Lennox hearth products Mldvtcd-35ne User manual

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.

INSTALLATION INSTRUCTIONS

™

MLDVTCD Direct-Vent

Contemporary Design

Gas Fireplaces

P/N 506015-03 Rev. G 02/2012

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.

Ce manuel est disponible en francais, simplement

en faire la demande. Numéro de la pièce 506223-05.

MODELS

MLDVTCD-35NM

MLDVTCD-35NM-FB

MILLIVOLT:

MLDVTCD-35NE

ELECTRONIC:

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

AVERTISSEMENT : Assurez-vous de bien suivre les

instructions données dans cette notice pour réduire au

minimum le risque d’incindie ou d’explosion ou pour

éviter tout dommage matériel, toute blessure ou la mort.

WARNING: If the information in these instructions

is not followed exactly, a ﬁre or explosion may

result, causing property damage, personal injury,

or death.

WARNING /AVERTISSEMENT/AVISO

• HOT GLASS WILL CAUSE

BURNS.

• DO NOT TOUCH GLASS

UNTIL COOLED.

• NEVER ALLOW CHILDREN

TO TOUCH GLASS.

• UNE SURFACE VITRÉE CHAUDE

PEUT CAUSER DES BRÛLURES.

• LAISSER REFROIDIR LA SURFACE

VITRÉE AVANT D'Y TOUCHER.

• NE PERMETTEZ JAMAIS À UN ENFANT

DE TOUCHER LA SURFACE VITRÉE.

• EL VIDRIO CALIENTE

CAUSARÁ QUEMADURAS.

• USTED DEBE NUNCA

TOCAR EL VIDRIO CALIENTE.

• LOS NIÑOS DEBEN NUNCA

TOCAR EL VIDRIO.

- Do not store or use gasoline or other flammable

vapors and liquids in the vicinity of this or any other

appliance.

- WHAT TO DO IF YOU SMELL GAS:

• Do not try to light any appliance.

• Do not touch any electrical switch; do not use any

phone in your building.

• Immediately call your gas supplier from a

neighbor’s phone. Follow the gas supplier’s

instructions.

• If you cannot reach your gas supplier, call the fire

department.

- Installation and service must be performed by a

qualified installer, service agency or the gas supplier.

- Ne pas entreposer ni utilizer d’essence ni d’autres vapeurs

ou liquides inﬂammables dans le voisinage de cet appareil

ou de tout autre appareil.

- QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ :

• Ne pas tenter d’allumer d’appareil.

• Ne touchez à aucan interrupteur. Ne pas vous servir des

téléphones se trouvant dans le bâtiment où vous trouvez.

• Appelez immédiatement votre fournisseur de gaz depuis

un voisin. Suivez les instructions du fournisseur.

• Si vous ne pouvez rejoindre le fournisseur de gaz,

appelez le service des incindies.

- L’installation et l’entretien doivent être assurés par un

installateur ou un service d’entretien qualiﬁé ou par le

fournisseur de gaz.

TABLE OF CONTENTS

Packaging .........................................Page 2

Introduction ......................................Page 2

General Information ..........................Page 2

Requirements for the

Commonwealth of Massachusetts .Page 4

New York City Approval .....................Page 4

Cold Climate Insulation .....................Page 5

Manufactured Home Requirements ..Page 5

Location ............................................Page 5

Vent Termination Clearances ............Page 6

Appliance and Vent Clearances .........Page 8

Detailed Installation Steps .................Page 9

Typical Installation Sequence ...........Page 9

Step 1. Framing .................................Page 9

Fireplace and Framing Speciﬁcations Page 10

Step 2. Routing Gas Line ..................Page 11

Step 3. Install the Venting System ....Page 12

Vertical Termination Systems ............Page 13

Vent Section Length Chart ................Page 13

Vertical Vent Tables and Figures ........Page 16

Horizontal Termination System .........Page 17

Horizontal Vent Tables and Figures ...Page 20

Venting Using Flexible Vent Pipe .......Page 23

Step 4. Field Wiring .........................Page 24

Step 5. Optional Blower Kit Wiring ..Page 25

Step 6. Connecting Gas Line ...........Page 26

Step 7. Verifying Appliance Operation Page 27

Step 8. Installing

Contemporary Media ......................Page 28

Step 9. Installing Glass Door ..........Page 30

Step 10. Burner Adjustments ............Page 30

Step 11. Hood Installation .................Page 32

Finishing Requirements ....................Page 32

Step 12. Attaching Safety-in-

Operation Warnings .......................Page 33

Installation Accessories ....................Page 34

Gas Conversion Kits .........................Page 36

Please read and understand these

instructions before beginning your

installation.

PACKAGING

The assembled vented gas ﬁreplace is pack-

aged with:

• One envelope containing the literature pack-

age which consists of the care and operations

manual, installation instructions, safety in

operation warning labels and warranty; en-

velope is located in the control compartment.

• One vent restrictor to be applied as shown on

Page 12; restrictor is taped to the envelope.

• One hood located behind the door assembly.

• One of the following contemporary ﬂoor media

kits (sold separately):

a. Tumbled River Stone

b. Crushed Glass, Obsidian Black

c. Crushed Glass, Diamond White

d. Crushed Glass, Deep Sea Blue

e. White Beach Sand

• Optional Contemporary facade kits (sold

separately)

INTRODUCTION

The Millivolt appliances have a millivolt gas

control valve with piezo ignition system. If any

optional accessories that will require electrical

power are to be installed, the electrical power

must be provided at the time of appliance in-

stallation.

The Electronic appliances have an electronic

intermittent pilot ignition system. External

electrical power is required to operate these

units. The battery back-up can be used in case

of a power outage.

These vented gas ﬁreplaces are sealed combus-

tion, air-circulating gas ﬁreplaces designed for

residential applications.

Use Only These Approved Vent Components:

These ﬁreplaces are designed, tested and

listed for operation and installation with, the

following (4-1/2" inner and 7-1/2" outer) vent

components only:

• Secure Vent™ Direct-Vent System Compo-

nents manufactured by Security Chimneys

International,

• Secure Flex™ Flexible Vent Components

manufactured by Security Chimneys Inter-

national and

• Z-FLEX™ Model GA Venting Systems listed

to UL1777 and ULCS635 manufactured by

Flexmaster Canada Limited.

These approved vent system components are

labeled for identiﬁcation. DO NOT use any

other manufacturer’s vent components with

these appliances.

WARNING

Young children should be care-

fully supervised when they are

in the same room as the appli-

ance. Toddlers, young children

and others may be susceptible

to accidental contact burns. A

physical barrier is recommended

if there are at risk individuals in

the house. To restrict access to

a ﬁreplace or stove, install an

adjustable safety gate to keep

toddlers, young children and

other at risk individuals out of

the room and away from hot

surfaces.

AVERTISSEMENT

Les jeunes enfants devraient être

surveillés étroitement lorsqu’ils

se trouvent dans la même pièce

que l’appareil. Les tout petits,

les jeunes enfants ou les adultes

peuvent subir des brûlures s’ils

viennent en contact avec la sur-

face chaude. Il est recommandé

d’installer une barrière physique

si des personnes à risques habi-

tent la maison. Pour empêcher

l’accès à un foyer ou à un poêle,

installez une barrière de sécu-

rité; cette mesure empêchera les

tout petits, les jeunes enfants et

toute autre personne à risque

d’avoir accès à la pièce et aux

surfaces chaudes.

GENERAL INFORMATION

Children and adults should be alerted to the

hazards of high surface temperature and

should stay away to avoid burns or clothing

ignition.

Les enfants et les adultes devraient être infor-

més des dangers que posent les températures

de surface élevées et se tenir à distance aﬁn

d’éviter des brûlures ou que leurs vêtements

ne s’enﬂamment.

DO NOT ATTEMPT TO ALTER OR MODIFY

THE CONSTRUCTION OF THE APPLIANCE OR

ITS COMPONENTS. ANY MODIFICATION OR

ALTERATION MAY VOID THE WARRANTY, CER-

TIFICATION AND LISTINGS OF THIS UNIT.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Input (BTU/HR) Manually-Modulated

Gas Valves (all models)

Models Input Rate (BTU / HR)

Nat. Gas Prop. Gas

MLDVTCD-35

14,500 high

11,500 low 13,500 high

10,500 low

Table 1

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.

Provide adequate clearances around air open-

ings and adequate accessibility clearance for

service and proper operation. Never obstruct

the front openings of the appliance.

These appliances are designed to operate on

natural or propane gas only. The use of other

fuels or combination of fuels will degrade

the performance of this system and may be

dangerous.

These ﬁreplaces are decorative and are designed

to provide supplemental heat. Therefore, it is

advisable to have an alternate primary heat source

when installed in a dwelling.

These appliances must not be connected to a

chimney or ﬂue serving a separate solid fuel

burning appliance.

Millivolt Models - The millivolt appliances are

manually controlled and feature a spark igniter

(piezo) that allows the appliance's pilot gas to

be lit without the use of matches or batteries.

This system provides continued service in the

event of a power outage.

Millivolt models come standard with a manu-

ally-modulated gas valve; ﬂame appearance and

heat output can be controlled at the gas valve.

The BTU Input for these appliances is shown

in Table 1.

Electronic Models - These electronic appli-

ances are manually controlled and feature an

electronic intermittent pilot ignition system.

External electrical power is required to operate

these units.

These electronic models come standard with a

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.

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.

WARNING

Failure to comply with these

installation instructions will result

in an improperly installed and

operating appliance, voiding its

warranty. Any change to this appli-

ance and/or its operating controls

is dangerous.

WARNING

Clothing or other flammable

material should not be placed

on or near the appliance.

AVERTISSEMENT

On ne devrait pas placer de

vêtements ni d’autres matières

inﬂammables sur l’appareil ni à

proximité.

WARNING

Any safety screen or guard

removed for servicing the appli-

ance must be replaced prior to

operating the appliance.

AVERTISSEMENT

Tout écran ou protecteur retiré

pour permettre l’entretien de

l’appareil doit être remis en

place avant de mettre l’appareil

en marche.

WARNING

Improper installation or use of

this appliance can cause serious

injury or death from ﬁre, burns,

explosion or carbon monoxide

poisoning.

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.

Remarque : L’installation et la réparation

devrait être conﬁées à un technicien qualiﬁé.

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. Des nettoyages plus fréquents peuvent

être nécessaires si les tapis, la literie, et

cetera produisent une quantité importante de

pous-sière. Il est essentiel que les comparti-

ments abritant les commandes, les brûleurs et

les conduits de circulation d’air de l’appareil

soient tenus propres.

Do not use these appliances if any part

has been under water. Immediately call a

qualiﬁed, professional service technician

to inspect the appliance and to replace any

parts of the control system and any gas

control which have been under water.

Ne pas utiliser cet appareil s’il a été plongé,

même partiellement, dans l’eau. Ap-

peler un technicien qualiﬁé pour inspecter

l’appareil et remplacer toute partie du

système de commande et toute commande

qui a été plongée dans l’eau.

Only trim kit(s) supplied by the manufacturer

shall be used in the installation of this ap-

pliance.

Seules les trousses de garniture fournies

par le fabricant doivent être utilisées pour

l’installation de cet appareil.

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.

Both millivolt and electronic versions of

these appliances are listed by ETL/Intertek

for installation in bedrooms and Manufac-

tured Homes.

Misc. Codes / Standards

The Installation must conform to local codes or,

in the absence of local codes, with the National

Fuel Gas Code, ANSI Z223.1/NFPA 54 - latest

edition (In Canada, the current CAN/CSA-B149.1

installation code).

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

4NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

Inlet Gas Supply Pressure

(all models)

Fuel # Minimum Maximum

Natural Gas 4.5" WC

(1.12 kPa)

10.5" WC

(2.61 kPa)

Propane 11.0" WC

(2.74 kPa)

13.0" WC

(3.23 kPa)

Table 2

Manifold Gas Supply Pressure

(all models)

Fuel # Low High

Natural

Gas

(Lo) 2.2" WC

(0.55 kPa)

(Hi) 3.5" WC

(0.87 kPa)

Propane (Lo) 6.3" WC

(1.57 kPa)

(Hi) 10.0" WC

(2.49 kPa)

Table 3

Gas Valve Diagrams

See Figure 1 for Millivolt models and Figure 2

For Electronic Models.

H T P T H T P T

IN OUT

HI/LO Variable

Flame Height

Adjustment

Figure 1 - SIT Millivolt Gas Valve

Manifold Pressure Tap

Inlet Pressure Tap

Pilot Adjustment

Screw

Main Gas Control Knob

OFF/PILOT/ON

Burner Oriﬁce Sizes

Elevation 0-4500 feet ( 0-1372 meters)

Model

Series Nat.Gas

drill size (inches) Propane

drill size (inches)

MLDVTCD-35

#49 (0.073") *

21L82 •

0.045" **

75L10 •

Table 4

* Standard size installed at factory

** Standard size in LP conversion kit

• Part /Cat. Number

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Gas Pressure - All Models

Tables 2 and 3 show the appliances' gas

pressure requirements:

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.

Propane tanks are at pressures that will cause

damage to valve components. Verify that the

tanks have step down regulators to reduce the

pressure to safe levels.

These appliances must be isolated from the

gas supply piping system (by closing their

individual manual shut-off valve) during any

pressure testing of the gas supply piping

system at test pressures equal to or less

than 1/2 psig (3.5 kPa).

These appliances and their individual

shut-off valves must be disconnected from

the gas supply piping system during any

pressure testing of that system at pressures

greater than 1/2 psig (3.5 kPa).

These appliances must not be connected to a

chimney or ﬂue serving a separate solid fuel

burning appliance.

Oriﬁce Sizes - Sea Level to High Altitude

(All Models)

These appliances are tested and approved for

installation at elevations of 0-4500 feet (0-1372

meters) above sea level using the standard

burner oriﬁce sizes (marked with an "*" in

Table

. For elevations above 4500 feet, contact your

gas supplier or qualiﬁed service technician.

Deration - At higher elevations, the amount

of BTU fuel value delivered must be reduced

by either:

• Using gas that has been derated by the gas

company.

• Changing the burner oriﬁce to a smaller size

as regulated by the local authorities having

jurisdiction and by the (USA) National Fuel

Gas Code NFPA 54/ANSI Z223.1 - latest

edition or, in Canada, the CAN/CSA-B149.1

codes - latest edition.

Install the appliance according to the regulations

of the local authorities having jurisdiction and,

in the USA, the National Fuel Gas Code NFPA

54 / ANSI Z223.1 - latest edition or, in Canada,

the CAN/CSA-B149.1 - latest edition.

NOTE:

Flame appearance will diminish 4% per

thousand feet.

Figure 2 - Dexen Electronic Gas Valve

Pilot Stage

Terminal

Pressure-Tap

(Inlet)

Pilot Gas

Outlet

Supply

Gas

Inlet

Pressure-Tap

(Manifold)

Burner Stage

Terminal

Ground

(TP)

PILOT

OUT

VENT

Regulator

Mounting Screw

REQUIREMENTS FOR THE COMMON-

WEALTH OF MASSACHUSETTS

These ﬁreplaces are approved for installation in

the US state of Massachusetts if the following

additional requirements are met:

• Install this appliance in accordance with

Massachusetts Rules and Regulations 248

C.M.R.

• Installation and repair must be done by a

plumber or gas ﬁtter licensed in the Com-

monwealth of Massachusetts.

• The ﬂexible gas line connector used shall

not exceed 36 inches (92 centimeters) in

length.

• The individual manual shut-off must be a

T-handle type valve.

Massachusetts Horizontal Vent Requirements

In the Commonwealth of Massachusetts, 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

the building at a minimum height of eight (8)

feet above grade and be directly in line with

the horizontal termination. The sign must

read, in print size no less than one-half (1/2)

inch in size, GAS VENT DIRECTLY BELOW.

KEEP CLEAR OF ALL OBSTRUCTIONS.

NEW YORK CITY, NEW YORK (MEA)

Installation of these ﬁreplaces are approved

for installation in New York City in the US state

of New York.

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

Figure 3 - Typical Locations

NOITACILPPA

TNEVPOT

APPLICATION

TOP VENT

TNEVPOT

NOITACILPPA

RECESSED

INSTALLATION

TOP VENT

APPLICATION

NOITACILPPA

TNEVPOT

NOITACILPPA

TNEVPOT

HORIZONTAL VENT

(Top Vent Application)

VERTICAL VENT

(Top Vent Application)

Note: When the unit is installed with one

side ﬂush with a wall, the wall on the other

side of the unit must not extend beyond the

front edge of the unit.

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.

If the ﬁreplace is being installed on a cement

slab in cold climates, a sheet of plywood or other

raised platform can be placed underneath to

prevent 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.

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-

tured Home Construction and Safety Standard,

Title 24 CFR, Part 3280, in the United States, or

the Standard for Installation in Mobile Homes,

CAN/CSA Z240 MH Series, in Canada.

Cet appareil peut être installé cómme du matéri-

el d'origine dans une maison préfabriquée (É.U.

seulement) ou mobile et doit être installé selon

les instructions du fabricant 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.

This appliance is only for use with the type of

gas indicated on the rating plate. This appliance

is not convertible for use with other gases,

unless a certiﬁed kit is used.

Cet appareil doit être utilisé uniquement avec le

type de gaz indiqué sur la plaque signalétique.

Cet appareil ne peut être converti à d'autres

gaz, sauf si une trousse de conversion est

utilisée.

CAUTION: Ensure that the cross mem-

bers are not cut or weakened during

installation. The structural integrity of

the manufactured home ﬂoor, wall, and

ceiling / roof must be maintained.

CAUTION: This appliance must be ground-

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.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

LOCATION

In selecting the location, the aesthetic and

functional use of the appliance are primary

concerns. However, vent system routing to

the exterior and access to the fuel supply are

also important.

Due to high temperatures, the appliance

should be located out of trafﬁc and away from

furniture and draperies (Figure 3).

En raison des températures élevées, l’appareil

devrait être installé dans un endroit où il y a

peu de circulation et loin du mobilier et des

tentures (Figure 3).

The location should also be free of electrical,

plumbing or other heating/air conditioning

ducting.

These direct-vent appliances are uniquely

suited for installations requiring a utility shelf

positioned directly above the ﬁreplace. Utility

shelves like these are commonly used for locat-

ing television sets and decorative plants.

Be aware that this is a heat producing ap-

pliance. Objects placed above the unit are

exposed to elevated temperatures.

Do not insulate the space between the ap-

pliance and the area above it (see Figure 7

on Page 8).

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.

The appliance should be mounted on a fully

supported base extending the full width and

depth of the unit. The appliance may be located

on or near conventional construction materials.

However, if installed on combustible materials,

such as carpeting, vinyl tile, etc., a metal or

wood barrier covering the entire bottom surface

must be used.

6NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Roof Pitch is X/12

2 FT

MIN.

2 FT MIN.

Lowest

Discharge

Opening

*H = MINIMUM HEIGHT FROM ROOF TO

LOWEST DISCHARGE OPENING OF VENT

TERMINATION HEIGHTS FOR VENTS ABOVE

FLAT OR SLOPED ROOFS

Horizontal Overhang

Vertical

Wall

Vent

Termination

Storm Collar

Concentric

Vent Pipe

Flashing

1 inch (25.4 mm) Minimum

Clearance to Combustibles

Figure 4B

Vertical Vent Termination Clearances

VENT TERMINATION CLEARANCES

These instructions should be used as a

guideline and do not supersede local codes

in any way. Install venting according to local

codes, these instructions, the current National

Fuel Gas Code (ANSI-Z223.1) in the USA or

the current standards of CAN/CSA-B149.1 in

Canada.

Vertical Vent Termination Clearances

Terminate multiple vent terminations according

to the installation codes listed above. Also see

Figure 4A.

Terminate single vent caps relative to building

components according to Figure 4B.

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.

Note - See Figure 28 on Page 19 for the exterior wall recess

allowances of the square horizontal termination.

The vent / air intake termination clearances

above the high side of an angled roof is as

shown in the following chart:

Figure 5

(152 mm)

12"

(305 mm)

Combustible Projection greater

Horizontal Vent Termination Clearances

Combustible Projection

2-1/2 inches or less in length

18"

(457 mm)

Ventilated

Soffit Unventilated

Soffit

than 2-1/2 inches in length

Termination Kit

Side Elevation View

Termination Kit

All horizontal terminations

may be located as close as

6 (152mm) to any

(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.

Termination Heights For Vents

Above Flat Or Sloped Roofs

Ref. NFPA 54 / ANSI Z223.1

Roof Pitch * Feet * Meters

Flat to 6/12 1.0 0.3

6/12 to 7/12 1.25 0.38

7/12 to 8/12 1.5 0.46

8/12 to 9/12 2.0 0.61

9/12 to 10/12 2.5 0.76

10/12 to 11/12 3.25 0.99

11/12 to 12/12 4.0 1.22

12/12 to 14/12 5.0 1.52

14/12 to 16/12 6.0 1.83

16/12 to 18/12 7.0 2.13

18/12 to 20/12 7.5 2.29

20/12 to 21/12 8.0 2.44

12”

(305mm)

Minimum

Figure 4A - Multiple Terminations

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

EXTERIOR HORIZONTAL VENT TERMINATION CLEARANCE REQUIREMENTS

Figure 6

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Fixed

Closed

Window

Operable

Window

= Area where Termination is not Permitted

= Air Supply Inlet

X= Vent Termination

3 ft.

= 9” in U.S.

= 12” in Canada

Inside

Corner Detail

*18”

Ventilated Soffit

Horizontal

Termination

Detail D

Exterior Wall

6”

Inside Corner

* See Item D in the Text Below.

NOTE: Local Codes Or Regulations

May Require Different Clearances.

NOTE: Location Of The Vent Termination

Must Not Interfere With Access To The

Electrical Service.



8NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

5 (127)

8-1/4

(209)

(356)

12 (305)

19 (483)

*Shelf Height

(see table)

Do not insulate the

space between the

appliance and the

area above it.

Shelf Above Fireplace With Top Venting

8 (203)

(51)

(102)

(152)

(203)

(254)

(305)

10 (254)

14 (356)

18 (457)

16 (406)

12 (305) Top of

Appliance

inches (millimeters)

Mantel Depth

Note - Hood shown

as positioned.

Figure 8 - Minimum Mantel Clearances

Header

Figure 9 - Minimum Distance to Unprotected Side Wall

Top View of

Fireplace

45o

Protected wall shown in white

Inches (millimeters)

MINIMUM CLEARANCES TO COMBUSTIBLES

Appliance And Vent Clearances

The appliance is approved with zero clearance to combustible materials on

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).

MINIMUM CLEARANCES* Inches (millimeters)

Back 0 (0) Spacers Or Dimples

Sides 1/2 (13)**

0 (0) Spacers or Dimples

Top 3 (76)

Floor 0 (0)

From Bottom of Unit To Ceiling 64 (1626)

Vent 3 (76) Top* / 1 (25.4) Sides & Bottom

SERVICE CLEARANCES Feet (meters)

Front 3 feet (0.9 meters)

Table 5

*Note: 3 in. (75 mm) above any horizontal/inclined vent component.

**Note: See Page 9, Step 1 for clearance requirements to the nailing ﬂange

located at each side of the unit and any screw heads adjacent to it.

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.

Shelf Height - To provide for the lowest possible shelf surface, the venting

attached to the top vent should be routed in a way to minimize obstructions

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.

Wall Finishes / Surrounds / Mantels

Note: Combustible wall ﬁnish materials and/or surround materials must

not be allowed to encroach the area deﬁned by the appliance front face

(black sheet metal). Never allow combustible materials to be positioned

in front of or overlapping the appliance front face (see Figure 47 on

Page 32).

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.

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.

NOTE: We recommend the use of high temperature paint (rated 175° F or higher)

on the underside of the mantel.

Combustible materials may

project beyond one side

of the ﬁreplace opening

as long as they are kept

within the shaded areas

illustrated here.

Combustible Materials

Allowed In Shaded Area

“Safe Zone”

Combustible Walls

shown in dark gray

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"

Figure 7 -

Shelf Height Minimum Clearances With Top Venting

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Model No. Combustible Shelf Height - Inches (millimeters)

Top Vent - with One 90 Degree Elbow

Secure Vent Secure Flex (ﬂex elbow)

MLDVTCD-35 *46-1/2 (1181) *48-1/4 (1226)

* Includes 3” clearance to combustibles (required above vent components)

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

DETAILED INSTALLATION STEPS

The appliance is shipped with all gas controls

and components installed and pre-wired.

1. Remove the shipping carton. Remove the

shipping pad, exposing the front glass

door.

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

and lifting it up. Set the door aside protecting

it from inadvertent damage. See Removing

Glass Panels on Page 30.

Figure 10

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.

Nailing Flanges Are

Provided At All Four

Corners At 5/8”, 1/2”

And Flush Settings

Side

Framing

Unit

Nailing Flange

Left Side Front Corner of Fireplace Shown

(Right Side Requirements the Same)

Unit Being Secured By Its Nailing Flanges

To The Framing

WARNING

Failure to position the parts in

accordance with these diagrams

or failure to use only parts speciﬁ-

cally approved with this appliance

may result in property damage or

personal injury.

AVERTISSEMENT

Risque de dommages ou de

blessures si les pièces ne sont

pas installées conformément à

ces schémas et ou si des pièces

autres que celles spéciﬁquement

approuvées avec cet appareil sont

utilisées.

Step 1. FRAMING

Frame these appliances as illustrated in Figures

11 and 12 on Pages 10 and 11 (Figure 12

applies to corner framing installations only).

All framing details must allow for a minimum

clearance to combustible framing members as

shown in Table 5 on Page 8.

If the appliance is to be elevated above ﬂoor

level, a solid continuous platform must be

constructed below the appliance.

Headers may be in direct contact with the appli-

ance top spacers when they are bent up vertically

maintaining the 3" clearance to the ﬁreplace top,

but must not be supported by them or notched

to ﬁt around them. All construction above the

appliance must be self-supporting. DO NOT use

the appliance for structural support.

The ﬁreplace should be secured to the side

framing members using the unit's nailing

ﬂanges - one top and bottom on each side of

the ﬁreplace front. See Figure 10. Use 8d nails

or their equivalent.

TYPICAL INSTALLATION SEQUENCE

The typical sequence of installation is outlined

below. However, each installation is unique

and may result in variations to the steps

described.

See the Page numbers references in the follow-

ing steps for detailed procedures.

Step 1. (Pages 10 and 11) Construct the

appliance framing. Position the ap-

pliance within the framing and secure

with nailing brackets. Bend up the

appropriate header spacing guides for

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).

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.

Step 11. (Page 32) Install the hoods.

Step 12. (Page 33) Attach Safety in Operation

Warnings.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

10 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

(178)

5-1/8

12-1/8

(308)

10-1/2

(267)

VENT FRAMING -

TOP VENT WITH ONE

90° ELBOW

Framing should be constructed

of 2x4 or larger lumber

Inches (mm)

(130)

D is the required framing depth dimension when the

finish material (drywall) thickness is 1/2 in. (13mm)

1/2

Raised Platform

Or Floor

Add Minimum Of 18” For

Raised Platform If Installing

With Contemporary Facade.

FIREPLACE AND FRAMING SPECIFICATIONS

Vent Size

Co-axial DV

Vent Size

4-1/2" Inner

7-1/2" Outer

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).

Input (BTU) - MV & Electronic

Natural & Propane Gas

Model Input Rate (BTU / HR)

MLDVTCD-35N 14,500

MLDVTCD-35P 13,500

Efﬁciencies %

Natural Gas Propane

Model P4 P4

MLDVTCD-35 48 51

Viewable Glass Size

35" Model 29-1/4" Wide

20-1/4" High

Figure 11

Framing

Framing Dimensions

Model No. A B C D

MLDVTCD-35 in. 35-1/4 35-1/4 39-1/4 16

mm 895 895 997 406

.oNledoM E F G H J K L M

.ni

32-1/4

819

28-1/8

715

23-1/4

587

813

35-1/4

892

635

12-1/2

317

838

MLDVTCD-35

Front View

Top View

*CONCENTRIC FLUE

FLUE - 4-1/2 (114)

COMBUSTION AIR

- 7-1/2 (190)

9-1/4 (235)

1/2

(13)

16 (406)

1-5/8 (42)

NOTE - Eyebrow

hood shown.

GAS INLET

KNOCKOUT

(Other Side)

Right Side View

5-7/8

(149)

NOTE - It is recommedned that the gas be studed in from the left

side only.

3 (76)

9-1/2

(241)

ELECTRICAL INLET

KNOCKOUT - 2-3/4 X 2

(70 X 51) COVER PLATE

(With KNOCKOUT -

Right Side Only)

OPTIONAL

ELECTRICAL

INLET KNOCKOUT,

REQUIRING A FIELD

PROVIDED

JUNCTION BOX

(Either Side)

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.

NOTE: It is recommended that the gas be

stubbed in from the left side only.

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

FIREPLACE FRAMING SPECIFICATIONS

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

appliance involves numerous considerations of

materials, protection, sizing, locations, controls,

pressure, sediment, and more. Certainly no one

unfamiliar and unqualiﬁed should attempt sizing

or installing gas piping.

Schedule 40

Black Iron Pipe

Inside Diameter (Inches)

Schedule 40 Pipe

Length (feet)

Natural

Gas

Propane

Gas

0-10 1/2 3/8

10-40 1/2 1/2

40-100 1/2 1/2

100-150 3/4 1/2

150-200 3/4 1/2

Table 6

Notes:

• All appliances are factory-equipped with a

ﬂexible gas line connector and 1/2 inch shutoff

valve (see Figure 38 on Page 26).

• See Massachusetts Requirements on Page 4

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).

• A pipe joint compound rated for gas should be

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. are below grade penetrations

of the gas line allowed?, etc).

IMPORTANT: If propane is used, be aware that

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.

Figure 12 - Corner Framing with Horizontal Termination

Inches

(millimeters)

Back wall of chase/enclosure

(including any finishing materials)

7 (178)

.oNledoM A B D E

35 1/4 57 1/2 40 5/8 28 3/4

in.

895 1461 1032 730

13 3/4

349

MLDVTCD-35

Also see Figure 11 on Page 10.

Figure 13 - ROUTE GAS LINE

*3"

(76 mm)

Left Side Front

Corner of Fireplace

Framing

6-1/2"

(152 mm)

Pipe Coupling

(Recommended)

*From Floor Or Raised Platform

Step 2. ROUTING GAS LINE

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

connector and 1/2 inch shutoff valve (see Step

6 on Page 26).

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).

12 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

Select Venting System - Horizontal or Vertical

With the appliance secured in framing, 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.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Installation of Vent Restrictor

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.

Determine the venting for the appliance. If the

vent run will include at least 8 feet of vertical

rise, then install the restrictor in the appliance

collar before connecting any vent (Refer to

Figure 14). Place the restrictor inside the ap-

pliance vent collar and press in place.

Note: The restrictor is included within the

ﬁrebox.

Step 3. INSTALL THE VENT SYSTEM

General Information

These instructions should be used as a

guideline and do not supersede local codes

in any way. Install venting according to local

codes, these instructions, the current National

Fuel Gas Code (ANSI-Z223.1) in the USA or

the current standards of CAN/CSA-B149.1

in Canada.

Clearance in accordance with local installa-

tion codes and the requirements of the gas

supplier.

Dégagement conforme aux codes d'installation

locaux et aux exigences du foumisseunde

gaz.

Use only approved venting components.

See Approved Vent Components on

Page 2.

These ﬁreplaces must be vented directly

to the outside.

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.

Figure 14

Appliance Top

Vent Outlet

Restrictor

Inner

Fireplace

Collar

Vent Restrictor Installation

(Top Vent)

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.

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

VERTICAL TERMINATION SYSTEMS (ROOF)

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

vertical 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 Vertical

Vent Table summarizes each system’s minimum

and maximum vertical and horizontal length

values that can be used to design and install the

vent components in a variety of applications.

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

local codes for speciﬁc requirements. A general

guide to follow is the Gas Vent Rule (refer to

Figure 4B on Page 6).

A vent restrictor may need to be installed when

vertical termination is used. See Installation of

Vent Restrictor on Page 12 for guidelines.

Vertical (Straight) Installation

Determine the number of straight vent sections

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" (1181 mm) net section lengths are available

(see Tables on this page and Page 34 - Vent

Sections). It is recommended that you plan the

vent lengths so that a joint does not occur at

the intersection of ceiling or roof joists. Refer

to the Vent Section Length Chart.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Note: Convert inches into metric equivalent

measurement, as follows:

Millimeters (mm) = Inches x 25.4

Centimeters (cm) = Inches x 2.54

Meters (M) = Inches x .0254

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5.79 521.8 1 0 0 0 2 3

201 5.8 2 0 0 0 2 4

5.301 526.8 0 0 0 3 0 3

801 9 1 0 0 3 0 4

411 5.9 0 2 0 0 2 4

711 57.9 1 0 5 0 0 6

5.811 578.9 1 1 0 3 0 5

621 5.01 0 0 1 3 0 4

5.031 578.01 1 0 1 3 0 5

531 52.11 0 0 6 0 0 6

831 5.11 0 0 0 4 0 4

5.931 526.11 0 0 0 0 3 3

5.241 578.11 1 0 0 4 0 5

TRAHCHTGNELNOITCESTNEV

noitceSlanimoN )sehcni(htgneL 6 21 42 63 84 T

noitceSteN )sehcni(htgneL 2/1-4 2/1-01 2/1-22 2/1-43 2/1-64

tneVfothgieH snoitceStneVforebmuN

sehcni tf

441 21 1 0 0 0 3 4

051 5.21 0 1 0 0 3 4

5.451 578.21 1 1 0 0 3 5

5.061 573.31 0 2 0 0 3 5

5.271 573.41 0 0 0 5 0 5

771 57.41 1 0 0 5 0 6

381 52.51 0 1 0 5 0 6

681 5.51 0 0 0 0 4 4

5.091 578.51 1 0 0 0 4 5

5.691 573.61 0 1 0 0 4 5

5.502 521.71 0 1 1 5 0 7

702 52.71 0 0 0 6 0 6

5.112 526.71 1 0 0 6 0 7

5.712 521.81 0 1 0 6 0 7

5.922 521.91 0 0 1 6 0 7

5.232 573.91 0 0 0 0 5 5

732 57.91 1 0 0 0 5 6

5.142 521.02 0 0 0 7 0 7

642 5.02 1 0 0 7 0 8

252 12 0 1 0 7 0 8

462 22 0 0 1 7 0 8

672 32 0 0 0 8 0 8

972 52.32 0 0 0 0 6 6

082 573.32 1 0 0 8 0 9

5.382 526.32 1 0 0 0 6 7

5.982 521.42 0 1 0 0 6 7

5.103 521.52 0 0 1 0 6 7

5.013 578.52 0 0 0 9 0 9

513 5.62 1 0 0 9 0 01

5.523 521.72 0 0 0 0 7 7

033 5.72 1 0 0 0 7 8

633 82 0 1 0 0 7 8

543 57.82 0 0 0 01 0 01

5.943 521.92 1 0 0 01 0 11

273 13 0 0 0 0 8 8

5.673 573.13 1 0 0 0 8 9

5.973 526.13 0 0 0 11 0 11

5.814 578.43 0 0 0 0 9 9

324 52.53 1 0 0 0 9 01

564 57.83 0 0 0 0 01 01

Effective Vent Length

Model Effective Length

SV4.5L6 4-1/2"

SV4.5L12 10-1/2"

SV4.5L24 22-1/2"

SV4.5L36 34-1/2"

SV4.5L48 46-1/2"

Table 7

Figure 15

SV4.5CGV-1

Termination SV4.5FA OR

SV4.5FB Flashing

AND SV4.5SC

STORM COLLAR



SV4.5VF

Firestop/Spacer

SV4.5L6/12/24/36/48

Vent Sections

40' Max

(12.2 M)

1" (25.4 mm)

Minimum

Clearance to

Combustibles



When using Secure Flex

use Firestop/Spacer

SF4.5VF

14 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

Vertical (Offset) Installation

Analyze the vent routing and determine the

quantities of vent sections and number of elbows

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

aid in selecting length combinations. Elbows are

available in 90° and 45° conﬁgurations. Refer

to Figure 19 on Page 15 for the SV4.5E45 and

SV4.5E90 elbow dimensional speciﬁcations.

Where required, a telescopic vent section

(SV4.5LA) may be used to provide the installer

with an option in installing in tight and 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

normal vent section component) and a plain end

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.

Maintain a minimum 1" (25 mm) clearance to

combustible materials for all vertical elements.

Clearances for all horizontal elements are 3"

(76 mm) on top, 1" (25 mm) on sides and 1"

(25 mm) on the bottom.

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).

To attach a vent component to the appliance collar,

align the dimpled end over the collar, adjusting the

radial alignment until the four locking dimples are

aligned with the inlet of the four inclined channels

on the collar (refer to Figure 17). Push the

vent component against the collar until it fully

engages, then twist the component clockwise,

running the dimples down and along the incline

channels until they seat at the end of the chan-

nels. The unitized design of the Secure Vent™

components will engage and seal both the inner

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.

Note: An elbow may also be attached to the

appliance collar. Attach in the same manner

as you would a vent section.

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.

B. Attach vent components to appliance

- Secure Vent SV4.5 direct-vent system compo-

nents are unitized concentric pipe components

featuring positive twist lock connections (see

Figure 17).

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.

Blocking

Support Straps

(Plumber's tape)

8 feet (2.4 m)

Maximum

1/2 inch (12.7

mm) minimum

clearance to

combustibles

Figure 18

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

component clockwise running the dimples down

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.

D. Install ﬁrestop/spacer at ceiling - When us-

ing Secure Vent, use SV4.5VF ﬁrestop/spacer

at ceiling joists; when using Secure Flex, use

SF4.5VF ﬁrestop/spacer. If there is living space

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.

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.

E. Support the vertical vent run sections -

Note - Proper venting support is very important.

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.

Figure 17

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.

Dimple

Locking

Incline

Channel

Connected Vent

Sections Arrow

Arrow

Appliance Collar or

Vent Section

Figure 16

10-1/2” Min.

(267mm)

10-1/2” Min.

(267mm)

Plumb

Bob

Roof

Framing

Ceiling

Framing

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

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.

G. Continue installation of horizontal/inclined

sections - Continue with the installation of the

straight vent sections in horizontal/inclined run

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

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. Use a carpenter’s

level to measure from a constant surface and

adjust the support straps as necessary.

It is important to maintain the required clear-

ances to combustibles: 1" (25 mm) at all sides

for all vertical runs; and 3" (76 mm) at the top,

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).

One method of support is by utilizing ﬁeld pro-

vided support straps (conventional plumber's

tape). Secure the plumber's tape to the framing

members with nails or screws. Loop the tape

around the vent, securing the ends of the tape

to the framing. If desired, sheet metal screws #6

x 1/2" length may be used to secure the support

straps to the vent pipe. Refer to Figure 18.

F. Change vent direction to horizontal/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

only so as to avoid the possibility of unlocking

any of the previously connected vent sections

(see Figure 19).

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

installed section, adjusting the radial alignment

until the four locking dimples of the termination

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.

I. Install the roof ﬂashing - Extend the vent

sections through the roof structure. Install the

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.

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-

justing screw. Apply non-combustible caulking

or mastic around the circumference of the joint

to provide a water tight seal.

Figure 19

7-5/8”

(194 mm)

4-13/16

(122 mm)

Swivel Joint

(360° swivel)

SV4.5E45

45° Elbow)

Swivel Joint

(360° swivel)

SV4.5E90

90° Elbow)

(206 mm)

8-1/8"

Framing Dimensions for Roof

Inches (millimeters)

Pitch C D

0/12 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

Figure 21

Figure 22

Storm

Collar

Flashing

16 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

u When using Se-

cure Flex, use

Firestop / Spac-

er SF4.5VF

u Ceiling Firestop /

Spacer (SV4.5VF)

A Vent

Restrictor, as

shown in Figure

14 on Page 12,

must be used in

this application

Figure 23 - Top Vent - STRAIGHT

u Ceiling Firestop /

Spacer (SV4.5VF)

vWall Firestop/

Spacer (SV4.5HF)

u When using Secure Flex, use Firestop /

Spacer SF4.5VF.

v When using Secure Flex, use Firestop /

Spacer SF4.5HF.

40 feet

(12.2 meters)

Maximum

Table A

H Maximum V Minimum

feet (meter) feet (meter)

5 (1.524) Elbow Only

5 (1.524) 1 (0.305)

10 (3.048) 2 (0.610)

15 (4.572) 3 (0.914)

20 (6.096) 4 (1.219)

V + V1 + H = 40 feet (12.2 m) Max.

H = 20 feet (6.096 meters) Max.

WARNING

Under no circumstances, may sepa-

rate sections of concentric ﬂexible

vent pipe be joined together.

VERTICAL VENT FIGURES/TABLES

Notes:

• Secure Vent™ (rigid vent pipe) is shown

in the Figures; Secure Flex™ (ﬂexible vent

pipe) may also be used.

• 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 (Secure Flex) ﬁrestop/spacer must

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

for 90 elbows, must be followed if 45 degree

elbows are used.

• 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 24 - Top Vent - TWO 90 DEGREE ELBOWS

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.

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.

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

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.

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.

C. Frame ceiling opening - If the vertical route

is to penetrate a ceiling, use plumb line to locate

the center above the appliance. Cut and/or frame

an opening, 10-1/2" x 10-1/2" (267 mm x 267

mm) inside dimensions, about this center (refer

to Figure 16 on Page 14).

VERTICAL VENT FIGURES/TABLES (CONTINUED)

HORIZONTAL (OUTSIDE WALL)

TERMINATION SYSTEM

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

each system’s minimum and maximum vertical

and horizontal length values that can be used

to design and install the vent components in a

variety of applications.

Both of these horizontal vent systems terminate

through an outside wall. Building Codes limit or

prohibit terminating in speciﬁc areas. Refer to

Figure 6 on Page 7 for location guidelines.

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.

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"

(572 mm), 34-1/2" (876 mm) and 46-1/2" (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.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

u Ceiling

Firestop / Spacer

(SV4.5VF) vWall Firestop/

Spacer (SV4.5HF)

u When using Secure Flex, use Firestop / Spacer SF4.5VF

v When using Secure Flex, use Firestop / Spacer SF4.5HF

Example: If 20 feet total (H+H1)

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+H1) horizontal run up to

a maximum total horizontal run

of 20 feet.

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.

Table B

H + H1 Maximum V Minimum

feet (meter) feet (meter)

5 (1.524) Elbow Only

5 (1.524) 1 (0.305)

10 (3.048) 2 (0.610)

15 (4.572) 3 (0.914)

20 (6.096) 4 (1.219)

H + H1 = 20 feet (6.096 m) Max.

V + V1 + H + H1 = 40 ft. (12.2 m) Max.

Figure 25 - Top Vent - THREE ELBOWS

18 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

Push the vent component against the previous

section until it fully engages, then twist the

component clockwise running the dimples down

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.

F. Install ﬁrestop/spacer at ceiling -

When using Secure Vent, use SV4.5VF ﬁrestop/

spacer at ceiling joists; when using Secure Flex,

use SF4.5VF ﬁrestop/spacer. If there is living

space 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. 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 Tables on Pages 34 and 35.

G. Support the vertical run sections -

See Section E on Page 14.

H. Change vent direction - At transition from or

to a horizontal/inclined 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 only

so as to avoid the possibility of unlocking any

of the previously connected vent sections (see

Figure 17 on Page 14).

I. Continue installation of horizontal/inclined

sections - Continue with the installation of the

straight vent sections in horizontal/inclined run

as described in Step E. Install support straps

every 5 ft. (1.52 m) along horizontal/inclined

vent runs using conventional plumber’s tape.

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.

It is important to maintain the required clear-

ances to combustibles: 1" (25 mm) at all sides

for all vertical runs; and 3" (76 mm) at the top,

1" (25 mm) at sides, and 1" (25 mm) at the

bottom for all horizontal/inclined runs.

Use a carpenters level to measure from a

constant surface and adjust the support straps

as necessary.

D. Attach vent components to appliance - To

attach a vent component to the appliance collar,

align the dimpled end over the collar, adjusting the

radial alignment until the four locking dimples are

aligned with the inlets of the four incline channels

on the collar (see Figure 17 on Page 14).

Push the vent component against the collar

until it fully engages, then twist the component

clockwise, running the dimples down and along

the incline channels until they seat at the end

of the channels.

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.

Note: An elbow may also be attached to the

appliance collar. Attach in the same manner

as you would a vent section.

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

vent component to a length of vent run, align the

dimpled end of the component over the inclined

channel end of the previously installed section,

adjusting the radial alignment until the four lock-

ing dimples are aligned with the inlets of the four

incline channels of the previous section.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

Support

Brackets

Building

Support

Framing

SV4.5E90

Elbow

Ceiling

Fireplace

SV4.5L6/12/24/36/48

Vent Sections

Vertical

Rise

Support Bracket Spacing

Every 5 ft (1.52 m)

See Figure 15 on Page 13 or Figure 18 on

Page 14 for vertical vent section support.

TYPICAL HORIZONTAL VENT INSTALLATION

u When Using Secure Flex,

Use Firestop / Spacer SF4.5VF

u Firestop / Spacer

SV4.5VF

Figure 26

Typical

Termination

Shown

Typical

Termination

Shown

Exterior

Wall

Horizontal / Inclined Run

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

J. Assemble vent run to exterior wall - If not

previously measured, locate the center of the

vent at the exterior wall. Prepare an opening as

described in Step B. Assemble the vent system

to point where the terminus of the last section is

located relative to the exterior surface to which

the termination is to be attached as shown in

Figure 28 and Table 8.

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.

K. Attach termination adapter - Attach the

adapter (adapter - SV4.5RCH - provided with the

termination) to the vent section or telescoping

vent section), elbow or appliance collar as shown

in Figure 27 in the same manner as any SV4.5

vent component (refer to Step E).

L. Install Firestop/Spacer at exterior wall -

When using the termination, install SV4.5HF

(Secure Vent™), SF4.5HF (Secure Flex™)

Firestop/Spacer over the opening at the exterior

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.

(The Firestop/Spacer may also be installed over

the opening at the interior side of framing).

M. Install the Termination (SV4.5HT-2 or

SV4.5HTSS)

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.

IMPORTANT: The vent termination is hot

while in operation and for a period of time

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.

Horizontal terminations have been designed to perform in a wide range of weather condi-

tions. Our terminations meet or exceed industry standards.

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.

Figure 28

Figure 27 - INSTALLING HORIZONTAL TERMINATION

Siding

Stucco

1-1/4" Maximum Recess of

the Square Termination into

Exterior Finishing Material

Exterior Surface of

Framing

6 in. to 9-1/4 in.

(152 to 235 mm)**

Exterior Surface of Siding

Interior Surface of

Finished Wall

Maximum wall thickness

9-1/4 in.(235 mm)**

SV4.5HT-2

Square Termination

Shown

Maximum Extent of

Vent Run Sections

Relative to Exterior

Surface of Framing

Last Vent Section. Use

Telescopic Vent

Section (SV4.5LA), If

Necessary

Adapter

SV4.5RCH

SV4.5HT-2

Square Termination

Shown

Venting Connection and Exterior Wall Recessing

of the Horizontal Termination

*Use silicone caulking to

seal the top and sides of

the termination, up to the

underlayment, stucco, or

masonry wall surface.

*Caulk

Firestop/Spacer (SV4.5HF) shown

on the exterior side of the wall. It

may also be installed on the

interior side.

Typical

Termination

Shown

(178)

5-1/8"

(130 mm)

12-1/8"

(308 mm)

Note: Centerline of Vent Piping is

NOT the Same as the Centerline of

the Frame Opening.

6 to 48 inch Vent Section,

Telescopic vent section,

Elbow or Appliance Collar

See Figure 12 on page 9

for Min. Distance to Base

of Appliance.

Base of Appliance

(76 mm)

(25.4 mm)

Adapter

SV4.5RCH

10-1/2"

(267 mm)

See Figure 11 on Page 10 for Min.

distance to Base of Appliance

**For thicknesses greater

than 9-1/4", see Table 8

on Page 20.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

20 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

Table C

H Maximum V Minimum

feet (meter) feet (meter)

3 (0.914) Elbow Only

Table D

H Maximum V Minimum

feet (meter) feet (meter)

5 (1.524) 1 (0.305)

10 (3.048) 2 (0.610)

15 (4.572) 3 (0.914)

20 (6.096) 4 (1.219)

V + H = 40 feet (12.2 m) Max.

H = 20 ft. (6.096 m) Max.

WARNING

Under no circumstances, may separate sections of

concentric ﬂexible vent pipe be joined together.

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • INSTALLATION INSTRUCTIONS

See Table 8 on Page 20 as an aid in venting component selection

for a particular range of exterior wall thicknesses.

See Table 8 on Page 20 as an aid in venting component selection

for a particular range of exterior wall thicknesses.

Wall

Firestop/Spacer

(SV4.5HF)

When using Secure Flex,

use Firestop/Spacer

SF4.5HF

HORIZONTAL VENT FIGURES/TABLES

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.

• 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.

• 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.

• 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.

• 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).

• 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.

Use Table 8 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

Figure 29 - Top Vent -

ONE 90 DEGREE ELBOW - ELBOW CONNECTION AT APPLIANCE



Wall Firestop/Spacer

(SV4.5HF)

When using Secure Flex,

use Firestop/Spacer

SF4.5VF.

Ceiling

Firestop/Spacer

(SV4.5VF)

When using Secure Flex,

use Firestop/Spacer

SF4.5HF.

Typical termination shown.

Venting Components Required for Various Exterior Wall Thick-

nesses, when using Typical Termination Kits

Vent Components Required Exterior Wall Thickness - inches (mm)

Termination Kit Only 6 to 9-1/4 (152 to 235)

Termination Kit and 6 In. Vent

Section (SV4.5L6) 10-3/4 to 14 (273 to 356)

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)

Table 8 Note: See Figure 28 on Page 19 showing wall thickness

range when using SV4.5HT-2 termination kit.

Example: If 20 feet of (H) hori-

zontal 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

vertical, you are allowed 5 feet

of (H) horizontal run up to a

maximum (H) horizontal run

of 20 feet.

This manual suits for next models

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