Lennox Hearth Products MPDT-3328CNM-B User manual

MODELS
MPD Direct-Vent
Gas Fireplaces
CARE AND OPERATION INSTRUCTIONS
P/N 875014M Rev. P 08/2011
This manual is one of a set of two supporting this product.
Refer to P/N 850014M for Installation Instructions.
Ce manuel est disponible en francais, simplement
en faire la demande. Numéro de la pièce 875014CF.
OTL Report No. 116-F-13-4
US
Portland
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.
DON’T
THROW
IT AWAY!
This manual contains
important operating
and safety
information.
Wait...
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See Page 2 For Details
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SAFETY
GUARD
PROTECTS AGAINST BURNS
Table of Contents ........................................... 2
Safety and Your Fireplace .................................... 2
FREE Safety Guard Offer (Protects Against Burns) . . . . . . . . . . . . . . . . . 2
Important Safety Information ................................. 4
Attaching the Safety-in-Operation Warnings ..................... 5
[EN FRANÇAIS] L’information de sûreté importante ............... 3–4
Apposition des mises en garde relatives à la sécurité d’utilisation . . . . 5
[EN ESPAÑOL] Información importante de seguridad . . . . . . . . . . . . . . 3–4
Colocación de advertencias de seguridad en operación ............ 5
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.
MILLIVOLT: ELECTRONIC:
MPDT-3328CNM-B
MPDT-3328CPM-B
MPDR-3328CNM-B
MPDR-3328CPM-B
MPD-3530CNM-B
MPD-3530CPM-B
MPD-4035CNM-B
MPD-4035CPM-B
MPD-4540CNM-B
MPD-4540CPM-B
MPDT-3328CNE-B
MPDT-3328CPE-B
MPDR-3328CNE-B
MPDR-3328CPE-B
MPD-3530CNE-B
MPD-3530CPE-B
MPD-4035CNE-B
MPD-4035CPE-B
MPD-4540CNE-B
MPD-4540CPE-B

2
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Safety and
Your Fireplace
 To prevent severe burns and injuries, install
a screen or physical barrier to prevent direct
contact with the glass.
To order a FREE Lennox
®
SAFETY GUARD
for your fireplace, see details at left.
 Follow the safety instructions below
and be sure everyone in your household
understands this burn hazard:
• The surfaces on your fireplace get
EXTREMELY HOT!
• The glass on the front
of the fireplace reaches
EXTREMELY HIGH
temperatures and can
cause severe burns if touched.
• Keep children away from an operating
fireplace. Closely supervise children in
any room where a fireplace is operating
to prevent contact with glass.
• Keep clothing, furniture,
gasoline, and other
flammable liquids away
from the fireplace.
• Even after the gas is turned off, fireplace
surfaces remain extremely hot.
 Be sure to attach the enclosed Safety-in-
Operation Warnings where you turn on your
fireplace, to help remind everyone of the
dangers associated with high temperatures
(see page 5).
 Read Important Safety Information on
page 4.
All parts of your Lennox
Hearth Products fireplace
get EXTREMELY HOT!
Table of Contents
Safety and Your Fireplace ........................................ 2
Important Safety Information ..................................... 4
Attaching the Safety-in-Operation Warnings ......................... 5
Appliance Installation, Service, and Maintenance Notices . . . . . . . . . . . . . . . . . 6
Appliance Operation Notices .......................................6
Warranty Information .............................................6
General Information ............................................. 6
BTU Input ....................................................7
Gas Pressure Requirements ......................................7
Orifice Sizes ..................................................7
Burn-In Period ................................................7
Operation/Care of Your Appliance ...................................8
Gas Controls Access .............................................8
Variable Flame Adjustment .........................................9
Maintenance ...................................................10
Front Glass Enclosure Panel, Removal and Installation . . . . . . . . . . . . . . . . . . 11
Install Volcanic Stone, Embers and Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Burner Flame Appearance/Sooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Burner Flame Adjustments ........................................17
Millivolt Appliance Checkout ......................................17
Electronic Appliance Checkout .....................................17
Wiring Diagrams ...............................................18
Warranty .....................................................18
Ordering Replacement Parts ......................................18
Product Reference Information ....................................18
Fireplace Shipping Weights/Volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Accessory Components ..........................................19
Maintenance Schedule ...........................................25
Lighting Instructions – Millivolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Lighting Instructions – Electronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Troubleshooting Guide – Millivolt Gas Control System . . . . . . . . . . . . . . . . . . 30
Troubleshooting Guide – Electronic Gas Control System . . . . . . . . . . . . . . . . . 31
Replacement Parts List ..........................................32
• FREE
SAFETY GUARD OFFER •
The Lennox® SAFETY GUARD protects against
severe burns and injuries by preventing direct contact
with the front glass surface of your fireplace.
To receive your FREE SAFETY GUARD, call 1-800-786-7976
or visit www.lennox.com (Hearth / Owner Resources).
Note: Safety Guards may not be available for some
older models that are no longer in production.
Thank you for your purchase. We appreciate your business!
Please carefully read and follow all instructions in this manual.
Pay special attention to all warnings and safety information.
Following these safety, care, and operation instructions will help ensure
many years of dependable and enjoyable service from your fireplace.
Register your product online today!
To help us keep you up-to-date on product information and offers,
please take a few moments to register your product online at
www.lennox.com (Hearth / Owner Resources) .

3
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
 Afin d'éviter de vous brûler gravement ou de
vous blesser, installez une grille ou une barrière
physique pour empêcher tout contact direct
avec la vitre.
Pour commander un PANNEAU DE PROTECTION
Lennox® GRATUIT pour votre foyer, consultez
les détails dans la partie gauche.
 Suivez les instructions de sécurité ci-dessous
et veillez à ce que tous les membres de votre
famille soient conscients du danger de brûlure
encouru :
• Les surfaces de votre foyer deviennent
EXTRÊMEMENT CHAUDES !
• La vitre située à l'avant du foyer
atteint des températures
EXTRÊMEMENT ÉLEVÉES et peut causer
de graves blessures en cas de contact.
• Tenez les enfants à l'écart du foyer lorsqu'il
fonctionne. Surveillez attentivement
les enfants dans les pièces où un foyer
est utilisé afin d'éviter qu'ils ne soient
en contact avec la vitre.
• Tenez tous les vêtements, les
meubles, l'essence et tout autre
liquide inflammable à l'écart du foyer.
• Même après fermeture du gaz, les surfaces
du foyer restent extrêmement chaudes.
 Veillez à coller les Étiquettes de mise en garde
relatives à la sécurité d'utilisation à l'endroit
où vous utilisez le foyer, pour rappeler à tous les
utilisateurs les dangers liés aux températures
élevées (voir page 5).
 Lisez la section Informations importantes
relatives à la sécurité, page 4.
Toutes les parties de votre foyer
Lennox Hearth Products deviennent
EXTRÊMEMENT CHAUDES !
 Instale una malla o barrera física para evitar
el contacto directo con el vidrio y prevenir
las quemaduras y lesiones graves.
Ver los detalles a la izquierda para ordenar
un Lennox® SAFETY GUARD GRATIS
para su chimenea.
 Siga las instrucciones de seguridad a
continuación y asegúrese de que todos
en su hogar sepan acerca de este peligro
de quemadura:
• ¡Las superficies de la chimenea se ponen
MUY CALIENTES!
• El vidrio delante de la chimenea alcanza
temperaturas EXTREMADAMENTE ALTAS y
puede causar quemaduras graves si se toca.
• Mantenga a los niños alejados de la
chimenea en funcionamiento. Supervise
en forma cercana a los niños en cualquier
cuarto donde haya una chimenea
funcionando para impedir el contacto
con el vidrio.
• Mantenga la ropa, mobiliario, gasolina
y otros líquidos inflamables alejados
de la chimenea.
• Aún después de haber apagado el gas,
las superficies de la chimenea permanecen
extremadamente calientes.
 Asegúrese de colocar las Etiquetas de
advertencia de seguridad de operación en
el lugar donde enciende la chimenea, para
que todos recuerden los peligros asociados
con las altas temperaturas (ver la página 5).
 Lea la Información importante de seguridad
en la página 4.
¡Todas las partes de la chimenea
Lennox Hearth Products se ponen
MUY CALIENTES!
Seguridad y
su chimenea
La sécurité et
votre foyer
[FRENCH] [SPANISH]

LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
4
Important Safety Information
1. WARNING: Do not operate appliance with the glass front
removed, cracked or broken. Replacement of the glass
should be done by a licensed or qualified service person .
2. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect
the appliance and to replace any part of the control system
and any gas control which has been under water.
3. Due to high temperatures, the appliance should be located
out of traffic and away from furniture and draperies.
4. Children and adults should be alerted to the hazards of
high surface temperature and should stay away to avoid
burns or clothing ignition.
5. Clothing or other flammable material should not be placed
on or near the appliance.
6. 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.
7. Any safety screen or guard removed for servicing an
appliance must be replaced prior to operating the
appliance.
8. 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, et cetera.
It is imperative that control compartments, burners, and
circulating air passageways of the appliance be kept
clean. See maintenance instructions on page 10.
L’information de sûreté importante
1. AVERTISSEMENT. Ne pas utiliser l’appareil si le panneau frontal
en verre n’est pas en place, est craqué ou brisé. Confiez le
remplacement du panneau à un technicien agréé
2. 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.
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.
4. Les enfants et les adultes devraient être informés 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.
5. On ne devrait pas placer de vêtements ni d’autres matières
inflammables sur l’appareil ni à proximité.
6. 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.
7. Tout écran ou protecteur retiré pour permettre l’entretien de
l’appareil doit être remis en place avant de mettre l’appareil en
marche.
8. 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 poussière. Il est essentiel que les
compartiments abritant les commandes, les brûleurs et les
conduits de circulation d’air de l’appareil soient tenus propres.
Voyez les instructions d’entretien à la page 10.
[SPANISH]
Información importante de seguridad
1. ADVERTENCIA: No opere el artefacto con el frente de vidrio quitado,
agrietado o roto. Un técnico de servicio licenciado o capacitado
debe reemplazar el vidrio.
2. No use este artefacto si alguna de sus partes ha estado bajo agua.
Llame de inmediato a un técnico de servicio calificado para que
inspeccione el artefacto y reemplace cualquier parte del sistema
de control y cualquier control de gas que haya estado bajo agua.
3. Debido a las altas temperaturas, el artefacto debe situarse fuera
de las áreas de tráfico y lejos del mobiliario y cortinas.
4. Se debe alertar a los niños y adultos sobre los peligros de
las altas temperaturas en la superficie y que se mantengan
alejados para evitar quemaduras o ignición de la ropa.
5. No debe colocarse ropa u otros materiales inflamables
sobre y cerca del artefacto.
6. Se debe supervisar de cerca a los niños cuando estén en el mismo
cuarto que el artefacto. Los niños pequeños, los jóvenes y otras
personas pueden ser susceptibles a quemaduras por contacto
accidental. Se recomienda instalar una barrera física si hay
personas en riesgo en la casa. Para restringir el acceso a una
chimenea o estufa, instale una puerta de seguridad ajustable
para mantener a los niños pequeños, jóvenes y otras personas
en riesgo fuera del cuarto y lejos de las superficies calientes.
7. Cualquier malla o resguardo de seguridad quitado para dar servicio
a un artefacto, debe reinstalarse antes de operar el artefacto.
8. Una persona de servicio competente debe realizar la instalación y
reparación. Una persona de servicio profesional debe inspeccionar
el artefacto antes de usar al menos una vez por año. Se puede
requerir limpieza más frecuente debido a la pelusa excesiva
del alfombrado, del material de cobijas, etc. Es imprescindible
mantener limpios los compartimientos de control, los quemadores
y los pasajes de circulación del aire del artefacto. Ver las
instrucciones de mantenimiento en la página 10.

LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
5
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
APPOSITION DES MISES EN GARDE RELATIVES
À LA SÉCURITÉ D’UTILISATION
Votre foyer a été livré avec des étiquettes de sécurité qui
doivent être collées à côté des dispositifs de contrôle
du foyer. Une étiquette de sécurité doit être collée sur
la plaque de l’interrupteur contrôlant l’allumage du
foyer (voir Figure A) ou sur le thermostat mural (voir
Figure B) et, le cas échéant, sur le boîtier de la télé-
commande (Figure C). Les mises en garde auraient dû
être collées au moment de l’installation initiale du foyer.
Si ce n’est pas le cas, prenez les étiquettes adhésives
multilingues fournies avec ces instructions et procédez
comme suit:
1. Repérez l’interrupteur ou le thermostat mural
qui contrôle le foyer (vérifiez que l’interrupteur
contrôle le fonctionnement du foyer en le faisant
basculer de Marche à Arrêt, et vice-versa). Nettoyez
soigneusement la plaque murale de l’interrupteur
ou le thermostat mural pour éliminer la poussière
et les traces de graisse ou d’huile. Collez l’étiquette
sur la surface de la plaque de l’interrupteur mural
qui contrôle le foyer (Figure A) ou du thermostat
mural (Figure B). Choisissez la langue qui est
principalement parlée dans la résidence du
propriétaire.
2. Si une télécommande est utilisée pour contrôler
le foyer, nettoyez la soigneusement pour éliminer
la poussière et les traces de graisse ou d’huile.
Collez l’étiquette sur le boîtier de la télécommande
(Figure C). Choisissez la langue qui est principale-
ment parlée dans la résidence du propriétaire.
3. Si vous ne trouvez pas les étiquettes, veuillez
appeler Lennox Hearth Products ou votre distribu-
teur Lennox Hearth Products local pour recevoir
gratuitement des étiquettes supplémentaires.
Étiquettes de remplacement, n° cat. H8024
LENNOX HEARTH PRODUCTS
1-800-9-LENNOX
Remarque : Le texte anglais est rouge sur un support
transparent. Le texte français et espagnol est blanc
sur un support noir.
COLOCACIÓN DE ADVERTENCIAS DE
SEGURIDAD EN OPERACIÓN
Su chimenea incluye etiquetas de instrucciones de
seguridad que deben colocarse en el punto de operación
y control de la chimenea. Se debe colocar una etiqueta de
instrucciones de seguridad en la placa del interruptor de
pared desde el cual se enciende y se apaga la chimenea
(ver la Figura A) o en el termostato de pared (ver la Figura
B) y en el transmisor de control remoto (Figura C) si
se usa. Las advertencias ya deben haberse colocado
cuando se completó la instalación inicial de la chimenea.
Si no están colocadas en estos lugares, encuentre las
etiquetas adhesivas multilingües proporcionadas con
estas instrucciones y prosiga de la siguiente manera:
1. Identifique el interruptor o el termostato de pared
que controla la chimenea (verifique que el interruptor
opera la chimenea encendiéndola y apagándola).
Limpie bien la placa del interruptor o el termostato de
pared para quitar el polvo y aceite. Pegue la etiqueta
en la superficie de la placa del interruptor que controla
la chimenea (Figura A) o en el termostato de pared
(Figura B). Seleccione el idioma que más se habla
en la casa.
2. Si se usa un control remoto para controlar la
chimenea, encuentre el transmisor y límpielo bien
para quitar el polvo y aceite. Pegue la etiqueta en la
superficie del transmisor (Figura C). Seleccione el
idioma que más se habla en la casa.
3. Si no puede encontrar las etiquetas, sírvase llamar a
Lennox Hearth Products o al distribuidor de Lennox
Hearth Products más cercano para recibir etiquetas
de instrucciones de seguridad adicionales gratuitas.
Juego de etiquetas de repuesto - Nº de cat. H8024
LENNOX HEARTH PRODUCTS
1-800-9-LENNOX
Nota: La etiqueta en inglés es transparente con texto
rojo. Las etiquetas en francés y español son negras
con texto blanco.
ATTACHING SAFETY-IN-OPERATION
WARNINGS
Your fireplace has been furnished with safety instruc-
tion labels that are to be affixed to the operation and
control point of the fireplace. A safety instruction
label should be affixed to the wall switch plate where
the fireplace is turned on and off (See Figure A) or
wall thermostat (See Figure B) and if used on the
remote control handheld transmitter (Figure C).
The warnings should already have been put in place
when the fireplace initial set-up was completed.
If they are not affixed at these spots, locate the
multi-lingual adhesive labels provided with these
instructions and proceed as follows:
1. Locate the wall switch or wall thermostat that
controls the fireplace (verify the switch operates
the fireplace by turning it on and off). Clean the
wall switch plate or wall thermostat thoroughly
to remove any dust and oils. Affix the label to
the surface of the plate of the wall switch that
controls the fireplace (Figure A) or the wall
thermostat (Figure B). Choose the language
primarily spoken in the home.
2. If a remote control is used to control the fireplace,
locate the transmitter and clean it thoroughly
to remove any dust and oils. Affix the label to
the surface of handheld transmitter (Figure C).
Choose the language primarily spoken in the
home.
3. If you are unable to locate the labels, please call
Lennox Hearth Products or your nearest Lennox
Hearth Products dealer to receive additional
safety instruction labels free of charge.
Cat. No. H8024 Replacement Label Kit
LENNOX HEARTH PRODUCTS
1-800-9-LENNOX
Note: English is red text on clear label. French and
Spanish are white text on black label.
Figure A Figure B Figure C
HOMEOWNER’S INSTRUCTIONS - ATTACHING SAFETY-IN-OPERATION WARNINGS
SAFETY LABEL
DIAGRAMS
DIAGRAMAS DE ETIQUETAS
DE SEGURIDAD
DIAGRAMMES DES ÉTIQUETTES
DE SÉCURITÉ

6
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
GENERAL INFORMATION
The fireplace models covered in this manual
are direct-vent sealed combustion gas fireplace
heaters designed for residential application.
These direct-vent appliances operate with the
combustion chamber completely isolated from
the indoor environment.
All air for combustion is brought in from the
outside and exhaust gases are vented through
the same direct-vent, co-axial (intake/exhaust)
vent system.
The Millivolt appliances have a millivolt gas
control valve with piezo ignition system. If any
optional accessories which require electrical
power are being installed, the electrical power
must be provided at the time of appliance in-
stallation.
The Electronic appliances are designed to
operate on either natural or propane gas. An
electronic intermittent pilot system provides
safe, efficient operation. External electrical
power is required to operate these units.
These appliances comply with National
Safety Standards and are tested and listed
by OMNI-Test Laboratories, Inc. (Report No.
116-F-13-4) to ANSI ZZ21.88 (in Canada, CSA-
2.33), and CAN/CGA-2.17-M91 in both USA and
Canada, as vented gas fireplace heaters.
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, or the Natural Gas and Propane
Installation Code, CAN/CSA B149.1-latest edi-
tion. The appliance, when installed, must be
electrically grounded in accordance with local
codes or, in the absence of local codes, the
latest edition of the National Electrical Code,
ANSI/NFPA 70, or the Canadian Electrical Code,
CSA C22.1 - latest editions.
WARRANTY INFORMATION
Your gas appliance is covered by a limited
twenty-year warranty. You will find a copy of
the warranty accompanying this manual. Please
read the warranty to be familiar with its coverage.
Retain this manual. File it with your other docu-
ments for future reference.
Failure to comply with the installation
and operating instructions provided
will result in an improperly installed
and operating appliance, voiding its
warranty.
Do not attempt to alter or modify the
construction of the appliance or its com-
ponents. Any modification or alteration
may void the warranty, certification, and
listings of this unit.
APPLIANCE OPERATION NOTICES
Do not operate appliance with the glass
front removed, cracked, or broken.
These fireplaces are vented gas appli-
ances. Do not burn wood or other
material in these appliances.
This appliance is only for use with the
type of gas indicated on rating plate. This
appliance is not convertible for use with
other gases, unless a certified kit is used.
These appliances are designed to operate
on natural gas or propane gas only. The
use of other fuels or combinations of
fuels will degrade the performance of this
system and may be dangerous.
Provide adequate clearances around
air openings and adequate accessibility
clearance for service and proper opera-
tion. Never obstruct the front openings
of the appliance.
Do not use this appliance if any part has
been under water. Immediately call a
qualified service technician to inspect
the appliance and to replace any part of
the control system and any gas control
that has been under water.
These fireplaces are designed as supple-
mental heaters. Therefore, it is advisable
to have an alternate primary heat source
when installed in a dwelling.
APPLIANCE INSTALLATION, SERVICE,
AND MAINTENANCE NOTICES
IMPORTANT: 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.
Only trim kit(s) supplied by the manufac-
turer shall be used in the installation of
this appliance.
Draft relief openings must not be covered
or blocked.
These appliances must not be connected
to a chimney or flue serving a separate
solid fuel burning appliance.
Any change to this appliance and/or
its operating controls is dangerous.
Improper installation or use of this
appliance can cause serious injury or
death from fire, burns, explosion or
carbon monoxide poisoning.
CARBON MONOXIDE POISONING: Early
signs of carbon monoxide poisoning are
similar to the flu with headaches, dizzi-
ness and/or nausea. If you have these
signs, obtain fresh air immediately.
Turn off the gas supply to the appliance
and have it serviced by a qualified
professional, as it may not be operating
correctly. Some people are more
affected by carbon monoxide than others,
including pregnant women, people with
heart or lung disease or anemia, those
under the influence of alcohol, and those
at high altitudes.
Turn off gas and electrical power to the
fireplace and allow it to cool before
cleaning or servicing the appliance.
The vent termination is hot while in
operation and for a period of time fol-
lowing the use of the fireplace. Young
children should be carefully supervised
when they are in the same area as a hot
termination

7
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-1372 meters)
Model
Series
Nat.Gas
drill size (inches)
Propane
drill size (inches)
MPDT-3328
MPDR-3328
#45 (0.0820")*
39L66•
0.048 inch
99K78•
MPD-3530 #44 (0.0860")*
60J80•
#55 (0.0520")*
19L52•
MPD-4035 #37 (0.1040")*
24M10• 0.063 inch
21L01•
MPD-4540 #36 (0.1065")*
18L40•
#52 (0.0635")*
37G00•
Table 4 * Standard size installed at factory
• Part /Cat. Number
NOTICE: A white film may develop
on the glass enclosure panel during
the first few fires as part of the burn-in
process.
The first few times you use the
fireplace, clean the glass after each use
(AFTER THE GLASS HAS COMPLETELY
COOLED); otherwise, the white film
will bake onto the glass and become
difficult to remove.
See glass cleaning instructions on
Page 9.
GENERAL INFORMATION (continued)
Manifold Gas Supply Pressure
(all models)
Fuel # Low High
Natural
Gas
(Lo) 1.6" WC
(0.40 kPa)
(Hi) 3.5" WC
(0.87 kPa)
Propane (Lo) 6.3" WC
(1.57 kPa)
(Hi) 10.0" WC
(2.49 kPa)
Table 3
BTU Input
These fireplaces are designed as supplemental
heaters. Therefore, it is advisable to have an
alternate primary heat source when installed
in a dwelling.
Millivolt Models - The millivolt appliances are
manually controlled and feature a spark igniter
(piezo) that allows the appliance's pilot gas to
be lit without the use of matches or batteries.
This system provides continued service in the
event of a power outage.
Millivolt models come standard with a manually-
modulated gas valve; flame appearance and heat
output can be controlled at the gas valve. The BTU
Input for these appliances is shown in Table 1.
Electronic Models - Electronic models have a
fixed rate gas valve. Input of electronic models
is shown in Table 1.
Burn-in Period
During the first few fires of this appliance there
will be some odor due to the curing of the
paint and burning off of lubricants used in the
manufacturing process. Depending on your
use, the burn-in period may take a few hours
or a few days.
KEEP YOUR HOUSE WELL VENTILATED
DURING THE CURING PROCESS. THE ODOR
AND HAZE EMITTED DURING THE CURING
PROCESS CAN BE QUITE NOTICEABLE AND
MAY SET OFF A SMOKE DETECTOR.
If an optional blower is installed, do not turn it
on during the burn-in period.
Test gauge connections are provided on the
front of the millivolt and electronic gas control
valve (identified IN for the inlet and OUT for the
manifold side). The control valves have a 3/8"
(10mm) NPT thread inlet and outlet side of the
valve (refer to Figures 1 and 2).
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.
These appliances must not be connected to a
chimney or flue serving a separate solid fuel
burning appliance.
Orifice Sizes - Sea Level to High Altitude
(All Models)
These appliances are tested and approved for
installation at elevations of 0-4500 feet (0-1372
meters) above sea level using the standard burner
orifice sizes (marked with an "*" in Table 4 ).
For elevations above 4500 feet, contact your
gas supplier or qualified service technician.
These appliances must be isolated from the
gas supply piping system (by closing their
individual manual shut-off valve) during any
pressure testing of the gas supply piping
system at test pressures equal to or less
than 1/2 psig (3.5 kPa).
These appliances and their individual shut-off
valves must be disconnected from the gas
supply piping system during any pressure
testing of that system at pressures greater
than 1/2 psig (3.5 kPa).
Inlet Gas Supply Pressure
(all models)
Fuel # Minimum Maximum
Natural Gas 4.5" WC
(1.12 kPa)
10.5" WC
(2.61 kPa)
Propane 11.0" WC
(2.74 kPa)
13.0" WC
(3.23 kPa)
Table 2
Gas Pressure - All Models
Tables 2 and 3 show the appliances' inlet and
manifold gas pressure requirements:
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 or by 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.
Install the appliance according to the regulations
of the local authorities having jurisdiction and,
in the USA, the National Fuel Gas Code NFPA
54 / ANSI Z223.1 - latest edition or, in Canada,
the CAN/CSA-B149.1 - latest edition.
Flame breadth, height and width will dimenish
4% for every 1,000 feet of altitude.
Input (BTU/HR) Gas Valves (all models)
Models Input Rate (BTU / HR)
Nat. Gas Prop. Gas
MPDT/R-3328
(Millivolt) 17,500 high 11,700 low 17,500 high 14,000 low
MPD-3530
(Millivolt) 20,000 high 12,800 low 20,000 high 15,200 low
MPD-4035
(Millivolt) 27,000 high 18,500 low 27,000 high 21,500 low
MPD-4540
(Millivolt) 29,000 high 20,500 low 29,000 high 22,500 low
MPDT/R-3328
(Electronic) 17,500 17,500
MPD3530
(Electronic) 20,000 20,000
MPD4035
(Electronic) 27,000 27,000
MPD4540
(Electronic) 29,000 29,000
Table 1

8
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
OPERATION AND CARE OF YOUR APPLIANCE
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 trou-
vent 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.
Gas Controls/Control Compartment
Access
Operation of millivolt and electronic gas con-
trol systems is different. Before lighting and
operating your appliance, determine whether
you have a millivolt or electronic appliance.
The gas controls can be found behind the lower
access panel.
To open the panel, press the upper right corner
of the panel until the spring-loaded magnetic
catch is released. Then gently pull the panel
forward to release the left magnetic catch and
allow the panel to swing down to open.
On millivolt systems, the piezo ignitor, Hi/Lo
flame adjustment knob, pilot and main gas ON/
OFF control knob, and gas valve (Figure 1) are
located behind the lower access panel.
On electronic systems, the gas valve is located
behind the lower access panel.
Refer to Figure 1 for access to the gas control
valve. Millivolt appliances will be fitted with the
gas control valve shown in Figure 2.
Appliances with electronic systems will be fitted
with the electronic valve shown in Figure 3.
Familiarize yourself with the gas control valve
that your appliance uses.
Figure 1
To remove the lower access panel, slide the
hinge pin on the left side of the panel to the
RIGHT until it disengages from the left corner
post hole. Pull the panel diagonally to the LEFT,
away from the fireplace.
To ease panel replacement, press the spring-
loaded catches to temporarily lock them in
their retracted position, and then close the
panel.
Piezo Ignitor on SIT Millivolt
Gas Valve
Piezo
Ignitor
SIT Gas Valve

9
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Figure 3
Honeywell Electronic
Gas Valve
Figure 2
Note: The piezo ignitor is located behind the lower access panel (see Figure 1).
Variable Flame Height Adjustment
(Millivolt appliances only)
1. All Millivolt appliances are equipped with
a variable gas control valve. Flame height for
these models may be adjusted through a range
between fixed low and high settings, alternately,
while the appliance is in operation.
Adjust the flame height as desired after lighting
the appliance by rotating the variable adjustment
control knob located on the front of the valve
(refer to Figure 2).
2. When lit for the first time, this appliance will
emit a slight odor for an hour or two. This is due
to the “burn-in” of internal paints and lubricants
used in the manufacturing process.
3. Keep lower control compartment clean by
vacuuming or brushing at least twice a year.
More frequent cleaning may be required due to
excessive lint from carpeting, bedding materials,
etc. It is important that control compartments,
burners and circulating air passageways of the
appliance be kept clean and clear of obstruction
of venting and combustion air.
4. Always turn off gas to the pilot (millivolt
appliances) before cleaning. Before re-lighting,
refer to the lighting instructions in this manual.
Instructions are also found on a pull-out panel
located on the floor of the appliance.
5. Always keep the appliance area clear and
free from combustible materials, gasoline and
other flammable liquids.
6. Remember, Millivolt appliances have a con-
tinuous burning pilot flame. Exercise caution
when using products with combustible vapors.
H
I
LO
W
TPTH TP TH
P
I
L
O
T
P
I
L
O
T
O
N
it
O
F
F
Variable Flame Height Adjustment
Manifold Pressure Port
Inlet Pressure Port
Main Gas
Control Knob
IN OUT
SIT Millivolt Gas Valve
ON/OFF Switch Manifold Pressure Port
OFF
IN
PSI
ON
CONTROL
IGNITER
Inlet
Pressure
Port
Electronic
Gas Control
Valve
Millivolt Appliances
To light millivolt appliances, refer to the detailed
lighting instructions found on page 26 (English)
and page 27 (French). Millivolt appliance
lighting instructions may also be found on the
pull-out lighting instruction labels attached to
the gas control valve.
Millivolt units are not provided with any
factory-installed controls; therefore, one of the
optional control switches is required to operate
the unit (ON/OFF Wall Switch, Unit-Mountable
ON/OFF Switch, Thermostat, Remote Control).
See “Accessories” in this manual for details.
Once the pilot is lighted, use the switch or re-
mote control to turn the appliance ON and OFF.
Electronic Appliances
To light electronic appliances, refer to the
detailed lighting instructions on Page 28
(English) and Page 29 (French). Electronic
appliance lighting instructions may also be
found on the pull-out lighting instruction label
attached to the gas control valve.
The electronic gas valve has an integrated ON/
OFF burner control switch.
The appliance can
be turned ON and OFF using this integrated
switch.
If your electronic appliance is equipped with an
optional wall switch or remote control kit, the
appliance main burner may be turned ON and
OFF using the wall switch or remote control.

10
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
MAINTENANCE
(See Maintenance Schedule, Page 25 )
Refer to the maintenance schedule for maintenance
tasks, procedures, periodicity and by whom they
should be performed. Always verify proper opera-
tion of the appliance after servicing.
Replacing Logs
If the logs become damaged by accident or
improper handling and need replacement,
use only the proper replacement logs from
manufacturer (see Pages 13,14 and 15 for
ordering information).
Reinstall Embers and Logs
Carefully follow placement instructions on
Pages 12 through 15. All logs should fit
onto corresponding pins and/or log stop-
pers. This will ensure a proper flame and safe
combustion.
Inspect Wiring
Refer to wiring diagrams on Page 18.
CAUTION: Label all wires prior to discon-
nection when servicing controls. Wiring
errors can cause improper and dangerous
operation. Verify proper operation after
servicing.
ATTENTION: Au moment de l'entretien
des commandes, étiquetez tous les fils
avant de les débrancher. Des erreurs
de cáblage peuvent entraîner un fonc-
tionnement inadéquat et dangereux.
Inspect and clean all wire connections. Ensure
that there is no melting or damage. Inspection
should include:
• Terminals at the Valve
• OFF/ON Switch
• (Optional Control Switch) Wall Thermostat,
Remote Control or Remote Wall Switch Kit
Inspect Burner Flame Appearance
Ensure that the burner flame appearance
resembles the flame shown in Figures 10, 11
and 12 and as described in Flame Appearance
and Sooting on Page 16. The Homeowner must
contact a qualified service technician at once if
any abnormal condition is observed.
Small Area Paint Touch-up
Only use a factory supplied paint kit for touch-
ups. Paint is available at your local authorized
Lennox Hearth Products dealer. Never attempt
to paint a hot fireplace.
Do not attempt to repaint the appliance until
the finish is completely cured (see Burn-In
Period on Page 4). If the surface later becomes
stained or marred, it may be lightly sanded and
touched up with spray paint.
CAUTION: Wear gloves and safety glasses
for protection while doing required
maintenance.
Verify proper operation after servicing.
S'assurer que l'appareil fonctionne adé-
quatement une fois l'entretien terminé.
Always turn off gas to the pilot (millivolt
appliances) before cleaning. Before re-
lighting, refer to the lighting instructions
in this manual. Instructions are also found
on a pull-out panel located in the control
compartment.
Inspect Venting System
The appliance and venting system should be
thoroughly inspected before initial use and
at least annually by a qualified service techni-
cian (inspection should include ensuring that
exhaust or intake passages are unobstructed
and vent components are properly assembled
and not damaged). Homeowner must contact
a qualified service technician at once if any
abnormal condition is observed.
If the venting system is disassembled for any
reason, a qualified service technician should
follow vent installation instructions for proper
reassembly and proper sealing of the venting
system components. However, more frequent
periodic inspections and cleanings should be
performed by the homeowner.
Cleaning Glass
(see Front Glass Enclosure Panel, Removal and
Installation on Page 11).
Note: Clean glass after first two weeks of opera-
tion (after Burn-In period is over) and then only
when necessary and when the fireplace is cool.
Wipe surface with a clean, dampened, soft cloth.
Follow with a dry, soft towel as desired. Take
care not to scratch the glass surface.
The viewing glass should be cleaned periodi-
cally to remove any build-up caused from the
following:
IMPORTANT: Do not use abrasive clean-
ers on glass. Never clean the glass when
it is hot.
• During start-up, it is normal for condensa-
tion to form on the inside of the glass (this
condensation and fog will usually disappear
in a few minutes). The moisture can cause
lint, dust and other airborne particles to cling
to the glass surface.
• Initial curing of the high temperature paint
and burning off of lubricants used in the
manufacturing process may result in a film
on the glass.
• A white coating may form on the glass as a
result of impurities and minerals in the fuel.
It is recommended that the glass be cleaned
two or three times during each heating season,
depending on the circumstances present. The
following cleaning solutions are approved for
use to clean glass:
• Non-ammonia based household cleaner
• 50%-50% mix of white vinegar and water
• Gas fireplace/stove glass cleaner
Inspect Glass Gasket - Visually inspect the
gasket on the backside of the glass enclosure
panels. The gasket surface must be clean, free
of irregularities and seated firmly.
Clean Control Compartment
Keep control compartment clean by vacuuming
or brushing at least twice a year. More frequent
cleaning may be required due to excessive lint
from carpeting, bedding materials, etc. It is
important that control compartments, burners
and circulating air passageways of the appliance
be kept clean.
Clean Logs And Burner
Carefully remove the logs (use care when han-
dling the fiber logs, as they become quite fragile
after curing). Vacuum out any foreign matter
(lint, carbon, etc.) on the burner. Ensure the
burner ports are “open.” Remove any carbon
deposits from the under side of the logs using
a vacuum cleaner, or a soft bristled brush (i.e.
paint brush).
Note: Improper positioning of logs can create
carbon build-up and will alter the performance
of the appliance.
WARNING
Turn off gas and electrical power
to the fireplace and allow it to
cool before cleaning or servicing
the appliance.

11
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Front Glass Enclosure Panel, Removal
and Installation WARNING
Any safety screen or guard
removed for servicing the appli-
ance 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
• Do not attempt to substitute the
materials used on this door, or
replace cracked or broken glass.
• Handle this glass with extreme
care! Glass is susceptible to
damage – Do not scratch or
handle roughly while reinstall-
ing the glass door frame.
• The glass door(s) of this appli-
ance must only be replaced as a
complete unit as provided by the
manufacturer. Do not attempt
to replace broken, cracked or
chipped glass separately.
• Do not attempt to touch the front
enclosure glass with your hands
while the fireplace is in use.
WARNING
Do not operate appliance with
the glass front removed, cracked
or broken.
AVERTISSEMENT
Ne pas utiliser l'appareil si le
panneau frontal en verre n'est
pas en place, est craqué ou
brisé.
Only doors certified with the appliance
shall be used.
Seules des portes certifiées pour cet
appareil doivent être utilisées.
CAUTION: DO NOT abuse glass door by
striking or slamming shut.
These are direct-vent appliances. They are
designed to operate only when the front glass
enclosure panels are installed. Generally the
front glass enclosure panel should not be re-
moved except to gain access to the components
within the firebox.
Removing Glass Enclosure Panels
(see Figure 4 )
Remove the top louver assembly or radiant
panel.
To access the glass door securing latches,
first open the lower control compartment door
(Figure 4 ) by pushing in simultaneously the left
and right top corners of the door. (The door
is hinged at the bottom.) Remove the bottom
compartment door by sliding the hinge pin,
located at the door’s left side, to the right until
it disengages from the left corner post hole.
Pull the door diagonally to the left, away from
the fireplace.
Glass Door Latch
Lower Compartment Door and Hinge
Glass Door
Firebox Floor
Bottom Vee-flange
Glass Door Frame
Top Flange
Glass Door Frame
Modesty
Panel
Figure 4
Locate the two (2) latches at the top of the
control compartment and disengage them from
the door frame bottom vee-flange, pulling down
on their handles to open them.
Retrieve the glass door. Visually inspect the
gasket on the backside of the frame. Gasket
surface must be clean, free of irregularities
and seated firmly.
Position the door in front of the firebox opening
with the bottom of the door held away from the
fireplace (Figure 4 ). Hook the top flange of the
door frame over the top of the firebox frame.
Let the bottom of the door frame swing gently
in towards the fireplace ensuring that the gasket
seats evenly as the door frame draws shut.
Fasten the two latches located underneath the
firebox floor to the door's vee-flange. Close
both the latches securely.

12
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
INSTALL VERMICULITE, VOLCANIC
STONE, GLOWING EMBERS, AND LOGS
NOTE: Turn off all electricity to the appliance
before you install vermiculite, volcanic stone,
embers and logs. DO NOT attempt to install
the logs until the appliance installation has been
completed, the gas line connected and tested
for leaks and the initial burner operation has
been checked out.
Step 1. Remove the appliance front door (see
Removing Glass Enclosure panel on page 11.
Step 2. Install vermiculite and volcanic stone -
Sprinkle the vermiculite and volcanic stone in a
pleasing pattern. The vermiculite and volcanic
stone should be placed directly on top of the
firebox bottom, along the front and to the back
at the right and left sides of the burner. Position
any optional ceramic fiber liners before plac-
ing the vermiculite and volcanic stone. Logs
should be positioned after the vermiculite and
volcanic stone.
Note: This appliance is provided with enough
Glowing Embers for several applications, do
not feel compelled to use all that is in a new
bag. For best glowing effect, replace the ember
material annually. Replacement Glowing Em-
bers are available (Catalog Number 88L53).
Glowing Embers
Bag of Glowing
Embers (rockwool)
Separate into Quarter
Size (separate) Pieces
Figure 5
Glowing Embers
Figure 6
REFERENCE
Firebox Accessories / Parts
Cat. No. Model No. Description
88L53 FGE Bag of Glowing Embers
80L42 FDVS Bag of Decorative
Volcanic Stone
H3696 — Bag of Vermiculite
Step 4. Placement of Logs -
All top logs that rest on lower logs, do so over
notches, indents or nubs. Proper log placement
is critical to prevent sooting. Logs should be
placed in the gaps between the flame peaks and
should be positioned so they do not impinge
the flames.
Step 5. Position the individual logs as shown
in Figures 7 and 8. Logs should be placed in
the order shown. All logs that have notches
to fit over the grate tines should be positioned
with these notches directly against the grate.
Handle logs carefully to prevent breakage.
Proper log placement is critical to encourage
outstanding flame appearance and prevent
sooting. When positioned properly as shown,
logs will be positioned between flame peaks
and will not impinge any flames.
Refer to Figure 7 for EDV3530 Series appli-
ances and to Figure 8 for EDV4035 & EDV4540
Series appliances.
Step 3. Separate the Glowing Ember
(Rockwool) into pieces about the size of a
quarter (Figure 5 ). Keep the pieces fluffed up,
not matted. Distribute these pieces over the
front surface of the burner, as shown in Figure
6. Do not use more than is necessary. When
properly positioned, the Glowing Embers will
cover approximately 65% of the front burner
and with no appreciable gaps or openings.
Ensure that the main burner ports remain
uncovered by the ember material.
WARNING
• DO NOT attempt to install the
logs until the appliance installa-
tion has been completed, the gas
line connected and tested for leaks
and the initial burner operation
has been checked out.
•
The size and position of the log
set was engineered to give the
appliance a safe, reliable and
attractive flame pattern. Any
attempt to use a different log set
in the fireplace will void the war-
ranty and will result in incomplete
combustion, sooting, and poor
flame quality.
•
Logs get very hot and will
remain hot up to one hour after gas
supply is turned off. Handle only
when logs are cool. Turn off all
electricity to the appliance before
you install grate, volcanic stone,
vermiculite, embers and logs.
•
This appliance is not designed
to burn wood. Any attempt to do so
could cause irreparable damage to
the appliance and prove hazardous
to your safety.
•
If logs are not installed
according to the log installation
instructions, flame impingement
and improper combustion could
occur and result in soot and/or
excessive production of carbon
monoxide (CO), a colorless,
odorless, toxic gas.

13
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
1
Log
Number Description (Stamped #)
1 Log, Rear (39-12)
2 Log, Left (39-1)
3 Log, Right (39-2)
4 Log, Top Center (39-13)
5 Log, Top/Left (39-3 )
6 Log, Top/Right (39-4)
Position the individual logs as shown below. Logs should be placed
in the order shown. Position the rear log on the brackets at the
rear of the firebox with the log's notches directly over the brackets.
Position the right log (log no. 3) by inserting the pin from the rear
log into the hole on its upper end. Place the left log and then the
smaller left and right top logs. All logs that have notches to fit over
the grate tines should be positioned with these notches directly
against the grate. All top logs that rest on lower logs, do so over
flattened mounting faces in the bottom logs.
Proper log and twig placement is critical to encourage outstanding
flame appearance and prevent sooting.
3
2
4
5
6
1
2
3
4
6
5
MPD-3328 LOG PLACEMENT
Catalog Number for the entire log set: 24M15
Figure 7

14
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Figure 8
MPD-3530 LOG PLACEMENT
Catalog Number for the entire log set: 24M22
Log
Number Description (Stamped #)
1 Log, Rear (39-5)
2 Log, Left (39-1)
3 Log, Right (39-2)
4 Log, Top Center (39-6)
5 Log, Top/Left (39-3)
6 Log, Top/Right (39-4)
1
Position the individual logs as shown below. Logs should be placed
in the order shown. Position the rear log on the brackets at the
rear of the firebox with the log's notches directly over the brackets.
Position the right log (log no. 3) by inserting the pin from the rear
log into the hole on its upper end. Place the left log and then the
smaller left and right top logs. All logs that have notches to fit over
the grate tines should be positioned with these notches directly
against the grate. All top logs that rest on lower logs, do so over
flattened mounting faces in the bottom logs.
Proper log and twig placement is critical to encourage outstanding
flame appearance and prevent sooting.
56
2
4
3
1
2
4 3
6
5

15
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Figure 9
MPD-4035 AND MPD-4540 LOG PLACEMENT
Catalog Number for the entire log set: 24M25
1
Log
Number Description (Stamped #)
1 Log, Center (39-8)
2 Log, Rear (138)
3 Log, Right (39-10)
4 Log, Left (39-9)
5 Log, Top/Left (39-11)
6 Log, Top/Right (39-11)
Position the individual logs as shown below. Logs should be placed
in the order shown. Position the center log on the burner first, then
place the glowing embers as shown in Figure 6. Place the rear
log, both the right and left, and then the smaller left and right top
logs. All logs that have notches to fit over the grate tines should
be positioned with these notches directly against the grate. All top
logs that rest on lower logs, do so over flattened mounting faces
in the bottom logs.
Proper log and twig placement is critical to encourage outstanding
flame appearance and prevent sooting.
2
3
4
56
1
2
3
4
6
5

16
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
BURNER ADJUSTMENTS
(QUALIFIED TECHNICIANS ONLY)
Flame Appearance and Sooting
Proper flame appearance is a flame which is
blue at the base and becomes yellowish-orange
in the body of the flame.
When the appliance is first lit, the entire flame
may be blue and will gradually turn yellowish-
orange during the first 15 minutes of operation.
If the flame remains blue, or if the flame is
orange with evidence of sooting (black tip), the
air shutter opening may need to be adjusted.
If the air shutter opening is closed too far,
sooting may develop. Sooting is indicated by
black puffs developing at the tips of very long
orange flames. Sooting results in black deposits
forming on the logs, appliance inside surfaces
and on exterior surfaces adjacent to the vent
termination.
Sooting is caused by incomplete combustion
in the flames and lack of combustion air enter-
ing the air shutter opening. To achieve a warm
yellowish-orange flame with an orange body
that does not soot, the shutter opening must be
adjusted between these two extremes.
Air Shutter Adjustment Guidelines
• If there is smoke or soot present, first check
the log set positioning to ensure that the
flames are not impinging on any of the logs.
If the log set is properly positioned and a
sooting condition still exists, then the air
shutter opening should be increased.
• The more offsets in the vent system, the larger
the air shutter opening will need to be.
• An appliance operated with the air shutter
opened too far, may have flames that appear
blue and transparent. These weak, blue and
transparent flames are termed anemic.
• Propane models may exhibit flames which
candle or appear stringy. If this is present
and persists, adjust the air shutter to a more
closed position, then operate the appliance
for a few more minutes to ensure that the
flame normalizes and the flames do not
appear sooty.
The following chart is provided to aid you in
achieving the correct air shutter adjustment
for your installation.
Air Shutter Adjustment Guidelines:
Amount of
Primary Air
Flame
Color
Air Shutter
Adjustment
If air shutter is
closed too far Flame will be orange Air shutter gap should be
increased
If air shutter is
open too far Flame will be blue Air shutter gap should be
decreased
Figure 10 : MPD-3328
Figure 11: MPD-3530
Figure 12: MPD-4035 and MPD-4540

17
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
WARNING
• Air shutter adjustment should
only be performed by a
qualified professional ser-
vice technician.
• Ensure front glass panel is
in place and sealed during
adjustment.
CAUTION
• Soot will be produced if
the air shutter is closed too
much. Any damage due
to sooting, resulting from
improperly setting the air
shutter, is not covered under
the warranty.
• The air shutter door and
nearby appliance surfaces
are HOT. Exercise caution to
avoid injury while adjusting
flame appearance.
BURNER FLAME ADJUSTMENTS
1. Refer to Figures 10, 11, and 12 for proper
flame appearance. To adjust the flame, rotate
the adjustment rod toward the back or toward
the front of the fireplace (rod located in the
lower control area). Position the air shutter
to the factory setting as shown in the table
in Figure 13.
2. Light appliance (follow lighting procedure
on lighting label in control compartment or
in this Care and Operation Instructions).
3. Allow the burner to operate for at least 15
minutes while observing the flame continu-
ously to ensure that the proper flame ap-
pearance has been achieved. If the following
conditions are present, adjust accordingly.
• If flame appears weak or sooty, adjust
the air shutter, incrementally, to a more
open position until the proper flame
appearance is achieved.
• If flame remains blue, adjust the air
shutter, incrementally, to a more closed
position until the proper flame appear-
ance is achieved.
4. When satisfied that the burner flame appear-
ance is normal, turn the ON/OFF control
(unit-mounted or remote switch, depending
on your application) to the OFF position.
5. Reinstall the lower control access panel,
then proceed to finish the installation.
Millivolt Appliance Checkout
To light the burner, rotate the gas valve control
knob counterclockwise to the ON position
(“ON” will be at the top side of the valve).
Turn the ON/OFF control (unit-mounted or
remote switch, depending on your application)
to the ON position.
The pilot flame should be steady, not lifting
or floating. Flame should be blue in color with
traces of orange at the outer edge.
The top 3/8" (10 mm) at the pilot generator
(thermopile) and the top 1/8" minimum (tip)
of the quick drop out thermocouple should be
engulfed in the pilot flame.
The flame should project 1" (25 mm) beyond
the hood at all three ports (see Figure 14).
Replace logs if removed for pilot inspection.
Electronic Appliance Checkout
To light the burner, turn the integrated ON/OFF
switch (or optional switch, depending on your
application) to the ON position.
The pilot flame should engulf the flame rod, as
shown in Figure 15.
MILLIVOLT
Thermocouple
Hood Igniter Rod
3/8" Min
(9 mm)
Thermopile
Pilot
Nozzels
Figure 14
ELECTRONIC
Proper Flame
Adjustment
Pilot
Nozzle
3/8 To 1/2 Inch
(9 mm to 13 mm)
Ground
Electrode
Flame Rod
Hot Surface
Igniter
Figure 15
Figure 13
Adjustment Rod Up
(Fully Open Position)
Air Shutter
Burner Tube
Adjusting Set Screw
Adjustment Rod Down
(minimum air
opening position)
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18
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
LENNOX HEARTH PRODUCTS
1508 Elm Hill Pike, Suite 108
Nashville, TN 37210
visit us at www.Lennox.com
1-800-9-LENNOX
PRODUCT REFERENCE INFORMATION
We recommend that you record the important
reference information about your fireplace in
the space provided below.
Please call Lennox Hearth Products for the
phone number of your nearest Lennox Hearth
Products dealer who will answer your questions
or address your concerns.
When ordering repair parts, always give the
following information:
1. The model number of the appliance.
2. The serial number of the appliance.
3. The part number.
4. The description of the part.
5. The quantity required.
6. The installation date of the appliance.
If you encounter any problems or have any
questions concerning the installation or ap-
plication of this system, please contact your
dealer or distributor.
ORDERING REPLACEMENT PARTS
A complete parts list is found at the end of
this manual. Use only parts supplied from the
manufacturer.
With proper care and maintenance, your appli-
ance will provide many years of enjoyment. If
you should experience any problem, first refer
to the troubleshooting guide in this manual. If
problem persists, contact your Lennox Hearth
Products dealer or distributor.
Normally, all parts should be ordered through
your Lennox Hearth Products distributor or dealer.
Parts will be shipped at prevailing prices at
time of order.
1. If any of the original wire as supplied must be replaced,
1. it must be replaced with Type AWM 105°C – 18 GA. wire.
2. 120V, 60Hz – Less than 3 amps.
BK
Transf.
120 V.
24 V
Factory Wired Field Wired
BL
Electronic Wiring Diagram (Honeywell)
Showing the Blower Wiring for the Optional
FBK-250 Kits
R
WH
BL
W
Gas Valve
B
R
IGNITER
BK
Schematic Representation Only
*ON/OFF Switch (Integral
with Gas Valve)
Optional
FBK-250
Module
*Leave the ON/OFF switch, which is integral
with the gas valve, in the ON position.
G
OPTIONAL APPLIANCE-MOUNTED ON/OFF SWITCH
OR OPTIONAL WALL SWITCH OR OPTIONAL THERMOSTAT
OR OPTIONAL REMOTE RECEIVER
PILOT
ASSEMBLY
OPT
BLOWER
Junction Box
White
Green
Red
Black
Neutral
Side of
Receptacle
Tab Intact
Green
Ground
Screw
Hot
Side of
Receptacle
Tab
Broken
Optional
Accessory
Switch
120 VAC - Black
neerG-dnuorG
etihW-lar
t
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1. If any of the original wire as supplied must be replaced,
1. it must be replaced with Type AWM 105°C – 18 GA. wire.
2. 120V, 60Hz – Less than 3 amps.
BK
Transf.
120 V.
24 V
Factory Wired Field Wired
BL
Electronic Wiring Diagram (Honeywell)
Showing the Blower Wiring for the Optional
FBK-100 and FBK-200 Kits
R
W
BL
W
Gas Valve
B
R
IGNITER
BK
*Blower speed control switch is provided in FBK200 blower kit.
Schematic Representation Only
**ON/OFF Switch (Integral
with Gas Valve)
**Leave the ON/OFF switch, which is integral
with the gas valve, in the ON position.
OPTIONAL APPLIANCE-MOUNTED ON/OFF SWITCH
OR OPTIONAL WALL SWITCH
OR OPTIONAL THERMOSTAT
OR OPTIONAL REMOTE RECEIVER
G
OPT
BLOWER
PILOT
ASSEMBLY
Junction Box
White
Green
Red
Black
Neutral
Side of
Receptacle
Tab Intact
Green
Ground
Screw
Hot
Side of
Receptacle
Tab
Broken
120 VAC - Black
neerG-dnuorG
Optional
Accessory
Switch
etihW-lar
t
ueN
WIRING DIAGRAMS
Wiring diagrams are provided here for reference
purposes only. This information is also provided
on schematics attached directly to the appliance
on a pullout panel located within the control
compartment.
CAUTION: LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN SERVICING
CONTROLS. WIRING ERRORS CAN CAUSE IMPROPER AND DANGEROUS
APPLIANCE OPERATION.
TP-TH
TP
TH
APPLIANCE- MOUNTED
ON/OFF SWITCH
(OPTIONAL)
BK/W(1)
BK/W(1)
WALL-MOUNTED ON/OFF SWITCH (OPTIONAL)
THERMOSTAT (OPTIONAL)
JUNCTION BOX
BLACK
W
GR
120 V
AC
WALL MOUNTED CONFIGURATION FOR FAN SWITCH (OPTIONAL)
BK
R
WIRING DIAGRAM MILLIVOLT GAS VALVES
THERMOPILE
GAS VALVE
FAN
(OPTIONAL)
Fireplace Model Number ________________________________________________
Fireplace Serial Number _________________________________________________
Date Installed _________________________________________________________
Type of Gas Used in Fireplace ____________________________________________
Dealer Name _________________________________________________________

19
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LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
ACCESSORY COMPONENTS
Digital Wall Thermostat
The wall thermostat kit provides temperature control
for optimum comfort.
Fireplace Shipping Weights/Volumes
Cat.
No. Model Ship. Weight
Ship.
Volume
H7785 MPDR-3328CNM-B 98 lb. 13.1 cu. ft.
H7786 MPDR-3328CPM-B 98 lb. 13.1 cu. ft.
H7787 MPDR-3328CNE-B 98 lb. 13.1 cu. ft.
H7782 MPDT-3328CNM-B 98 lb. 13.1 cu. ft.
H7783 MPDT-3328CPM-B 98 lb. 13.1 cu. ft.
H7784 MPDT-3328CNE-B 98 lb. 13.1 cu. ft.
H0804 MPD-3530CNM-B 113 lb. 15.8 cu. ft.
H7789 MPD-3530CPM-B 113 lb. 15.8 cu. ft.
H1939 MPD-3530CNE-B 113 lb. 15.8 cu. ft.
H0805 MPD-4035CNM-B 147 lb. 20.2 cu. ft.
H7790 MPD-4035CPM-B 147 lb. 20.2 cu. ft.
H1940 MPD-4035CNE-B 147 lb. 20.2 cu. ft.
H0805 MPD-4540CNM-B 160 lb. 23.0 cu. ft.
H7790 MPD-4540CPM-B 160 lb. 23.0 cu. ft.
H1940 MPD-4540CNE-B 160 lb. 23.0 cu. ft.
Standard Remote Control System
The Model RCL (Standard) Remote Control
System features a simple ON/OFF control
function for the fireplace. Includes a hand-held
transmitter, a remote receiver with wall-mount
coverplate, and all required hardware to install
the unit. The remote receiver can be wall- or
hearth-mounted.
Remote Control System (Standard) H0249 RCL
Deluxe Remote Control System
The Model RCL-T (Deluxe) Remote Control
System has all of the features of the standard
system along with an added easy-to-read LCD
screen that provides access to many enhance-
ments, including battery power level indicator,
timer, mode of operation, thermostatic display
with room temperature in either F° or C°, flame
indicator, and clock. Fully programmable, the
Model RCL-T allows for command over nearly
all operational and temperature variables using
the hand-held remote control transmitter.
Remote Control System (Deluxe) H0251 RCL-STAT
Touch-Up Paint (Black) Kit 90L73 TPK-B
Touch-Up Paint Kit
Repair of minor scratches and discoloration of
the appliance painted surfaces may be accom-
plished with the touch-up paint kit.
ON/OFF Wall Switch Kit 85L87 FWSK
Rocker Switch Kit 80L41 FRS
Unit-Mountable ON/OFF Rocker Switch Kit
(Millivolt systems only)
The rocker switch may be used to provide ON/
OFF operation as an alternative to the optional
wall switch. The rocker switch installs directly
in the gas valve mounting bracket (millivolt gas
valve-equipped fireplaces only).
Forced Air Blower Kits:
Single Speed 80L84 FBK-100
Variable Speed with
wall-mountable switch 80L85 FBK-200
Variable Speed with
unit-mountable switch 80L86 FBK-250
Forced Air Blower Kit
The FBK-100 blower assembly provides con-
stant-velocity forced-air circulation.
The FBK-200 blower assembly provides vari-
able-speed forced-air circulation and includes
a wall-mountable variable-speed switch.
The FBK-250 blower assembly provides vari-
able-speed forced-air circulation and includes
a unit-mountable variable-speed switch.
(FBK-200 Models Only)
Wall Thermostat Kit, White H4635 DWTK
ON/OFF Wall Switch Kit
The ON/OFF wall switch may be used to control
the operation of the fireplace burner as an
alternative to the optional unit-mountable ON/
OFF rocker switch. Install the wall switch in a
convenient location near the fireplace.

20
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LENNOX HEARTH PRODUCTS • MERIT® PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
These louvers are designed to replace the
standard charcoal louvers that are provided with
the appliance. The brass and brushed stainless
louver kits include six (6) louvers.
ACCESSORY COMPONENTS (continued)
Clean faced panel kits are available to convert the
standard louvered fireplaces to radiant models
which are more suited for finishing around the
firebox opening with non-combustible materi-
als, such as tile.
These kits are designed to attach directly to the
front face of the fireplace at the four edges of
the glass enclosure panel.
The kits attach to the glass enclosure panel
without the use of hardware. The decorative
arch kits can not be used in conjunction with
the screen panel kit.
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