Lennox Merit MLDVT-35NM-FB User manual

INSTALLATION INSTRUCTIONS
Please read and understand these instructions
before starting installation.
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.
P/N 506015-10 Rev. A 03/2013
This manual is one of a set of two supporting this product.
Refer to P/N 506017-09 for Care and Operation Instructions.
Ce manuel est disponible en francais, simplement
en faire la demande. Numéro de la pièce 506223-56.
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, unless a certified kit is used.
Report No. 100326540PRT-001
ELECTRONIC:MILLIVOLT:
MLDVT Direct-Vent
Gas Fireplaces
MLDVT30NE-2
MLDVT35NE-2
MLDVT40NE-2
MLDVT45NE-2
MLDVT-30PM
MLDVT-35PM
MLDVT-35PM-FB
MLDVT-40PM
MLDVT-45PM
MLDVT-30NM
MLDVT-35NM
MLDVT-35NM-FB
MLDVT-40NM
MLDVT-40NM-FB
MLDVT-45NM
MODELS
™

DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
2
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
TABLE OF CONTENTS
Packaging ............................ 2
Introduction .......................... 2
General Information .................... 2
Requirements for the Commonwealth
of Massachusetts ...................... 4
Cold Climate Insulation.................. 4
Manufactured Home Requirements ........ 5
Location ............................. 5
Vent Termination Clearances ............. 6
Minimum Clearance to Combustibles ....... 8
Pre-Installation Steps ................... 8
Typical Installation Sequence ............. 9
Detailed Installation Steps................ 9
Optional Blower Kit Wiring ............... 9
Framing.............................. 9
Fireplace and Framing Specifications ...... 10
Routing Gas Line ..................... 11
Installing the Venting System . . . . . . . . . . . . 12
Vertical Termination Systems ............ 12
Vent Section Length Chart .............. 13
Vertical Vent Tables and Figures .......... 16
Horizontal Vent Tables and Figures ........ 20
Venting Using Flexible Vent Pipe.......... 22
Field Wiring.......................... 23
Optional Blower Kit Wiring .............. 24
Connecting Gas Line................... 24
Verifying Appliance Operation............ 25
Installing Logs ....................... 26
Removing/Installing Glass Door .......... 29
Adjusting Burner...................... 29
Installing Hood ....................... 31
Finishing Requirements ................ 31
Attaching Safety-in-Operation Warnings.... 32
Installation Accessories ................ 33
Gas Conversion Kits ................... 35
Please read and understand these
instructions before beginning
your installation.
PACKAGING
The assembled vented gas fireplace heater
is packaged with:
• (1 set) Logs
(Packaged in a carton inside the firebox)
• (1 bag) Volcanic Stone
(In bottom compartment)
• (1 bag) Glowing Embers
(In bottom compartment)
• Literature Kit
(Envelope in bottom compartment
containing Care and Operation
Instructions, Installation Instructions,
Safety-In-Operation Warning Labels,
Warranty)
• (1) U-Shaped Vent Restrictor
(Attached to Literature Kit envelope)
• (1) Hood
(Inside firebox)
INTRODUCTION
Millivolt appliances have a millivolt gas
control valve with piezo ignition system. If
any optional accessories that will require
electrical power are to be installed, the
electrical power must be provided at the
time of appliance installation.
Electronic appliances are designed to
operate on natural or propane gas. An
electronic intermittent pilot ignition system
provides safe, efficient operation. External
electrical power is required to operate
these units. In the event of a power outage,
four (4) “AA” batteries (in battery holder)
provide backup power for appliance
operation (excluding [optional] blower).
These vented gas fireplace heaters
are sealed combustion, air-
circulating gas fireplaces designed for
residential applications.
Approved Vent Components
These fireplaces are designed, tested and
listed for operation and installation with the
following vent components only:
• Secure Vent®Direct-Vent System
Components manufactured by Security
Chimneys International,
• Secure Flex®Flexible Vent Components
manufactured by Security Chimneys
International, and
• Z-FLEX®Model GA Venting Systems
listed to UL1777 and ULCS635
manufactured by Flexmaster
Canada Limited.
Use only the correct size venting (4 1/2 in.
inner and 7 1/2 in. outer).
These approved vent system components
are labeled for identification. DO NOT use
any other manufacturer’s vent components
with these appliances.
GENERAL INFORMATION
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.
NOTE: Children and adults should be alerted
to the hazards of high surface temperature
and should stay away to avoid burns or
clothing ignition.
Remarqué : 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.

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3
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
Codes and Standards
These appliances comply with National
Safety Standards and are tested and
listed by ETL/Intertek. (Report No.
100326540PRT-001) to ANSI Z21.88
(in Canada, CSA-2.33), and CAN/
CGA-2.17-M91 in both USA and Canada, as
vented gas fireplace heaters.
These appliances are listed by ETL/
Intertek for installation in bedrooms and
manufactured homes.
The installation must conform to local
codes or, in the absence of local codes, with
the National Fuel Gas Code, ANSI Z223.1/
NFPA 54—latest edition (In Canada, the
current CAN/CSA-B149.1 installation code).
The appliance, when installed, must
be electrically grounded and wired 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 or back openings
of the appliance.
These appliances are designed to operate
on natural or propane gas only. The use
of other fuels or combination of fuels will
degrade the performance of this system and
may be dangerous.
It is advisable to have an alternate primary
heat source when installed in a dwelling.
These appliances must not be connected to
a chimney or flue serving a separate solid
fuel burning appliance.
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.
Table 1: Input Rate, Gas Valves
Models Input Rate (BTU/HR)
Natural Gas Propane Gas
MLDVT-30 13,500 high
10,500 low 12,500 high 9,000 low
MLDVT-35 16,000 high
12,500 low 15,000 high 11,500 low
MLDVT-40 20,000 high
15,500 low 20,000 high 15,800 low
MLDVT-45 23,000 high
17,500 low 22,000 high 17,000 low
WARNING
Failure to position the parts in
accordance with these diagrams
or failure to use only parts
specifically 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.
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.
Remarqué : 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.
NOTE: 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.
Remarqué : 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.
NOTE: Only trim kit(s) supplied by
the manufacturer shall be used in the
installation of this appliance.
Remarqué : Seules les trousses de
garniture fournies par le fabricant
doivent être utilisées pour l’installation
de cet appareil.
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
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
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.
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 • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
4
REQUIREMENTS FOR THE
COMMONWEALTH OF
MASSACHUSETTS
These fireplaces are approved for
installation in the U.S. 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 fitter licensed in the
Commonwealth of Massachusetts.
• The flexible gas line connector used
shall not exceed 36 in. (92 cm)
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 floor level where the
gas fireplace is installed. The carbon
monoxide detector must comply with
NFPA 720, be ANSI/UL 2034 listed and
be ISA certified.
• A metal or plastic identification 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.
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 floor on which appliance rests, if
floor is above ground level. Gas line holes
and other openings should be caulked or
stuffed with unfaced fiberglass insulation.
If the fireplace is being installed on a
cement slab in cold climates, a sheet of
plywood or other raised platform can be
placed underneath to prevent conduction
of cold transferring to the fireplace and
into the room. It also helps to sheetrock
inside surfaces and tape for maximum air
tightness and caulk firestops.
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).
Orifice Sizes—Sea Level to
High Altitude
These appliances are tested and approved
for installation at elevations of 0–4500 ft
(0–1372 m) above sea level using the
standard burner orifice sizes (marked with
an “*” in Table 4).
For elevations above 4500 ft, contact your
gas supplier or qualified 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 orifice 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/CSA-B149.1 codes—
latest edition.
NOTE: Flame breadth, height and width will
diminish 4% for every 1,000 feet of altitude.
Table 4: Burner Orifice Sizes,
Elevation 0–4500 ft ( 0–1372 m)
Model Natural Gas drill size
(inches)
Propane
drill size
(inches)
MLDVT-30 #50 (0.070 in.)*
H4873•
#59 (0.041 in.)*
H7838•
MLDVT-35 (0.0748 in.)*
H1355•
(0.045 in.)*
75L10•
MLDVT-40 #44 (0.086 in.)*
60J80•
#55 (0.052 in.)*
19L52•
MLDVT-45 (0.090 in.)*
37L70•
#54 (0.055 in.)*
99K79•
* Standard size installed at factory
• Catalog number
In Canada—CAN/CGA-2.17-M91
(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.
Gas Pressure
Table 2 and Table 3 show the appliance
inlet and manifold gas pressure
requirements.
Table 2: Inlet Gas Supply Pressure
Fuel Minimum Maximum
Natural Gas 4.5 in. WC
(1.12 kPa) 10.5 in. WC (2.61 kPa)
Propane 11.0 in. WC
(2.74 kPa) 13.0 in. WC (3.23 kPa)
Table 3: Manifold Gas Supply Pressure
Fuel Low High
Natural Gas 2.2 in. WC
(0.55 kPa) 3.5 in. WC (0.87 kPa)
Propane 6.3 in. WC
(1.57 kPa) 10.0 in. WC (2.49 kPa)
Test gauge connections are provided on
the front of the electronic gas control valve
(identified IN for the inlet and OUT for the
manifold side). The control valves have a
3/8 in. (10 mm) NPT thread inlet and outlet
side of the valve (Figure 1 and Figure 2 ).
Figure 1: SIT Millivolt Gas Valve
H
I
LO
W
HTPTHTPT
P
I
L
O
T
P
I
L
O
T
O
N
it
O
F
F
IN OUT
HI/LO Variable
Flame Height
Adjustment
Manifold Pressure Tap
Inlet Pressure Tap
Pilot Adjustment
Screw
Main Gas Control Knob
OFF/PILOT/ON
Figure 2: SIT Electronic Gas Valve
Orange Wire
(from DFC
Wire
Harness)
Main
Gas Inlet
3/8 in. NPT
Green Wire
(from DFC Wire
Harness)
Inlet (IN) Test Port
Manifold (OUT)
Test Port
Hi/Lo
Flame
Control
Knob
Yellow Ground Wire
(from DFC
Wire Harness)
Propane tanks are at pressures that will
cause damage to valve components. Verify
that the tanks have step down regulators to
reduce the pressure to safe levels.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
5
The minimum height from the base of the
appliance to the underside of combustible
materials used to construct a utility shelf in
this fashion is shown in Table 8.
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 flooring, the
appliance shall be installed on a metal or
wood panel extending the full width and
depth of the appliance.
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 3).
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 3).
Figure 3: Typical Locations
NOITACILPPA
TNEVPOT
APPLICATION
TOP VENT
TNEVPOT
NOITACILPPA
RECESSED
INSTALLATION
TOP VENT
APPLICATION
NOITACILPPA
TNEVPOT
NOITACILPPA
TNEVPOT
HORIZONTAL VENT
(Top Vent Application)
VERTICAL VENT
(Top Vent Application)
NOTE: When the unit is installed with
one side flush with a wall, the wall
on the other side of the unit must
not extend beyond the front edge of
the unit.
The location should also be free of
electrical, plumbing or other heating/air
conditioning ducting.
These direct-vent appliances are uniquely
suited for installations requiring a utility
shelf positioned directly above the fireplace.
Utility shelves like these are commonly
used for locating television sets and
decorative plants.
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 (Table 8).
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, unless a certified kit is used.
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, sauf si une
trousse de conversion est utilisée.
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 or
the Canadian Electrical Code CSA
C22.1—latest edition.