Installing The Venting System; Vertical Termination Systems - Lennox Merit MLDVT-35NM-FB Installation Instructions Manual

LENNOX HEARTH PRODUCTS • MERIT
Table 13: Schedule 40 Black Iron Pipe—
Inside Diameter
Schedule 40
Natural
Pipe Length
Gas
(feet)
0–10 1/2 in.
10–40 1/2 in.
40–100 1/2 in.
100–150 3/4 in.
150–200 3/4 in.
NOTE:
• All appliances are factory-equipped with
a flexible gas line connector and 1/2 in.
shutoff valve (Figure 29).
• See Massachusetts Horizontal Vent
Requirements on Page 4 for
additional requirements for installations
in the state of Massachusetts in the
USA.
• The gas supply line should Not be
connected to the appliance until
Connect the Gas Line on Page 24.
• A pipe joint compound rated for gas
should be used on the threaded joints.
Ensure propane resistant compounds
are used in propane applications. Be
very careful that the pipe compound
does not get inside the pipe.
• It is recommended to install a sediment
trap in the supply line as close as
possible to the appliance.
• Check with local building official for
local code requirements.
NOTE: If propane is used, be aware
that if tank size is too small (i.e., under
100 lbs, if this is the only gas appliance
in the dwelling. Ref. NPFA 58), there
may be loss of pressure, resulting
in insufficient fuel delivery (which
can result in sooting, severe delayed
ignition or other malfunctions). Any
damage resulting from an improper
installation, such as this, is not covered
under the limited warranty.
12
SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
®
Install the Vent System
These instructions should be used
as a guideline and do not supersede
Propane
local codes in any way. Install venting
Gas
according to local codes, these
instructions, the current National Fuel
3/8 in.
Gas Code (ANSI-Z223.1) in the USA or
1/2 in.
the current standards of CAN/CSA-B149.1
in Canada.
1/2 in.
Ensure clearances are in accordance
1/2 in.
with local installation codes and the
1/2 in.
requirements of the gas supplier.
Dégagement conforme aux codes
d'installa tion locaux et aux exigences
du foumisseunde gaz.
Use only approved vent components
(Page 2).
NOTE: These fireplaces must be vented
directly to the outside.
The vent system may not service multiple
appliances, and must never be connected to
a flue serving a separate solid fuel burning
appliance. The vent pipe is tested to be run
inside an enclosed wall (such as a chase).
There is no requirement for inspection
openings in the enclosing wall at any of the
joints in the vent pipe.
Installation of Vent Restrictor
A vent restrictor may be needed with
this appliance, install vent restrictor
(provided) in the appliance top flue outlet
as shown in Figure 12. It is held in place by
friction, only.
NOTE: The vent restrictor is included in
the firebox.
DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Select Venting System—
Horizontal or Vertical
With the appliance secured in framing,
determine vent routing and identify the
exterior termination location. The following
sections describe vertical (roof) and
horizontal (exterior wall) vent applications.
Refer to the section relating to your
installation. A list of approved venting
components are shown on Page 33.
A vent restrictor may be needed when
vertically terminating the vent system above
the roof (when using the appliance top
vent), install vent restrictor in the top vent
A vent restrictor may be needed when
of the fireplace outlet (top vent units). If
vertically terminating the vent system above
needed, install the restrictor orientated as the roof (when using the appliance top vent),
install vent restrictor in the top vent of the
shown, either from inside or outside the
fireplace outlet on MPD35/40/45
unit, in the inner fireplace collar.
If needed, install the restrictor orientated as
Figure 12: Vent restrictor installation—
shown, either from inside or outside the unit,
Top vent
in the inner fireplace collar.
U-SHAPED VENT
RESTRICTOR
INNER
FIREPLACE
COLLAR
APPLIANCE TOP
VENT OUTLET

Vertical Termination Systems

See Figure 13, Figure 20, Table 17, and
Table 18 on Page 16 that illustrate the
various vertical venting configurations that
are possible for use with these appliances.
Secure Vent pipe applications are shown in
®
these Figures; Secure Flex
®
be used. A vertical vent table summarizes
each system's minimum and maximum
vertical and horizontal length values that
can be used to design and install the vent
components in a variety of applications.
Both these vertical vent systems terminate
through the roof. The minimum vent height
above the roof and/or adjacent walls is
specified in ANSI Z223.1 (In Canada, the
current CAN/CSA-B149.1 installation code)
by major building codes. Always consult
your local codes for specific requirements.
A general guide to follow is the Gas Vent
Rule (Figure 6 on Page 6).
pipe may also