7
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT PLUS
®
B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
PRE-INSTALLATION STEPS
The appliance is shipped with all gas controls
and components installed and pre-wired.
1.
Before installing the appliance, follow these
steps:
2.
Remove the shipping carton.
3.
Remove the shipping pad, exposing the front
glass door.
4.
Open the spring latch securing the glass
door (under the firebox floor). Remove the
door by tilting it outward at the bottom and
lifting it up.
Set the door aside, taking care
to protect it from inadvertent damage
. See
Removing the Glass Enclosure Panel on
Page
19
.
5.
Remove the log set from the firebox. Handle
logs carefully to prevent breakage.
6.
Remove the embers and volcanic stone from
the control compartment.
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 pages referenced in the following steps
for detailed procedures.
Step 1. FRAMING
(
Page 7
): Construct the
appliance framing. Position the appliance within
the framing and secure with nailing flanges and
floor anchor tabs.
Bend out the appropriate nailing flanges for
the drywall/finish material to be used. Nailing
flanges are provided for flush framing, 1/2" and
5/8" framing depths (see
Figure 8
).
Step 2. ROUTING GAS LINE
(
Page 9
): Route
gas supply line to appliance location.
Step 3. INSTALLING VENT SYSTEM
(
Page 10
):
Install the vent system and exterior termination.
Step 4. FIELD WIRING
(
Page 11
).
a.
Millivolt Appliances - Install the operating
control switch (not factory provided). If
installing the optional forced air circulating
blower, bring in electrical service line.
b.
Electronic Appliances - Field wire and
install operating control switch.
Step 5. WIRING - OPTIONAL FORCED AIR
BLOWER KIT
(
Page 12
).
Step 6. CONNECTING GAS LINE
(
Page 12
):
Make connection to gas supply.
Step 7. INSTALLING OPTIONAL OUTSIDE AIR
KIT
(Page 13)
Step 8. VERIFYING APPLIANCE OPERATION
(
Page 14
).
Step 9. INSTALLING VOLCANIC STONE,
GLOWING EMBERS, AND LOGS
(
Page 14
).
FLOOR NAILING TABS
Fireplace may be anchored to floor. Bend down
two anchor tabs (one on each side) located
at the base of the fireplace and secure to the
floor by nailing with 8d nails or equivalent (see
Figure 10).
Anchor
Tab
Step 10. REMOVING AND INSTALLING THE
GLASS DOOR
(
Page 19
).
Step 11. BURNER ADJUSTMENTS
(
Page 19
):
Adjust burner primary air shutter to achieve
proper flame appearance.
Step 12. TESTING VENT OPERATION
(Page 21)
Vent operation test and (safety limit) switch
operation.
Step 13. HOOD INSTALLATION
(
Page 21
).
Step 14. FINISHING REqUIREMENTS
(
Page 21
)
Step 15. ATTACHING SAFETY-IN-OPERATION
WARNINGS
(
Page 22
).
DETAILED INSTALLATION STEPS
STEP 1. FRAMING
Frame the appliance as illustrated in
Figure 11
on
Page 8
. All framing details must allow for
a minimum clearance to combustible framing
members as shown in the table on
Page 8
.
If the appliance is to be elevated above floor
level, a solid continuous platform must be
constructed below the appliance.
NOTE:
The framed depth, 16" (406 mm) from
a framed wall, must always be measured from
a finished surface. If a wall covering such as
drywall is to be attached to the rear wall, then
the 16" (406 mm) must be measured from the
drywall surface. It is important that this dimen-
sion be exact.
Headers may be in direct contact with the
appliance top standoff spacers,
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.
Secure the fireplace to the side framing members
using the unit’s nailing flanges - one top and
bottom on each side of the fireplace front (see
Figure 9
)
.
Use 8d nails or their equivalent.
NOTE:
Some units only have one anchor tab
on each side.
Figure 9 - Unit Secured to Framing by
Nailing Flange
Note: The nailing flanges, combustible members
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.
Side
Framing
Unit Nailing Flange
(No clearance to
combustible
framing is required)
Left Side Front Corner of Fireplace Shown
(Right Side Requirements the Same)
Figure 10 - Floor Anchor Tabs
