9
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
WARNING
Failure to position the parts in accordance with these diagrams or failure to use only parts specifi-cally approved with this appliance may result in property damage or personal injury.
AVERTISSEMENT
Risque de dommages ou de blessures si les pièces ne sont pas installées conformément à ces schémas et ou si des pièces autres que celles spécifiquement approuvées avec cet appareil sont utilisées.
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MODELS MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS

PRE-INSTALLATION STEPS

The appliance is shipped with all gas controls
and components installed and pre-wired.
1. Remove the shipping carton. Remove the
shipping pad, exposing the front glass door.
2. Open the two latches (located under the
rebox oor) securing the glass door. Re-
move the door by tilting it outward at the
bottom and lifting it up. Set the door aside
protecting it from inadvertent damage. See
Removing Glass Panels on Page 31.

Figure 12 - Nailing Flanges

Nailing Flanges Are
Provided At All Four
Corners At 5/8”, 1/2”
And Flush Settings
Side
Framing
Unit
Nailing Flange

DETAILED INSTALLATION STEPS

Step 1. FRAMING

Frame these appliances as illustrated in Figures
13 and 14 on Pages 10 and 11. (Figure 14
applies to corner framing installations only.)
All framing details must allow for a minimum
clearance to combustible framing members as
shown in Table 5 on Page 8.
If the appliance is to be elevated above floor level,
a solid continuous platform must be constructed
below the appliance.
Headers may be in direct contact with the appli-
ance top spacers when they are bent up vertically
maintaining the 3" clearance to the replace top,
but must not be supported by them or notched
to fit around them. All construction above the
appliance must be self-supporting. DO NOT use
the appliance for structural support.
The fireplace should be secured to the side
framing members using the unit’s nailing
flanges — one top and bottom on each side
of the fireplace front (see Figure 12 ). Use 8d
nails or their equivalent.
Unit Being Secured by its Nailing
Flanges to the Framing
Left Side Front Corner of Fireplace Shown
(Right side requirements are the same.)
NOTE: The nailing flanges, combustible mem-
bers and screw heads located in areas directly
adjacent to the nailing flanges, are EXEMPT from
the 1/2” clearance to combustible requirements
for the firebox outer wrapper.
Combustible framing may be in direct contact
with the nailing flanges and may be located
closer than 1/2” from screw heads and the
firebox wrapper in areas adjacent to the nailing
flanges.
Frame the opening to the exact dimensions
specified in the framing details of this manual.

TYPICAL INSTALLATION SEQUENCE

The typical sequence of installation is outlined
below; however, each installation is unique and
may result in variations to the steps described.
See the page numbers references in the follow-
ing steps for detailed procedures.
Step 1. (Page 9) Construct the appliance
framing. Position the appliance within
the framing and secure with nailing
brackets.
Bend up the appropriate header spac-
ing guides for the drywall/finish mate-
rial thickness to be used (see Figure
49). Bend up the outer pair for 1/2"
materials and the inner pair for 5/8"
materials.
Bend out the appropriate nailing
flanges for the drywall/finish material
to be used. Nailing flanges are provided
for flush framing, 1/2-inch, and 5/8-
inch framing depths (see Figure 12).
Step 2. (Page 11) Route gas supply line to
appliance location.
Step 3. (Page 12) Install the vent system and
exterior termination.
Step 4. (Page 24) Field Wiring
a. Millivolt Appliances – Install the
operating control switch (not fac-
tory provided) and bring in electrical
service line for forced air-circulating
blower (optional equipment).
b. Electronic Appliances – Field wire
and install operating control switch.
Step 5. (Page 25) Install blower kit (optional
equipment).
Step 6. (Page 26) Make connection to gas
supply.
Step 7. (Page 27) Verify appliance operation.
Step 8. (Page 28) Install the logs, decorative
volcanic stone and glowing embers.
Step 9. (Page 31) Install glass door assembly.
Step 10. (Page 31) Adjust burner primary air
shutter to achieve proper flame ap-
pearance.
Step 11. (Page 33) Install the hood.
Step 12. (Page 34) Attach Safety-in-Operation
Warnings.