Lennox Montebello MDLX40IN-PV User manual

MODELS
This appliance may be installed in an aftermarket permanently located, manufactured home (USA only) or mobile
home, where not prohibited by local codes. This appliance is only for use with the type of gas indicated on the rating
plate. This appliance is not convertible for use with other gases.
INSTALLATION INSTRUCTIONS
Montebello®DLX Power Vent
Direct-Vent Gas Fireplaces
MDLX40IN-PV MDLX45IN-PV
ELECTRONIC:
P/N 506023-16 Rev. NC 08/2012
This manual is one of a set of two supporting this product.
Refer to P/N 506025-08 for Care and Operation Instructions.
Ce manuel est disponible en francais, simplement
en faire la demande. Numéro de la pièce 506223-49.
INSTALLER: Leave this manual with the appliance.
CONSUMER: Retain this manual for future reference.
INSTALLATEUR : Laissez cette notice avec l'appareil.
CONSOMMATEUR : Conservez cette notice pour
consultation ultérieure.
AVERTISSEMENT : Assurez-vous de bien suivre les
instructions données dans cette notice pour réduire au
minimum le risque d’incindie ou d’explosion ou pour
éviter tout dommage matériel, toute blessure ou la mort.
WARNING: If the information in these instructions
is not followed exactly, a fire or explosion may
result, causing property damage, personal injury,
or death.
WARNING/AVERTISSEMENT/AVISO
• HOT GLASS WILL CAUSE
BURNS.
• DO NOT TOUCH GLASS
UNTIL COOLED.
• NEVER ALLOW CHILDREN
TO TOUCH GLASS.
• UNE SURFACE VITRÉE CHAUDE
PEUT CAUSER DES BRÛLURES.
• LAISSER REFROIDIR LA SURFACE
VITRÉE AVANT D'Y TOUCHER.
• NE PERMETTEZ JAMAIS À UN ENFANT
DE TOUCHER LA SURFACE VITRÉE.
• EL VIDRIO CALIENTE
CAUSARÁ QUEMADURAS.
• USTED DEBE NUNCA
TOCAR EL VIDRIO CALIENTE.
• LOS NIÑOS DEBEN NUNCA
TOCAR EL VIDRIO.
- Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
appliance.
- WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call the fire
department.
- Installation and service must be performed by a
qualified installer, service agency or the gas supplier.
- Ne pas entreposer ni utilizer d’essence ni d’autres vapeurs
ou liquides inflammables dans le voisinage de cet appareil
ou de tout autre appareil.
- QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ :
• Ne pas tenter d’allumer d’appareil.
• Ne touchez à aucan interrupteur. Ne pas vous servir des
téléphones se trouvant dans le bâtiment où vous trouvez.
• Appelez immédiatement votre fournisseur de gaz depuis
un voisin. Suivez les instructions du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur de gaz,
appelez le service des incindies.
- L’installation et l’entretien doivent être assurés par un
installateur ou un service d’entretien qualifié ou par le
fournisseur de gaz.
Intertek Report No.
100513650PRT-001
®
Please read and understand these instructions
before starting installation.

2
WARNING
Young children should be
carefully supervised when they
are in the same room as the
appliance. Toddlers, young
children and others may be
susceptible to accidental contact
burns. A physical barrier is
recommended if there are at
risk individuals in the house.
To restrict access to a fireplace
or stove, install an adjustable
safety gate to keep toddlers,
young children and other at risk
individuals out of the room and
away from hot surfaces.
AVERTISSEMENT
Les jeunes enfants devraient
être surveillés étroitement
lorsqu’ils se trouvent dans la
même pièce que l’appareil.
Les tout petits, les jeunes
enfants ou les adultes
peuvent subir des brûlures
s’ils viennent en contact
avec la surface chaude. Il
est recommandé d’installer
une barrière physique si des
personnes à risques habitent
la maison. Pour empêcher
l’accès à un foyer ou à un
poêle, installez une barrière
de sécurité; cette mesure
empêchera les tout petits,
les jeunes enfants et toute
autre personne à risque
d’avoir accès à la pièce et aux
surfaces chaudes.
GENERAL INFORMATION
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS
TABLE OF CONTENTS
Packaging .........................................Page 2
Introduction ......................................Page 2
General Information ..........................Page 2
Massachusetts Requirements...........Page 4
Cold Climate Insulation .....................Page 5
Manufactured Home Requirements ..Page 5
Location............................................Page 5
Vent Termination Clearances ............Page 6
Minimum Clearances to Combustibles Page 8
Pre-Installation Steps........................Page 9
Typical Installation Sequence ...........Page 9
Detailed Installation Steps.................Page 9
Step 1. Framing...............................Page 9
Fireplace and Framing Specifications Page 10
Step 2. Routing Gas Line ................Page 11
Proper Sizing of Gas Line..................Page 11
Step 3. Install the Vent System .......Page 12
General Vent Information..................Page 12
Power Vent Components...................Page 12
Vent Section Length Chart ................Page 13
Offset Installation..............................Page 13
Horizontal Termination System .........Page 16
Installing Power Vent Termination ....Page 16
Step 4. Field Wiring.........................Page 18
Step 5. Removing Glass Door
Frame Assembly ...............................Page 20
Step 6. Connecting Gas Line ...........Page 21
Step 7 Install Firebox Liner ............Page 21
Step 8. Verifying Appliance
Operation ..........................................Page 21
Step 9. Installing Logs ...................Page 22
Step 10. Install/Remove Glass
Door Assembly .................................Page 24
Step 11. Burner Adjustments............Page 24
Finishing Requirements ....................Page 26
Step 12. Attaching Safety-in-
Operation Warnings ................... Page 27
Installation Accessories ....................Page 28
PACKAGING
The assembled vented gas fireplace is packaged with:
BOX 1—Fireplace:
• Literature Kit (plastic bag shipped
inside rebox),
• Bags of Glowing Embers, Platinum Embers,
and Volcanic Stone
•Pull Screen
• Door Modesty Shield
• Adaptor with Probe Assembly
• (1) Remote Control Kit and Receiver Kit
BOX 2—Power Vent Components:
• (1) Power Vent Termination
• (1) Termination Adaptor
• (1) Horizontal Firestop Assembly
• (1) Vacuum Hose
• (1) 11/32 in. Hose Clamp
• (1) Strain Relief
• (1) Bushing
• (4) Insulated 1/4 in. Male Terminals
• (2) #10 Ring Terminals
REQUIRED ACCESSORIES
The following accessories are required:
• One of the following Firebox Liner Kits:
a. Ceramic Liner Kit—Buff Rustic
b. Ceramic Liner Kit—Red Rustic
c. Porcelain Liner Kit—Black
d. Ceramic Liner Kit—Red Herringbone
e. Ceramic Liner Kit—Buff Herringbone
NOTE: Porcelain kits include side and back
panels. Optional for use with log sets.
Required when using the contemporary
burner/floor kit.
• One of the following Floor Options:
a. Oak Log Set (For use with fireplace as
shipped from factory only. Not for use with
contemporary burner/floor kit.)
b. Contemporary Burner/Floor Kit
Contemporary Burner/Floor Kit requires
one of the following Media Kits:
i. Crushed Glass—Reective Black
ii. Crushed Glass—Platinum
iii. Crushed Glass—Reective Blue
iv. Crushed Glass—Goldfinger
v. Crushed Glass—Copper
NOTE: The Contemporary Burner/Floor Kit
installation instructions are provided
with the kit, and are not detailed in this
manual.
INTRODUCTION
These Electronic appliances are designed to
operate on natural gas and have an electronic
intermittent pilot ignition system. External
120 Volt AC electrical power is required to
operate these units.
These vented gas fireplaces are sealed
combustion gas replaces designed for
residential, manufactured home, and
commercial applications.
Use Only These Approved Vent Components
These replaces are designed, tested and
listed for operation and installation with, the
following (4 1/2 in. inner and 7 1/2 in. outer)
vent components only:
• Secure Vent®Direct-vent system
components manufactured by Security
Chimneys International.
These approved vent system components
are labeled for identication. Do NOT use any
other manufacturer’s vent components with
these appliances.
Children and adults should be alerted to the
hazards of high surface temperature and should
stay away to avoid burns or clothing ignition.
Les enfants et les adultes devraient être
infor-més des dangers que posent les
températures de surface élevées et se
tenir à distance afin d’éviter des brûlures
ou que leurs vêtements ne s’enflamment.
DO NOT ATTEMPT TO ALTER OR MODIFY
THE CONSTRUCTION OF THE APPLIANCE
OR ITS COMPONENTS. ANY MODIFICATION
OR ALTERATION MAY VOID THE
WARRANTY, CERTIFICATION AND LISTINGS
OF THIS UNIT.

3
NOTE: Installation and repair should be
done by a qualified service person. The
appliance should be inspected before use
and at least annually by a professional
service person. More frequent cleaning
may be required due to excessive lint from
carpeting, bedding material, etcetera. It
is imperative that control compartments,
burners and circulating air passageways of
the appliance be kept clean.
Remarque : L’installation et la
réparation devrait être confiées à un
technicien qualifié. L’appareil devrait
faire l’objet d’une inspection par un
technicien professionnel avant d’être
utilisé et au moins une fois l’an par la
suite. Des nettoyages plus fréquents
peuvent être nécessaires si les tapis,
la literie, et cetera produisent une
quantité importante de pous-sière. Il
est essentiel que les compartiments
abritant les commandes, les brûleurs
et les conduits de circulation d’air de
l’appareil soient tenus propres.
Do not use these appliances if any part
has been under water. Immediately call a
qualified, professional service technician
to inspect the appliance and to replace any
parts of the control system and any gas
control which have been under water.
Ne pas utiliser cet appareil s’il a été
plongé, même partiellement, dans
l’eau. Appeler un technicien qualifié
pour inspecter l’appareil et remplacer
toute partie du système de commande
et toute commande qui a été plongée
dans l’eau.
Only trim kit(s) supplied by the
manufacturer shall be used in the
installation of this appliance.
Seules les trousses de garniture
fournies par le fabricant doivent
être utilisées pour l’installation de
cet appareil.
WARNING
Failure to position the parts in
accordance with these diagrams
orfailure touse onlyparts specifi-
callyapprovedwiththisappliance
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
approuvéesaveccetappareilsont
utilisées.
WARNING
Clothing or other flammable
material should not be placed
on or near the appliance.
AVERTISSEMENT
On ne devrait pas placer de
vêtements ni d’autres matières
inflammables sur l’appareil ni à
proximité.
WARNING
Improper installation or use
of this appliance can cause
serious injury or death from
fire, burns, explosion or
carbon monoxide poisoning.
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS
WARNING
Improper installation,
adjustment, alteration, service
or maintenance can cause
injury or property damage.
Refer to this manual. For
assistance or additional
information consult a qualified
installer, service agency or the
gas supplier.
WARNING
Failure to comply with these
installation instructions will
result in an improperly installed
and operating appliance,
voiding its warranty. Any change
to this appliance and/or its
operating controls is dangerous.
WARNING
Any safety screen or guard
removed for servicing the
appliance must be replaced
prior to operating the appliance.
AVERTISSEMENT
Tout écran ou protecteur retiré
pour permettre l’entretien
de l’appareil doit être remis
en place avant de mettre
l’appareil en marche.
Codes and Standards
These appliances comply with National
Safety Standards and are tested and listed
by Intertek (Report No. 100513650) to
Z21.50b-2009 (in Canada, CSA-2.22b-2009),
and CAN/CGA-2.17-M91 (R2009) in both
USA and Canada, as vented gas replaces.
These appliances are listed by Intertek for
installation in bedrooms and manufactured
(mobile) homes.
Installation must conform to local codes. In
the absence of local codes, installation must
comply with the current National Fuel Gas
Code, ANSI Z223.1/NFPA 54 (in Canada, the
current CAN/CGA-B149.1 installation code).
The appliance, when installed, must be
electrically grounded in accordance with local
codes or, in the absence of local codes, with
the National Electrical Code, ANSI/NFPA 70—
latest edition, or the Canadian Electrical Code,
CSA C22.1—latest edition.
Provide adequate clearances around
air openings and adequate accessibility
clearance for service and proper operation.
Never obstruct the front openings of
the appliance.
These appliances are designed to operate
on natural gas. The use of other fuels
or combination of fuels will degrade the
performance of this system and may
be dangerous.
These appliances must not be connected to a
chimney or flue serving a separate solid fuel
burning appliance.
These electronic appliances are remotely
controlled and feature an electronic
intermittent pilot ignition system. External
electrical power is required to operate
these units.
These electronic models come standard
with a remotely-modulated gas valve; flame
appearance and heat output cannot be
controlled at the gas valve. The BTU Input
for these appliances is shown in Table 1.
Model No. Input (BTU/Hr)
MDLX40IN-PV 26,500–42,000
MDLX45IN-PV 35,000–48,000
Table 1: Input (BTU/HR), Natural Gas

4
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
In Canada - CAN/CGA-2.17-M91 (R2009)
(high altitude):
THE CONVERSION SHALL BE CARRIED OUT
BY A MANUFACTURER’S AUTHORIZED
REPRESENTATIVE, IN ACCORDANCE
WITH THE REQUIREMENTS OF THE
MANUFACTURER, PROVINCIAL OR
TERRITORIAL AUTHORITIES HAVING
JURISDICTION AND IN ACCORDANCE
WITH THE REQUIREMENTS OF THE
CAN/CGA-B149.1 OR CAN/CGA-B149.2
INSTALLATION CODES.
REQUIREMENTS FOR THE
COMMONWEALTH OF MASSACHUSETTS
These fireplaces are approved for installation
in the US state of Massachusetts if the
following additional requirements are met:
• Install this appliance in accordance with
Massachusetts Rules and Regulations
248 C.M.R.
• Installation and repair must be done by
a plumber or gas tter licensed in the
Commonwealth of Massachusetts.
• The exible gas line connector used shall
not exceed 36 in. (92 centimeters) in
length.
• The individual manual shut-off must be a
T-handle type valve.
Massachusetts Horizontal Vent Requirements
In the Commonwealth of Massachusetts,
horizontal terminations installed less than
seven (7) feet above the finished grade
must comply with the following additional
requirements:
• A hard wired carbon monoxide detector
with an alarm and battery back-up must
be installed on the oor level where the
gas replace is installed. The carbon
monoxide detector must comply with
NFPA 720, be ANSI/UL 2034 listed and be
ISA certified.
• A metal or plastic identication plate must
be permanently mounted to the exterior
of the building at a minimum height of
eight (8) feet above grade and be directly
in line with the horizontal termination.
The sign must read, in print size no less
than one-half (1/2) inch in size, GAS VENT
DIRECTLY BELOW. KEEP CLEAR OF ALL
OBSTRUCTIONS.
Gas Valve Diagram
See Figure 1 for gas valve diagram.
Figure 1: SIT Electronic Gas Valve
Wire
(From DFC Wire
Harness)
Pressure
Regulator
Tower
Yellow Ground Wire
(From DFC Wire
Harness)
Green Wire
(From DFC Wire
Harness)
Inlet (In) Test Port
Manifold (Out)
Test Port
Connect GTMS
Wire Harness
Main Gas Inlet
3/8 in. NPT
Test gauge connections are provided on the
front of the gas control valve; identified IN
for the inlet and OUT for the manifold side
(see Figure 1).
Orifice Sizes—Sea Level To High Altitude
These appliances are tested and approved
for installation at elevations of 0–4500 ft
(0–1370 m) above sea level, using the
standard burner orice sizes (marked with an
"*" in Table 4). For elevations above 4500 ft,
contact your gas supplier or qualied service
technician.
Deration—At higher elevations, the amount
of BTU fuel value delivered must be reduced
by either:
• Using gas that has been derated by the
gas company.
• Changing the burner orice to a smaller
size as regulated by the local Authorities
Having Jurisdiction and by the (USA)
National Fuel Gas Code NFPA 54/ANSI
Z223.1—latest edition, or in Canada, the
CAN/CGA-B149.1 code—latest edition.
Install the appliance according to the
regulations of the local authorities having
jurisdiction, and the (USA) National Fuel Gas
Code NFPA 54 / ANSI Z223.1—latest edition,
or (Canada) CAN/CSA-B149.1—latest edition.
NOTE: Flame appearance will diminish 4%
per one thousand feet of altitude.
Model Orifice Size / Catalog Number
MDLX40IN-PV 0.125 in. (1/8 in.) * H7924 •
MDLX45IN-PV 0.136 in. (#29) * H8141 •
* Standard size installed at factory
• Part /Cat. Number
Table 4: Burner Orifice Size
Elevation 0–4500 ft (0–1370 m)
The appliance and its appliance main gas
valve must be disconnected from the gas
supply piping system during any pressure
testing of that system at test pressures in
excess of 1/2 psi (3.5 kPa).
The appliance must be isolated from
the gas supply piping system by closing
its equipment shutoff valve during any
pressure testing of the gas supply piping
system at test pressures equal to or less
than 1/2 psi (3.5 kPa).
PURGE CYCLE
This is a power vented fireplace
that requires household electrical
power to operate. It will not operate
during a power failure. When the
fireplace is turned off, the exhaust
blower will continue to operate for
approximately fifteen (15) seconds
after shutdown to expel the exhaust
gases from the venting system.
LENNOX HEARTH PRODUCTS • MONTEBELLO® POWER VENT DV GAS FIREPLACES (LSM40/45EN-PV) • INSTALLATION INSTRUCTIONS
Gas Pressure—All Models
Tables 2 and 3 show the appliance inlet and
manifold gas pressure requirements.
Minimum Maximum
5.5 in. WC
(1.37 kPa)
10.5 in. WC
(2.62 kPa)
Table 2: Inlet Gas Supply Pressure
Low High
1.6 in. WC
(.40 kPa)
3.5 in. WC
(.87 kPa)
Table 3: Manifold Gas Supply Pressure

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
5
COLD CLIMATE INSULATION
For cold climate installations, seal all cracks
around your appliance with noncombustible
material and wherever cold air could enter the
room. It is especially important to insulate
outside chase cavity between studs and
under oor on which appliance rests, if oor
is above ground level. Gas line holes and
other openings should be caulked or stuffed
with unfaced berglass insulation.
If the replace is being installed on a cement
slab in cold climates, a sheet of plywood
or other raised platform can be placed
underneath to prevent cold transfer to the
fireplace and into the room. It also helps
to sheetrock inside surfaces and tape for
maximum air tightness and caulk restops.
MANUFACTURED HOME
REQUIREMENTS
This appliance may be installed in
an aftermarket permanently located,
manufactured home and must be installed
in accordance with the manufacturer's
instructions.
Cet appareil peut être installé cómme
du matéri-el d'origine dans une maison
préfabriquée (É.U. seulement) ou mobile
et doit être installé selon les instructions
du fabricant.
This appliance is only for use with the type
of gas indicated on the rating plate. This
appliance is not convertible for use with
other gases.
Cet appareil doit être utilisé uniquement
avec le type de gaz indiqué sur la plaque
signalétique. Cet appareil ne peut être
converti à d'autres gaz.
CAUTION: Ensure that the cross
members are not cut or weakened
during installation. The structural
integrity of the manufactured home
floor, wall, and ceiling/roof must
be maintained.
CAUTION: This appliance must
be grounded to the chassis of the
manufactured home in accordance with
local codes or in the absence of local
codes, with the National Electrical
Code ANSI / NFPA 70—latest edition.
LOCATION
In selecting the location, the aesthetic and
functional use of the appliance are primary
concerns. However, vent system routing to
the exterior and access to the fuel supply are
also important.
Due to high temperatures, the appliance
should be located out of traffic and away
from furniture and draperies (Figure 2).
En raison des températures élevées,
l’appareil devrait être installé dans
un endroit où il y a peu de circulation
et loin du mobilier et des tentures
(Figure 2).
The location should also be free of
electrical, plumbing or other heating/air
conditioning ducting.
Recessed
Application
Cross Corner
Application
Flat
Application
Flat on Wall
Application
Room Divider
Application
Island
Application
Figure 2: Typical Installation
Top of Fireplace
Opening
Drywall
Noncombustible
Horizontal
Termination
Fireplace
Be aware that this is a heat producing
appliance. Objects placed above the unit
are exposed to elevated temperatures.
Do not insulate the space between the
appliance and the area above it.
The appliance must be mounted on a
fully supported base extending the full
width and depth of the unit. The appliance
may be located on or near conventional
construction materials. However, if installed
on combustible materials, such as carpeting,
vinyl tile, or other combustible material other
than wood ooring, the appliance shall be
installed on a metal or wood panel extending
the full width and depth of the appliance.
NOTE: When the unit is installed with one
sideflushwith awall, the wallon theother
sideof theunit mustnot extendbeyondthe
front edge of the unit.
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS

6
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
VENT TERMINATION CLEARANCES
These instructions should be used as a
guideline and do not supersede local codes
in any way. Install venting according to
local codes, these instructions, and the
current (USA) National Fuel Gas Code
ANSI-Z223.1 / NFPA 54, or (Canada) CAN/
CSA-B149.1 standards.
Horizontal Vent Termination Clearances
The horizontal vent termination must have
a minimum of 3 in. (76 mm) clearance to
any overhead combustible projection of
2 1/2 in. (64 mm) or less (see Figure 3).
For projections exceeding 2 1/2 in. (64 mm),
see Figure 4. For additional vent location
restrictions refer to Figure 4 and Table 5 on
Page 7.
LENNOX HEARTH PRODUCTS • MONTEBELLO® POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS
See Figure 19 on Page 17 for the re-
cess allowances,into exteriorwalls,
of the power vent terminations.
Combustible Projection
2 1/2 in. or less in length
Combustible Projection
Greater than 2 1/2 in. in length
Ventilated or
Unventilated Soffit
3 in.
(76 mm)
24 in.
(610 mm)
Power Vent Termination
Side Elevation View
Figure 3: Horizontal Vent Termination Clearances
Combustible
18 in.
(457 mm)

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
7
Minimum Clearances Canadian Installation * US Installation **
AClearance above grade, veranda, porch, deck
or balcony. 12 in. (30 cm) * 12 in. (30 cm) **
BClearance to window or door that may be opened.
6 in. (15.2 cm) for appliances < 10,000 BTU/hr (3kW),
12 in. (30 cm) for appliances > 10,000 BTU/hr (3kW)
and < 100,000 BTU/hr (30kW),
36 in. (91 cm) for appliances > 100,000 BTU/hr
(30kW)*
6 in. (15.2 cm) for appliances < 10,000 BTU/hr (3kW),
9 in. (23 cm) for appliances > 10,000 BTU/hr (3kW)
and < 50,000 BTU/hr (15kW),
12 in. (30 cm) for appliances > 50,000 BTU/hr
(15kW)*
CClearance to permanently closed window 12 in. (305 mm) recommended to prevent
window condensation
9 in. (229 mm) recommended to prevent
window condensation
D
Vertical clearance to ventilated soft located above
the terminal within a horizontal distance of 36 in.
(91.4cm) from the center line of the terminal 24 in. (61.0 cm) 24 in. (61.0 cm)
EClearance to unventilated soffit 24 in. (61.0 cm) 24 in. (61.0 cm)
FClearance to outside corner 5 in. (12.7 cm) 5 in. (12.7 cm)
GClearance to inside corner 36 in. (91.4 cm) 24 in. (61.0 cm)
HClearance to each inside of center line extended
above meter / regulator assembly 3 ft (91 cm) within a height of 15 ft above the meter / regulator assembly * 3 ft (91 cm) within a height of 15 ft above the meter / regulator assembly **
IClearance to service regulator vent outlet 3 ft (91 cm) * 3 ft (91 cm) **
J
Clearance to non-mechanical air supply inlet to
building or the combustion air inlet to any other
appliance
6 in. (15.2 cm) for appliances < 10,000 BTU/hr (3kW),
12 in. (30 cm) for appliances > 10,000 BTU/hr (3kW)
and < 100,000 BTU/hr (30kW),
36 in. (91 cm) for appliances > 100,000 BTU/hr
(30kW)*
6 in. (15.2 cm) for appliances < 10,000 BTU/hr (3kW),
9 in. (23 cm) for appliances > 10,000 BTU/hr (3kW)
and < 50,000 BTU/hr (15kW),
12 in. (30 cm) for appliances > 50,000 BTU/hr
(15kW)*
KClearance to mechanical air supply inlet 6 ft (1.83 m) * 3 ft (91 cm) above, if within 10 ft (3 m) horizontally**
LClearance above paved sidewalk or paved
driveway located on public property 7 ft (2.13 m) ‡ 7 ft (2.13 m) ‡
M Clearance under veranda, porch, deck or balcony 18 in. (46.0 cm) * ‡ 18 in. (46.0 cm) ** ‡
Table 5: Exterior Horizontal Vent Termination Clearance Requirements
* In accordance with the current CAN/CGA-B149.1 National Gas and B149.2 Propane Installation Code—Latest Editions.
** In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code—Latest Edition.
‡ A vent shall not terminate directly above a sidewalk or paved driveway which is located between two single family dwellings and serves both dwellings.
*‡ Only permitted if veranda, porch, deck or balcony is fully open on a minimum 2 sides beneath the oor.
NOTE: Local Codes Or Regulations May Require
Different Clearances.
NOTE: Location Of The Vent Termination Must Not
Interfere With Access To The Electrical Service.
V
V V
V
V
F
C
B
B
A
B
H
M
I
X V
D
V
A A
A
V
L
B
J
X E
V
A
G
*18”
18”
B
C
C
C
K
X



* See Item D in the Text Below.
Center Line
of Termination
Exterior Wall
Horizontal
Termination
Ventilated Soffit
Inside Corner
DETAIL D
Inside
Corner Detail
Operable
Window
Fixed
Closed
Window
= 9 in. in U.S.
=12 in. in Canada
3 ft.
3 ft.
= Air Supply Inlet = Vent Terminal = Area where Terminal is NOT permitted
24 in.
36 in.
Figure 4: Exterior Horizontal Vent Termination Clearance Requirements
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS

8
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
* 3 in. (75 mm) above any horizontal/inclined vent component.
** See Page 9, Step 1 for clearance requirements to the nailing
flange located at each side of the unit and any screw heads adjacent
to it.
Wall Finishes / Surrounds / Mantels
NOTE: Combustible wall finish materials and/or surround materials
must not be allowed to encroach the area defined by the appliance
front face (black sheet metal). Never allow combustible materials
to be positioned in front of or overlapping the appliance face. See
Figure 6 and Figure 44 on Page 26.
Noncombustible materials, such as surrounds and other appliance
trim, may be installed on the appliance front face with these
exceptions: they must not cover any portion of the removable glass
panel.
Vertical installation clearances to combustible mantels vary according
to the depth of the mantel (see Figure 5). Mantels constructed of
noncombustible materials may be installed at any height above the
appliance. Minimum clearance requirements include any projections
such as shelves, window sills, mantels, etc. above the appliance.
NOTE: We recommend the use of high temperature paint (rated
175 °F or higher) on the underside of the mantel.
MINIMUM CLEARANCES TO COMBUSTIBLES
Appliance And Vent Clearances
The appliance is approved with zero clearance to combustible materials
on all sides. Refer to Table 6 for minimum clearance values. For typical
installations, see Figure 2 on Page 5.
Figure 6: Minimum Distance to Unprotected Side Wall
Figure 5: Minimum Mantel Clearances
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS
Sides 1/2 in. (13 mm)
0 in. (0 mm) Spacers **
Top Spacers 0 in. (0 mm)
Floor 0 in. (0 mm)
Back 1/2 in. (13 mm)
0 in. (0 mm) Spacers
Bottom of Appliance To Ceiling 64 in. (1626 mm)
Vent 3 in. (76 mm) Top*
1 in. (25.4 mm) Sides & Bottom
Table 6: Appliance Minimum Clearances
Front 3 ft (0.9 m)
Table 7: Appliance Service Clearances
3 1/2 in.
(89 mm)
Top View of
Fireplace
Combustiblematerials
may project beyond
either side of the
fireplace opening as
long as they are kept
within the shaded
“Safe Zone” area.
At 0 in. minimum
side wall clearance,
one combustible
wall can project to
any length.
45o
Mantel Leg,
Trim, or Wall
12 (305) MANTEL
10 (254) MANTEL
8 (203) MANTEL
6 (152) MANTEL
4 (102) MANTEL
4
(102)
14
(356) 12
(305) 10
(254) 2 (51) MANTEL
TOP OF
APPLIANCE
6
(152)
NOTE: Hood shown as positioned in louvered
front model. The hood position in the flush
faced front model is lower than shown.
8
(203)
MANTEL CLEARANCES
Inches (mm)

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
9
PRE-INSTALLATION STEPS
The appliance is shipped with all gas controls
and components installed and pre-wired.
Before installing the appliance, follow these steps:
1. Remove the shipping carton.
2. Remove the shipping pad, exposing the
front glass door.
3. Using a Phillips screwdriver, unfasten the
two (2) screws located at the top of the glass
frame (see Figure 40 on Page 24). Tilt the
top of the glass frame away from the unit.
Lift it carefully off the bottom door track
and set the door aside, protecting it from
inadvertent damage.
4. 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 page numbers references in the
following steps for detailed procedures.
Step 1. (Page 9) Construct the appliance
framing. Position the appliance
within the framing and secure with
nailing brackets.
Step 2. (Page 11) Route gas supply line to
the right side.
Step 3. (Page 12)Install the vent system and
exterior termination.
Step 4. (Page 18) Field Wiring
Connect 120 VAC electrical power to
the appliance receptacle.
Step 5. (Page 20)Remove glass door
assembly.
Step 6. (Page 21) Make connection to gas
supply.
Step 7. (Page 21) Install rebox liner kit.
Step 8. (Page 21)Verify appliance operation.
Step 9. (Page 22) Install volcanic stone,
glowing embers, and logs.
Step 10. (Page 24)Install glass door
assembly.
Step 11. (Page 24) Adjust burner to ensure
proper flame appearance.
Step 12.(Page 27) Attach Safety-in-
Operation Warnings.
Unit Being Secured by Its Nailing
Flanges to the Framing
Note: The nailing flanges, combustible members
and screw heads located in areas directly adjacent
to the nailing flanges, are EXEMPT from the 1/2 in.
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 in. 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.
Use Top Flange For
1/2 in. Thick Drywall
Use Bottom Flange For
5/8 in. Thick Drywall
Front Of
Fireplace
Use Center Flange
For Flush Mount
Left Side Front Corner of Fireplace Shown
(Right Side Requirements the Same)
Unit Being Secured By Its Nailing Flanges
To The Framing
Note: The nailing flanges, combustible members
and screw heads located in areas directly adjacent
to the nailing flanges, are EXEMPT from the 1/2 in.
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 in. 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.
Left Side Front Corner of Fireplace Shown
(Right Side Requirements the Same).
Figure 7: Unit Secured by Nailing
Flanges to the Framing
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS
DETAILED INSTALLATION STEPS
Step 1. FRAMING
Frame these appliances as illustrated in
Figure 8 on Page 10, unless the appliance is
to be installed in a corner. See Figure 9 on
Page 11 for corner framing installations. All
framing details must allow for a minimum
clearance to combustible framing members
as shown in Table 6 on Page 8.
If the appliance is to be elevated above oor
level, a solid continuous platform must be
constructed below the appliance.
Headers may be in direct contact with
the appliance top spacers but must not
be supported by them or notched to t
around them.
The replace should be secured to the side
framing members using the unit nailing
anges—one top and bottom on each side
of the fireplace front (see Figure 7). Use 8d
nails or their equivalent.

10
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Vent Size
Co-axial DV
Vent Size
4 1/2 in. Inner
7 1/2 in. Outer
E
A
B
D
Top View
Front View
5 3/32 in. (129)
Right Side View
14 1/8 in.
8 1/2 in.
(216)
5 1/4 in.
(133)
(359) 26 15/32 in.
(672)
C
25 29/32 in.
(658)
25 1/2 in.
(648)
7 in.
2 1/2 in. (64)
(178)
19 5/8 in.
(498)
Gas Inlet
(This
Side
Only)
Electrical
Inlet
8 3/8 in.
(213)
F
G
H
J
8 / 11 in.
Vent / Intake
Notes
Diagrams, illustrations andphotographs
are not to scale – consult installation
instructions. Product designs, materi-
als, dimensions, specifications, colors
and prices are subject to change or
discontinuance without notice.
* C = Adaptor Plus 4 ft Vertical Vent (min.) and 90° Elbow
Model
No. A B C D E F G H J
MDLX40IN-PV in. 50 5/8 37 1/4 42 7/8 25 5/16 34 37 5/8 33 3/32 29 9/32 34 3/4
mm 1286 946 1089 643 864 956 840 744 883
MDLX45IN-PV in. 56 11/16 42 1/4 47 7/8 28 3/8 40 1/8 43 5/8 38 3/32 34 1/2 40 59/64
mm 1440 1073 1216 721 1019 1108 968 876 1039
Table 9: Fireplace Dimensions
Figure 8: Fireplace and Framing Specifications
LENNOX HEARTH PRODUCTS • MONTEBELLO® DLX POWER VENT DV GAS FIREPLACES (MDLX40/45IN-PV) • INSTALLATION INSTRUCTIONS
FIREPLACE AND FRAMING SPECIFICATIONS
A
BC
VENT FRAMING
TOP VENT WITH 2 FEET
VERTICAL VENT AND
ONE 90° ELBOW
Framing should be constructed
of 2x4 or larger lumber.
Inches (mm)
(641)
25 1/4 in.
1/2 A
10 1/2 in.
(267)
7 in.
(178)
5 1/8 in.
(130) 12 1/8 in.
(308)
Model No. A B C *
MDLX40IN-PV in. 50 3/4 43 139 1/8
mm 1289 1092 3534
MDLX45IN-PV in. 56 7/8 48 144 1/8
mm 1445 1219 3661
Table 8: Framing Dimensions
Adaptor Plus 4 ft
Vertical
Vent (min.)
and 90° Elbow