inner flexible
vent pipe, and push out of the way.
3. Pull and extend the inner flexible vent.
4. Slide the inner vent onto the adapter collar, for a
minimum 1
C\v
" overlap.
5. Locate the clamp at approximately 3/4" from the
flex end and tighten.
6. Secure the clamped inner section with three self-
tapping screws, drilled equidistant, just above the
clamp perimeter.
B. Installing the outer flex pipe.
Figure 36
1. Firmly insert the 8" outer adapter ring into the
outer appliance starting collar and secure with
screws.
2. Slide the large gear clamp over the outer flexible
vent pipe, and push out of the way.
3. Pull and extend the outer flexible vent.
4. Slide the outer vent onto the appliance collar outer
adapter for a minimum 1
C\v
" overlap.
5. Locate the clamp at approximately 3/4" from the
flex end and tighten.
6. Secure the clamped outer section with three self-
tapping screws, drilled equidistant, just above the
clamp perimeter.
C. Routing UL1777 flex pipe.
1. Always maintain the required clearance when
routing the flex vent assembly.
