Lennox Hearth Burner MLDVTCD 35NE User Manual

INSTALLATION INSTRUCTIONS  
MLDVTCD Direct-Vent  
Contemporary Design  
Gas Fireplaces  
P/N 506015-03 Rev. F 06/2011  
MODELS  
This manual is part of a set of three supporting this product.  
Refer to manual 506017-02 for Care and Operation information  
and 506019-40 for Facade Installation Instructions.  
MILLIVOLT:  
ELECTRONIC:  
MLDVTCD-35NE  
MLDVTCD-35NM  
Ce manuel est disponible en francais, simplement  
en faire la demande. Numéro de la pièce 506223-05.  
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.  
Report No. 100353019PRT-002  
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.  
/
/
WARNING AVERTISSEMENT AVISO  
• HOT GLASS WILL CAUSE  
BURNS.  
• DO NOT TOUCH GLASS  
UNTIL COOLED.  
• UNE SURFACE VITRÉE CHAUDE  
PEUT CAUSER DES BRÛLURES.  
• LAISSER REFROIDIR LA SURFACE  
VITRÉE AVANT D'Y TOUCHER.  
• EL VIDRIO CALIENTE  
CAUSARÁ QUEMADURAS.  
• USTED DEBE NUNCA  
TOCAR EL VIDRIO CALIENTE.  
• NEVER ALLOW CHILDREN  
TO TOUCH GLASS.  
• NE PERMETTEZ JAMAIS À UN ENFANT • LOS NIÑOS DEBEN NUNCA  
DE TOUCHER LA SURFACE VITRÉE.  
TOCAR EL VIDRIO.  
WARNING: If the information in these instructions  
is not followed exactly, a fire or explosion may  
result, causing property damage, personal injury,  
or death.  
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.  
- Do not store or use gasoline or other flammable  
vapors and liquids in the vicinity of this or any other  
appliance.  
- 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.  
- 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.  
- 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.  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
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, bed-  
ding material, etcetera. It is imperative  
that control compartments, burners and  
circulating air passageways of the appliance  
be kept clean.  
The appliance, when installed, must be electri-  
cally 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.  
WARNING  
Improper installation, adjust-  
ment, 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.  
Provide adequate clearances around air open-  
ings and adequate accessibility clearance for  
service and proper operation. Never obstruct  
the front openings of the appliance.  
Remarque : Linstallation et la réparation  
devraitêtreconfiéesàuntechnicienqualifié.  
Lappareil devrait faire l’objet d’une inspec-  
tion par un technicien professionnel avant  
d’être utilisé et au moins une fois l’an par la  
suite.Desnettoyagesplusfréquentspeuvent  
être nécessaires si les tapis, la literie, et  
ceteraproduisentunequantitéimportantede  
pous-sière. Il est essentiel que les comparti-  
mentsabritantlescommandes,lesbrûleurset  
les conduits de circulation d’air de l’appareil  
soient tenus propres.  
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.  
WARNING  
Failure to comply with these  
installationinstructionswillresult  
in an improperly installed and  
operating appliance, voiding its  
warranty. Anychangetothisappli-  
anceand/oritsoperatingcontrols  
is dangerous.  
Thesereplacesaredecorativeandaredesigned  
to provide supplemental heat. Therefore, it is  
advisabletohaveanalternateprimaryheatsource  
when installed in a dwelling.  
These appliances must not be connected to a  
chimney or flue serving a separate solid fuel  
burning appliance.  
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.  
WARNING  
Clothing or other flammable  
material should not be placed  
on or near the appliance.  
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.  
Nepasutilisercetappareils’ilaétéplongé,  
même partiellement, dans l’eau. Ap-  
peler un technicien qualifié pour inspecter  
l’appareil et remplacer toute partie du  
systèmedecommandeettoutecommande  
qui a été plongée dans l’eau.  
AVERTISSEMENT  
Millivolt models come standard with a manu-  
ally-modulatedgasvalve;ameappearanceand  
heat output can be controlled at the gas valve.  
The BTU Input for these appliances is shown  
in Table 1.  
On ne devrait pas placer de  
vêtements ni d’autres matières  
inflammables sur l’appareil ni à  
proximité.  
Only trim kit(s) supplied by the manufacturer  
shall be used in the installation of this ap-  
pliance.  
Electronic Models - These electronic appli-  
ances are manually controlled and feature an  
electronic intermittent pilot ignition system.  
External electrical power is required to operate  
these units.  
WARNING  
Seules les trousses de garniture fournies  
par le fabricant doivent être utilisées pour  
l’installation de cet appareil.  
Any safety screen or guard  
removed for servicing the appli-  
ance must be replaced prior to  
operating the appliance.  
These appliances comply with National Safety  
Standards and are tested and listed by ETL/  
Intertek (Report No. 100353019PRT-002) to  
ANSI Z21.50 (in Canada, CSA-2.22), and CAN/  
CGA-2.17-M91 in both USA and Canada, as  
vented gas fireplaces.  
These electronic models come standard with a  
manually-modulated gas valve; flame appear-  
ance and heat output can be controlled at the  
gas valve. The BTU Input for these appliances  
is shown in Table 1.  
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.  
Both millivolt and electronic versions of  
these appliances are listed by ETL/Intertek  
for installation in bedrooms and Manufac-  
tured Homes.  
Input (BTU/HR) Manually-Modulated  
Gas Valves (all models)  
Input Rate (BTU / HR)  
Models  
Nat. Gas  
Prop. Gas  
Misc. Codes / Standards  
WARNING  
14,500 high  
11,500 low  
13,500 high  
10,500 low  
MLDVTCD-35  
TheInstallationmustconformtolocalcodesor,  
in the absence of local codes, with the National  
Fuel Gas Code, ANSI Z223.1/NFPA 54 - latest  
edition(InCanada,thecurrentCAN/CSA-B149.1  
installation code).  
Improper installation or use of  
thisappliancecancauseserious  
injury or death from fire, burns,  
explosion or carbon monoxide  
poisoning.  
Table 1  
3
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Orifice Sizes - Sea Level to High Altitude  
(All Models)  
Gas Pressure - All Models  
Tables 2 and 3 show the appliances' gas  
pressure requirements:  
Supply  
Gas  
Inlet  
Pressure-Tap  
(Manifold)  
Regulator  
Burner Stage  
Terminal  
Mounting Screw  
These appliances are tested and approved for  
installation at elevations of 0-4500 feet (0-1372  
meters) above sea level using the standard  
burnerorificesizes(marked with an "*" inTable  
4). Forelevationsabove4500feet,contactyour  
gas supplier or qualified service technician.  
Inlet Gas Supply Pressure  
(all models)  
L O  
H I  
PILOT  
Fuel #  
Minimum  
Maximum  
4.5" WC  
(1.12 kPa)  
10.5" WC  
(2.61 kPa)  
Natural Gas  
Deration - At higher elevations, the amount  
of BTU fuel value delivered must be reduced  
by either:  
Pressure-Tap  
(Inlet)  
Ground  
(TP)  
Pilot Stage  
Terminal  
Pilot Gas  
Outlet  
11.0" WC  
(2.74 kPa)  
13.0" WC  
(3.23 kPa)  
Propane  
Using gas that has been derated by the gas  
company.  
Figure 2 - Dexen Electronic Gas Valve  
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.  
Table 2  
REQUIREMENTS FOR THE COMMON-  
WEALTH OF MASSACHUSETTS  
Manifold Gas Supply Pressure  
(all models)  
Fuel #  
Low  
High  
These fireplaces are approved for installation in  
the US state of Massachusetts if the following  
additional requirements are met:  
• Install this appliance in accordance with  
Massachusetts Rules and Regulations 248  
C.M.R.  
• Installation and repair must be done by a  
plumber or gas fitter licensed in the Com-  
monwealth of Massachusetts.  
Installtheapplianceaccordingtotheregulations  
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.  
Natural (Lo) 2.2" WC  
(Hi) 3.5" WC  
(0.87 kPa)  
Gas  
(0.55 kPa)  
(Lo) 6.3" WC (Hi) 10.0" WC  
(1.57 kPa) (2.49 kPa)  
Propane  
Table 3  
NOTE: Flame appearance will diminish 4% per  
thousand feet.  
• The flexible gas line connector used shall  
not exceed 36 inches (92 centimeters) in  
length.  
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.  
Burner Orifice Sizes  
Elevation 0-4500 feet ( 0-1372 meters)  
• The individual manual shut-off must be a  
T-handle type valve.  
Model  
Nat.Gas  
Propane  
Series  
drill size (inches)  
drill size (inches)  
#49 (0.073")  
21L82 •  
0.045"  
**  
75L10 •  
*
Massachusetts Horizontal Vent Requirements  
MLDVTCD-35  
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.  
* Standard size installed at factory  
** Standard size in LP conversion kit  
• Part /Cat. Number  
IntheCommonwealthofMassachusetts,hori-  
zontal 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  
thebuildingataminimumheightofeight(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.  
Table 4  
Gas Valve Diagrams  
These appliances must be isolated from the  
gas supply piping system (by closing their  
individualmanualshut-offvalve)duringany  
pressure testing of the gas supply piping  
system at test pressures equal to or less  
than 1/2 psig (3.5 kPa).  
See Figure 1 for Millivolt models and Figure 2  
For Electronic Models.  
Pilot Adjustment  
Screw  
Main Gas Control Knob  
OFF/PILOT/ON  
T
L
I
P
These appliances and their individual  
shut-off valves must be disconnected from  
the gas supply piping system during any  
pressuretestingofthatsystematpressures  
greater than 1/2 psig (3.5 kPa).  
N
O
T
W O  
L
O
L I  
P
F
O
H
I
IN OUT  
NEW YORK CITY, NEW YORK (MEA)  
Manifold Pressure Tap  
These appliances must not be connected to a  
chimney or flue serving a separate solid fuel  
burning appliance.  
HI/LO Variable  
Flame Height  
Adjustment  
Inlet Pressure Tap  
Installation of these fireplaces are approved  
for installation in New York City in the US state  
of New York.  
Figure 1 - SIT Millivolt Gas Valve  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
4
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
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 open-  
ings should be caulked or stuffed with unfaced  
fiberglass insulation.  
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.  
T
N
N
E
O
I
V
T
P
A
C
O
I
T
L
P
P
A
APPLICATION  
TOP VENT  
If the fireplace is being installed on a cement  
slabincoldclimates,asheetofplywoodorother  
raised platform can be placed underneath to  
prevent cold transfer to the fireplace and into  
the room. It also helps to sheetrock inside  
surfaces and tape for maximum air tightness  
and caulk firestops.  
RECESSED  
INSTALLATION  
TOP VENT  
APPLICATION  
MANUFACTURED HOME  
REQUIREMENTS  
This appliance may be installed in an aftermar-  
ket permanently located, manufactured home  
and must be installed in accordance with the  
manufacturer's instructions and the Manufac-  
turedHomeConstructionandSafetyStandard,  
Title 24 CFR, Part 3280, in the United States, or  
the Standard for Installation in Mobile Homes,  
CAN/CSA Z240 MH Series, in Canada.  
HORIZONTAL VENT  
(Top Vent Application)  
Cetappareilpeutêtreinstallécómmedumatéri-  
eld'originedansunemaisonpréfabriquée(É.U.  
seulement) ou mobile et doit être installé selon  
les instructions du fabricant et conformément  
à la norme Manufactured Home Constructions  
and Safety, Title 24 CFR, Part 3200 aux Unis ou  
à la norme Can/CSA-Z240 Série MM, Maisons  
mobiles au Canada.  
VERTICAL VENT  
(Top Vent Application)  
Figure 3 - Typical Locations  
Be aware that this is a heat producing ap-  
pliance. Objects placed above the unit are  
exposed to elevated temperatures.  
LOCATION  
This appliance is only for use with the type of  
gasindicatedontheratingplate. Thisappliance  
is not convertible for use with other gases,  
unless a certified kit is used.  
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.  
Do not insulate the space between the ap-  
pliance and the area above it (see Figure 7  
on Page 8).  
Cetappareildoitêtreutiliséuniquementavecle  
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.  
Due to high temperatures, the appliance  
should be located out of traffic and away from  
furniture and draperies (Figure 3).  
The minimum height from the base of the appli-  
ance to the underside of combustible materials  
used to construct a utility shelf in this fashion  
is shown in Figure 7 on Page 8.  
CAUTION: Ensure that the cross mem-  
bers are not cut or weakened during  
installation. The structural integrity of  
the manufactured home floor, wall, and  
ceiling / roof must be maintained.  
Enraisondestempératuresélevées,l’appareil  
devrait être installé dans un endroit où il y a  
peu de circulation et loin du mobilier et des  
tentures (Figure 3).  
The appliance should be mounted on a fully  
supported base extending the full width and  
depth of the unit. The appliance may be located  
onornearconventionalconstructionmaterials.  
However, if installed on combustible materials,  
such as carpeting, vinyl tile, etc., a metal or  
woodbarriercoveringtheentirebottomsurface  
must be used.  
The location should also be free of electrical,  
plumbing or other heating/air conditioning  
ducting.  
CAUTION:Thisappliancemustbeground-  
ed 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.  
These direct-vent appliances are uniquely  
suited for installations requiring a utility shelf  
positioned directly above the fireplace. Utility  
shelveslikethesearecommonlyusedforlocat-  
ing television sets and decorative plants.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
5
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
VENT TERMINATION CLEARANCES  
Vertical Vent Termination Clearances  
Termination Heights For Vents  
Above Flat Or Sloped Roofs  
Ref. NFPA 54 / ANSI Z223.1  
These instructions should be used as a  
TERMINATION HEIGHTS FOR VENTS ABOVE  
guideline and do not supersede local codes  
in any way. Install venting according to local  
FLAT OR SLOPED ROOFS  
Horizontal Overhang  
Roof Pitch  
Flat to 6/12  
* Feet  
1.0  
*Meters  
0.3  
codes,theseinstructions,thecurrentNational  
Fuel Gas Code (ANSI-Z223.1) in the USA or  
the current standards of CAN/CSA-B149.1 in  
Canada.  
2 FT  
Vertical  
Wall  
MIN.  
2 FT MIN.  
Lowest  
Discharge  
Opening  
6/12 to 7/12  
1.25  
1.5  
0.38  
0.46  
0.61  
0.76  
0.99  
1.22  
1.52  
1.83  
2.13  
2.29  
2.44  
Vent  
Termination  
7/12 to 8/12  
H*  
8/12 to 9/12  
2.0  
Storm Collar  
Flashing  
X
Vertical Vent Termination Clearances  
12  
9/12 to 10/12  
10/12 to 11/12  
11/12 to 12/12  
12/12 to 14/12  
14/12 to 16/12  
16/12 to 18/12  
18/12 to 20/12  
20/12 to 21/12  
2.5  
Roof Pitch is X/12  
3.25  
4.0  
Terminate multiple vent terminations according  
to the installation codes listed above. Also see  
Figure 4A.  
1 inch (25.4 mm) Minimum  
Clearance to Combustibles  
Concentric  
Vent Pipe  
5.0  
*H = MINIMUM HEIGHT FROM ROOF TO  
LOWEST DISCHARGE OPENING OF VENT  
6.0  
Terminate single vent caps relative to building  
components according to Figure 4B.  
The vent / air intake termination clearances  
above the high side of an angled roof is as  
shown in the following chart:  
7.0  
7.5  
8.0  
Figure 4B  
12”  
(305mm)  
Minimum  
Horizontal Vent Termination Clearances  
The horizontal vent termination must have a minimum of 6" (152 mm) clearance to any overhead  
combustible projection of 2-1/2" (64 mm) or less. See Figure 5. For projections exceeding 2-1/2"  
(64 mm), see Figure 5. For additional vent location restrictions refer to Figure 6 on Page 7.  
Horizontal Vent Termination Clearances  
Figure 4A - Multiple Terminations  
Combustible Projection  
2-1/2 inches or less in length  
All horizontal terminations  
may be located as close as  
6 (152mm) to any  
Combustible Projection greater  
than 2-1/2 inches in length  
(non-combustible and  
combustible) exterior  
sidewall. This distance  
may be decreased to 2  
(51mm) for non-  
combustible exterior  
sidewalls only, if the  
SV4.5HT-2 termination  
is used.  
Ventilated  
Soffit  
Unventilated  
Soffit  
6"  
(152 mm)  
18"  
12"  
(457 mm)  
(305 mm)  
Termination Kit  
Side Elevation View  
Termination Kit  
Note - See Figure 28 on Page 19 for the exterior wall recess  
allowances of the square horizontal termination.  
Figure 5  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
6
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
ExTERIOR HORIZONTAL VENT TERMINATION CLEARANCE REQUIREMENTS  
NOTE: Local Codes Or Regulations  
May Require Different Clearances.  
* See Item D in the Text Below.  
Exterior Wall  
P
V
N
N
NOTE: Location Of The Vent Termination  
Must Not Interfere With Access To The  
Electrical Service.  
Inside  
Corner Detail  
O
*18”  
V
G
V
Q
Horizontal  
Termination  
6”  
Inside Corner  
Detail D  
Ventilated Soffit  
A
= 9” in U.S.  
= 12” in Canada  
A
H
3 ft.  
B
B
B
D
E
X
C
C
A
A
V
V
V
Fixed  
Operable  
Window  
L
V
Closed  
3 ft.  
Window  
V
F
J
M
V
C
B
B
C
X
V
I
A
X
K
V
= Air Supply Inlet  
= Vent Termination  
= Area where Termination is not Permitted  
Canadian Installation*  
US Installation**  
12 inches (30cm)**  
6 inches (15cm) for appliances  
< 10,000 Btuh (3kW), 9 inches (23cm)  
for appliances > 10,000 Btuh (3kW) and  
< 50,000 Btuh (15kW), 12 inches (30cm)  
for appliances > 50,000 Btuh (15kW)**  
A = Clearance above grade, veranda, porch, deck, or balcony. 12 inches (30cm)*  
B = Clearance to window or door that may be opened.  
6 inches (15cm) for appliances  
< 10,000 Btuh (3kW), 12 inches (30cm)  
for appliances > 10,000 Btuh (3kW)  
C = Clearance to permanently closed window  
12 inches (305mm) recommended to  
prevent window condensation  
9 inches (229mm) recommended to  
prevent window condensation  
D = Vertical clearance to ventilated soffit located above the  
termination within a horizontal distance of 18 inches (458mm)  
from the center line of the termination  
18 inches (458mm)  
18 inches (458mm)  
E = Clearance to unventilated soffit***  
12 inches (305mm)  
12 inches (305mm)  
F = Clearance to outside corner  
5 inches (12.7cm) minimum  
6 inches (15.2cm) minimum  
5 inches (12.7cm) minimum  
6 inches (15.2cm) minimum  
G = Clearance to inside corner (Refer to Figure 5)  
H = Clearance to each inside of center line extended above  
meter/regulator assembly  
I = Clearance to service regulator vent outlet  
3 feet (91cm) within a height of 15 feet  
above the meter/regulator assembly*  
3 feet (91cm)*  
3 feet (91cm) within a height of 15 feet  
above the meter/regulator assembly**  
3 feet (91cm)**  
J = Clearance to nonmechanical air supply inlet to building or 6 inches (15cm) for appliances  
6 inches (15cm) for appliances  
the combustion air inlet to any other appliance  
< 10,000 Btuh (3kW), 12 inches (30cm)  
for appliances > 10,000 Btuh (3kW)  
< 10,000 Btuh (3kW), 9 inches (23cm)  
for appliances > 10,000 Btuh (3kW) and  
< 50,000 Btuh (15kW), 12 inches (30cm)  
for appliances > 50,000 Btuh (15kW)**  
K = Clearance to a mechanical air supply inlet  
6 feet (1.83m)*  
3 feet (91cm) above if within 10 feet  
(3m) horizontally**  
L = Clearance above paved sidewalk or paved diveway located 7 feet (2.13m)‡  
7 feet (2.13m)‡  
on public property  
M = Clearance under veranda, porch, deck or balcony  
12 inches (30cm)*‡  
6 feet (1.83m)*  
12 inches (30cm)‡  
6 feet (1.83m)**  
N = Depth of Alcove (Maximum)  
O = Clearance to Termination (Alcove)  
P = Width of Alcove (Minimum)  
6 inches (15.2mm)*  
3 feet (91cm)*  
6 inches (15.2mm)**  
3 feet (91cm)*  
Q = Clearance to Combustible Above (Alcove)  
18 inches (457mm)*  
18 inches (457mm)**  
* In accordance with the current CAN/CSA-B149.1 National Gas And Propane Installation Code.  
** In accordance with the curent ANSI SZ223.1/NFPA 54 National Fuel Gas Codes.  
*** Clearance required to vinyl soffit material - 30 inches (76cm) minimum.  
‡ A vent shall not terminate directly above a sidewalk or paved driveway which is located between two single family dwellings and serves both  
dwellings.  
*‡ Only permitted if veranda, porch, deck or balcony is fully open on a minimum 2 sides beneath the floor:  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
Figure 6  
7
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
MINIMUM CLEARANCES TO COMBUSTIBLES  
Combustible Shelf Height - Inches (millimeters)  
Model No.  
Appliance And Vent Clearances  
Top Vent - with One 90 Degree Elbow  
Secure Vent  
Secure Flex (flex elbow)  
*48-1/4 (1226)  
Theapplianceisapprovedwithzeroclearancetocombustiblematerialson  
all sides (as detailed in Table 5), with the following exception: 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. In  
addition, when the unit is recessed, the side walls surrounding the unit  
must not extend beyond the front edge of the unit (see Figure 3).  
MLDVTCD-35  
*46-1/2 (1181)  
* Includes 3” clearance to combustibles (required above vent components)  
Do not insulate the  
space between the  
appliance and the  
area above it.  
MINIMUM CLEARANCES* Inches (millimeters)  
Back  
0 (0) Spacers Or Dimples  
Sides  
1/2 (13)**  
0 (0) Spacers or Dimples  
*Shelf Height  
(
see table)  
Top  
3 (76)  
Floor  
FromBottom of Unit To Ceiling  
Vent  
0 (0)  
64 (1626)  
Figure 7 - Shelf Height Minimum Clearances With Top Venting  
3 (76) Top* / 1 (25.4)Sides & Bottom  
SERVICE CLEARANCES Feet (meters)  
Front  
3 feet (0.9 meters)  
Mantel Depth  
Table 5  
18 (457)  
inches (millimeters)  
16 (406)  
14 (356)  
*Note: 3 in. (75 mm) above any horizontal/inclined vent component.  
**Note: SeePage9,Step1forclearancerequirementstothenailingange  
located at each side of the unit and any screw heads adjacent to it.  
Header  
12 (305)  
Top of  
Appliance  
Hearth Extension A hearth extension is not required with this appliance.  
If a hearth extension is used, do not block the lower control compartment  
door. Any hearth extension used is for appearance only and does not have  
to conform to standard hearth extension installation requirements.  
10 (254)  
8 (203)  
ShelfHeight-Toprovideforthelowestpossibleshelfsurface,theventing  
attachedtothetopventshouldberoutedinawaytominimizeobstructions  
to the space above the appliance. Do not insulate the space between the  
appliance and the area above it (see Figure 7). 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 Figure 7.  
Note - Hood shown  
as positioned.  
12 10  
8
6
4
2
(305) (254) (203) (152) (102) (51)  
Figure 8 - Minimum Mantel Clearances  
Wall Finishes / Surrounds / Mantels  
Note: Combustible wall finish materials and/or surround materials must  
not be allowed to encroach the area defined by the appliance front face  
(blacksheetmetal).Neverallowcombustiblematerialstobepositioned  
in front of or overlapping the appliance front face (see Figure 47 on  
Page 32).  
At 14" minimum  
side wall clearance,  
a combustible wall  
can project to any  
length.  
At 8-1/4" side  
wall clearance, a  
combustible wall  
can project 12"  
Top View of  
Fireplace  
Combustible Materials  
Allowed In Shaded Area  
“Safe Zone”  
Non-combustible materials, such as surrounds and other appliance trim,  
may be installed on the appliance face with these exceptions: they must  
not cover any portion of the removable glass panel.  
45o  
5 (127)  
Combustible Walls  
shown in dark gray  
Vertical installation clearances to combustible mantels vary according  
to the depth of the mantel. See Figure 8. Mantels constructed of non-  
combustible materials may be installed at any height above the appliance  
opening; however, do not allow anything to hang below the hood.  
Combustiblematerialsmay  
project beyond one side  
of the fireplace opening  
as long as they are kept  
within the shaded areas  
illustrated here.  
12 (305)  
19 (483)  
NOTE: We recommend the use of high temperature paint (rated 175° F or higher)  
on the underside of the mantel.  
Inches (millimeters)  
Protected wall shown in white  
14  
(356)  
8-1/4  
(209)  
Figure 9 - Minimum Distance to Unprotected Side Wall  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
8
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
TYPICAL INSTALLATION SEQUENCE  
Step 1. FRAMING  
WARNING  
FrametheseappliancesasillustratedinFigures  
11 and 12 on Pages 10 and 11 (Figure 12  
applies to corner framing installations only).  
All framing details must allow for a minimum  
clearancetocombustibleframingmembersas  
shown in Table 5 on Page 8.  
The typical sequence of installation is outlined  
below. However, each installation is unique  
and may result in variations to the steps  
described.  
Failure to position the parts in  
accordance with these diagrams  
orfailuretouseonlypartsspecifi-  
callyapprovedwiththisappliance  
may result in property damage or  
personal injury.  
See the Page numbers references in the follow-  
ing steps for detailed procedures.  
If the appliance is to be elevated above floor  
level, a solid continuous platform must be  
constructed below the appliance.  
Step 1. (Pages 10 and 11) Construct the  
appliance framing. Position the ap-  
pliancewithintheframingandsecure  
with nailing brackets. Bend up the  
appropriateheaderspacingguidesfor  
the drywall/finish material thickness  
to be used (see Figure 47 on Page  
32). Bend up the outer pair for 1/2"  
materials and the inner pair for 5/8"  
materials. Bend out the appropriate  
nailing flanges for the drywall/finish  
material to be used. Nailing flanges  
are provided for flush framing, 1/2  
inch and 5/8 inch framing depths  
(see Figure 10).  
AVERTISSEMENT  
Headersmaybeindirectcontactwiththeappli-  
ancetopspacerswhentheyarebentupvertically  
maintainingthe3"clearancetothereplacetop,  
but must not be supported by them or notched  
to fit around them. All construction above the  
appliancemustbeself-supporting. DONOTuse  
the appliance for structural support.  
Risque de dommages ou de  
blessures si les pièces ne sont  
pas installées conformément à  
ces schémas et ou si des pièces  
autres que celles spécifiquement  
approuvéesaveccetappareilsont  
utilisées.  
The fireplace should be secured to the side  
framing members using the unit's nailing  
flanges - one top and bottom on each side of  
thereplacefront. SeeFigure10. Use8dnails  
or their equivalent.  
DETAILED INSTALLATION STEPS  
The appliance is shipped with all gas controls  
and components installed and pre-wired.  
Step 2. (Page 11) Route gas supply line to  
appliance location.  
Step 3. (Page 12) Install the vent system and  
exterior termination.  
Step 4. (Page 24) Field Wiring  
a. Millivolt Appliances – Bring in  
electrical service line for forced air-  
circulating blower (optional equip-  
ment).  
b. Electronic Appliances – Field wire.  
Step 5. (Page 25) Install blower kit (optional  
equipment).  
Step 6. (Page 26) Make connection to gas  
supply.  
Step 7. (Page 27) Verify appliance opera-  
tion.  
Step 8. (Page 28) Install contemporary me-  
dia.  
Step 9. (Page 30) Install glass door assem-  
bly.  
Step 10. (Page 30) Adjust burner primary air  
shutter to achieve proper flame ap-  
pearance.  
1.Remove the shipping carton. Remove the  
shipping pad, exposing the front glass  
door.  
Unit  
Nailing Flange  
2.Open the two latches (located under the fire-  
box floor) securing the glass door. Remove  
the door by tilting it outward at the bottom  
andliftingitup. Setthedoor asideprotecting  
it from inadvertent damage. See Removing  
Glass Panels on Page 30.  
Side  
Framing  
Nailing Flanges Are  
Provided At All Four  
Corners At 5/8”, 1/2”  
And Flush Settings  
Left Side Front Corner of Fireplace Shown  
(Right Side Requirements the Same)  
Unit Being Secured By Its Nailing Flanges  
To The Framing  
Note: The nailing flanges, combustible members  
and screw heads located in areas directly adjacent  
to the nailing flanges, are EXEMPT from the 1/2”  
clearance to combustible requirements for the  
firebox outer wrapper. Combustible framing may be  
in direct contact with the nailing flanges and may  
be located closer than 1/2” from screw heads and  
the firebox wrapper in areas adjacent to the nailing  
flanges. Frame the opening to the exact dimensions  
specified in the framing details of this manual.  
Step 11. (Page 32) Install the hoods.  
Step 12. (Page33) AttachSafetyinOperation  
Warnings.  
Figure 10  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
9
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
FIREPLACE AND FRAMING SPECIFICATIONS  
Inches (mm)  
Framing should be constructed  
of 2x4 or larger lumber  
10-1/2  
Framing  
VENT FRAMING -  
TOP VENT WITH ONE  
Framing Dimensions  
)
(267  
Model No.  
A
B
C
D
°
90 ELBOW  
in.  
35-1/4  
895  
35-1/4  
895  
39-1/4  
997  
16  
MLDVTCD-35  
mm  
406  
7
(178)  
5-1/8  
(130)  
12-1/8  
(308)  
Efficiencies %  
Natural Gas  
Propane  
Model  
P4  
48  
P4  
51  
MLDVTCD-35  
Vent Size  
C
B
Co-axial DV  
Vent Size  
4-1/2" Inner  
7-1/2" Outer  
Viewable Glass Size  
29-1/4" Wide  
35" Model  
20-1/4" High  
D
Input (BTU) - MV & Electronic  
Natural & Propane Gas  
1/2  
A
Model  
MLDVTCD-35N  
MLDVTCD-35P  
Input Rate (BTU / HR)  
A
Raised Platform  
Or Floor  
14,500  
13,500  
Add Minimum Of 18” For  
Raised Platform If Installing  
With Contemporary Facade.  
D is the required framing depth dimension when the  
finish material (drywall) thickness is 1/2 in. (13mm)  
Notes  
Diagrams, illustrations and photographs are not to scale – consult  
installation instructions. Product designs, materials, dimensions,  
specifications, colors and prices are subject to change or discontinu-  
ance without notice.  
Vertical Venting Through the Ceiling:  
Frame ceiling opening - Use a plumb line from the ceiling above the appliance to locate  
center of the vertical run. Cut and/or frame an opening, 10-1/2" x 10-1/2" (267 mm x 267  
mm) inside dimensions, about this center mark (see Figure 16 on Page 14).  
NOTE: Itisrecommendedthatthe gas be  
stubbedinfromtheleftsideonly.  
NOTE - Eyebrow  
ELECTRICAL INLET  
KNOCKOUT - 2-3/4 X 2  
(70 X 51) COVER PLATE  
(With KNOCKOUT -  
Right Side Only)  
hood shown.  
J
16 (406)  
GAS INLET  
KNOCKOUT  
(Other Side)  
K
5-7/8  
(149)  
L
*CONCENTRIC FLUE  
E
FLUE - 4-1/2 (114)  
COMBUSTION AIR  
- 7-1/2 (190)  
G
OPTIONAL  
ELECTRICAL  
INLET KNOCKOUT,  
REQUIRING A FIELD  
PROVIDED  
9-1/2  
(241)  
F
H
1-5/8 (42)  
3 (76)  
1/2  
(13)  
9-1/4 (235)  
JUNCTION BOX  
(Either Side)  
M
Top View  
3 (76)  
Right Side View  
Front View  
Model No.  
E
F
G
H
J
K
L
M
28-1/8  
32  
12-1/2  
33  
32-1/4  
35-1/4  
25  
23-1/4  
in.  
MLDVTCD-35  
819  
892  
635  
587  
813  
715  
317  
838  
mm  
Figure 11  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
10  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
FIREPLACE FRAMING SPECIFICATIONS  
C
Model No.  
A
B
D
E
E
in.  
35 1/4 57 1/2  
28 3/4 13 3/4  
730  
40 5/8  
1032  
MLDVTCD-35  
7 (178)  
mm  
1461  
895  
349  
C
D
A
B
Back wall of chase/enclosure  
(including any finishing materials)  
Inches  
(millimeters)  
Figure 12 - Corner Framing with Horizontal Termination  
Step 2. ROUTING GAS LINE  
Notes:  
Never use galvanized or plastic pipe. Refer  
to Table 6 for proper sizing of the gas sup-  
ply line, if black iron pipe is being used. Gas  
lines must be routed, constructed and made  
of materials that are in strict accordance with  
local codes and regulations. We recommend  
that a qualified individual such as a plumber or  
gas fitter be hired to correctly size and route  
the gas supply line to the appliance. Installing  
a gas supply line from the fuel supply to the  
applianceinvolvesnumerousconsiderationsof  
materials,protection,sizing,locations,controls,  
pressure,sediment,andmore.Certainlynoone  
unfamiliarandunqualifiedshouldattemptsizing  
or installing gas piping.  
• All appliances are factory-equipped with a  
flexiblegaslineconnectorand1/2inchshutoff  
valve (see Figure 38 on Page 26).  
• SeeMassachusettsRequirementsonPage4  
for additional requirements for installations in  
the state of Massachusetts in the USA.  
• The gas supply line should Not be connected  
to the appliance until Step 6 (Page 26).  
Apipejointcompoundratedforgasshouldbe  
used on the threaded joints. Ensure propane  
resistant compounds are used in propane  
applications. Be very careful that the pipe  
compound does not get inside the pipe.  
• It is recommended to install a sediment trap  
in the supply line as close as possible to the  
appliance. Appliances using Propane should  
have a sediment trap at the base of the tank.  
• Check with local building official for local code  
requirements(i.e.arebelowgradepenetrations  
of the gas line allowed?, etc).  
Route a 1/2" (13mm) gas line to the left side  
of the appliance as shown in Figure 13. Gas  
lines must be routed, constructed and made  
of materials that are in strict accordance with  
local codes and regulations. All appliances  
are factory-equipped with a flexible gas line  
connectorand1/2inchshutoffvalve(seeStep  
6 on Page 26).  
Left Side Front  
Corner of Fireplace  
Framing  
Pipe Coupling  
(Recommended)  
Schedule 40  
Black Iron Pipe  
Inside Diameter (Inches)  
6-1/2"  
(152 mm)  
Schedule 40 Pipe  
Length (feet)  
Natural  
Gas  
Propane  
Gas  
*3"  
(76 mm)  
IMPORTANT:Ifpropane isused, beawarethat  
if tank size is too small (i.e. under 100-lbs, if  
this is the only gas appliance in the dwelling.  
Ref. NPFA 58), there may be loss of pressure,  
resulting in insufficient fuel delivery (which  
can result in sooting, severe delayed ignition  
or other malfunctions). Any damage resulting  
from an improper installation, such as this, is  
not covered under the limited warranty.  
*From Floor Or Raised Platform  
0-10  
10-40  
1/2  
1/2  
1/2  
3/4  
3/4  
3/8  
1/2  
1/2  
1/2  
1/2  
Also see Figure 11 on Page 10.  
40-100  
Figure 13 - ROUTE GAS LINE  
100-150  
150-200  
Table 6  
Proper Sizing of Gas Line  
Properly size and route the gas supply line  
from the supply regulator to the area where the  
appliance is to be installed per requirements  
outlined in the National Fuel Gas Code, NFPA  
54 - latest edition (USA) or CAN/CSA-B149.1  
- latest edition (Canada).  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
11  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Installation of Vent Restrictor  
Step 3. INSTALL THE VENT SYSTEM  
General Information  
Vent Restrictor Installation  
(Top Vent)  
A vent restrictor may be needed with this  
appliance. The restrictor is installed in the  
appliance top flue outlet as shown in Figure  
14, either before adding vent, from above, or  
after installation of vent from below, within the  
firebox. The restrictor is self securing through  
a positive friction fit.  
A vent restrictor may be needed when vertical-  
ly terminating the vent system above the roof  
(when using the appliance top vent), install  
vent restrictor in the top vent of the fireplace  
outlet on all MLDVTCD series models. If need-  
ed, install the restrictor orientated as shown,  
either from inside or outside the unit,in the  
inner fireplace collar.  
These instructions should be used as a  
guideline and do not supersede local codes  
in any way. Install venting according to local  
codes,theseinstructions,thecurrentNational  
Fuel Gas Code (ANSI-Z223.1) in the USA or  
the current standards of CAN/CSA-B149.1  
in Canada.  
Determine the venting for the appliance. If the  
vent run will include at least 8 feet of vertical  
rise,theninstalltherestrictorintheappliance  
collar before connecting any vent (Refer to  
Figure 14). Place the restrictor inside the ap-  
pliance vent collar and press in place.  
Restrictor  
Clearance in accordance with local installa-  
tion codes and the requirements of the gas  
supplier.  
Dégagementconformeauxcodesd'installation  
locaux et aux exigences du foumisseunde  
gaz.  
Note: The restrictor is included within the  
firebox.  
Inner  
Fireplace  
Appliance Top  
Collar  
Useonlyapprovedventingcomponents.  
See Approved Vent Components on  
Page 2.  
Vent Outlet  
Figure 14  
These fireplaces must be vented directly  
to the outside.  
Select Venting System - Horizontal or Vertical  
The vent system may not service multiple  
appliances, and must never be connected to a  
flue serving a solid fuel burning appliance. The  
vent pipe is tested to be run inside an enclosed  
wall (such as a chase). There is no requirement  
for inspection openings in the enclosing wall at  
any of the joints in the vent pipe.  
Withtheappliancesecuredinframing,determine  
vent routing and identify the exterior termina-  
tion location. The following sections describe  
vertical (roof) and horizontal (exterior wall)  
vent applications. Refer to the section relating  
to your installation. A list of approved venting  
components is shown on Pages 34 and 35.  
Note: It is not recommended that this unit be  
vented more than forty feet (40') vertically.  
Extended vertical vent runs will diminish the  
fire.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
12  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
VERTICAL TERMINATION SYSTEMS (ROOF)  
VENT SECTION LENGTH CHART  
VENT SECTION LENGTH CHART  
Nominal  
T
O
T
A
L
T
O
T
A
L
Nominal Section  
6
12  
24  
36  
48  
Section Length  
(inches)  
6
12  
24  
36  
48  
See Figure 15 on Page 13 and Figures 23-  
25 on Pages 16 and 17 and their associated  
Vertical Vent Tables which illustrate the various  
verticalventingconfigurationsthatarepossible  
for use with these appliances. Secure Vent™  
pipe applications are shown in these Figures;  
SecureFlex™ pipemayalsobeused.AVertical  
VentTablesummarizeseachsystem’sminimum  
and maximum vertical and horizontal length  
values that can be used to design and install the  
vent components in a variety of applications.  
Length (inches)  
Net Section  
4-1/2 10-1/2 22-1/2 34-1/2 46-1/2  
Number of Vent Sections  
Net Section  
Length (inches)  
4-1/2 10-1/2 22-1/2 34-1/2 46-1/2  
Number of Vent Sections  
Length (inches)  
Height of Vent  
Height of Vent  
Q
T
Q
T
inches  
144  
ft  
inches  
4.5  
ft  
Y
Y
12  
1
0
1
0
0
1
0
0
1
0
0
0
1
0
1
1
2
0
0
1
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
5
5
5
0
0
0
5
6
6
3
3
3
3
0
0
0
4
4
4
0
0
0
4
4
5
5
5
6
6
4
5
5
7
6
7
0.375  
0.75  
1
2
0
1
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
1
2
1
2
9
150  
12.5  
10.5 0.875  
15 1.25  
19.5 1.625  
21 1.75  
154.5 12.875  
160.5 13.375  
172.5 14.375  
0
0
2
1
0
0
3
0
0
1
0
0
1
2
0
2
3
0
1
0
1
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
2
1
3
3
1
3
177  
183  
186  
14.75  
15.25  
15.5  
Both these vertical vent systems terminate  
through the roof. The minimum vent height  
above the roof and/or adjacent walls is speci-  
fied in ANSI Z223.1-(latest edition) (In Canada,  
the current CAN/CSA-B149.1 installation code)  
by major building codes. Always consult your  
localcodesforspecificrequirements.Ageneral  
guide to follow is the Gas Vent Rule (refer to  
Figure 4B on Page 6).  
22.5 1.875  
25.5 2.125  
31.5 2.625  
34.5 2.875  
37.5 3.125  
190.5 15.875  
196.5 16.375  
205.5 17.125  
43.5 3.625  
0
0
0
1
2
0
0
0
1
2
0
2
0
0
0
0
0
0
1
0
3
2
1
3
207  
17.25  
45  
3.75  
211.5 17.625  
46.5 3.875  
49.5 4.125  
A vent restrictor may need to be installed when  
vertical termination is used. See Installation of  
Vent Restrictor on Page 12 for guidelines.  
217.5 18.125  
229.5 19.125  
232.5 19.375  
0
0
0
1
0
1
0
0
0
0
1
1
0
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
6
6
0
0
5
5
0
0
0
0
0
6
0
6
6
6
0
0
7
7
7
0
0
8
8
0
9
9
7
7
51  
4.25  
1
0
0
0
0
0
1
1
0
0
0
0
0
1
1
0
1
0
2
0
0
0
0
1
0
2
0
0
0
0
0
2
1
2
3
0
3
0
0
0
1
2
0
1
0
0
0
1
0
0
2
0
2
2
1
0
0
0
2
0
1
0
0
0
0
0
0
0
0
1
1
1
2
0
2
2
3
2
4
3
2
4
3
3
2
4
3
2
4
3
0
5
55.5 4.625  
237  
19.75  
0
6
Vertical (Straight) Installation  
57  
66  
4.75  
5.25  
241.5 20.125  
7
7
Determinethenumberofstraightventsections  
required. 4-1/2" (114 mm), 10-1/2" (267 mm),  
22-1/2" (572 mm), 34-1/2" (876 mm) and 46-  
1/2"(1181mm)netsectionlengthsareavailable  
(see Tables on this page and Page 34 - Vent  
Sections). Itisrecommendedthatyouplanthe  
vent lengths so that a joint does not occur at  
the intersection of ceiling or roof joists. Refer  
to the Vent Section Length Chart.  
246  
252  
264  
276  
279  
20.5  
21  
7
8
67.5 5.625  
7
8
69  
72  
5.75  
6
22  
7
8
23  
8
8
73.5 6.125  
79.5 6.625  
23.25  
0
6
280.5 23.375  
283.5 23.625  
289.5 24.125  
301.5 25.125  
310.5 25.875  
8
9
81  
90  
6.75  
7.5  
0
7
0
7
91.5 7.625  
0
7
93  
96  
7.75  
8
9
9
SV4.5CGV-1  
315  
26.5  
9
10  
7
SV4.5FA OR  
Termination  
97.5 8.125  
102 8.5  
103.5 8.625  
325.5 27.125  
0
SV4.5FB Flashing  
AND SV4.5SC  
2
0
1
0
0
0
0
0
0
0
3
3
2
0
0
4
3
4
330  
336  
345  
27.5  
28  
0
8
STORM COLLAR  
0
8
108  
114  
117  
9
28.75  
10  
10  
0
10  
11  
8
9.5  
9.75  
0
1
1
0
1
0
0
0
1
2
0
1
0
0
0
0
0
0
0
5
0
1
1
6
0
0
0
0
0
3
3
3
0
4
0
4
2
0
0
0
0
0
0
3
0
4
6
5
4
5
6
4
3
5
349.5 29.125  
372 31  
1" (25.4 mm)  
Minimum  
Clearance to  
Combustibles  
118.5 9.875  
126 10.5  
130.5 10.875  
376.5 31.375  
379.5 31.625  
418.5 34.875  
0
9
11  
0
11  
9
135  
138  
11.25  
11.5  
423  
465  
35.25  
38.75  
0
10  
SV4.5VF  
Firestop/Spacer  
0
10 10  
139.5 11.625  
142.5 11.875  
Effective Vent Length  
40' Max  
(12.2 M)  
SV4.5L6/12/24/36/48  
Vent Sections  
Model  
Effective Length  
4-1/2"  
SV4.5L6  
SV4.5L12  
SV4.5L24  
SV4.5L36  
SV4.5L48  
Note: Convert inches into metric equivalent  
measurement, as follows:  
When using Secure Flex  
use Firestop/Spacer  
10-1/2"  
SF4.5VF  
22-1/2"  
Millimeters (mm) = Inches x 25.4  
Centimeters (cm) = Inches x 2.54  
Meters (M) = Inches x .0254  
34-1/2"  
46-1/2"  
Table 7  
Figure 15  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
13  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Push the vent component against the previous  
section until it fully engages, then twist the  
componentclockwiserunningthedimplesdown  
and along the incline channels until they seat at  
the end of the channels. This seating position  
is indicated by the alignment of the arrow and  
dimple as shown in Figure 17.  
B. Attach vent components to appliance  
-SecureVentSV4.5direct-ventsystemcompo-  
nents are unitized concentric pipe components  
featuring positive twist lock connections (see  
Figure 17).  
Vertical (Offset) Installation  
Analyze the vent routing and determine the  
quantitiesofventsectionsandnumberofelbows  
required. Refer to Vertical Vent Figures and  
Tables on Pages 16 and 17 to select the type  
of vertical installation desired. Vent sections  
are available in net lengths of 4-1/2" (114 mm),  
10-1/2" (267 mm), 22-1/2" (572 mm), 34-1/2"  
(876 mm) and 46-1/2" (1181 mm). Refer to the  
Vent Section Length Charts on Page 13 for an  
aidinselectinglengthcombinations.Elbowsare  
available in 90° and 45° configurations. Refer  
to Figure 19 on Page 15 for the SV4.5E45 and  
SV4.5E90 elbow dimensional specifications.  
All of the appliances covered in this document  
are fitted with collars having locking inclined  
channels. The dimpled end of the vent com-  
ponents fit over the appliance collar to create  
the positive twist lock connection.  
D.Installrestop/spaceratceiling-Whenus-  
ing Secure Vent, use SV4.5VF firestop/spacer  
at ceiling joists; when using Secure Flex, use  
SF4.5VFrestop/spacer. Ifthereislivingspace  
above the ceiling level, the firestop/spacer  
must be installed on the bottom side of the  
ceiling. If attic space is above the ceiling, the  
firestop/spacer must be installed on the top  
side of the joist.  
Align the dimple (4 places) of the  
upper vent section with the opening  
of the locking incline channel on  
the lower vent section or appliance  
collar. Twist vent component  
clockwise to engage and seal until  
arrow and dimple align.  
Where required, a telescopic vent section  
(SV4.5LA) may be used to provide the installer  
withanoptionininstallingintightand confined  
spaces or where the vent run made up of fixed  
length pieces develops a joint in a undesirable  
location, or will not build up to the required  
length. The SV4.5LA Telescopic Vent Section  
has an effective length of from 1-1/2" (38 mm)  
to 7-1/2" (191 mm). The SV4.5LA is fitted with  
a locking inclined channel end (identical to a  
normalventsectioncomponent)andaplainend  
with 3 pilot holes. Slip the plain end over the  
locking channel end of a standard SV4.5 vent  
component the required distance and secure  
with three screws.  
Route the vent sections through the framed  
opening and secure the firestop/spacer with  
8d nails or other appropriate fasteners at  
each corner. Remember to maintain 1" (25  
mm) clearance to combustibles, framing  
members, and attic or ceiling insulation  
when running vertical chimney sections.  
Attic insulation shield (H3907) may be used  
to obtain the required clearances indicated  
here. See installation accessories Pages 34  
and 35. The gap between the vent pipe and  
a vertical firestop can be sealed with non-  
combustible caulking.  
Arrow  
Dimple  
Locking  
Incline  
Channel  
Connected Vent  
Arrow  
Sections  
Appliance Collar or  
Vent Section  
Figure 17  
E. Support the vertical vent run sections -  
Toattachaventcomponenttotheappliancecollar,  
alignthedimpledendoverthecollar,adjustingthe  
radialalignmentuntilthefourlockingdimplesare  
alignedwiththeinletofthefourinclinedchannels  
on the collar (refer to Figure 17). Push the  
vent component against the collar until it fully  
engages, then twist the component clockwise,  
runningthedimplesdownandalongtheincline  
channels until they seat at the end of the chan-  
nels. The unitized design of the Secure Vent™  
componentswillengageandsealboththeinner  
and outer pipe without the need for sealant or  
screws. If desired, a #6 x 1/2" screw may be  
used at the joint, but is not required as the pipe  
will securely lock when twisted.  
Maintainaminimum1"(25mm)clearanceto  
combustiblematerialsforallverticalelements.  
Clearances for all horizontal elements are 3"  
(76 mm) on top, 1" (25 mm) on sides and 1"  
(25 mm) on the bottom.  
Note-Properventingsupportisveryimportant.  
The weight of the vent must not be supported  
by the fireplace in any degree.  
Support the vertical portion of the venting  
system every 8 feet (2.4m) above the fireplace  
vent outlet.  
A. Frame ceiling opening - Use a plumb line  
from the ceiling above the appliance to locate  
center of the vertical run. Cut and/or frame an  
opening, 10-1/2" x 10-1/2" (267mm x 267mm)  
inside dimensions, about this center mark  
(Figure 16).  
10-1/2” Min.  
(267mm)  
Blocking  
Note: An elbow may also be attached to the  
appliance collar. Attach in the same manner  
as you would a vent section.  
SupportStraps  
(Plumber'stape)  
Roof  
Framing  
10-1/2” Min.  
(267mm)  
C. Attach vent components to each other  
- Other vent sections may be added to the  
previously installed section in accordance with  
the requirements of the vertical vent Figures  
and Tables. To add another vent component  
to a length of vent run, align the dimpled end  
over the inclined channel end of the previously  
installed section, adjusting the radial alignment  
until the four locking dimples are aligned with  
the inlets of the four incline channels of the  
previous section.  
8 feet(2.4m)  
Maximum  
Ceiling  
Plumb  
Bob  
Framing  
1/2inch(12.7  
mm)minimum  
clearanceto  
combustibles  
Figure 16  
Figure 18  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
14  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
K. Install the vertical termination - The final  
step involves installation of the SV4.5CGV-1  
Vertical Termination. Extend the vent sections  
to the height as shown in the "Vertical vent  
termination section" in Figure 4B on Page 6.  
The SV4.5CGV-1 Vertical Termination (Figure  
22) can be installed in the exact same fashion  
as any other Secure Vent™ section. Align the  
termination over the end of the previously  
installedsection,adjustingtheradialalignment  
untilthefourlockingdimplesofthetermination  
are aligned with the inlets of the four incline  
channels of the last vent section. Push the ter-  
mination down until it fully engages, then twist  
the termination clockwise running the dimples  
down and along the incline channels until they  
are seated at the end of the channels.  
One method of support is by utilizing field pro-  
vided support straps (conventional plumber's  
tape). Securetheplumber'stapetotheframing  
members with nails or screws. Loop the tape  
around the vent, securing the ends of the tape  
totheframing.Ifdesired,sheetmetalscrews#6  
x 1/2" length may be used to secure the support  
straps to the vent pipe. Refer to Figure 18.  
C
D
F.Changeventdirectiontohorizontal/inclined  
run - At transition from or to a horizontal/in-  
clined run, install the SV4.5E45 and SV4.5E90  
elbows in the same manner as the straight vent  
sections. The elbows feature a twist section to  
allow them to be routed about the center axis  
of their initial collar section to align with the  
required direction of the next vent run element.  
Twist elbow sections in a clockwise direction  
onlysoastoavoidthepossibilityofunlocking  
any of the previously connected vent sections  
(see Figure 19).  
Framing Dimensions for Roof  
Inches (millimeters)  
Pitch  
0/12  
C
D
10-1/2 in.  
(267 mm)  
10-1/2 in.  
(267 mm)  
6/12  
10-1/2 in.  
(267 mm)  
12 in.  
(305 mm)  
12/12  
10-1/2 in.  
(267 mm)  
17 3/4 in.  
(451 mm)  
Figure 20 - Roof Framing  
I. Install the roof flashing - Extend the vent  
sectionsthroughtheroofstructure. Installthe  
roof flashing over the vent section and posi-  
tion such that the vent column rises vertically  
(use carpenters level) (Figure 21). Nail along  
perimeter to secure flashing or adjust roofing  
to overlap the flashing edges at top and sides  
only and trim where necessary. Seal the top  
and both sides of the flashing with waterproof  
caulking.  
8-1/8"  
(206 mm)  
4-13/16  
(122 mm)  
Swivel Joint  
(360° swivel)  
SV4.5E45  
Swivel Joint  
(360° swivel)  
SV4.5E90  
45° Elbow)  
90° Elbow)  
Figure 19  
Figure 22  
G.Continueinstallationofhorizontal/inclined  
sections - Continue with the installation of the  
straightventsectionsinhorizontal/inclinedrun  
as described in Step C. Install support straps  
every 5 ft. (1.52 m) along horizontal/inclined  
vent runs using conventional plumber’s tape.  
See Page 18, Figure 26. It is very important  
thatthehorizontal/inclinedrunbemaintained  
inastraight(nodips)andrecommendedtobe  
inaslightlyelevatedplane,inadirectionaway  
from the fireplace of 1/4 " rise per foot (20 mm  
per meter) which is ideal, though rise per foot  
run ratios that are smaller are acceptable all the  
way down to at or near level. Use a carpenter’s  
level to measure from a constant surface and  
adjust the support straps as necessary.  
J. Install the storm collar - Install the storm  
collar, supplied with the flashing, over the  
vent/flashing joint. See Figure 21. Loosen the  
storm collar screw. Slide collar down until it  
meets the top of the flashing. Tighten the ad-  
justingscrew.Applynon-combustiblecaulking  
or mastic around the circumference of the joint  
to provide a water tight seal.  
If the vent system extends more than 5 feet (1.5  
m) above the roof flashing, stabilizers may be  
necessary. Additional screws may be used at  
section joints for added stability. Guide wires  
may be attached to the joint for additional sup-  
port on multiple joint configurations.  
Storm  
Collar  
Flashing  
It is important to maintain the required clear-  
ancestocombustibles:1"(25mm)atallsides  
forallverticalruns;and3"(76mm)atthetop,  
1" (25 mm) at sides, and 1" (25 mm) at the  
bottom for all horizontal/inclined runs.  
H. Frame roof opening - Identify location for  
vent at the roof. Cut and/or frame opening per  
Roof Framing Chart (Figure 20).  
Figure 21  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
15  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
VERTICAL VENT FIGURES/TABLES  
Table A  
Notes:  
H Maximum  
feet (meter)  
V Minimum  
feet (meter)  
Elbow Only  
• Secure Vent™ (rigid vent pipe) is shown  
intheFigures;SecureFlex(flexiblevent  
pipe) may also be used.  
H
5
(1.524)  
(1.524)  
(3.048)  
(4.572)  
(6.096)  
• It is very important that the horizontal/in-  
clined run be maintained in a straight (no  
dips) and recommended to be in a slightly  
elevated plane, in a direction away from  
the fireplace of 1/4" rise per foot (20 mm  
per meter) which is ideal, though rise per  
foot run ratios that are smaller are accept-  
able all the way down to at or near level.  
SV4.5VF (Secure Vent), SF4.5VF (Secure  
Flex) firestop/spacer must be used anytime  
vent pipe passes through a combustible  
floor or ceiling. SV4.5HF (Secure Vent),  
SF4.5HF(SecureFlex)restop/spacermust  
be used anytime vent pipe passes through  
a combustible wall.  
Two 45 degree elbows may be used in place  
of one 90 degree elbow. The same rise to  
run ratios, as shown in the venting Figures  
for90elbows,mustbefollowedif45degree  
elbows are used.  
• AN ELBOW IS ACCEPTABLE AS 1 FOOT OF  
VERTICALRISEEXCEPTWHEREANELBOW  
IS THE ONLY VERTICAL COMPONENT IN  
THE SYSTEM (See Figure 29).  
5
1
(0.305)  
(0.610)  
(0.914)  
(1.219)  
uCeiling Firestop /  
Spacer (SV4.5VF)  
10  
15  
20  
2
3
4
V + V + H = 40 feet (12.2 m) Max.  
H = 20 feet (6.096 meters) Max.  
1
V1  
V
Example: If 20 feet of (H) horizontal vent run  
is needed, then 4 feet minimum of (V) vertical  
vent will be required.  
This table shows a 1(V) to 5(H) ratio. For  
every 1 foot of (V) vertical, you are allowed 5  
feet of (H) horizontal run, up to a maximum  
horizontal run of 20 feet.  
vWall Firestop/  
Spacer (SV4.5HF)  
An elbow is acceptable as 1 foot of vertical  
rise except where an elbow is the only vertical  
component in the system. See Figure 29.  
uWhen using Secure Flex, use Firestop /  
vSWphaecnerusSiFn4g.5SVeFc.ure Flex, use Firestop /  
Spacer SF4.5HF.  
Figure 24 - Top Vent - TWO 90 DEGREE ELBOWS  
WARNING  
Undernocircumstances,maysepa-  
rate sections of concentric flexible  
vent pipe be joined together.  
40 feet  
(12.2 meters)  
Maximum  
uCeiling Firestop /  
Spacer (SV4.5VF)  
WhenusingSe-  
cure Flex, use  
Firestop/Spac-  
er SF4.5VF  
u
A Vent  
Restrictor, as  
shown in Figure  
14 on Page 12,  
must be used in  
this application  
Figure 23 - Top Vent - STRAIGHT  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
16  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
VERTICAL VENT FIGURES/TABLES (CONTINUED)  
Example: If 20 feet total (H+H1)  
horizontalventrunisneeded,then  
Table B  
V Minimum  
(meter)  
Elbow Only  
(0.305)  
4feetminimumof(V)verticalvent  
will be required.  
H + H Maximum  
1
Ceiling  
u
Firestop / Spacer  
(SV4.5VF)  
feet  
(meter)  
(1.524)  
(1.524)  
(3.048)  
(4.572)  
(6.096)  
feet  
V
1
WallFirestop/  
v
This table shows a 1(V) to 5(H)  
ratio. For every 1 foot of (V)  
vertical, you are allowed 5 feet  
of (H+H1) horizontal run up to  
a maximum total horizontal run  
of 20 feet.  
5
Spacer (SV4.5HF)  
5
1
2
3
4
10  
15  
20  
(0.610)  
(0.914)  
(1.219)  
H
An elbow is acceptable as 1 foot  
of vertical rise except where  
an elbow is the only vertical  
component in the system. See  
Figure 29.  
V
H
H + H = 20 feet (6.096 m) Max.  
V + V + H + H = 40 ft. (12.2 m) Max.  
1
1
1
1
uWhenusingSecureFlex, use Firestop / Spacer SF4.5VF  
vWhenusingSecureFlex, use Firestop / Spacer SF4.5HF  
Figure 25 - Top Vent - THREE ELBOWS  
HORIZONTAL (OUTSIDE WALL)  
TERMINATION SYSTEM  
Secure Vent SV4.5 direct-vent system compo-  
nents are unitized concentric pipe components  
featuring positive twist lock connection, (refer  
to Figure 17 on Page 14). All of the appli-  
ances covered in this document are fitted with  
collars having locking inclined channels. The  
dimpled end of the vent components fit over  
the appliance collar to create the positive twist  
lock connection.  
Maintain a minimum 1" (25 mm) clearance to  
combustibles on the vertical sections. Clear-  
ances for the horizontal runs are; 3" (76 mm)  
on top, 1" (25 mm) on sides, and 1" (25 mm)  
at the bottom.  
Figure 26 on Page 18, and Figures 27 to 32  
on Pages 19 through 22 and their associated  
Horizontal Vent Table which illustrate the  
various horizontal venting configurations that  
are possible for use with these appliances.  
Secure Vent™ pipe applications are shown in  
these Figures; Secure Flex™ pipe may also  
be used. A Horizontal Vent Table summarizes  
eachsystem’sminimumandmaximumvertical  
and horizontal length values that can be used  
to design and install the vent components in a  
variety of applications.  
B. Frame exterior wall opening -  
Locate the center of the vent outlet on  
the exterior wall according to the dimen-  
sions shown in Figure 11 on Page 10. Cut  
and/or frame an opening, 10-1/2" x 12-1/8"  
(267 mm x 308 mm) inside dimensions, about  
this center.  
A. Plan the vent run -  
Analyze the vent routing and determine the  
types and quantities of sections required  
4-1/2" (114 mm), 10-1/2" (267 mm), 22-1/2"  
(572mm),34-1/2"(876mm)and46-1/2"(1181  
mm) net section lengths are available. It is  
recommended that you plan the vent lengths  
so that a joint does not occur at the intersection  
of ceiling or roof joists. Make allowances for  
elbows as indicated in Figure 19 on Page 15.  
C. Frame ceiling opening - If the vertical route  
istopenetrateaceiling,useplumblinetolocate  
thecenterabovetheappliance.Cutand/orframe  
an opening, 10-1/2" x 10-1/2" (267 mm x 267  
mm)insidedimensions,aboutthiscenter(refer  
to Figure 16 on Page 14).  
Bothofthesehorizontalventsystemsterminate  
throughanoutsidewall. BuildingCodeslimitor  
prohibit terminating in specific areas. Refer to  
Figure 6 on Page 7 for location guidelines.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
17  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Building  
Support  
Framing  
Support  
Brackets  
TYPICALHORIZONTALVENTINSTALLATION  
Horizontal/InclinedRun  
Typical  
Termination  
Shown  
SV4.5E90  
Elbow  
SV4.5L6/12/24/36/48  
VentSections  
Exterior  
Wall  
u Firestop / Spacer  
Ceiling  
SV4.5VF  
SupportBracketSpacing  
Every5ft(1.52m)  
Vertical  
Rise  
u WhenUsingSecureFlex,  
Typical  
Termination  
Shown  
UseFirestop/SpacerSF4.5VF  
See Figure 15 on Page 13 or Figure 18 on  
Page 14 for vertical vent section support.  
Fireplace  
Figure 26  
Push the vent component against the previous  
section until it fully engages, then twist the  
componentclockwiserunningthedimplesdown  
and along the incline channels until they seat at  
the end of the channels. This seating position  
is indicated by the alignment of the arrow and  
dimple as shown in Figure 17 on Page 14.  
D. Attach vent components to appliance - To  
attach a vent component to the appliance collar,  
alignthedimpledendoverthecollar,adjustingthe  
radialalignmentuntilthefourlockingdimplesare  
alignedwiththeinletsofthefourinclinechannels  
on the collar (see Figure 17 on Page 14).  
The elbows feature a twist section to allow  
them to be routed about the center axis of their  
initial collar section to align with the required  
direction of the next vent run element. Twist  
elbow sections in a clockwise direction only  
so as to avoid the possibility of unlocking any  
ofthepreviouslyconnectedventsections(see  
Figure 17 on Page 14).  
Push the vent component against the collar  
until it fully engages, then twist the component  
clockwise,runningthedimplesdownandalong  
the incline channels until they seat at the end  
of the channels.  
F. Install firestop/spacer at ceiling -  
WhenusingSecureVent,useSV4.5VFrestop/  
spaceratceilingjoists;whenusingSecureFlex,  
use SF4.5VF firestop/spacer. If there is living  
spaceabovetheceilinglevel,therestop/spacer  
must be installed on the bottom side of the  
ceiling. If attic space is above the ceiling, the  
firestop/spacermustbeinstalledonthetopside  
of the joist. Route the vent sections through the  
framed opening and secure the firestop/spacer  
with 8d nails or other appropriate fasteners at  
each corner.  
I. Continue installation of horizontal/inclined  
sections - Continue with the installation of the  
straightventsectionsinhorizontal/inclinedrun  
as described in Step E. Install support straps  
every 5 ft. (1.52 m) along horizontal/inclined  
vent runs using conventional plumber’s tape.  
The unitized design of the Secure Vent  
components will engage and seal both the  
inner and outer pipe elements with the same  
procedure. Sealant and securing screws are  
not required.  
See Figure 26. It is very important that the  
horizontal/inclined run be maintained in a  
straight (no dips) and recommended to be in  
a slightly elevated plane, in a direction away  
from the fireplace of 1/4" rise per foot (20 mm  
per meter) which is ideal, though rise per foot  
run ratios that are smaller are acceptable all the  
way down to at or near level.  
Note: An elbow may also be attached to the  
appliance collar. Attach in the same manner  
as you would a vent section.  
Remember to maintain 1" (25 mm) clearance  
to combustibles, framing members, and attic  
or ceiling insulation when running vertical  
chimney sections. Attic insulation shield  
(H3907) may be used to obtain the required  
clearances indicated here. See installation  
accessories Tables on Pages 34 and 35.  
E. Attach vent components to each other  
- Other vent sections may be added to the pre-  
viously installed section in accordance with the  
requirements of the vent tables. To add another  
ventcomponenttoalengthofventrun, alignthe  
dimpled end of the component over the inclined  
channel end of the previously installed section,  
adjustingtheradialalignmentuntilthefourlock-  
ingdimplesarealignedwiththeinletsofthefour  
incline channels of the previous section.  
It is important to maintain the required clear-  
ancestocombustibles:1"(25mm)atallsides  
forallverticalruns;and3"(76mm)atthetop,  
1" (25 mm) at sides, and 1" (25 mm) at the  
bottom for all horizontal/inclined runs.  
G. Support the vertical run sections -  
See Section E on Page 14.  
Use a carpenters level to measure from a  
constant surface and adjust the support straps  
as necessary.  
H.Changeventdirection -Attransitionfromor  
toahorizontal/inclinedrun,installtheSV4.5E45  
and SV4.5E90 elbows in the same manner as  
the straight vent sections.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
18  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
J. Assemble vent run to exterior wall - If not  
Typical  
Termination  
Shown  
Firestop/Spacer (SV4.5HF) shown  
on the exterior side of the wall. It  
may also be installed on the  
interior side.  
previously measured, locate the center of the  
vent at the exterior wall. Prepare an opening as  
described in Step B. Assemble the vent system  
topointwheretheterminusofthelastsectionis  
located relative to the exterior surface to which  
the termination is to be attached as shown in  
Figure 28 and Table 8.  
10-1/2"  
7"  
(267 mm)  
(178)  
12-1/8"  
(308 mm)  
5-1/8"  
(130 mm)  
3"  
(76 mm)  
If the terminus of the last section is not within  
this distance, use the telescopic vent section  
SV4.5LA, as the last vent section. For wall  
thicknesses greater than that shown in Figure  
28, refer to Table 8 on Page 20. This Table lists  
the additional venting components needed (in  
addition to the termination and adapter) for a  
particular range of wall thicknesses.  
1"  
(25.4 mm)  
Adapter  
SV4.5RCH  
Note: Centerline of Vent Piping is  
NOT the Same as the Centerline of  
the Frame Opening.  
See Figure 11 on Page 10 for Min.  
K. Attach termination adapter - Attach the  
adapter(adapter-SV4.5RCH-providedwiththe  
termination) to the vent section or telescoping  
ventsection),elboworappliancecollarasshown  
in Figure 27 in the same manner as any SV4.5  
vent component (refer to Step E).  
distance to Base of Appliance  
6 to 48 inch Vent Section,  
Telescopic vent section,  
Elbow or Appliance Collar  
Base of Appliance  
Figure 27 - INSTALLING HORIZONTAL TERMINATION  
L. Install Firestop/Spacer at exterior wall -  
When using the termination, install SV4.5HF  
(Secure Vent™), SF4.5HF (Secure Flex™)  
Firestop/Spacerovertheopeningattheexterior  
side of the framing, long side up, with the 3  
inch spacer clearance at the top as shown in  
Figure 27, and nail into place.  
*Use silicone caulking to  
seal the top and sides of  
the termination, up to the  
Maximum wall thickness  
9-1/4 in.(235 mm)**  
Interior Surface of  
underlayment, stucco, or  
Finished Wall  
Exterior Surface of Siding  
masonry wall surface.  
Maximum Extent of  
Exterior Surface of  
Framing  
Vent Run Sections  
Siding  
Relative to Exterior  
*Caulk  
Surface of Framing  
6 in. to 9-1/4 in.  
(152 to 235 mm)**  
Last Vent Section. Use  
Telescopic Vent  
Section (SV4.5LA), If  
Necessary  
(TheFirestop/Spacermayalsobeinstalledover  
the opening at the interior side of framing).  
SV4.5HT-2  
Square Termination  
Shown  
M. Install the Termination (SV4.5HT-2 or  
SV4.5HTSS)  
*Caulk  
SV4.5HT-2  
Square Termination  
Shown  
Adapter  
SV4.5RCH  
For the last step, from outside the exterior  
wall, slide the collars of the termination onto  
the adapter (the outer inside the outer and the  
inner outside the inner) until the termination  
seats against the exterior wall surface to which  
it will be attached. Orient the housing of the  
termination with the arrow pointed upwards.  
Secure the termination to the exterior wall. The  
horizontal termination must not be recessed  
into the exterior wall or siding by more than  
the 1-1/4" (32 mm) as shown in Figure 28.  
1-1/4" Maximum Recess of  
the Square Termination into  
Exterior Finishing Material  
**For thicknesses greater  
than 9-1/4", see Table 8  
on Page 20.  
Stucco  
Venting Connection and Exterior Wall Recessing  
of the Horizontal Termination  
Figure 28  
Horizontal terminations have been designed to perform in a wide range of weather condi-  
tions. Our terminations meet or exceed industry standards.  
IMPORTANT: The vent termination is hot  
whileinoperationandforaperiodoftime  
following the use of the fireplace. Young  
children should be carefully supervised  
when they are in the same area as a hot  
termination. To prevent contact with hot  
surfaces, we recommend the use of a  
Termination Guard. See Page 34. This  
can be purchased at your local dealer.  
When selecting the locations of your horizontal terminations, do not place the termina-  
tion where water from eaves and adjoining rooflines may create a heavy flow of cascad-  
ing water onto the termination cap. If the cap must be placed where the possibility of  
cascading water exists, it is the responsibility of the builder to direct the water away  
from the termination cap by using gutters or other means.  
Take care to carefully follow the installation instructions for the termination, including  
the use of silicone caulking where required.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
19  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Use Table 8 as an aid in venting component selection for a particular  
range of exterior wall thicknesses.  
Table C  
V Minimum  
feet (meter) feet (meter)  
(0.914) Elbow Only  
H Maximum  
Venting Components Required for Various Exterior Wall Thick-  
nesses, when using Typical Termination Kits  
3
Vent Components Required Exterior Wall Thickness - inches (mm)  
Typical termination shown.  
Termination Kit Only  
6 to 9-1/4 (152 to 235)  
H
TerminationKitand 6In.Vent  
Section (SV4.5L6)  
10-3/4 to 14 (273 to 356)  
V
Termination Kit and 12 in.  
Vent Section (SV4.5L12)  
16-3/4 to 20 (426 to 508)  
Termination Kit and Tele-  
scopic Section (SV4.5L12)  
11-3/4 to 20 (299 to 508)  
When using Secure Flex,  
Wall  
uuse Firestop/Spacer  
Firesutop/Spacer  
Note: See Figure 28 on Page 19 showing wall thickness  
range when using SV4.5HT-2 termination kit.  
Table 8  
SF4.5HF  
(SV4.5HF)  
See Table 8 on Page 20 as an aid in venting component selection  
for a particular range of exterior wall thicknesses.  
HORIZONTAL VENT FIGURES/TABLES  
Figure 29 - Top Vent -  
ONE 90 DEGREE ELBOW - ELBOW CONNECTION AT APPLIANCE  
Notes:  
• Secure Vent™ components (rigid vent pipe and terminal) are shown  
in the Figures; Secure Flex™ components (flexible vent pipe and  
terminal) may also be used.  
Table D  
V Minimum  
feet (meter) feet (meter)  
Example: If20feetof(H) hori-  
zontal vent run is needed, then  
4 feet minimum of (V) vertical  
vent will be required.  
H Maximum  
Two 45 degree elbows may be used in place of one 90 degree elbow.  
The same rise to run ratios, as shown in the venting Figures for 90  
elbows, must be followed if 45 degree elbows are used.  
This table shows a 1(V) to  
5(H) ratio. For every 1 foot of  
vertical, you are allowed 5 feet  
of (H) horizontal run up to a  
maximum (H) horizontal run  
of 20 feet.  
5
(1.524)  
(3.048)  
(4.572)  
(6.096)  
1
2
3
4
(0.305)  
(0.610)  
(0.914)  
(1.219)  
10  
15  
20  
SV4.5VF (Secure Vent), SF4.5VF (Secure Flex) firestop/spacer must  
be used anytime vent pipe passes through a combustible floor or ceil-  
ing. SV4.5HF (Secure Vent), SF4.5HF (Secure Flex) firestop/spacer  
must be used anytime vent pipe passes through a combustible wall.  
V + H = 40 feet (12.2 m) Max.  
H = 20 ft. (6.096 m) Max.  
• It is very important that the horizontal/inclined run be maintained  
in a straight (no dips) and recommended to be in a slightly elevated  
plane, in a direction away from the fireplace of 1/4" rise per foot (20  
mm per meter) which is ideal, though rise per foot run ratios that are  
smaller are acceptable all the way down to at or near level.  
H
When using Secure Flex,  
use Firestop/Spacer  
SF4.5VF.  
V
The tables show a 1(V) to 5(H) ratio up to a maximum horizontal run  
of 20 feet except for installations where an elbow is the only vertical  
vent section in the system (see Figure 29).  
When using Secure Flex,  
use Firestop/Spacer  
SF4.5HF.  
Wall Firestop/Spacer  
(SV4.5HF)  
• AN ELBOW IS ACCEPTABLE AS 1 FOOT OF VERTICAL RISE EXCEPT  
WHERE AN ELBOW IS THE ONLY VERTICAL COMPONENT IN THE  
SYSTEM. See Figure 29.  
Ceiling  
Firestop/Spacer  
(SV4.5VF)  
Typical termination shown.  
WARNING  
Under no circumstances, may separate sections of  
concentric flexible vent pipe be joined together.  
See Table 8 on Page 20 as an aid in venting component selection  
for a particular range of exterior wall thicknesses.  
Figure 30 - Top Vent - ONE 90 DEGREE ELBOW -  
ELBOW CONNECTION NOT DIRECTLY AT APPLIANCE  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
20  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
HORIZONTAL VENT FIGURES / TABLES (CONTINUED)  
Wall Firestop/Spacer  
Table E  
H + H Maximum  
(SV4.5HF)  
V Minimum  
feet (meter)  
Elbow Only  
1
H
feet  
3
(meter)  
(0.914)  
(1.524)  
(3.048)  
(4.572)  
(6.096)  
H
1
V
5
1
2
3
4
(0.305)  
(0.610)  
(0.914)  
(1.219)  
10  
15  
20  
Note - When using  
TM  
Secure Flex , use  
Wall Firestop/Spacer  
(SV4.5HF)  
Firestop/Spacer SF4.5VF.  
V + H + H = 40 feet (12.2 m) Max.  
When using Secure Flex,  
1
use Firestop/Spacer  
SF4.5HF.  
H + H = 20 ft. (6.096 m) Max.  
1
Ceiling  
Firestop/Spacer  
(SV4.5VF)  
Example: If 20 feet of (H + H1) horizontal vent run is needed,  
then 4 feet minimum of (V) vertical vent will be required.  
Typical termination shown.  
This table shows a 1(V) to 5(H) ratio. For every 1 foot of (V)  
vertical, you are allowed 5 feet of (H+ H ) horizontal run, up  
to a maximum horizontal run of 20 feet. 1  
See Table 8 on Page 20 as an aid in venting  
component selection for a particular range of  
exterior wall thicknesses.  
An elbow is acceptable as 1 foot of vertical rise except where  
an elbow is the only vertical component in the system. See  
Figure 29.  
Figure 31 - Top Vent - TWO 90 DEGREE ELBOWS  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
21  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
HORIZONTAL VENT FIGURES / TABLES (CONTINUED)  
Table F  
Typical termination shown.  
V Minimum  
feet (meter)  
Elbow Only  
H + H Maximum  
When using Secure Flex,  
use Firestop/Spacer  
SF4.5VF.  
1
feet  
5
(meter)  
(1.524)  
(1.524)  
(3.048)  
(4.572)  
(6.096)  
When using Secure  
H
1
Flex, use Firestop/Spacer  
SF4.5HF.  
5
1
2
3
4
(0.305)  
(0.610)  
(0.914)  
(1.219)  
10  
15  
20  
Ceiling  
Firestop/Spacer  
(SV4.5VF)  
H + H = 20 feet (6.096 m) Max.  
1
V + V + H + H = 40 ft. (12.2 m) Max.  
H
1
1
Wall Firestop/Spacer  
(SV4.5HF)  
V
1
Example: If 20 feet total (H+H ) horizontal vent  
run is needed, then 4 feet minim1um of (V) vertical  
vent will be required.  
V
See Table 8 on Page 20 as  
anaidinventingcomponent  
selection for a particular  
range of exterior wall thick-  
nesses.  
This table shows a 1(V) to 5(H) ratio. For every 1  
foot of (V) vertical, you are allowed 5 feet of (H+  
H1) horizontal run, up to a maximum horizontal  
run of 20 feet.  
Anelbowisacceptableas1footofverticalriseexcept  
where an elbow is the only vertical component in  
the system. See Figure 29.  
Wall Firestop/Spacer  
(SV4.5HF)  
Figure 32 - Top Vent - THREE 90 DEGREE ELBOWS  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
22  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
VERTICAL OR HORIZONTAL VENTING USING  
Flex Vent  
NOTE: Outer pipe is pulled away to  
show the detail of the inner pipe.  
SECuRE FLEX™ KITS AND COMPONENTS  
Securing Screw - 3 places,  
equally spaced, just below  
gear clamp.  
Secure Flex™ venting kits and components  
may be used in any venting application in place  
of rigid Secure Vent™ (SV4.5) direct-vent  
components. All restrictions, clearances and  
allowancesthatpertaintotherigidpipingapply  
to the flexible venting. Secure Flex kits may  
notbemodified;also,undernocircumstances  
may separate sections of flex pipe be joined  
together.  
APPLY ONLY MIL-PAC BLACK  
HIGH TEMPERATURE SEALANT  
(Cat. No. 10K81) to the outside  
surface of both collars of the  
adapter (be especially careful to  
fill the grooves of the outer collar  
tobecoveredbytheexiblepipe)  
and slide flexible pipe over inner  
and outer adapter collars.  
Gear Clamps  
Using adapter (SV4.5RF), Secure Flex kits  
may be added to the end of a vent run made  
up of rigid Secure Vent (SV4.5) vent sections  
provided that doing so does not violate any of  
the venting length, height, routing, horizontal  
to vertical ratio requirements or clearance  
considerations detailed in this manual.  
1 3/4 inch (44 mm) Flexible  
PipeandAdapterOuterCollar  
Overlap  
1 3/4 in. (44 mm) Flexible  
PipeandAdapterInnerCollar  
Overlap  
Adapter (SV4.5RF)  
Securing Screw  
- 3 places, 120° apart  
(equally spaced) just  
below gear clamp  
Secure Flex kits come with an adapter that  
can be fitted to the inclined channel end of  
the last Secure Vent (SV4.5) vent section in a  
rigid system in the exact same fashion as any  
other Secure Vent section. Align the dimpled  
end of the adapter over the previously installed  
section or appliance collar, adjusting the radial  
alignment until the four locking dimples of the  
adapter are aligned with the inlets of the four  
inclinechannelsofthelastventsectionorcollar.  
Push on the adapter until it fully engages, then  
twisttheadapterclockwiserunningthedimples  
down and along the incline channels until they  
seat at the end of the channels.  
Attach adaptor to appliance  
Figure 33  
Collar, or secure vent sections  
B. Install the Outer Flex Pipe -  
D. Install Firestop / Spacers at ceilings and walls  
- When Secure Flex penetrates a wall or ceiling,  
a firestop / spacer is required: use the SF4.5 VF  
firestop / spacer for ceilings and the SF4.5 HF  
firestop / spacer for walls. See the appropriate  
sectionsandFiguresshownthroughoutthevent-  
ing section for their installation requirements.  
1. Install the large gear clamp loosely around  
the outer flexible vent pipe, push it back out  
of the way.  
2. ApplyabeadofMill-PacBlack(700°F,high  
temperature sealant - Catalog No. 10K81)  
to the outer adapter collar; to the grooves  
of the collar which extend approximately 1  
inch from the end and to the flat surface,  
approximately 1-3/8 inches from the end.  
3. Pull and extend outer flexible vent pipe.  
4. Slidetheouterexpipeovertheadaptercol-  
lar. Ensure the flexible vent pipe completely  
engages the adapter collar to a distance of  
1-3/8 inches from the end, and that it is free  
from damage or tears.  
5. Slide the gear clamp down and tighten it  
fullytosecuretheexibleventtotheadapter  
outer collar approximately3/4 inch from the  
end of the flex.  
6. Install three screws, 120 degrees apart,  
through the flexible vent pipe and into the  
adapter collar just below the gear clamp to  
provide additional security to the connec-  
tion.  
Flexible Vent  
Section  
Attach the flexible vent to the adapter as fol-  
lows (see also Figure 33):  
A. Install the Inner Flex Pipe -  
1. Install the small gear clamp loosely around  
the inner flexible vent pipe, push it back out  
of the way.  
2. ApplyabeadofMill-PacBlack(700°F)high  
temperature sealant - Catalog No. 10K81  
to the inner adapter collar, approximately  
1/2 inch from the end.  
3. Pull and extend the inner flexible vent pipe.  
4. Slidetheinnerexpipeovertheadaptercol-  
lar. Ensure the flexible vent pipe completely  
engages the adapter collar to a distance of 1  
3/4 inches from the end, and that it is free  
from damage or tears.  
5. Slide the gear clamp down and tighten it  
fullytosecuretheexibleventtotheadapter  
inner collar approximately 3/4 inch from the  
end of the flex.  
6. Install three screws, 120 degrees apart,  
through the flexible vent pipe and into the  
adapter collar just below the gear clamp to  
provide additional security to the connec-  
tion.  
5” (127 mm)  
Radius  
Minimum  
Figure 34  
E. Attach Flex Vent to Termination -  
Secure Flex components can be purchased  
separately and attached to bulk lengths of Se-  
cure Flex flexible tubing cut to size at the job  
site. Secure the flexible vent to the Secure Flex  
terminations in the same manner (see Figure  
33) as it was attached to the adapter.  
C. Route Flex Vent -  
Ensure that the flex vent is properly routed to  
providetherequiredclearance.Donotallowthe  
flexible vent to bend in a radius tighter than 5"  
(127 mm). Refer to Figure 34. Space out the  
internalexventspacersevenly-approximately  
every 6 inches - and avoid kinking of inner pipe.  
Support horizontal sections of flex with metal  
straps at 2 foot (0.61 m) intervals.  
Note: SecureFlexventmustbeattachedtoSe-  
cureFlexterminationsonly.DONOTsubstitute  
Secure Vent terminations or the Secure Vent  
adapter for Secure Flex components. The col-  
lars of Secure Flex terminations and adapters  
have a different diameter than that used with  
theSecureVentpipe. Additionally,SecureFlex  
components have an extended length center  
tube for use in attaching the flexible vent.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
23  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Refer to Section A for millivolt appliances and  
Section B for electronic appliances. The gas  
valve is set in place and pre-wired at the factory  
on both models.  
3. Remove the cover plate's knockout and  
then feed the power supply wire through the  
knockout opening and into the unit junction  
box.  
4. Connect the black power supply wire to the  
lower outlet's red pigtail lead and the white  
power supply wire to the common terminal  
of the outlet as shown in Figure 36.  
5. Connect the ground supply wire to the pig-  
tail lead attached to outlet's green ground  
screw.  
6. Either wall-mounted switch, unit mounted  
rocker switch (FRS), thermostat, or one of  
the optional remote control kits is to be  
used. Mount wall switch or thermostat in  
a convenient location on a wall near the  
fireplace.  
Step 4. FIELD WIRING  
CAUTION  
Ground supply lead must be con-  
nected to the wire attached to the  
green ground screw located on the  
outletbox. SeeFigure37.Failureto  
dosowillresultinapotential safety  
hazard. The appliance must be  
electricallygroundedinaccordance  
withlocalcodesor,intheabsenceof  
localcodes, theNationalElectrical  
Code,ANSI/NFPA70-latestedition.  
(In Canada, the current CSA C22-1  
Canadian Electrical Code).  
A. Millivolt Wiring (See Figure 35) –  
1. An optional wall-mounted switch, unit  
mounted rocker switch, wall thermostat, or  
one of the optional remote control kits may  
used with this appliance.  
2. Wire the control switch within the millivolt  
controlcircuitusingthe15feetof2conductor  
wire supplied with the unit.  
Note:Thesupplied15feetof2conductorwire  
has one end of each conductor connected  
to the gas valve circuit and the other end  
of each conductor placed loose inside the  
bottom compartment.  
Note: Remote receiver should be located  
in the wall, or if installed in the control  
compartment, pulled all the way forward  
andcompletelytotheleftorrightagainstthe  
corner posts. The door must be removed  
firsttoplacethereceiverinthelowercontrol  
compartment.  
3. If an optional control switch is installed,  
turn the appliance-mounted ON/OFF burner  
control switch to the OFF position (if in-  
stalled).  
CAUTION: Label all wires prior to disconnec-  
tionwhenservicingcontrols.Wiringerrorscan  
cause improper and dangerous operation.  
ATTENTION: Au moment de l'entretien des  
commandes, étiquetez tous les fils avant de  
les débrancher. Des erreurs de cáblage peu-  
vent entraîner un fonctionnement inadéquat  
et dangereux.  
7. If an optional control is to be used, wire it in  
the low voltage circuit as shown in Figure  
36.  
CAUTION: Do Not connect the optional wall  
switch to a 120V power supply.  
Note:Thesupplied15feetof2conductorwire  
has one end of each conductor connected  
to the gas valve circuit and the other end  
of each conductor placed loose inside the  
bottom compartment.  
B. Electronic Wiring (See Figure 36) –  
Note: The electronic appliance must be con-  
nected to the main power supply.  
Verify proper operation after servicing.  
1. Route a 3-wire 120Vac 60Hz 1ph power  
supply to the appliance junction box.  
2. Remove the electrical inlet cover plate from  
the side of the unit by removing the plate's  
securing screws. See Figure 11 on Page  
10.  
S'assurer que l'appareil fonctionne adé-  
quatement une fois l'entretien terminé.  
8. If the optional unit mounted ON/OFF (FRS)  
control switch is installed, turn the ON/OFF  
switch to the OFF position.  
9. After the wiring is complete, replace the  
cover plate.  
WIRING DIAGRAM MILLIVOLT GAS VALVES  
THERMOPILE  
APPLIANCE- MOUNTED  
INTERMITTENT ELECTRONIC WIRING DIAGRAM  
ON/OFF SWITCH  
(OPTIONAL)  
120 VAC  
SPARK TO PILOT IGNITER  
BK  
W
GR  
TP-TH  
TP  
TH  
GAS VALVE  
BK/W(1)  
BK/W(1)  
OPTIONAL BLOWER  
SWITCH  
IGNITER MODULE  
3V  
JUNCTION BOX  
BLACK (IGNITER)  
BLACK (SENSOR)  
WALL-MOUNTED ON/OFF SWITCH (OPTIONAL)  
THERMOSTAT (OPTIONAL)  
TRANSFORMER 3V  
WALL MOUNTED CONFIGURATION FOR FAN SWITCH (OPTIONAL)  
FAN  
(OPTIONAL)  
BLACK  
BK  
R
W
ORANGE (THTP)  
BATTERY BACK-UP  
BLACK (TP)  
GREEN (TH)  
GR  
T O P I L  
HI  
LO  
RED  
TO WALL  
SWITCH, FRS  
FAN  
OR THERMOSTAT  
BROWN  
(OPTIONAL)  
JUNCTION BOX  
BROWN  
Figure 36  
See Figure 37 for detailed drawing of junction box / receptaclewiring  
Figure 35  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
24  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Note: No batteries to be installed in the battery  
holder until a power outage, or if the appli-  
ance is to be operated solely with two (2) "D"  
batteries.  
Step5.WIRING-OPTIONALFORCEDAIR  
BLOWER KIT  
120V, 60HZ, 1PH  
* Wall-mounted  
ON/ OFF Blower  
Blower Access  
Switch or Variable  
Speed Control Switch.  
Blower access is through the firebox bottom.  
Remove the front panel, the porcelain panels,  
the sub-floor, remove the burner and remove  
ten screws securing the GTA assembly to the  
firebox.  
Junction Box  
Anelectricaloutletboxisprovidedfortheinstal-  
lation of the FBK-100 and FBK-200 forced air  
blower kit. Electrical power must be provided  
to this box to operate these blowers. Install the  
blower kit according to the installation instruc-  
tions provided with the kit.  
Tab  
Broken  
Hot  
Side of  
Red  
Black  
Receptacle  
Reposition and reinstall the GTA assembly,  
burner and sub-floor.  
Neutral  
Side of  
Receptacle  
Plug blower  
Tab Intact  
into this  
Green  
Ground  
Screw  
receptacle  
Blower  
Field Wired  
Factory Wired  
Ground  
Figure 37 - J-BOX WIRING  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
25  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Step 6. CONNECTING GAS LINE  
GAS CONNECTION  
Gas Flex Line Connector  
All codes require a shut-off valve mounted  
3/8" NPT x  
Flare Fitting  
Gas  
in the supply line. The orientation of the  
shut-off valve should face the front. Figure  
38 illustrates two methods for connecting the  
gas supply. A Sediment Trap is recommended  
to prevent moisture and debris in gas line from  
damaging the valve.  
1/2" x 3/8" Flare  
Shut-off Valve  
Valve  
Note: The gas supply line  
must be installed in accor-  
dance with building codes  
by a qualified installer  
approved and/or licensed  
as required by the locality.  
In the Commonwealth of  
Massachusetts, installation  
must be performed by a  
licensed plumber or gas  
fitter.  
3/8" Flex Tubing  
Gas  
1/2" x 3/8"  
The flex-line method is acceptable in the U.S.A.  
where local codes permit, however, Canadian  
requirementsvarydependingonlocality.Instal-  
lation must be in compliance with local codes.  
These appliances are equipped with a gas flex-  
lineforuseinconnectingtheunittothegasline.  
See Figure 38 for flex-line description. The  
flex-line is rated for both natural and propane  
gas. A manual shut off valve is also provided  
with the flex-line.  
Stub  
Reducer  
3/8" Nipple  
3/8" Union  
3/8" Close  
Nipple  
3/8" Shut-off Valve  
Gas Solid Line Connector  
Figure 38  
The gas control valve is located in the lower  
control compartment.  
Accessthevalvecompartmentbyremovingthe  
lower control compartment panel (see Figure  
39) by sliding and pulling the panel forward.  
The panel is mounted at the extreme right and  
lefthandsides, throughslots. Engagethetabs  
into the slots in the panel.  
The millivolt and electronic control valve has a  
3/8" (10mm) NPT thread inlet port.  
Secure all joints tightly using appropriate  
toolsandsealingcompounds(ensurepropane  
resistant compounds are used in propane ap-  
plications). Itisrecommendedtosealaround  
the gas line to prevent cold air leakage.  
Gas Shut-Off  
Valve  
Gas Flex Line  
Valve  
Piezo  
Spring Door  
Latch  
Lower Control  
Compartment  
Figure 39  
Gas line connection may be performed largely  
outside of the confines of the control compart-  
ment and without having to enter the firebox  
behind the glass. Proceed as follows:  
Refer to Figure 40 and insert the last length  
of gas pipe with its attached shut-off valve  
into the lower control compartment and pass  
it through the gas line access hole on the left  
side of the appliance outer wrapper. Using ap-  
propriate materials for the gas type, thread the  
last length of pipe into the end of the gas vent  
run and tighten in place using a pipe wrench  
external totheappliancebetweentheappliance  
outer wrapper and the framing.  
Acquire the shut-off valve and gas lex line and  
pull the assembly forward out of the compart-  
ment. Separate the shut-off valve from the gas  
flex-line. Determine the length of pipe needed  
to route the gas line from the last fitting (shown  
in Figure 13 on Page 11) to a point within the  
control compartment that will allow the shut-  
off valve to be easily attached by hand to the  
gas flex-line.  
Length Of Pipe With  
Important: Turn the last piece of gas pipe in  
the last fitting until the shut-off valve is posi-  
tioned in a way that allows the shut-off valve  
handle to be accessed in the lower control  
compartment, easilyoperated throughoutits  
full range of motion.  
Attached Shut-Off Valve  
Figure 40  
Using pipe-dressing materials appropriate for  
the gas type, securely affix the shut-off valve  
to this determined pipe length at a convenient  
location outside of the appliance lower control  
compartment.  
Bring the flex-line to the shutoff valve by hand  
and align the flare fittings. Tighten the fittings  
by hand, and then use an open end wrench to  
tighten completely, 1/4 turn at a time.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
26  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
TEST ALL CONNECTIONS FOR GAS LEAKS  
(FACTORY AND FIELD):  
The flame should project 1" (25 mm) beyond  
the hood at all three ports (see Figure 41).  
Replace contemporary floor media if removed  
for pilot inspection.  
Step 7. VERIFYING APPLIANCE  
OPERATION  
Turn on burner then observe the individual  
tongues of flame on the burner. Make sure  
all ports are open and producing flame evenly  
across the burner. If any ports are blocked, or  
partially blocked, clean out the ports.  
WARNING  
Never use an open flame to  
check for leaks.  
To light the burner; turn “ON” the remote wall  
switch and rotate the gas valve control knob  
counterclockwise to the “ON” position (“ON”  
will be at the top side of the valve).  
With gas line installed run initial system  
checkoutbeforeclosingupthefrontoftheunit.  
Follow the pilot lighting instructions provided  
in the Care and Operation Instructions. For  
piezo igniter location see Figure 39 on Page  
26 (millivolt appliances only).  
Turn on gas supply and test for gas leaks, us-  
ing a gas leak test solution (also referred to as  
bubble leak solution).  
Hood Igniter Rod  
MILLIVOLT  
Thermocouple  
Note: Using a soapy water solution is an  
effective leak test solution but it is not recom-  
mended, because the soap residue that is left  
on the pipes/fittings can result in corrosion  
over time. Never use an open flame to check  
for leaks.  
Note: Lighting Instructions are also found on  
the literature tag tied to the gas piping next to  
thegasvalve. Toaccessthetag, openthelower  
controlcompartmentdoor(Figure39 onPage  
26) by pulling the panel forward.  
3/8" Min  
(9 mm)  
Pilot  
Nozzels  
A. Light the appliance (refer to the lighting  
instructionslabelinthecontrolcompartment  
or in the Care and Operation Instructions  
manual).  
Thermopile  
Figure 41  
Whenrstlightingtheappliance,itwilltakeafew  
minutes for the line to purge itself of air. Once  
purging is complete, the pilot and burner will  
light and operate as indicated in the instruction  
manual. Subsequent lighting of the appliance  
will not require such purging. Inspect the pilot  
flame (remove contemporary floor media, if  
necessary, handling carefully).  
Electronic Appliance Checkout  
B. Brush all joints and connections with the  
gas leak test solution to check for leaks. If  
bubbles are formed, or gas odor is detected,  
turn the gas control knob to the “OFF” posi-  
tion. Either tighten or refasten the leaking  
connection and retest as described above.  
To light the burner, turn ‘ON’ the unit mounted  
On/Offswitchortheoptionalremotewallswitch.  
Ensure the igniter lights the pilot. The pilot  
flame should engulf the flame rod as shown  
in Figure 42.  
Millivolt Appliance Checkout  
C. Whenthegaslinesaretestedandleakfree,be  
sure to rinse off the leak testing solution.  
The pilot flame should be steady, not lifting  
or floating. Flame should be blue in color with  
traces of orange at the outer edge.  
ELECTRONIC  
Pilot  
Hood  
Sensor  
Igniter  
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.  
Figure 42  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
27  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Step 8. INSTALLING CONTEMPORARY  
MEDIA  
Install Tumbled River Stone (MTRS) -  
Table Of Contemporary Media  
Cat.  
No.  
Model  
Contemporary Media  
Name  
IMPORTANT: Refractorypanelsshouldbe  
installed before any of the contemporary  
media are installed.  
NOTE: Turn off all electricity to the appliance  
before you install contemporary floor media.  
H7536  
H7537  
MTRS  
Tumbled River Stone  
Contemporary Glass  
Obsidian Black  
MCCG-OB  
1. Place stones on the firebox sub-floor, in  
any atheistically pleasing manner to suite  
individual taste. See Figure 43 - Detail C  
on Page 29 for an example.  
Contemporary Beach  
Sand  
H7538  
H7578  
H7579  
MBSK  
WARNING  
Contemporary Glass  
Diamond White  
• DO NOT attempt to install the  
contemporary media until the  
applianceinstallationhasbeen  
completed, the gas line con-  
nected and tested for leaks and  
the initial burner operation has  
been checked out.  
• The size and position of the  
contemporary media was engi-  
neered to give the appliance  
a safe, reliable and attractive  
flame pattern. Any attempt to  
use a different media in the  
fireplace will void the warranty  
and will result in incomplete  
combustion, sooting, and poor  
flame quality.  
• Contemporary media get very  
hot and will remain hot up to  
one hour after gas supply is  
turned off. Handle only when  
contemporary media are cool.  
• Thisapplianceisnotdesignedto  
burnwood. Anyattempttodoso  
couldcauseirreparabledamage  
to the appliance and prove haz-  
ardous to your safety.  
• If contemporary media are  
not installed according to the  
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.  
MCCG-DW  
MCCG-SB  
IMPORTANT: Be sure stones do not im-  
pinge on the burner outlet.  
Contemporary Glass  
Deep Sea Blue  
Merit Liner Kit, Zen  
Garden  
H7581 MBLPK-35ZG  
Install Crushed Glass And Sand (MCCG and  
MBSK) -  
Remove the front glass enclosure panel  
(see Removing Glass Enclosure Panels on  
Page 30).  
IMPORTANT: Refractorypanelsshouldbe  
installed before any of the contemporary  
media are installed.  
This fireplace is designed to accept a number  
of alternate contemporary media options,  
allowing the homeowner to customize this  
product to fit any decor.  
1. Pour out glass or sand on firebox sub-  
floor, completely covering the sub-floor.  
See Figure 43 - Detail D on Page 29 for  
an example.  
Install Zen Garden Refractory Panels  
(MBLPK-35ZG) -  
IMPORTANT: Avoid letting glass or sand  
fall into the burner outlet. Make sure  
no glass or sand falls into the burner  
ports.  
1. Porcelain panels come installed in the ap-  
pliance. Remove them by bending the tab,  
sliding the left and right side panels out  
first, then removing the rear panel.  
Install Contemporary Facade -  
2. Install Zen Garden panels:  
1. Refer to the Facade Installation Instruc-  
tions (P/N 506019-40) to install the Con-  
temporary Facade.  
Remove the lintel by removing two  
screws.  
Insert the rear panel into firebox and po-  
sition against the rear wall of the firebox  
(see Figure 43 - Detail A on Page 29).  
Carefully insert the left side panel into  
firebox, at a slight angle away from the  
sidewall. Position the side panel as far  
back along the wall as it will go (until it  
is against the rear panel) and lower it into  
place, while standing it upright and press-  
ing it down over the knife edge at the rear  
of the sub-floor. The sub-floor knife edge  
will cut into the refractory panel. Repeat  
the same procedure for the right side panel  
(see Figure 43 - Detail B on Page 29).  
Re-install the lintel.  
• Only use materials listed here.  
Only contemporary media  
authorized have been tested  
for use within the firebox and  
itsenvironment. Donotattempt  
to use any different materials  
in the fireplace. Doing so may  
be dangerous and will void  
the warranty and will result in  
incomplete combustion, soot-  
ing, and poor flame quality.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
28  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
MLDVTCD-35 REFRACTORY PANELS AND CONTEMPORARY MEDIA PLACEMENT  
Rear Zen Garden Panel  
Burner Outlet  
Tumbled River Stone  
(Note: River Stone And Beach Sand May Be Used Together)  
Burner Outlet  
Black Obsidian Contemporary Glass  
Detail A  
Detail C  
Right Zen Garden Panel  
Left Zen Garden Panel  
Burner Outlet  
Contemporary Beach Sand  
(Note: Beach Sand And River Stone May Be Used Together)  
Diamond White Contemporary Glass  
Burner Outlet  
Detail B  
Detail D  
Figure 43  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
29  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Step 9. INSTALLATION AND REMOVAL  
OF GLASS DOOR  
3. Pull the bottom of the door out a few inches  
and grasp it on the right and left. Gently lift  
to release the door from its channel above  
the door. Pull the door forward.  
4. 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.  
5. Inspect the gasket for defects. Ensure it is  
properly located. Make sure the bead is not  
rolled up into the channel at the top of the  
door, but remains flat against the top of the  
glass (see Figure 44).  
6. Position the door in front of the firebox  
opening with the bottom of the door held  
away from the fireplace (Figure 44). Hook  
the top flange of the door frame over the top  
of the firebox frame.  
7. 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  
underneaththereboxoortothedoor'svee-  
flange. Close both the latches securely.  
8. Install the hood. Note the location of the  
three clips inside the top air channel above  
the door. The clips are equally spaced on  
the top surface of the air channel opening.  
Use a screwdriver to open the clips slightly  
if needed. Engage the back edge of the  
eyebrow into the clips to secure.  
Step 10. BURNER ADJUSTMENTS  
Flame Appearance and sooting  
Proper flame appearance is a flame which is  
blueatthebaseandbecomesyellowish-orange  
in the body of the flame.  
WARNING  
Donotattempttosubstitutethe  
materialsusedonthesedoors,  
or replace cracked or broken  
glass.  
When the appliance is first lit, the entire flame  
may be blue and will gradually turn yellowish-  
orangeduringtherst15minutesofoperation.  
After 15 minutes of operation, if the flame is  
blue, or if the flame is orange with evidence of  
sooting (black tip), the air shutter opening may  
need to be adjusted.  
• Handlethisglasswithextreme  
care! Glass is susceptible to  
damage – Do not scratch or  
handleroughlywhilereinstall-  
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,  
crackedorchippedglasssepa-  
rately.  
If the air shutter openings 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 appliance inside sur-  
faces and on exterior surfaces adjacent to the  
vent termination.  
Sootingiscausedbyincompletecombustionin  
the flames and lack of combustion air entering  
the air shutter opening. To achieve a warm yel-  
lowish-orange flame with an orange body that  
does not soot, the shutter opening must be  
adjusted between these two extremes.  
Do not attempt to touch the  
frontenclosureglasswithyour  
hands while the fireplace is in  
use.  
Air Shutter Adjustment Guidelines  
WARNING  
Do not operate appliance with  
theglassfrontremoved,cracked  
or broken.  
• If there is smoke or soot present, the air  
shutter opening should be increased.  
• Themoreoffsetsintheventsystem,thelarger  
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.  
Ensure Gasket Is Not Rolled  
Up Into Door Frame Channel  
Header  
Spacing  
Top  
AVERTISSEMENT  
Standoffs  
Ne pas utiliser l'appareil si le  
panneau frontal en verre n'est  
pas en place, est craqué ou  
brisé.  
5/8”  
Nailing  
Flange  
1/2”  
Nailing  
Flange  
Only doors certified with the appliance  
shall be used.  
Glass  
Door  
The following chart is provided to aid you in  
achieving the correct air shutter adjustment  
for your installation.  
Seules des portes certifiées pour cet  
appareil doivent être utilisées.  
Flush  
Nailing  
Flange  
Air Shutter Adjustment Guidelines:  
CAUTION: DO NOT abuse glass door by  
striking or slamming shut.  
Glass Door  
Spring Latch  
Amount of  
Primary Air  
Flame  
Color  
Air Shutter  
Adjustment  
Control  
Compartment  
Panel  
Removing Glass Enclosure Panels  
(see Figure 44)  
If air shutter is  
closed too far  
Flame will Air shutter  
be orange gap should be  
increased  
Hood  
Note: When installing the glass door, ensure the  
spacing on both sides are equal.  
1. To access the glass door securing latches,  
first open the lower control compartment  
door (Figure 44) by sliding and pulling the  
bottom panel forward.  
2. Pull the latches forward and down to release  
them from the door channel.  
If air shutter is  
open too far  
Flame will Air shutter  
be blue gap should be  
decreased  
Figure 44 -  
INSTALLING OR REMOVING GLASS DOOR  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
30  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Burner Air Shutter Adjustment Procedure  
Adjustment Set-Screw  
Main Burner Factory Air Shutter  
Adjustment Rod Up  
Opening Setting - Inches (millimeter)  
WARNINGS  
(closed min. position)  
Model  
Natural Gas Propane Gas  
Air shutter adjustment should  
only be performed by a quali-  
fiedprofessionalservicetech-  
nician.  
Ensure front glass panel are  
in place and sealed during  
adjustment.  
Burner Tube  
Air Shutter  
Expose Half  
(Closed)  
MLDVTCD-35  
Of The Hole  
Ref. Air shutter Patent:  
U.S. Pat. 5,553,603  
Figure 45 - Burner Air Shutter Adjustment  
CAUTIONS  
Soot will be produced if the  
airshutterisclosedtoomuch.  
Any damage due to carboning  
resulting from improperly  
setting the air shutter is not  
covered under the warranty.  
Theairshutterdoorandnearby  
appliance surfaces are hot.  
Exercise caution to avoid  
injury while adjusting flame  
appearance.  
Ensure the air shutter setting  
is at least equivalent to 1/2  
of the air hole exposed when  
operating the unit with pro-  
pane gas.  
1. Locate and adjust the air shutter to the  
standard setting as shown in Figure 45.  
2. Light appliance (follow lighting procedure  
on lighting label in control compartment or  
see the Care and Operations manual).  
3. Allow the burner to operate for at least 15  
minutes while observing the flame con-  
tinuously to ensure that the proper flame  
appearance has been achieved (see Figure  
46). Ifthefollowingconditionsarepresent,  
adjust accordingly.  
(River Stone And Beach Sand With Porcelain Panels Shown)  
Figure 46 - Burner Flame Appearance Model MLDVTCD-35  
• If flame appears weak or sooty, adjust the  
air shutter, incrementally, to a more open  
positionuntiltheproperameappearance  
is achieved.  
• If flame stays lowered blue, adjust the air  
shutter, incrementally, to a more closed  
positionuntiltheproperameappearance  
is achieved.  
4. Leave the control knob (off/pilot/on) in the  
ON position and the burner ON/OFF switch  
OFF (and remote switches, if applicable).  
5. Whensatisfiedthattheburnerameappear-  
ance is normal, re-install the lower control  
compartment door then proceed to finish  
the installation.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
31  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
FINISHING REQUIREMENTS - Contemporary Facade  
Step 11. HOOD INSTALLATION  
This contemporary unit is uniquely suited for mid-wall installations with an  
available self-finishing decorative contemporary Facade. The decorative  
contemporary Facade is listed in the accessories sections of the Care And  
Operations manual and consists of three elements that can be mixed and  
matched for finishes to taste. This appliance, without the decorative con-  
temporary Facade, may be installed on the floor as any traditional fireplace  
(use the framing dimensions as-is as shown in Figure 11 on Page 10),  
but if the decorative contemporary Facade is to be installed, the unit must  
be raised on a platform at least 18" high (greater than 28" recommended)  
(refer to Figure 48).  
(Refer to Figure 47) All of these appliances must have hoods installed  
prior to operating.  
Install hood by sliding it into the slots on the lower edge of the cabinet top.  
FINISHING REQUIREMENTS - Wall Details  
Complete finished interior wall. To install the appliance facing flush with  
the finished wall, position framework to accommodate the thickness of  
the finished wall (Figure 47).  
See Page 5 for Cold Climate Insulation  
and Page 8 for Clearances  
Note: When raising the MLDVTCD appliance on a platform for mid-wall  
installations, add the platform height to any of the framing dimensions  
shown in Figure 11 on Page 10 and adjust the gas line dimensions shown  
in Figure 13 o Page 11 upwards accordingly.  
The decorative contemporary Facade's significant dimensions are shown  
in Figure 48. The decorative contemporary Facade may be installed over  
drywall that is butted directly against the sides of the fireplace, or non-  
combustible wall finish materials, no more than 3/4" thick, that are placed  
in front of the fireplace black painted face. DO NOT place the Facade over  
combustiblematerialsthatareplacedinfrontofthereplace'sblacknished  
face. Refer to the installation instructions that accompany the decorative  
contemporary Facade for installation details.  
This Area Must  
Remain Clear of  
Combustible  
3"  
Materials  
(76 mm)  
Combustible Finished  
1 in. Min.  
(25 mm)  
Wall Materials  
Header  
Combustible material may  
touch the appliance top  
35”  
Top of Appliance  
3" Clearance Min.  
Bend Up  
Tab  
44-3/4”  
Hood  
35-1/2”  
Figure 47 - Combustible Wall Framing  
33”  
29”  
32”  
24”  
16”  
18” Min. Required  
> 28” Recommended  
Floor  
Fireplace  
Figure 48 - Contemporary Facade Dimensions  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
32  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Step 12. ATTACHING SAFETY-IN-OPERATION WARNINGS  
It is the installers responsibility to ensure these warnings are properly affixed during installation. These warning labels are a  
critical step in informing consumers of safe operation of this appliance.  
ATTACHING SAFETY-IN-OPERATION  
WARNINGS  
APPOSITION DES MISES EN GARDE RELATIVES  
à LA SéCURITé D’UTILISATION  
COLOCACIóN DE ADVERTENCIAS DE  
SEGURIDAD EN OPERACIóN  
Yourreplacehasbeenfurnishedwithsafetyinstruc- Votrefoyeraétélivréavecdesétiquettesdesécuritéqui Su chimenea incluye etiquetas de instrucciones  
tion labels that are to be affixed to the operation and doivent être collées à côté des dispositifs de contrôle de seguridad que deben colocarse en el punto de  
control point of the fireplace. A safety instruction du foyer. Une étiquette de sécurité doit être collée sur operación y control de la chimenea. Se debe colocar  
labelshouldbeaffixedtothewallswitchplatewhere la plaque de l’interrupteur contrôlant l’allumage du una etiqueta de instrucciones de seguridad en la placa  
the fireplace is turned on and off (See Figure A) or foyer (voir Figure A) ou sur le thermostat mural (voir del interruptor de pared desde el cual se enciende y se  
wall thermostat (See Figure B) and if used on the Figure B) et, le cas échéant, sur le boîtier de la télé- apaga la chimenea (ver la Figura A) o en el termostato  
remote control handheld transmitter (Figure C). commande(FigureC). Lesmisesengardeauraientdû depared(verlaFiguraB)yeneltransmisordecontrol  
The warnings should already have been put in place êtrecolléesaumomentdel’installationinitialedufoyer. remoto(FiguraC)siseusa.Lasadvertenciasyadeben  
when the fireplace initial set-up was completed. Si ce n’est pas le cas, prenez les étiquettes adhésives haberse colocado cuando se completó la instalación  
If they are not affixed at these spots, locate the multilinguesfourniesaveccesinstructionsetprocédez inicial de la chimenea. Si no están colocadas en estos  
multi-lingual adhesive labels provided with these comme suit:  
lugares,encuentrelasetiquetasadhesivasmultilingües  
instructions and proceed as follows:  
1. Repérez l’interrupteur ou le thermostat mural proporcionadas con estas instrucciones y prosiga de  
qui contrôle le foyer (vérifiez que l’interrupteur la siguiente manera:  
1. Locate the wall switch or wall thermostat that  
controlsthereplace(verifytheswitchoperates  
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.  
contrôle le fonctionnement du foyer en le faisant 1. Identifique el interruptor o el termostato de pared  
basculerdeMarcheàArrêt,etvice-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.  
quecontrolalachimenea(verifiquequeelinterruptor  
opera la chimenea encendiéndola y apagándola).  
Limpiebienlaplacadelinterruptoroeltermostatode  
paredparaquitarelpolvoyaceite.Peguelaetiqueta  
enlasuperficiedelaplacadelinterruptorquecontrola  
la chimenea (Figura A) o en el termostato de pared  
(Figura B). Seleccione el idioma que más se habla  
en la casa.  
2. Ifaremotecontrolisusedtocontrolthereplace,  
locate the transmitter and clean it thoroughly  
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.  
to remove any dust and oils. Affix the label to 2. Si une télécommande est utilisée pour contrôler  
the surface of handheld transmitter (Figure C).  
Choose the language primarily spoken in the  
home.  
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  
3. If you are unable to locate the labels, please call  
LennoxHearthProductsoryournearestLennox  
(Figure C). Choisissez la langue qui est principale- 3. Si no puede encontrar las etiquetas, sírvase llamar  
ment parlée dans la résidence du propriétaire.  
a Lennox Hearth Products o al distribuidor de  
Lennox Hearth Products más cercano para recibir  
etiquetasdeinstruccionesdeseguridadadicionales  
gratuitas.  
Hearth Products dealer to receive additional 3. Si vous ne trouvez pas les étiquettes, veuillez  
safety instruction labels free of charge.  
appeler Lennox Hearth Products ou votre distribu-  
teur Lennox Hearth Products local pour recevoir  
gratuitement des étiquettes supplémentaires.  
Cat. No. H8024 Replacement Label Kit  
Juego de etiquetas de repuesto - Nº de cat. H8024  
LENNOx HEARTH PRODUCTS  
1-800-9-LENNOx  
Étiquettes de remplacement, n° cat. H8024  
LENNOx HEARTH PRODUCTS  
1-800-9-LENNOx  
LENNOx HEARTH PRODUCTS  
1-800-9-LENNOx  
Note: English is red text on clear label. French and  
Spanish are white text on black label.  
Nota: La etiqueta en inglés es transparente con texto  
rojo. Las etiquetas en francés y español son negras  
con texto blanco.  
Remarque : Le texte anglais est rouge sur un support  
transparent. Le texte français et espagnol est blanc  
sur un support noir.  
SAFETY LABEL  
DIAGRAMS  
DIAGRAMMES DES éTIQUETTES  
DIAGRAMAS DE ETIQUETAS  
DE SEGURIDAD  
DE SéCURITé  
Figure C  
Figure B  
Figure A  
33  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
INSTALLATION ACCESSORIES  
Listed Secure Vent™Components  
Listed Secure Vent™Components  
Cat.No.  
Model No. Description  
Cat.No.  
Model No. Description  
H1968  
SV4.5HT-2 Horizontal Square Termination  
with Firestop/Spacer (H2246)  
and Adapter (74L61)  
77L78  
SV4.5F Flat Roof Flashing  
1/12 to 7/12 Adjustable  
77L79  
SV4.5FA  
Flashing  
94L10  
H5817  
H2152  
SV4.5HTSS Horizontal Termination Small  
Square with Firestop/Spacer  
7/12 to 12/12 Adjustable  
Flashing  
SV4.5SC6 Storm Collars (6  
77L80  
SV4.5FB  
(H2246) and Adapter (74L61)  
77L81  
collars/box)  
SV4.5-20SS- Small Square Termination,  
H2246  
H2247  
96K93  
SV4.5HF Firestop/Spacer - 10 pack  
Horizontal (3-1-1 spacing)  
SV4.5VF Firestop/Spacer - 10 pack  
Vertical (1-1-1 spacing)  
WSK 20" With Shield  
SV4.5CGV-1 Vertical Termination  
(High Wind)  
SV4.5SU Support Strap  
77L70  
77L71  
SV4.5L6 6 inch (152 mm) Vent Section  
12 inch (305 mm) Vent  
H3907  
H5816  
SV4.5ARSA Adjustable Attic Insulation  
Shield (12" to 22")  
SV4,5TWSK Through Wall Shield Kit  
(not illustrated) (10 pack)  
SV4.5L12  
Section  
24 inch (610 mm) Vent  
Section  
77L72  
77L73  
77L74  
SV4.5L24  
36 inch (914 mm) Vent  
Section  
96K92  
SV4.5SP Support Plate  
SV4.5L36  
48 inch (1219 mm) Vent  
SV4.5L48  
Section  
87L02  
H5820  
SV4.5HGS Termination Guard Square  
(not illustrated)  
4.5HTSK Horizontal Termination  
Shroud Kit  
Telescopic Section  
(2" to 7.5" Rigid)  
77L75  
77L76  
SV4.5LA  
SV4.5E45 45 Degree Elbow  
99L03  
99L02  
SV4.5HRK36 Horizontal Riser Kit 36"  
SV4.5HRK14 Horizontal Riser Kit 14"  
77L77  
SV4.5E90 90 Degree Elbow  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
34  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
INSTALLATION ACCESSORIES CONTINUED  
Listed Secure Flex™Components  
Listed Secure Flex™Components  
Cat.  
No.  
Cat.  
No.  
Model No. Description  
Model No.  
Description  
H1988 CTSA-33  
H1985 CTSO-33  
H1987 CTSO-44  
H1986 CTSO-46  
Chase Top Shroud Kit,  
Arch Top - 3 X 3  
Chase Top Shroud Kit,  
Open Top - 3 X 3  
Chase Top Shroud Kit,  
Open Top - 4 X 4  
Chase Top Shroud Kit,  
Open Top - 4 X 6  
These termination kits include firestop/spacer, gear clamps and flex adapter.  
H1969 SF4.5HT-2  
Horizontal Square  
Termination without Flex  
Flex Square Term. with  
12 in. (305 mm of  
77L87 SFKIT12  
*compressed Flex  
77L88 SFKIT18  
77L89 SFKIT24  
77L90 SFKIT36  
77L91 SFKIT48  
94L09 SF-HTSS  
Flex Square Term. with  
18 in. (457 mm) of  
*compressed Flex  
60L10 SF-18  
18 ft. (5.49 m)  
*compressed Flex  
12 ft.(3.66 m)  
Flex Square Term. with  
24 in. (610 mm) of  
*compressed Flex  
Flex Square Term. with  
36 in. (914 mm) of  
*compressed Flex  
Flex Square Term. with  
48 in. (1219 mm) of  
*compressed Flex  
Horizontal Termination -  
Small Square for Flex Vent  
98K03 SF-12  
10K81 SFMP  
89L40 SFMP-12  
*compressed Flex  
Mil Pac Black Hi-  
Temperature Sealant  
Mil Pac Black Hi-  
Temperature Sealant -  
Bulk Pack 12  
Gear Clamp 4.5in. (114  
mm) for Flex (6 pieces)  
Gear Clamp 7.5 in.  
(190.5 mm) for Flex  
(6 pieces)  
t
n
a
l
a
e
S
91L66 SF-GC4-6  
91L67 SF-GC7-6  
94L04 SFKIT12SS Flex Small Termination with  
12 in. (305mm) Flex Vent  
94L05 SFKIT18SS Flex Small Termination with  
18 in. (457mm) Flex Vent  
H2248  
H2249  
SF4.5HF-10 Firestop/Spacer - 10  
Pack Horizontal (3-1-1  
spacing)  
SF4.5VF-10 Firestop/Spacer - 10  
Pack Vertical (1-1-1  
spacing)  
94L06 SFKIT24SS Flex Small Termination with  
24 in. (610mm) Flex Vent  
94L07 SFKIT36SS Fle in. Small Termination  
with  
36 in. (914mm) Flex Vent  
94L08 SFKIT48SS Flex Small Termination with  
48 in. (1219mm) Flex Vent  
56L74 SFVT30  
Vertical Termin. for Flex  
(flat to 6/12) with Flex  
Adapter, section of rigid  
vent, roof support collar  
assembly, roof flashing and  
storm collar.  
Vertical Termin. for Flex  
(6/12 to 12/12) with Flex  
Adapter section of rigid  
vent, roof support collar  
assembly, roof flashing and  
storm collar.  
*All compressed flex vents can be expanded up to two times.  
56L75 SFVT45  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
35  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
GAS CONVERSION KITS  
INSTALLATION INSTRUCTIONS  
WARNING  
Step 1. TURN OFF THE GAS SUPPLY TO THE  
APPLIANCE, and disconnect power supply at  
the circuit breaker. Ensure appliance is COLD.  
Thisconversionkitshallbeinstalledbyaqualifiedserviceagencyinaccor-  
dance with the manufacturer’s instructions and all applicable codes and  
requirementsoftheauthorityhavingjurisdiction.Iftheinformationinthese  
instructionisnotfollowedexactly,are,explosionorproductionofcarbon  
monoxide may result causing property damage, personal injury or loss of  
life.Thequalifiedserviceagencyisresponsiblefortheproperinstallation  
of this kit. The installation is not proper and complete until the operation  
of the converted appliance is checked as specified in the manufacturer’s  
instructionssuppliedwiththekit.Thequalifiedserviceagencyperforming  
this installation assumes responsibility for this conversion.  
CAUTION: THE GAS SUPPLY SHALL BE  
SHUT OFF PRIOR TO DISCONNECTING  
THE ELECTRICAL POWER, BEFORE  
PROCEEDING WITH THE CONVERSION.  
ATTENTION : AVANT D’EFFECTUER  
LA CONVERSION, COUPEZ D’ABORD  
LALIMENTATION EN GAZ, ENSUITE,  
COUPEZ LALIMENTATION éLECTRIQUE.  
AVERTISSEMENT  
Step 2. Remove the front glass door assembly.  
See Figure 44 on Page 30.  
Cette trousse de conversion doit être installée par un technicien agréé,  
selonlesinstructionsdufabricantetselontouteslesexigencesettousles  
codes pertinents de l’autorité compétente. Assurez-vous de bien suivre  
les instructions dans cette notice pour réduire au minimum le risque  
d’incendie,d’explosionoulaproductiondemonoxydedecarbonepouvant  
causer des dommages matériels, des blessures ou la mort. Le tecnicien  
agrééestresponsabledel’installationdecettetrousse.Linstallationn’est  
pas adéquate ni complète tant que le bon fonctionnement de l’appareil  
convertinapasétévérifiéselonlesinstructionsdufabricantfourniesavec  
la trousse. Le fournisseur de service qualifié ayant réalisé l'installation  
assume les responsabilités liées à la conversion.  
Step 3. Carefully remove the contemporary  
floor media. Exercise care so as not to break  
the contemporary floor media.  
Step 4. Refer to Figure 49.  
Remove the burner assembly with attached  
venturi tube.  
Burner Assembly  
In Canada:  
THE CONVERSION SHALL BE CAR-  
Millivolt SIT Systems  
Natural Gas To Propane Gas  
RIED OUT IN ACCORDANCE WITH THE  
REQUIREMENTS OF THE PROVINCIAL  
AUTHORITIES HAVING JURISDICTION  
AND IN ACCORDANCE WITH THE RE-  
QUIREMENTS OF THE CAN/CSA-B149.1  
INSTALLATION CODE.  
Conversion Kits  
Model  
MLDVTCD-35  
Cat. No.  
H7292  
Gas Valve  
Assembly  
Millivolt SIT Systems  
Propane to Natural Gas  
Conversion Kits  
Orifice  
LA CONVERSION DEVRA êTRE EF-  
FECTUéE CONFORMéMENT AUx RE-  
COMMANDATIONS DES AUTORITéS  
PROVINCIALES AYANT JURIDICTION  
ET CONFORMéMENT AUx ExIGENCES  
DU CODE D'INSTALLATION CAN/CSA-  
B149.1.  
Model  
MLDVTCD-35  
Cat. No.  
H7293  
Electronic DExEN Systems  
Natural Gas To Propane Gas  
Conversion Kits  
Model  
Cat. No.  
H7295  
Gas conversion kits are available to adapt  
your appliance from the use of one type of  
gas to the use of another. These kits contain  
all the necessary components needed to  
completethetaskincludinglabelingthatmust  
be affixed to ensure safe operation.  
Figure 49  
MLDVTCD-35  
Electronic DExEN Systems  
Propane Gas To Natural Gas  
Conversion Kits  
Kit part numbers are listed here and the  
following steps detail the conversion pro-  
cedure. Refer to the instructions provided  
with the conversion kit when performing any  
gas conversion.  
Model  
Cat. No.  
H7296  
MLDVTCD-35  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
36  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Electronic Appliances  
Millivolt Appliances  
All Models  
Step7. Dexen Electronic Valves - See Figure  
52 and the instructions provided with the kit.  
Remove and discard the two pressure regula-  
tor mounting screws. Remove the pressure  
regulatoranddiaphragm. Discardallremoved  
components. Ensure the provided diaphragm  
is installed properly onto the replacement  
pressure regulator and install the new pres-  
sure regulator using the new screws supplied  
with the kit. Tighten screws.  
Step 8. (Refer to Figure 49 on Page 36 and  
Figure 54)  
Step 5. SIT Systems - Refer to Figure 50 on  
Page 37 and the instructions provided with  
the kit. Using a Torx T20 (with 1/4" shank and  
center hole), tool or standard flat screwdriver  
removeanddiscardthethreepressureregulator  
mounting screws. Remove the pressure regu-  
lator, spring, poppet, diaphragm and bushing.  
Discard all removed components.  
VERIFY THE PROPER ORIFICE SIZE  
BEFORE INSTALLING IT.  
A. Remove the orifice from the manifold and  
replace it with the one provided in the kit. See  
Table 9 for orifice sizes for natural and pro-  
pane models. Figure 54 illustrates the orifice.  
Use pipe joint compound or Teflon tape on all  
pipe fittings before installing (ensure propane  
resistant compounds are used in propane ap-  
plications, do not use pipe joint compounds  
on flare fittings).  
Ensuretherubbergasketinstalledonthebackof  
the replacement pressure regulator is properly  
positioned and install the new pressure regula-  
tor using the new screws supplied with the kit.  
Tighten screws to 25 In. lb. torque.  
See Figure 53 and replace the pilot orifice as  
follows: Removepilothoodassemblytoaccess  
thephillippedpilotorifice. Removeandreplace  
the orifice with the one provided with the kit.  
Exercise extreme care to prevent damage to  
or breakage of the igniter assembly.  
B. Retrieve the burner and slide the venturi  
tube over the orifice. Set the shutter adjusting  
opening as shown in Figure 49 on Page 36.  
Pressure  
Regulator  
Pressure-Tap  
(Manifold)  
Burner Stage  
Terminal  
Burner Orifice Sizes  
Elevation 0-4500 feet ( 0-1372 meters)  
Regulator  
Gas  
Supply Gas  
Inlet  
Mounting  
Screw  
Outlet  
To Burner  
Model  
Nat.Gas  
Propane  
Series  
drill size (inches)  
drill size (inches)  
Remove  
These  
Components  
#49 (0.073")  
21L82 •  
(0.045")  
**  
75L10 •  
*
MLDVTCD-35  
L O  
H I  
PILOT  
Figure 50  
* Standard size installed at factory  
** Standard size in LP conversion kit  
• Part /Cat. Number  
Table 9  
Pressure-Tap  
(Inlet)  
Step 6. See Figure 51 and remove the pilot  
hoodassemblytoaccessthehexedpilotorifice.  
Remove and replace the orifice with the one  
provided with the kit.  
Pilot Stage  
Terminal  
Ground (TP)  
Pilot Gas Outlet  
Figure 52 - Dexen Electronic Gas Valve  
ELECTRONIC  
Figure 54  
Pilot  
Hood  
Sensor  
Igniter  
Step9.Reassembletheremainingcomponents  
by reversing the procedures outlined in the  
preceding steps.  
Pilot  
Orifice  
Step 10. Attach the conversion label provided  
in the conversion kit to the rating plate on the  
appliance.  
Figure 51  
Step 11. Turn on gas supply and test for gas  
leaks. See Test All Connections For Gas Leaks  
on Page 27.  
Step 12. Attach manometer to the manifold  
side pressure test fitting and verify manifold  
pressure reads 3.5 inches water column (0.87  
kPa) for natural gas, and 10.0 inches water  
column (2.49 kPa) for propane gas.  
Note: If the igniter is damaged, a re-  
placement kit is available, order Catalog  
Number 87L54.  
Figure 53  
ALWAYS TEST PRESSURES WITH THE VALVE  
REGULATOR CONTROL AT THE HIGHEST  
SETTING.  
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.  
37  
 
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS  
Lennox Hearth Products reserves the right to make changes at any time, without notice, in design,  
materials, specifications, prices and also to discontinue colors, styles and products.  
Consult your local distributor for fireplace code information.  
Printed in U.S.A. © 2009 Lennox Hearth Products  
1508 Elm Hill Pike, Suite 108 • Nashville, TN 37210  
P/N 506015-03 Rev. F 06/2011  
 

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