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 : L’installation et la réparation
devraitêtreconfiéesàuntechnicienqualifié.
L’appareil 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.
Thesefireplacesaredecorativeandaredesigned
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;flameappearanceand
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,Step1forclearancerequirementstothenailingflange
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"clearancetothefireplacetop,
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
thefireplacefront. 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.Installfirestop/spaceratceiling-Whenus-
ing Secure Vent, use SV4.5VF firestop/spacer
at ceiling joists; when using Secure Flex, use
SF4.5VFfirestop/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)firestop/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,useSV4.5VFfirestop/
spaceratceilingjoists;whenusingSecureFlex,
use SF4.5VF firestop/spacer. If there is living
spaceabovetheceilinglevel,thefirestop/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
tobecoveredbytheflexiblepipe)
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. Slidetheouterflexpipeovertheadaptercol-
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
fullytosecuretheflexibleventtotheadapter
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. Slidetheinnerflexpipeovertheadaptercol-
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
fullytosecuretheflexibleventtotheadapter
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
internalflexventspacersevenly-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
Whenfirstlightingtheappliance,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
underneaththefireboxfloortothedoor'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-
orangeduringthefirst15minutesofoperation.
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
positionuntiltheproperflameappearance
is achieved.
• If flame stays lowered blue, adjust the air
shutter, incrementally, to a more closed
positionuntiltheproperflameappearance
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. Whensatisfiedthattheburnerflameappear-
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
combustiblematerialsthatareplacedinfrontofthefireplace'sblackfinished
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
Yourfireplacehasbeenfurnishedwithsafetyinstruc- 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
controlsthefireplace(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. Ifaremotecontrolisusedtocontrolthefireplace,
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,afire,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
L’ALIMENTATION EN GAZ, ENSUITE,
COUPEZ L’ALIMENTATION 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.L’installationn’est
pas adéquate ni complète tant que le bon fonctionnement de l’appareil
convertin’apasétévérifiéselonlesinstructionsdufabricantfourniesavec
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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