Lennox Hearth MERIT PLUS MP-36OD - Manual (Page 20)

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE. 20
COLD CLIMATE INSULATION
If you live in a cold climate, it is especially
important to seal all cracks around the fi replace
opening with noncombustible material and
wherever cold air could enter the room. Sur-
rounding materials must be caulked where it
meets the black metal facing of the fi replace to
avoid cold air intrusion. Use noncombustible
caulking material only on fi replace facing to seal.
Also, the outside air inlet duct should be wrapped
with noncombustible insulation to minimize
the formation of condensation. Do not place
insulation materials on top of fi replace or against
chimney sections. If gas logs are installed, the
gas line holes and other openings should be
caulked with high temperature caulk or stuffed
with unfaced fi berglass insulation.
Note: A 1"* air space must be preserved for all
insulation and construction materials extend-
ing for any continuous length adjacent to the
chimney.
It is especially important to insulate between the
studs of an outside chase cavity and under the
fl oor if the fl oor is above ground level. Do not
place insulation directly against the fi replace
or chimney system.
FIREPLACE FINISHES
Mantels and Trim
It is sometimes best to frame your fi replace after
it is positioned and the chimney is installed.
Frame enclosure for chimney and fi replace with
2 x 4’s (or heavier) lumber.
Note: The header may touch but not rest its
weight on the two (2) metal top spacers on top
of the unit. The header must not be notched to
fi t around the spacers.
These fi replaces may sit directly on a com-
bustible surface. A 1"* air space is required
between insulation and building materials
and the chimney. A 1" air space is required
between combustible framing and fi replace
outer wrapper.
In Canada, the minimum height for a combus-
tible mantel is 18" (457 mm) above the fi replace
opening. Figure 51 shows typical Canadian
installations. Combustible mantels and trim
may be installed 12" above the fi replace opening
as per NFPA 211-latest edition and Figure 52.
If a mantel is of a noncombustible material,
it is exempt from these requirements as long
as it does not interfere with the installation or
operation of glass doors.
*Note: 2" clearance to combustibles required
in Canada.
Note: Do not place any combustible materials
on the fi replace face.
Figure 52 - Typical Installation
12"*
Min. 9-5/8"*
Min.
Fireplace
Opening
Spacer
Combustible
Mantel
and Trim
12"
Max.
1 1/2"
Finished
Wall
Header
*Both Of These Dimensions Must Be At Least 18”
When An Unvented Gas Log Set Rated At 26,000
BTU Or Higher Is Used. (Maximum 40,000 BTU).
❂ 1-5/8" Min.
❂ The shaded gray area showing 1-5/8" Min.
indicates non-combustible materal is required.
Hearth Extensions and Wall Shields
A hearth extension must be installed with
all fi replaces. It is to protect the combustible
fl oor in front of the fi replace from both radiant
heat and sparks. The hearth extension must
extend 8" beyond both sides of the fi replace
opening and 16" beyond the front (see Figure
53). Use a hearth extension constructed of a
durable noncombustible material having an
equal or better (lower k value) insulating value of
k = .84 BTU IN/FT
2 HR °F or a thermal resistance
that equals or exceeds r = 1.19 HR °F FT 2 /BTU
IN. With these values, determine the minimum
thickness/material required using the formula
and Table 5 on Page 21.
Note: Any noncombustible material having
a thickness of 1" whose k value is less than
.84 or whose r value is more than 1.19 is ac-
ceptable.
If the fi replace is installed on a combustible
fl oor, use the metal safety strips (provided)
on the fl oor extending half under the fi replace
and half under the hearth extension (refer to
Figures 21 & 22).
A wall shield is required where a continuous
perpendicular side wall is within 12" of the
fi replace opening (Figure 53). Use a 24" W x
30" H x 1/2" wall shield constructed of a durable,
noncombustible material having an equal or
better (lower k value) insulating value than
k = .54 BTU IN/FT
2 HR °F. At no time may a
perpendicular side wall be located closer than
7" from the fi replace opening.
If fi replace is installed diagonally across a 90°
corner; no wall shields are required.
Fireplace
Opening
Top Spacer
on Appliance
Combustible
Mantel
8" Max.
(203mm)
Finished
Wall
Header
18" Max.
❂ 1-5/8" Min.
(457mm)
❂ The shaded gray area showing 1-5/8" Min.
indicates non-combustible materal is required.
ATTENTION
Certaines portes de verre recou-
vrent le revêtement noir en métal
du foyer. SI la façade du foyer a
été recouverte avec des matériaux
non-combustibles, il se pourrait
qu’il n’y ait pas suffi sament de
dégagement pour installer les
portes de verre de votre choix.
Assurez d’avoir un dégagmet suf-
fi sant à tout moment afi n de ne
pas interférer avec l’installation et
l’opération des portes de verre.
Figure 51 - Canadian Installation
WARNING
Only non-combustible materials
are allowed on front face (front
fi replace frame) and around the
perimeter within 1-5/8" minimum
on top and 1/2" on sides.
AVERTISSEMENT
Seulement on permet des matéri-
aux non-combustibles sur le visage
avant (armature avant de chemi-
née) et autour du périmètre à moins
de 1-5/8 pouces sur le dessus et
de pouce de 1/2 des côtés.