Lennox MPB33CNM, MPB33CPM, MPB35CPM, MPB40CNM, MPB35CNM Installation Instructions Manual
...Page 1
INSTALLATION INSTRUCTIONS
éviter tout dommage matériel, toute blessure ou la mort.
WARNING /AVERTISSEMENT/AVISO
MPB B-Vent
Gas Fireplaces
MODELS
P/N 506015-05 Rev. D 04/2013
This manual is one of a set of two supporting this product.
Refer to P/N 506017-04 for Care and Operation Instructions.
Ce manuel est disponible en francais, simplement
en faire la demande. Numéro de la pièce 506223-45.
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.
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.
Decorative Product: Not for use as a heating appliance.
NOTICE: Fireplace is not to be operated by a thermostat.
MPB33CNM
MPB33CPM
MPB35CNM
MILLIVOLT:
MPB35CPM
MPB40CNM
MPB45CNM
OTL Report No. 116-F-36d-5
EL VIDRIO CALIENTE
CAUSARÁ QUEMADURAS.
USTED DEBE NUNCA
TOCAR EL VIDRIO CALIENTE.
LOS NIÑOS DEBEN NUNCA
TOCAR EL VIDRIO.
ELECTRONIC:
MPB33CNE
MPB35CNE
MPB40CNE
MPB45CNE
WARNING: If the information in these instructions
is not followed exactly, a fire or explosion may
result, causing property damage, personal injury,
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
or death.
- 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.
Page 2
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
TABLE OF CONTENTS
Packaging .................................................... 2
Introduction ................................................. 2
General Information ..................................... 2
Requirements for the
Commonwealth of Massachusetts ............ 4
Cold Climate Insulation ................................ 4
Manufactured Housing ................................. 4
Location ........................................................5
Vent Termination Clearances ....................... 5
Appliance and Vent Clearances .................... 6
Pre-Installation Steps ................................... 7
Typical Installation Sequence ...................... 7
Detailed Installation Steps ............................ 7
Step 1. Framing ............................................ 7
Framing Specifications ................................ 8
Fireplace Specifications .............................. 9
Step 2. Routing Gas Line ............................. 9
Step 3. Installing Vent System ................... 10
Step 4. Field Wiring ................................... 11
Step 5. Wiring Optional
Forced Air Blower Kit .................... 12
Step 6. Connecting Gas Line ..................... 12
Step 7. Installing Optional Outside Air Kit ..13
Step 8. Verifying Appliance Operation ........... 14
Step 9. Installing Volcanic Stone, Glowing
Embers, and Logs ........................ 14
Step 10. Removing and
Installing the Glass Door ............. 19
Step 11. Burner Adjustments ..................... 19
Step 12. Testing Vent Operation ..................21
Step 13. Hood Installation .......................... 21
Step 14. Finishing Requirements ............... 21
Step 15. Attaching Safety-in-Operation
Warnings ............................ 22
Gas Conversion Kits ......................... 23
Please read and understand these
instructions before beginning your
installation.
2
PACKAGING
The assembled vented gas fireplace is packaged with:
• (1 set) Logs (packaged in a carton inside
the firebox).
• (1 bag) Volcanic Stone (included in the
firebox or bottom compartment).
• (1 bag) Glowing Embers (in bottom compartment).
• Literature Kit (envelope in bottom compartment containing Care and Operation
Instructions, Installation Instructions,
Safety-In-Operation Warning Labels, Warranty).
• (1) Hood (behind the top louver assembly).
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 installation.
The Electronic appliances are designed to operate on natural or propane gas. An electronic
intermittent pilot ignition system provides safe,
efficient operation. External electrical power is
required to operate these units. In the event of a
power outage, four (4) "AA" batteries (in battery
holder) provide backup power for appliance
operation (excluding [optional] blower).
APPROVED VENT COMPONENTS
These vented gas fireplaces are designed for
residential applications. They must be installed
with approved Type-B, double wall vent pipe
systems and a listed vent termination routed
to the outside atmosphere. Use only the proper
size listed below.
REQUIRED PIPE DIAMETER:
MPB33 series: Requires 4" (102 mm)
MPB35 series: Requires 5" (127 mm)
MPB40 series: Requires 5" (127 mm)
MPB45 series: Requires 6" (152 mm)
WARNING
B-Vent appliances are not
designed to operate in negatively
pressured environments (pressure within the home is less than
pressures outside). Significant
negatively pressured environments caused by weather, home
design, or other devices may
impact the operation of these
appliances. Negative pressures may result in poor flame
appearance, sooting, damage to
property and/or severe personal
injury. Do not operate these
appliances in negatively pressured environments.
GENERAL INFORMATION
WARNING
Young children should be carefully supervised when they are
in the same room as the appliance. Toddlers, young children
and others may be susceptible
to accidental contact burns. A
physical barrier is recommended
if there are at risk individuals in
the house. To restrict access to
a fireplace or stove, install an
adjustable safety gate to keep
toddlers, young children and
other at risk individuals out of
the room and away from hot
surfaces.
AVERTISSEMENT
Les jeunes enfants devraient être
surveillés étroitement lorsqu’ils
se trouvent dans la même pièce
que l’appareil. Les tout petits,
les jeunes enfants ou les adultes
peuvent subir des brûlures s’ils
viennent en contact avec la surface chaude. Il est recommandé
d’installer une barrière physique
si des personnes à risques habitent la maison. Pour empêcher
l’accès à un foyer ou à un poêle,
installez une barrière de sécurité; cette mesure empêchera les
tout petits, les jeunes enfants et
toute autre personne à risque
d’avoir accès à la pièce et aux
surfaces chaudes.
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
informés des dangers que posent les
températures de surface élevées et se
tenir à distance afin d’éviter des brûlures
ou que leurs vêtements ne s’enflamment.
DO NOT ATTEMPT TO ALTER OR MODIFY
THE CONSTRUCTION OF THE APPLIANCE
OR ITS COMPONENTS. ANY MODIFICATION
OR ALTERATION MAY VOID THE WARRANTY,
CERTIFICATION AND LISTINGS OF THIS UNIT.
Page 3
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause injury
or property damage. Refer to
this manual. For assistance or
additional information consult
a qualified installer, service
agency or the gas supplier.
WARNING
Failure to comply with these installation instructions will result
in an improperly installed and
operating appliance, voiding its
warranty. Any change to this appliance and/or its operating controls
is dangerous.
WARNING
Clothing or other flammable
material should not be placed
on or near the appliance.
AVERTISSEMENT
On ne devrait pas placer de
vêtements ni d’autres matières
inflammables sur l’appareil ni à
proximité.
WARNING
Any safety screen or guard removed for servicing the appliance must be replaced prior to
operating the appliance.
AVERTISSEMENT
Tout écran ou protecteur retiré
pour permettre l’entretien de
l’appareil doit être remis en
place avant de mettre l’appareil
en marche.
WARNING
Improper installation or use of
this appliance can cause serious
injury or death from fire, burns,
explosion or carbon monoxide
poisoning.
WARNING
Failure to position the parts in
accordance with these diagrams
or failure to use only parts
specifically approved with this
appliance may result in property
damage or personal injury.
AVERTISSEMENT
Risque de dommages ou de
blessures si les pièces ne sont
pas installées conformément à
ces schémas et ou si des pièces
autres que celles spécifiquement
approuvées avec cet appareil sont
utilisées.
Installation and repair should be done by
a qualified service person. The appliance
should be inspected before use and at least
annually by a professional service person.
More frequent cleaning may be required due
to excessive lint from carpeting, bedding
material, etcetera. It is imperative that control
compartments, burners and circulating air
passageways of the appliance be kept clean.
L’installation et la réparation devrait
être confiées à un technicien qualifié.
L’appareil devrait faire l’objet d’une
inspection par un technicien professionnel
avant d’être utilisé et au moins une fois
l’an par la suite. Des nettoyages plus
fréquents peuvent être nécessaires si les
tapis, la literie, et cetera produisent une
quantité importante de pous-sière. Il est
essentiel que les compartiments abritant
les commandes, les brûleurs et les
conduits de circulation d’air de l’appareil
soient tenus propres.
Do not use this appliance if any part has
been under water. Immediately call a
qualified service technician to inspect the
appliance and to replace any part of the
control system and any gas control which
has been under water.
Ne pas utiliser cet appareil s’il a été
plongé, même partiellement, dans
l’eau. Appeler un technicien qualifié
pour inspecter l’appareil et remplacer
toute partie du système de commande
et toute commande qui a été plongée
dans l’eau.
Only trim kit(s) supplied by the manufacturer
shall be used in the installation of this
appliance.
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 OMNI-Test Laboratories, Inc. (Report No.
116-F-36d-5) to ANSI Z21.50b-2009 (in Canada,
CSA 2.22b-2009), and CAN/CGA-2.17-M91
(R2009) in both USA and Canada, as vented
gas fireplaces.
Both millivolt and electronic versions of these
appliances may be used in bedrooms only
when the room is an "unconfined space" as
defined by the National Fuel Gas Code. Use
in bedrooms may not be allowed by your local
building codes. You should obtain prior approval from the Authority having jurisdiction
prior to installation.
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/CGA-B149.1 installation
code).The appliance, when installed, must be
electrically grounded and wired in accordance with
local codes or, in the absence of local codes, with
the National Electrical Code, ANSI/NFPA 70 - latest
edition, or the Canadian Electrical Code, CSA C22.1
- latest edition.
Provide adequate clearances around air
openings and adequate accessibility clearance for
service and proper operation. Never obstruct the
front or back openings of the appliance.
These appliances are designed to operate on
natural or propane gas only. The use of other
fuels or combination of fuels will degrade
the performance of this system and may be
dangerous.
These fireplaces are designed as decorative
appliances and are not intended for use as
area heaters. They must not be equipped
with wall thermostats or remote controls with
thermostat functions.
OUTSIDE COMBUSTION AIR HOOK UP
These appliances are equipped with an
integral combustion air door and actuator arm.
Combustion air kits are optional. Install as shown
in Step 7 on Page 13.
These appliances must not be connected to a
chimney or flue serving a separate solid fuel
burning appliance.
Both millivolt and electronic systems can be
operated during a power outage, and feature
manually operated hi-low flame control. The BTU
Input for these appliances is shown in Table 1.
Natural Gas Propane Gas
Model Input Rate
MPB33 13,500 to
MPB35 16,000 to
MPB40 24,000 to
MPB45 24,750 to
Table 1 - BTU Input Ratings
(BTU/HR)
17,500
20,000
30,000
31,000
Input Rate
BTU/HR)
13,500 to
17,500
16,500 to
20,000
22,300 to
28,000
23,000 to
29,000
3
Page 4
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
GAS PRESSURE - ALL MODELS
Tables 2 and 3 show the appliances' inlet and
manifold gas pressure requirements:
Fuel # Minimum Maximum
Natural Gas 4.5" WC
Propane 11.0" WC
(1.12 kPa)
(2.74 kPa)
10.5" WC
(2.62 kPa)
13.0" WC
(3.24 kPa)
Table 2 - Inlet Gas Supply Pressure
Fuel # Low High
Natural Gas 2.2" WC
Propane 6.3" WC
(0.55 kPa)
(1.57 kPa)
3.5" WC
(0.87 kPa)
10.0" WC
(2.49 kPa)
Table 3 - Manifold Gas Supply Pressure
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"
(10 mm) NPT thread inlet and outlet side of the
valve (refer to Figures 1 and 2).
Propane tanks are at pressures that will cause
damage to valve components. Verify that the
tanks have step down regulators to reduce the
pressure to safe levels.
The appliance and its appliance main gas
valve must be disconnected from the gas
supply piping system during any pressure
testing of that system at test pressures in
excess of 1/2 psi (3.5 kPa).
The appliance must be isolated from the gas
supply piping system by closing its equipment
shutoff valve during any pressure testing of
the gas supply piping system at test pressures equal to or less than 1/2 psi (3.5 kPa).
ORIFICE SIZES - SEA LEVEL TO HIGH
ALTITUDE (ALL MODELS)
These appliances are tested and approved for
installation at elevations of 0 - 4500 ft (0 - 1372
m) above sea level using the standard burner
orifice sizes (marked with an "*" in Table 4).
For elevations above 4500 ft, contact your gas
supplier or qualified service technician.
Deration - At higher elevations, the amount
of BTU fuel value delivered must be reduced
by either:
• Using gas that has been derated by the gas
company.
Install the appliance according to the regulations
of the local authorities having jurisdiction and,
in the USA, the National Fuel Gas Code NFPA
54 - latest edition / ANSI Z223.1 or, in Canada,
the CAN/CGA-B149.1 - latest edition.
Flame breadth, height and width will diminish
4% for every 1,000 feet of altitude. Gas Valve
Diagrams
. See Figure 1 for millivolt models
and Figure 2 for electronic models.
In Canada - CAN/CGA-2.17-M91 (R2009)
(high altitude): THE CONVERSION SHALL
BE CARRIED OUT BY A MANUFACTURER’S AUTHORIZED REPRESENTATIVE,
IN ACCORDANCE WITH THE REQUIREMENTS OF THE MANUFACTURER, PROVINCIAL OR TERRITORIAL AUTHORITIES
HAVING JURISDICTION AND IN ACCORDANCE WITH THE REQUIREMENTS OF
THE CAN/CGA-B149.1 OR CAN/CGAB149.2 INSTALLATION CODES.
Main Gas Control Knob
OFF/PILOT/ON
N
O
T
O
it
L
I
P
O
F
F
OUT
IN
Manifold Pressure Tap
Inlet Pressure Tap
Pilot Adjustment
I
P
W
O
L
H
I
HI/LO Variable
Flame Height
Adjustment
Screw
T
O
L
HTPTHTPT
Figure 1 - SIT Millivolt Gas Valve
(from DFC Wire Harness)
Inlet (IN) Test Port
Manifold (OUT) Test Port
Orange Wire
(from DFC Wire
Harness)
Green Wire
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-1372 meters)
Model
MPB33
MPB35
MPB40
MPB45
Table 4
Nat.Gas
drill size (inches)
#47 (0.0785")*
99K74 •
#44 (0.086")*
60J80 •
#38 (0.102")*
99K76 •
#37 (0.104")*
24M10 •
* Standard size installed at factory
• Part /Cat. Number
Propane
drill size (inches)
(0.048")*
99K78 •
#55 (0.052")*
19L52 •
(0.062")*
21L01 •
#52 (0.0635")*
37G00 •
REQUIREMENTS FOR THE COMMONWEALTH 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 Commonwealth of Massachusetts.
• The exible 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.
Cold Climate Insulation
For cold climate installations, seal all cracks
around your appliance with noncombustible
material and wherever cold air could enter
the room. It is especially important to insulate
outside chase cavity between studs and under
floor on which appliance rests, if floor is above
ground level. Gas line holes and other openings
should be caulked or stuffed with unfaced
fiberglass insulation.
Hi/Lo Flame
Control Knob
• Changing the burner orice 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/CGA-B149.1
codes - latest edition.
4
Main Gas Inlet
3/8" NPT
Yellow Ground Wire
(from DFC Wire Harness)
Figure 2 - SIT Electronic Gas Valve
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 5
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
If the fireplace is being installed on a cement
slab in cold climates, a sheet of plywood or
other raised platform can be placed underneath
to prevent conduction of cold transferring to
the fireplace and into the room. It also helps to
sheetrock inside surfaces and tape for maximum
air tightness and caulk firestops.
MANUFACTURED HOUSING
B-Vent Fireplaces are not approved for use in
OEM or aftermarket manufactured housing built
to HUD standards.
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.
Be aware that this is a heat producing appliance. Objects placed above the unit are
exposed to elevated temperatures.
Do not insulate the space between the appliance and the area above it (see Figure 10
on Page 8).
The appliance must be mounted on a fully
supported base extending the full width
and depth of the unit. The appliance may be
located on or near conventional construction
materials. However, if installed on combustible
materials, such as carpeting, vinyl tile or other
combustible material other than wood flooring,
the appliance shall be installed on a metal or
wood panel extending the full width and depth
of the appliance
VENT TERMINATION CLEARANCES
Gas Vent Rule - Gas vent caps are not per-
mitted within 8 feet (2.4 mm) of a vertical
wall or similar obstruction. Gas vent caps
that are located 8' or more from a portion
of a building which extends at an angle
greater than 45° upward from the horizontal
may terminate in accordance with Figure 4,
provided that in no case shall any discharge
opening on the cap be less than 2' (610 mm)
horizontally from the roof surface (National
Fuel Gas Code ANSI Z223.1 (NFPA 54) Gas
Vent Termination) (CAN/CGA B149.1).
MULTIPLE TERMINATIONS
These appliances may vent adjacent to and at
the same level with any other gas appliances
(including direct-vent appliances) provided that
there is at least 2 ft. (0.6m) between the proximal
edges of the vent caps. These appliances may
be vented adjacent to a chimney vent servicing
a solid fuel fireplace provided the B-vent cap
is at least 2 ft. (0.6m) away from the nearest
point of the chimney opening.
Vertical
Venting
Shown with Outside Air Kit
installed (model FOAK-4 or
FOAK-4LD)
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.
Figure 3 - Typical Installations
X
12
Roof Pitch is X/12
Minimum Height from Roof to
Lowest Discharge Opening
1“ (25 mm)
Minimum
Figure 4 - Vertical Vent Termination
Clearances
2 ft.
(0.6m)
Minimum
Figure 5 - Multiple Terminations
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Offset
Venting
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
5
Page 6
12 (305) MANTEL
10 (254) MANTEL
8 (203) MANTEL
6 (152) MANTEL
4 (102) MANTEL
4
(102)
14
(356)
12
(305)
10
(254)
2 (51) MANTEL
TOP OF
APPLIANCE
6
(152)
NOTE - Hood shown as positioned in louvered
front model. The hood position in the flush
faced front model is lower than shown.
8
(203)
MANTEL CLEARANCES
Inches (mm)
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
APPLIANCE AND VENT CLEARANCES
MINIMUM CLEARANCES TO COMBUSTIBLES
The appliance is approved with zero
clearance to combustible materials on
all sides. Refer to Table 5 for minimum
clearance values. For typical installations,
see Figure 3 on Page 5.
Minimum Clearances
Back 1/2" (13 mm)
Sides 1/2" (13 mm)
Top Spacers 3" (76 mm)
Floor 0" (0 mm)
Bottom of
Appliance
To Ceiling
Vent 1" (25.4 mm)
Front 3' (0.9 m)
0 (0) from Spacers or Dimples
0 (0) from Spacers or Dimples
0" (0 mm)
with standoff(s) in vertical
position
64" (1626 mm)
SERVICE CLEARANCES
Table 5
NOTE: 3" (75 mm) minimum clearance is
required above any inclined vent component.
1" minimum clearance is required to the sides
of vertical vent.
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.
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 face.
Refer to Figure 36 on Page 21 for clearance
recommendations and requirements.
Figures 6 and 7 illustrate the areas surrounding
the fireplace where clearances are an issue. The
outer edge of the metal trim on only one side
of the fireplace may abutt a perpendicular wall.
For this type of installation, the other side of the
fireplace must be a flat wall to allow for proper
air flow and burner operation.
Combustible materials may project beyond one
or both sides of the fireplace opening when
these materials are kept within the "Safe Zone"
illustrated in Figure 6.
Top View of
Fireplace
At 0 in. minimum
side wall clearance,
one combustible
wall can project to
any length.
Figure 6 - Clearance References
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, louvers, or control compartment.
Vertical installation clearances to combustible
mantels vary according to the depth of the
mantel (see Figure 7). 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 fireplace hood.
Minimum clearance requirements include any
projections such as shelves, window sills,
mantels, etc. above the appliance.
NOTE: We recommend the use of high
temperature paint (rated 175 °F, or higher)
on the underside of the mantel.
Mantel Leg,
Trim, or Wall
3 1/2 in.
(89 mm)
45
o
Combustible materials
may project beyond
either side of the
fireplace opening as
long as they are kept
within the shaded
“Safe Zone” area.
0” Clearance
to Combustible
Side Wall
Bottom of Fireplace
Figure 7 - Wall Clearances
Ceiling
64"
(1626 mm)
6
Figure 8 - Minimum Mantel Clearances
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 7
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Anchor
Ta b
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.
Side
Framing
Unit Nailing Flange
(No clearance to
combustible
framing is required)
Left Side Front Corner of Fireplace Shown
(Right Side Requirements the Same)
PRE-INSTALLATION STEPS
The appliance is shipped with all gas controls
and components installed and pre-wired.
1. Before installing the appliance, follow these
steps:
2. Remove the shipping carton.
3. Remove the shipping pad, exposing the front
glass door.
4. Open the spring latch securing the glass
door (under the firebox floor). Remove the
door by tilting it outward at the bottom and
lifting it up. Set the door aside, taking care
to protect it from inadvertent damage. See
Removing the Glass Enclosure Panel on Page
19.
5. Remove the log set from the firebox. Handle
logs carefully to prevent breakage.
6. Remove the embers and volcanic stone from
the control compartment.
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 pages referenced in the following steps
for detailed procedures.
Step 1. FRAMING (Page 7): Construct the
appliance framing. Position the appliance within
the framing and secure with nailing flanges and
floor anchor tabs.
Bend out the appropriate nailing flanges for
the drywall/finish material to be used. Nailing
flanges are provided for flush framing, 1/2" and
5/8" framing depths (see Figure 8).
Step 2. ROUTING GAS LINE (Page 9): Route
gas supply line to appliance location.
Step 3. INSTALLING VENT SYSTEM (Page 10):
Install the vent system and exterior termination.
Step 4. FIELD WIRING (Page 11).
a. Millivolt Appliances - Install the operating
control switch (not factory provided). If
installing the optional forced air circulating
blower, bring in electrical service line.
b. Electronic Appliances - Field wire and
install operating control switch.
Step 5. WIRING - OPTIONAL FORCED AIR
BLOWER KIT (Page 12).
Step 6. CONNECTING GAS LINE (Page 12):
Step 7. INSTALLING OPTIONAL OUTSIDE AIR
Make connection to gas supply.
KIT (Page 13)
Step 8. VERIFYING APPLIANCE OPERATION
(Page 14).
Step 9. INSTALLING VOLCANIC STONE,
GLOWING EMBERS, AND LOGS (Page 14).
Step 10. REMOVING AND INSTALLING THE
GLASS DOOR (Page 19).
Step 11. BURNER ADJUSTMENTS (Page 19):
Adjust burner primary air shutter to achieve
proper flame appearance.
Step 12. TESTING VENT OPERATION (Page 21)
Vent operation test and (safety limit) switch
operation.
Step 13. HOOD INSTALLATION (Page 21).
Step 14. FINISHING REQUIREMENTS (Page 21)
Step 15. ATTACHING SAFETY-IN-OPERATION
WARNINGS (Page 22).
DETAILED INSTALLATION STEPS
STEP 1. FRAMING
Frame the appliance as illustrated in Figure 11
on Page 8. All framing details must allow for
a minimum clearance to combustible framing
members as shown in the table on Page 8.
If the appliance is to be elevated above floor
level, a solid continuous platform must be
constructed below the appliance.
NOTE: The framed depth, 16" (406 mm) from
a framed wall, must always be measured from
a finished surface. If a wall covering such as
drywall is to be attached to the rear wall, then
the 16" (406 mm) must be measured from the
drywall surface. It is important that this dimension be exact.
Headers may be in direct contact with the
appliance top standoff spacers, 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.
Secure the fireplace to the side framing members
using the unit’s nailing flanges - one top and
bottom on each side of the fireplace front (see
Figure 9). Use 8d nails or their equivalent.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
FLOOR NAILING TABS
Fireplace may be anchored to floor. Bend down
two anchor tabs (one on each side) located
at the base of the fireplace and secure to the
floor by nailing with 8d nails or equivalent (see
Figure 10).
Figure 9 - Unit Secured to Framing by
Nailing Flange
Figure 10 - Floor Anchor Tabs
NOTE: Some units only have one anchor tab
on each side.
7
Page 8
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
HH
. o N l e d o M
A
t i n U
e z i S
A
g n i m a r F
e z i S
BCDEFGHJ K
. n i5 38 / 1 -5 34 / 1 -5 34 / 1 -9 18 / 5 - 9 17 52 / 1 -4 / 3 - 8 26 14 6 1 / 9 - 68 / 5 - 0 4
m m2 9 85 9 85 9 83 8 48 9 40 6 4 10 3 76 0 42 0 17 6 12 3 0 1
. n i8/ 1 - 0 44 / 1 - 0 44 / 1 - 0 44 28 / 5 - 4 26 1 / 3 1 - 1 66 1 / 1 - 0 36 14 6 1 / 9 - 62 3 / 1 1 - 3 4
m m9 1 0 12 2 0 12 2 0 10 1 65 2 60 7 5 19 7 76 0 42 0 17 6 11 0 1 1
. n i8 / 1 - 0 44 / 1 - 5 44 / 1 - 0 44 28 / 5 - 9 28 / 3 - 6 66 1 / 3 - 3 36 14 6 1 / 9 - 66 1 / 5 1 - 6 4
m m6 4 1 19 4 1 12 2 0 10 1 62 5 76 8 6 13 4 86 0 42 0 17 6 12 9 1 1
MPB33
MPB35
MPB40
MPB45
in.
mm
845
842
33-1/4
845
33-1/4
546
21-1/2
286
11-1/4
1232
48-1/2
616
24-1/4
330
13
102
4
103
4-1/16
872
34-5/16 33-1/8
12-3/4
14-11/16
17-3/16
437
373
324
1146
45-1/8
24-7/8
29-7/8
34-7/8
886
759
632
30-11/16
7-1/16
7-1/16
7-1/16
179
179
179
Back Wall of Chase/Enclosure
*Optional FOAK
Outside
Air Kit
Including Finishing Materials
C
if any
B
Fireplace Framing
K
Corner Installation
Header
A
Back Wall of Chase/Enclosure
Including Finishing Materials
D
C
A
E
if any
G
Rough
Framing Face
(Unfinished Shown)
J
A
Rough Framing Face
(Unfinished Shown)
Outside Chase
Back Wall of Chase/Enclosure
Including Finishing Materials
C
F
A
Inside Chase
if any
G
G
Rough
Framing Face
(Unfinished Shown)
All framing dimensions calculated for 1/2" dry wall at the appliance face. If sheathing the chase or finishing with other thickness materials,
calculations will need to be made.
* Outside air kit - FOAK (without adaptor). See Figure 23 on Page 14.
8
Figure 11 - Framing Specifications
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 9
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
F
E
B
D
C
G
T op View
FRAMING
STANDOFFS
(Top, Sides,
and Rear)
Front View
3 (76)
A
J
H
Flue Outlet For B-V ent Connection
OPTIONAL ELECTRICAL
INLET KNOCKOU T
REQUIRING A FIELD
PROVIDED JUNCTION
BOX (Either Side)
GAS INLET
(Either Side
and bottom )
NOTE - Hood shown
as positioned
in louvered
front model.
ELECTRICAL INLET
2-3/4 x 2 (70 x 51) COVER
PLA TE with KNOCKOUT)
K
1/2 (13)
3 (76)
1-3/8
(35)
(140)
5-1/2
9-3/8
(238)
2
(53)
Right Side View
(140)
5-1/2
9-3/8
(238)
1-3/8
(35)
Left Side View
GAS INLET
(See Also
Right Side View
)
ELECTRICAL INLET
(See Also
Right Side View )
3
(76)
OUTSIDE AIR
SHUTTER
8-15/16
(227)
7-3/8
(187)
ELECTRICAL
INLET
(Optional)
. o N l e d o MA BC DE FG
MPB33
MPB35
MPB40
MPB45
in.
mm
. n i538 / 1 -8 / 1 - 2 39 12 / 1 - 9 25 38 / 1 -8 / - 6 1 / 7 - 25 8-3/4
m m29 86 1 83 8 49 4 72 9 82 3 66 1 37 2 1 222
. n i8/ 1 - 0 48 / 1 - 7 34 22 / 1 - 4 38 / 1 - 0 48 / 7 - 9 21 6 1 / 5 1 - 45 8-3/4
m m9 1 0 13 4 90 1 66 7 89 1 0 19 5 79 7 37 2 1
. n i8 / 1 - 0 48 / 1 - 7 34 22 / 1 - 9 38 / 1 - 5 48 / 7 - 4 36 1 / 7 - 7 16 8-3/4
m m6 4 1 13 4 90 1 63 0 0 16 4 1 16 8 83 4 42 5 1 222
Figure 12 - Fireplace Specifications
STEP 2. ROUTING GAS LINE
Route a 1/2" (13 mm) gas line 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. The appliance,
as set up at the factory, is best suited for use
with a gas line routed from the left side. The gas
line may however be alternately routed from the
right side. All appliances are factory-equipped
with a flexible gas line connector and 1/2" shutoff
valve
(see Step 6 on Page 12).
3"
(76 mm)
Figure 13 - Gas Line Routing
Pipe Coupling
(Recommended)
6-1/2"
(152 mm)
Also see Figure 11.
33-1/8
841 432
765 841
17 30-1/8
27-1/2
33-1/8
699
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, ANSI
Z223.1 (NFPA 54) - latest edition (USA) or CAN/
CGA-B149.1 - latest edition (Canada).
Never use galvanized or plastic pipe. Refer to
Table 6 for proper sizing of the gas supply
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.
NOTES:
• All appliances are factory-equipped with a
flexible gas line connector and 1/2" shutoff
valve (see Figure 21 on Page 13).
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
H
21-1/2
546
24-7/8
621
10-3/4
12-7/16
4
102 273
Schedule 40 Pipe
Length (feet)
Table 6
• 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 on
Page 12).
• 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.
• Check with local building official for local code
requirements.
K
J
6-1/2
13
165
330
16
406
16
2
22
406
16
406
Schedule 40 - Black Iron Pipe
Inside Diameter (Inches)
Natural
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"
Propane
Gas
9
Page 10
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Back View
Of Appliance
*12 ft. Min.
**15 ft. Min.
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.
STEP 3. INSTALLING VENT SYSTEM
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/CGA-B149.1
in Canada.
Ensure clearances are in accordance with
local installation codes and the requirements
of the gas supplier.
Dégagement conforme aux codes d'installation locaux et aux exigences du foumisseunde gaz.
Use only approved vent components (see
Approved Vent Components on Page 2).
Type B-Vent - 4" (102 mm) for MPB33 Models,
5" (127 mm) for MPB35 / 40 Models or 6"
(152 mm) for MPB45 Models
Securing
Screws
Flue Outlet
Collar
Figure 14 - Initial B-Vent Installation
USE ONLY APPROVED B-VENT DIAMETER
MPB33, MPB35, MPB40 and MPB45 series
fireplaces must be vertically vented using
listed type-B, double-walled vent pipe with
the proper diameter as listed below and a
listed vent termination.
Required Pipe Diameter:
MPB33 series: Requires 4" (102 mm)
MPB35 series: Requires 5" (127 mm)
MPB40 series: Requires 5" (127 mm)
MPB45 series: Requires 6" (152 mm)
CAUTION
This appliance cannot be vented
horizontally.
Refer to the vent manufacturers installation
instructions for variations of venting techniques.
If common venting of several units is contemplated, it should be discussed with an architect
and the local Building Department.
Do not place insulation materials within 1" of
the gas vent system.
These fireplaces must be vented vertically to
the outside.
Refer to Figure 14, and slip the first section
of B-Vent over the fireplace flue outlet and
secure with sheet metal screws (# 8 or larger),
then install the remainder of the B-Vent vertically
to the outside. Minimum overall height of the
vent system and appliance must be 10' (2.54
m) vertical with no offset, or 12' (3.7 m) when
an offset up to 45 degrees from the vertical is
used; or 15' (4.6 m) when an offset is greater
than 45 degrees and up to 60 degrees (see
Figure 17).
The offset may start at the fireplace flue collar.
The maximum overall height of the vent system
and appliance should not exceed 40 feet.
Install the B-vent system in accordance with
the vent manufacturer's instructions.
Vertical
Installations
10 ft.
Minimum
Back View
Of Appliance
The maximum overall height of the vent system
and appliance should not exceed 40 feet.
Figure 17 - Vent System Installation
Offset
Installations
*12 ft. Min.
**15 ft. Min.
Back View
Of Appliance
*with an offset up to 45 degrees
** with an offset greater than 45
degrees and up to 60 degrees
10
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 11
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
JUNCTION BOX
If any of the original wire as supplied must be replaced,
E CONTROL KNOB;
SWITCH OR REMOTE CONTROL RECEIVER TO OPERATE UNIT.
STEP 4. FIELD WIRING
CAUTION
The ground supply lead must be
connected to the wire attached to the
green ground screw located on the
outlet box (see wiring diagrams).
Failure to do so will result in a
potential safety hazard. The appliance must be electrically grounded
in accordance with local codes or,
in the absence of local codes, the
National Electrical Code, ANSI/
NFPA 70 - latest edition (in Canada,
the current CSA C22.1 Canadian
Electrical Code).
CAUTION: Label all wires prior to disconnection when servicing controls. Wiring
errors can 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 peuvent entraîner un fonctionnement inadéquat et dangereux.
Verify proper operation after servicing.
S’assurer que l’appareil fonctionne adéquatement une fois l'entretien terminé.
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.
120V AC
B
W
G
OPTIONAL
REMOTE RECEIVER
ON/OFF SWITCH
WALL SWITCH
WIRING COLOR CODE
B = BLACK
BR = BROWN
GY = GRAY
PU = PURPLE
R = RED
P/N 580491-01
Figure 16 - Wiring Diagram - Electronic Gas Valves
HOT
NEUTRAL
GROUND
SAFETY LIMIT SWITCH
B-VENT MODELS ONLY
BL = BLUE
G = GREEN
O = ORANGE
W = WHITE
Y = YELLOW
SCHEMATIC REPRESENTATION ONLY
R
BATTERY HOLDER
AC/DC
POWER
ADAPTOR
Y
G
O
B
CAUTION: ENSURE THAT WIRES ARE POSITIONED AWAY FROM HOT SURFACES AND
SHARP EDGES.
it must be replaced with Type AWM105 ° C – 18 GA. wire.
BK
H C T I W S T I M I L
P T
P T
BK
Thermopile
BK
AB
*OPTIONAL ON/OFF SWITCH,
WALL SWITCH, OR REMOTE
CONTROL RECEIVER
*TWIST WIRES “ A ” AND “ B ” TOGETHER TO OPERATE UNIT
SOLELY BY MANIPULATING THE GAS VALV
OR CONNECT WIRES TO OPTIONAL ON/OFF SWITCH OR WALL
Schematic Representation Only
WT
Figure 17 - SIT Milivolt Wiring
Diagram
See Figure 12 on Page 9
for Optional Electrical Inlet
Knockout Location.
* Field-Provided
Junction Box and
Duplex Receptacle
* Narrow (2-1/8" Wide)
J-Box Required
Figure 18 - Optional J-Box/Outlet Box
(Left Side Shown)
ELECTRONIC PILOT ASSEMBLY
IGNITER ROD
B
Y
G
O
W
BL
PROFLAME DFC BOARD
G
DFC WIRE HARNESS
CPI SWITCH
OFF (O) = INTERMITTENT PILOT MODE
ON (-) = STANDING PILOT MODE
B
PROFLAME VALVE
W
R
PILOT TUBE
SPARK WIRE CABLE
PILOT GROUND WIRE
R
BL
HOOD
Y
B
R
B
H T
H T
FLAME SENSOR
B
PILOT
SENSOR
CABLE
A. Millivolt Wiring (see Figure 18)
Millivolt units are not provided with any factoryinstalled controls; therefore, one of the optional
control switches is required to operate the unit
(ON/OFF Wall Switch, Unit-Mountable ON/OFF
Switch*, Remote Control). See the fireplace
Care and Operation Instructions for details.
[*If using a Unit-Mountable ON/OFF Rocker
Switch with an optional Style View Door,
mount the Rocker Switch on the door instead
of the unit.]
1. If installing an ON/OFF wall switch or
receiver, mount it in a convenient location
on a wall near the fireplace.
2. Wire the control switch within the millivolt
control circuit using the 15 feet of 2
conductor wire supplied with the unit.
NOTE: The supplied 15 feet of 2 conductor wire
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.
CAUTION
In millivolt systems, do not connect
optional control switch to 120 V power
supply.
B. Electronic Wiring
One of the following optional controls also
may be used: ON/OFF Wall Switch, Remote
Control (see fireplace Care and Operation
Instructions for details.).
NOTE: Electronic models must be connected
to the main power supply.
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 12 on Page
9).
3. Remove the cover plate knockout; then
feed the power supply wire through
the knockout opening and into the unit
junction box.
4. See Figure 18. Connect the black power
supply wire to the lower outlet’s red
pigtail lead.
Connect the white power supply wire to
the outlet’s common terminal.
5. Connect the ground supply wire to the
pigtail lead attached to the outlet’s green
ground screw.
NOTE: Remote receiver should be located in the
wall, or if installed in the control compartment,
pulled all the way forward and completely to the
left or right against the corner posts.
(see Figure 18)
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
11
Page 12
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
BLOWER CONTROL CIRCUIT WIRING
6. If wall-mounted ON/OFF control is to be
used, mount it in a convenient location on
a wall near the fireplace.
7. If an optional control is to be used, wire it in
the low voltage circuit as shown in Figure
18.
NOTE: The supplied 15 feet of 2 conductor wire
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.
8. After the wiring is complete, replace the
cover plate.
WARNING
Electronic models of these appliances are equipped with a threeprong (grounding) plug utilized
in connecting the electronic
components to the junction box
in the lower compartment. This
grounding plug provides protection against shock hazard and
should be plugged directly into
the properly grounded threeprong receptacle. DO NOT cut
or remove the grounding prong
from the plug.
STEP 5. WIRING OPTIONAL FORCED
AIR BLOWER KIT
FBK-100, FBK-200, and FBK-250 Kits
(see Figure 18)
An electrical outlet box is provided for the
installation of the FBK-100, FBK-200 and FBK250 forced air blower kits. Electrical power
must be provided to this box to operate these
blowers. Install the blower kits according to the
installation instructions provided with the kits.
NOTE: The tab connecting the two receptacles
of the outlet box must be broken in the
FBK-100 and FBK-200 blower kit applications
(see Figure 19).
120V, 60HZ, 1PH
neerG - dnuorG
Black
White
Green
Plug blower
into this
receptacle
Ground
etihW - lar
t
ueN
Blower
* Wall-mounted
ON/ OFF Blower
Switch or Variable
Speed Control Switch.
120 VAC - Black
Junction Box
Tab Intact
Field Wired
Factory Wired
Tab
Broken
Red
Hot
Side of
Receptacle
Neutral
Side of
Receptacle
Green
Ground
Screw
Figure 19 - Junction Box Wiring
STEP 6. CONNECTING GAS LINE
Make gas line connections. All codes require a
shut-off valve mounted in the supply line. The
orientation of the shut-off valve should face the
front (see Figure 22). Figure 21 illustrates two
methods for connecting the gas supply. The flexline method is acceptable in the U.S.; however,
Canadian requirements vary depending on
locality. Installation must be in compliance
with local codes.
A sediment trap is recommended in the gas
piping within the home to prevent moisture
and debris in the line from damaging the valve.
These appliances are equipped with a gas flex
line for use (where permitted) in connecting the
unit to the gas line. A gas flex line is provided
to aid in attaching the direct vent appliance to
the gas supply. The gas flex line can only be
used where local codes permit. Refer to Figure
21 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.
To access the valve, open the control
compartment access panel. Actuate the spring
loaded magnetic catches securing the panel.
First, gently depress the upper right top corner
of the panel until the magnet catch "pops" the
door free. Then, gently pulling the panel forward,
disengage the left magnet catch and allow the
panel to swing down to open.
The control valves have a 3/8" (10 mm) NPT
thread inlet and outlet side of the valve (refer to
Figure 1 [Millivolt] and Figure 2 [Electronic]
on Page 4).
Secure all joints tightly using appropriate
tools and sealing compounds (ensure propane
resistant compounds are used in propane
applications). Optional: Seal around the gas
line to prevent cold air leakage. Gas line holes
and other openings can be caulked or stuffed
with unfaced fiberglass insulation.
TEST ALL CONNECTIONS FOR GAS LEAKS
(FACTORY AND FIELD)
WARNING
Never use an open flame to
check for leaks.
Turn on gas supply and test for gas leaks, using
a gas leak test solution (also referred to as
bubble leak solution).
NOTE: Using a soapy water solution is
an effective leak test solution but it is not
recommended, because the soap residue
that is left on the pipes/fittings can result in
corrosion over time.
A. Light the appliance (refer to the lighting
instructions label in the control compartment
or in the Care and Operation Instructions
manual).
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 (off/pilot/on) to the “OFF”
position (millivolt units), or turn the receiver,
remote control or control switch to the “OFF”
position (electronic units). Either tighten or
refasten the leaking connection, then retest as
described above.
C. When the gas lines are tested and leak free,
be sure to rinse off the leak testing solution.
12
The gas control valve is located in the lower
control compartment.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 13
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Gas
Stub
1/2" x 3/8" Flare
Shut-Off Valve
3/8" Flex Tubing
3/8" NPT x 3/8"
Flare Fitting
3/8" Nipple
3/8" Union
3/8" Close Nipple
3/8" Shut-Off Valve
1/2" x 3/8"
Reducer
Gas
Valve
Optional Gas Flex Line Connector
Figure 20 - Gas Connection
To open the outside air shutter, open the bottom
control access panel, reach into the control
compartment, and pull the outside air control
lever all the way out. The outside air shutter
should be fully open when the fireplace is in
use and completely closed when the fireplace
is not being used. Closing it when not in use
will prevent outside cold air from entering the
dwelling.
WARNING
DO NOT operate the outside
air control lever with a fire in
the firebox unless a complete
outside combustion air vent
system has been installed with
the appliance.
Outside Air Control Lever
Main Gas
Shut-Off Valve
B-Vent Units Have
A Single Door Latch
Gas Valve
(Optional) Burner
ON/OFF Switch
Figure 21 - Millivolt Gas Valve - Lower Control Compartment
STEP 7. INSTALLING OUTSIDE AIR KIT
Optional outside make-up air kits, Model
FOAK-4 or FAOK-4LD (see Figure 23 on Page
14), may be used with these appliances. Refer
to the installation instructions packaged with
the air kits for specific installation information.
If used, the outside air kit must be installed
before the fireplace is framed and enclosed in
the finished wall.
Outside air drawn into the fireplace supplies
air to the fire for combustion. Only one outside
air duct is necessary, if installed. See Figure 3
on Page 5 for the location of the unit's outside
air inlet.
If additional length of duct is necessary,
purchase locally available U.L. Class 0
or Class 1 metallic ducting. The duct may extend
up to 50' (15.24 m) in any direction.
NOTE: When installing the air duct vertically,
DO NOT terminate the duct closer than 3' below
the chimney top.
Outside supplemental combustion air ducting
may be run upwards or vertically through
framing and ceiling joists, with the hood
installed through an outside wall and 3' (1 m)
below the termination. Ducting may also be run
downward through floor joists and under the
home to a ventilated crawlspace not considered
part of the living area of the home.
NOTE: Do not terminate an outside air kit in the
attic space under any circumstances.
After completing the installation of the optional
outside air vent system the outside air control
lever must be put in service and tested to
ensure proper operation before completing
any enclosure around the firebox. Failure to do
so may result in extensive and costly rework.
Before the operation of the vent system can
be tested, the lever securing screw must be
removed (see Figure 20).
The hand operated outside air control lever is
located on the left side of the fireplace opening
(see Figure 20).
Never locate inlet where it can be
blocked by shrubs, snow drifts,
etc. Never locate inlet in garage
or any area where there is another
fuel burning appliance or products
emitting combustible gases such
as paint, gasoline, etc. In cold
climates, it is recommended the
outside air duct be insulated.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Piezo
CAUTION
Outside Air Control Lever
Securing screw
Air Shutter in Closed Position
Outside Air Control Lever
Outside Air Control Lever
Securing Screw Removed
Air Shutter in Open Position
Figure 22 - Outside Air Control Lever
Operate the actuator through several cycles
including the closed position. Ensuring proper
operation and freedom of movement. Return
the actuator arm to the closed position.
13
Page 14
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Igniter
Thermocouple
Hood Igniter Rod
Thermopile
Pilot
Nozzels
3/8”
(9 mm)
Min
Outside Combustion Air Kits
Cat. No. Model No. Description
81L87 FOAK-4 Combustion Air Kit (w/duct)
81L88 FOAK-4LD Combustion Air Kit (w/o duct)
Figure 23 - Outside Combustion Air
Kits
Step 8. VERIFYING APPLIANCE
OPERATION
With gas line installed, run initial system
checkout before closing up the front of the
unit. Follow the pilot lighting instructions
provided in the Care and Operation Instructions. For piezo igniter location on millivolt
appliances, see Figure 22.
NOTE: Lighting Instructions are also found on
the literature tag tied to the gas piping next to
the gas valve. To access the tag, open the lower
control compartment door (see Figure 22). To
open the control compartment access panel,
actuate the spring loaded magnetic catches
securing the panel. First, gently depress the
upper right top corner of the panel until the
magnet catch "pops" the door free. Then, gently
pulling the panel forward, disengage the left
magnet catch and allow the panel to swing
down to open. When first lighting the appli-
ance, it will take a few 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 logs,
if necessary, handling carefully).
Millivolt Appliance Checkout
The pilot flame should be steady, not lifting
or floating. Flame should be blue in color with
traces of orange at the outer edge.
The top 3/8" (10 mm) at the pilot generator
(thermopile) and the top 1/8" minimum (tip)
of the quick drop out thermocouple should
be engulfed in the pilot flame.
The flame should project 1" (25 mm) beyond
the hood at all three ports (see Figure 24).
Replace logs if removed for pilot inspection.
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).
Figure 24 - Millivolt Pilot
Electronic Appliance Checkout
To light the burner, turn ‘ON’ the wall or remote
control switch. Ensure the igniter lights the
pilot. The pilot flame should engulf the flame
rod as shown in Figure 25.
Pilot
Hood
Flame Rod
Sensor
(sensor)
Figure 25 - Electronic Pilot
STEP 9. INSTALLING VOLCANIC STONE,
GLOWING EMBERS, AND LOGS
Locate the packaged carton of logs (which
were located in the firebox). The decorative
volcanic stone and glowing embers were
packaged separately in plastic bags located
in the control area of the fireplace.
DO NOT attempt to install the logs until the
appliance installation has been completed, the
gas line connected and tested for leaks, and the
initial burner operation has been checked out.
Proper log placement is critical to encourage
outstanding flame appearance and prevent
sooting. When positioned properly as shown,
logs will be positioned between flame peaks
and will not impinge any flames.
Refer to Figure 28 for MPB33 Series
appliances, Figure 29 for MPB35 Series
appliances and Figure 30 for MPB40 and
MPB45 Series appliances.
NOTE: Turn off all electricity to the appliance
before you install volcanic stone, embers
and logs.
WARNING
• .DO NOT attempt to install the
logs until the appliance installation has been completed, the
gas line connected and tested
for leaks and the initial burner
operation has been checked out.
•
.The size and position of the log
set was engineered to give the
appliance a safe, reliable and
attractive flame pattern. Any
attempt to use a different log
set in the fireplace will void
the warranty and will result in
incomplete combustion, sooting, and poor flame quality.
•
.Logs get very hot and will remain
hot up to one hour after gas
supply is turned off. Handle only
when logs are cool. Turn off all
electricity to the appliance before
you install grate, volcanic stone,
embers and logs.
•
.This appliance is not designed
to burn wood. Any attempt to
do so could cause irreparable
damage to the appliance and
prove hazardous to your safety.
•
.If logs are not installed accord-
ing to the log installation
instructions, flame impingement and improper combustion
could occur and result in soot
and/or excessive production
of carbon monoxide (CO), a
colorless, odorless, toxic gas.
14
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 15
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Glowing Embers
Step 1. Remove the appliance front door.
(see Removing the Glass Enclosure Panel on
Page 19).
Step 2. Install decorative volcanic stone
Sprinkle the decorative volcanic stone in a
pleasing pattern. The volcanic stone should
be placed directly on top of the firebox bottom,
along the front and to the back at the right and
left sides of the burner. Position any optional
ceramic fiber liners before placing the stone.
Logs should be positioned after the volcanic
stone.
NOTE: This appliance is provided with enough
glowing embers for several applications, do
not feel compelled to use all that is in a new
bag. For best glowing effect, replace the ember
material annually. Replacement glowing embers
are available (Catalog Number 88L53).
Glowing Embers
Separate into Quarter
Size (separate) Pieces
Bag of Glowing
Embers (rockwool)
Figure 26 - Glowing Embers
Figure 27 - Glowing Embers Placement
Step 4. Placement of Logs - All top logs
that rest on lower logs, do so over notches,
indents or nubs. Proper log placement is
critical to prevent sooting. Logs should be
placed in the gaps between the flame peaks
and should be positioned so they do not
impinge the flames.
Step 5. Position the individual logs as shown
in Figures 28, 29, and 30. Logs should be
placed in the order shown. All logs that have
notches to fit over the grate tines should be
positioned with these notches directly against
the grate. Handle logs carefully to prevent
breakage.
REFERENCE
Cat. No. Model No. Description
88L53 FGE Bag of Glowing Embers
80L42 FDVS Bag of Decorative
Volcanic Stone
Table 7 - Firebox Accessories/Parts
Step 3. Separate the glowing embers (rockwool)
into pieces about the size of a quarter (see Figure
26). Keep the pieces fluffed up, not matted.
Distribute these pieces over the front surface
of the burner, as shown in Figure 27. Do not
use more than is necessary. When properly
positioned, the Glowing Embers will cover
approximately 65% of the front burner and
with no appreciable gaps or openings. Ensure
that the main burner ports remain uncovered
by the ember material.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
15
Page 16
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
MPB33 LOG PLACEMENT
* Item
1
1
2
3
4
3
2
5
6
Description (stamped #)
Log, Rear (39-12)
Log, Left (39-1)
Log, Right (39-2)
Log, Top Center (39-13)
Log, Top/Left (39-3)
Log, Top/Right (39-4)
Catalog Number for the entire log set: 24M15
Position the individual logs as shown below. Logs should be
4
6
5
1
placed in the order shown. Position the rear log on the brackets
at the rear of the firebox with the log's notches directly over the
brackets. Position the right log (log no. 3) by inserting the pin
from the rear log into the hole on its upper end. Place the left log
and then the smaller left and right top logs. All logs that have
notches to fit over the grate tines should be positioned with these
notches directly against the grate. All top logs that rest on lower
logs, do so over flattened mounting faces in the bottom logs.
Proper log and twig placement is critical to encourage outstanding
flame appearance and prevent sooting.
4
3
2
5
6
16
Figure 28 - Log Set 24M15 Placement
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 17
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
MPB35 LOG PLACEMENT
Log
1
3
2
Number Description (Stamped #)
1 Log, Rear (39-5)
2 Log, Left (39-1)
3 Log, Right (39-2)
4 Log, Top Center (39-6)
5 Log, Top/Left (39-3)
6 Log, Top/Right (39-4)
Catalog Number for the entire log set: H6197
4
5
6
Position the individual logs as shown below. Logs should be placed
in the order shown. Position the rear log on the brackets at the rear
of the firebox with the log's notches directly over the brackets.
Position the right log (log no. 3) by inserting the pin from the rear
log into the hole on its upper end. Place the left log and then the
smaller left and right top logs. All logs that have notches to fit over
the grate tines should be positioned with these notches directly
against the grate. All top logs that rest on lower logs, do so over
flattened mounting faces in the bottom logs.
Proper log and twig placement is critical to encourage outstanding
flame appearance and prevent sooting.
1
4 3
2
Figure 29 - Log Set H6197 Placement
5
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
6
17
Page 18
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
MPB40 AND MPB45 LOG PLACEMENT
Log
1
2
3
Number Description (Stamped #)
1 Log, Center (39-8)
2 Log, Rear (138)
3 Log, Right (39-10)
4 Log, Left (39-9)
5 Log, Top/Left (39-11)
6 Log, Top/Right (39-11)
Catalog Number for the entire log set: 24M25
4
5
6
Position the individual logs as shown below. Logs should be placed
in the order shown. Position the center log on the burner first, then
place the glowing embers as shown in Figure 27. Place the rear
log, both the right and left, and then the smaller left and right top
logs. All logs that have notches to fit over the grate tines should
be positioned with these notches directly against the grate. All top
logs that rest on lower logs, do so over flattened mounting faces
in the bottom logs.
Proper log and twig placement is critical to encourage outstanding
flame appearance and prevent sooting.
1
4
3
2
18
Figure 30 - Log Set 24M25 Placement
5
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
6
Page 19
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
STEP 10. REMOVING AND INSTALLING
THE GLASS DOOR
WARNING
• Do not attempt to substitute
the materials used on the door,
or replace cracked or broken
glass.
•
Handle this glass with extreme
care! Glass is susceptible to
damage - Do not scratch or
handle roughly while reinstalling the glass door frame.
•
The glass door of this appliance
must only be replaced as a complete unit as provided by the
manufacturer. Do not attempt
to replace broken, cracked or
chipped glass separately.
•
Do not attempt to touch the front
enclosure glass with your hands
while the fireplace is in use.
WARNING
Do not operate appliance with
the glass front removed, cracked
or broken.
AVERTISSEMENT
Ne pas utiliser l'appareil si le
panneau frontal en verre n'est
pas en place, est craqué ou
brisé.
Only doors certified with the appliance
shall be used.
Removing the Glass Enclosure Panel
(see Figure 31)
Remove the top louver assembly. Open the lower
control compartment door (see Figure 22 on
Page 13) by pressing in simultaneously at the
left and right top corners of the door (the door
is hinged at the bottom).
Remove the bottom compartment door by
sliding the hinge pin, located at the door’s left
side, to the right until it disengages from the
left corner post hole. Pull the door diagonally
to the left, away from the fireplace.
Locate the latch at the top of the control
compartment and disengage it from the door
frame bottom vee-flange, pulling down on the
handle to open it.
Installing the Glass Enclosure Panel
(see Figure 31)
Retrieve the glass door. Visually inspect the
gasket on the backside of the frame. Gasket
surface must be clean, free of irregularities
and seated firmly.
Position the door in front of the firebox opening
with the bottom of the door held away from the
fireplace (see Figure 31 ). Hook the top flange of
the door frame over the top of the firebox frame.
Let the bottom of the door frame swing gently
in towards the fireplace ensuring that the
gasket seats evenly as the door frame draws
shut. Fasten the latch located underneath the
firebox floor to the door's vee-flange. Close the
latch securely.
Top Flange on
Glass Door
Glass Door
Latch
STEP 11. BURNER ADJUSTMENTS
Flame Appearance and Sooting
Proper flame appearance is a flame that is blue
at the base and becomes yellowish-orange in
the body of the flame.
When the appliance is first lit, the entire flame
may be blue and will gradually turn yellowishorange during the first 15 minutes of operation.
If the flame remains blue, or if the flame is
orange with evidence of sooting (black tip), the
air shutter opening may need to be adjusted.
If the air shutter opening is closed too far,
sooting may develop. Sooting is indicated by
black puffs developing at the tips of very long
orange flames. Sooting results in black deposits
forming on the logs, appliance inside surfaces
and on exterior surfaces adjacent to the vent
termination.
Sooting is caused by incomplete combustion in
the flames and lack of combustion air entering
the air shutter opening. To achieve a warm
yellowish-orange flame with an orange body
that does not soot, the shutter opening must be
adjusted between these two extremes.
Air Shutter Adjustment Guidelines
• If there is smoke or soot present, rst check
the log set positioning to ensure that the
flames are not impinging on any of the logs.
If the log set is properly positioned and a
sooting condition still exists, then the air
shutter opening should be increased.
• The more offsets in the vent system, the larger
the air shutter opening will need to be.
• An appliance operated with the air shutter
opened too far, may have flames that appear
blue and transparent. These weak, blue and
transparent flames are termed anemic.
• Propane models may exhibit ames 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.
Seules des portes certifiées pour cet
appareil doivent être utilisées.
WARNING: DO NOT abuse glass door by
striking or slamming shut.
Bottom Vee-flange
Glass Door
NOTE: When installing the glass door,
ensure the spacing on both sides are equal.
Firebox Floor
Figure 31 - Installing or Removing
the Glass Door
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
NOTE: The following chart is provided to aid you
in achieving the correct air shutter adjustment
for your installation.
Air Shutter Adjustment Guidelines
Amount of
Primary Air
If air shutter is
closed too far
If air shutter is
open too far
Flame
Color
Flame will
be orange
Flame will
be blue
Air Shutter
Adjustment
Air shutter
gap should be
increased
Air shutter
gap should be
decreased
19
Page 20
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Adjustment Rod Up
(minimum air
opening position)
Air Shutter
Burner Tube
Adjusting Set Screw
Adjustment Rod Down
(fully open position)
Burner Air Shutter Adjustment
WARNING
• Air shutter adjustment should
only be performed by a
qualified professional service
technician.
• Ensure the front glass panel
is in place and sealed during
adjustment.
• Soot will be produced if the
• The air shutter door and
1. Refer to Figures 32, 33, and 34 for proper
2. Light appliance (follow lighting procedure
3. Allow the burner to operate for at least
• If ame appears weak or sooty, adjust
• If ame remains blue, adjust the air
4. When satisfied that the burner flame appear-
20
CAUTION
air shutter is closed too much.
Any damage due to sooting,
resulting from improperly
setting the air shutter, is not
covered under the warranty.
nearby appliance surfaces
are hot. Exercise caution to
avoid injury while adjusting
flame appearance.
flame appearance. To adjust the flame, refer
to Figure 35 and move the rod up and down
(the adjustment rod is located in the lower
control area). Position the air shutter to the
factory setting as shown in Table 8.
on lighting label in control compartment or
in the Care and Operation Instructions).
15 minutes while observing the flame
continuously to ensure that the proper
flame appearance has been achieved. If the
following conditions are present, adjust
accordingly.
the air shutter, incrementally, to a more
open position until the proper flame
appearance is achieved.
shutter, incrementally, to a more
closed position until the proper flame
appearance is achieved.
ance is normal, reinstall the lower control
compartment door, then proceed to finish
the installation.
Figure 32 - MPB33 MODEL
Figure 33 - MPB35 MODEL
Figure 34 - MPB40 AND MPB45 MODEL
Main Burner Factory Air Shutter
Opening Setting - Inches (millimeter)
Model Natural Gas Propane Gas
MPB33 Fully Closed 3/16" (4.76 mm)
MPB35 Fully Closed 3/16" (4.76 mm)
MPB40 Fully Closed 3/16" (4.76 mm)
MPB45 Fully Closed 3/16" (4.76 mm)
Figure 35 - Air Shutter Opening Setting
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 21
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Lintel Securing Screw
Firebox Top
Limit Switch
Limit Switch/Bracket
Securing Screws
Lintel Securing-Screw
Hole in Cabinet Top
View Without Scoop
Wire
STEP 12. TESTING VENT OPERATION
After appliance installation, perform this vent
operation test to verify that proper venting
conditions exist:
1. Place unit in its normally-operated condition,
with the glass enclosure panel in place.
2. Close all doors and windows in the room.
Turn on all exhaust fans in the building.
3. Light the appliance.
4. Wait fifteen (15) minutes.
5. To check for venting action, start by holding
a smoke producing device within an inch
of one side edge (not top or bottom edge)
of the glass enclosure panel. The smoke
should be drawn toward the edge of the glass
enclosure. Continue the test by moving the
smoke producing device along the entire
length of both side edges of the glass door.
6. If the smoke is not drawn into the firebox,
turn off the appliance and call a qualified
service technician.
RESETTING THE SAFETY LIMIT SWITCH
This appliance is equipped with a manually resettable safety limit switch. Refer to
Figure 37 for its location. If, during appliance
operation, the flame goes out (independently
of the burner on/off wall switch), it may be due
to a blocked vent. If this condition occurs, the
safety limit switch will activate, causing the
fireplace burner to shut off.
To reset the safety limit switch, perform the
following steps.
NOTE: Allow the appliance to cool completely.
7. Remove the top louver panel.
8. Reset the safety limit switch by pushing the
red reset button, located between the wire
terminals on the back of the switch (see
Figure 37, Detail A).
9. The appliance should then relight and remain
lit.
NOTE: If the appliance does not relight, turn
off the appliance and call for a qualified service
technician.
Reinstall the top louver panel.
REPLACING THE SAFETY LIMIT SWITCH
To replace the blocked vent safety limit switch,
refer to Figure 37, Details B & C).
13. Remove the glass enclosure panel by
tilting it outward at the bottom and lifting it
up. Carefully set the door aside to protect
it from inadvertent damage (see Figure 31
on Page 19).
14. Remove the three (3) screws securing the
lintel, and then remove the lintel. One of the
lintel cabinet top holes is shown in Figure
37, Detail B.
15. Remove the three (3) screws securing the
scoop, and then remove the scoop (see
Figure 37, Detail B).
16. Remove the two (2) screws securing
the safety switch bracket, and remove
the switch/bracket assembly, with low
voltage wires attached, through the
side panel slot into the firebox (see Figure
37, Detail C).
17. Replace the switch.
18. Reinstall the switch/bracket assembly.
19. Reinstall the scoop and lintel.
Terminals
Reset Button
Cabinet
Corner
Back Of
Limit
Switch
Door
Frame
Detail A
Firebox Top
Hole in Cabinet Top
Scoop
Scoop Securing Screws
Detail B
20. Reinstall the glass enclosure panel.
21. Raise the bottom control compartment
access panel.
22. The appliance should then relight and remain
lit. If this does not occur, check unit for a
blocked vent condition.
STEP 13. HOOD INSTALLATION
Refer to Figure 36. All models must have
hoods installed prior to operating.
On louvered face units, slide the hood into the
slots on the lower edge of the cabinet top above
the louvered vent (see Figure 36).
STEP 14. 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 (see Figure 11
on Page 8).
See Page 4 for
Cold Climate Insulation and
Page 6 for Clearances.
Combustible
Finished Wall
Materials
Combustible
material may
touch top of
appliance.
Combustible
materials
NOT allowed
below this point
on face
of appliance.
Hood must be installed as shown.
Figure 37 - Louver Face Models
This area must remain
clear of combustible
materials.
Min. 1 in.
(25 mm)
Header
Spacing
Top Standoff
Top of Appliance
Louvers
Top of Door Frame
NOTE: This procedure should only be performed
by a qualified service technician.
10. Turn electrical power off before beginning
this procedure.
11. Lower the bottom control compartment
access panel.
12. Remove the glass enclosure panel by
unfastening the latch (located in the center
of the unit front opening, under the firebox
floor) securing the glass enclosure panel.
Detail C
Blocked Flue Safety Limit Switch Location, Inside
View of Firebox, Top/Right Side Intersection
Figure 36 - Safety Limit Switch
21
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Page 22
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
STEP 15. 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
It is required that the safety instruction labels furnished with the fireplace be affixed to the operation
and control point of the fireplace. A safety instruction
label must be affixed to the wall switch plate where
the fireplace is turned on and off (See Figure A) and
if used on the remote control handheld transmitter
(Figure B). To properly complete the installation of
this fireplace, locate the multi-lingual adhesive labels
provided with the Care and Operation Instructions
and proceed as follows:
1. Locate the wall switch that controls the fireplace
(verify the switch operates the fireplace by turning it on and off). Clean the wall switch plate
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). Choose
the language primarily spoken in the home. If
unknown, affix the English language label.
2. If a remote control is used to control the fireplace,
locate the transmitter and clean it thoroughly
to remove any dust and oils. Affix the label to
the surface of handheld transmitter (Figure B).
Choose the language primarily spoken in the
home. If unknown, affix the English language
label.
3. If you are unable to locate the labels, please call
Lennox Hearth Products or your nearest Lennox
Hearth Products dealer to receive additional
safety instruction labels free of charge.
Cat. No. H8024 Replacement Label Kit
LENNOX HEARTH PRODUCTS
1-800-655-2008
Note: English is red text on clear label. French and
Spanish are white text on black label.
APPOSITION DES MISES EN GARDE RELATIVES
À LA SÉCURITÉ D’UTILISATION
Il est impératif que les étiquettes de sécurité fournies avec
le foyer soient collées à côté des dispositifs de contrôle
du foyer. Une étiquette de sécurité doit être collée sur la
plaque de l’interrupteur contrôlant l’allumage du foyer
(voir Figure A) et, le cas échéant, sur le boîtier de la
télécommande (Figure B). Pour achever l’installation
correcte de ce foyer, procédez comme suit avec les
étiquettes adhésives en langues étrangères fournies
avec les instructions d’utilisation et d’entretien :
1. Repérez l’interrupteur qui contrôle le foyer (vérifiez
que l’interrupteur contrôle le fonctionnement du
foyer en le faisant basculer de Marche à Arrêt, et
vice-versa). Nettoyez soigneusement la plaque
murale de l’interrupteur 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). Choisissez la
langue qui est principalement parlée dans la
résidence du propriétaire. En cas de doute, collez
l’étiquette en anglais.
2. Si une télécommande est utilisée pour contrôler
le foyer, nettoyez la soigneusement pour éliminer
la poussière et les traces de graisse ou d’huile.
Collez l’étiquette sur le boîtier de la télécommande
(Figure B). Choisissez la langue qui est principalement parlée dans la résidence du propriétaire. En
cas de doute, collez l’étiquette en anglais.
3. Si vous ne trouvez pas les étiquettes, veuillez
appeler Lennox Hearth Products ou votre distributeur Lennox Hearth Products local pour recevoir
gratuitement des étiquettes supplémentaires.
Étiquettes de remplacement, n° cat. H8024
LENNOX HEARTH PRODUCTS
1-800-655-2008
Remarque : Le texte anglais est rouge sur un support
transparent. Le texte français et espagnol est blanc
sur un support noir.
COLOCACIÓN DE ADVERTENCIAS DE SEGURIDAD
EN OPERACIÓN
Se requiere que las etiquetas de instrucciones de
seguridad incluidas con la chimenea se coloquen en
el punto de operación y control de la misma. Se debe
colocar una etiqueta de instrucciones de seguridad
en la placa del interruptor de pared desde el cual se
enciende y se apaga la chimenea (ver la Figura A) y
en el transmisor de control remoto (Figura B) si se
usa. Para completar correctamente la instalación de
esta chimenea, encuentre las etiquetas adhesivas
multilingües incluidas con las instrucciones de cuidado
y operación y haga lo siguiente:
1. Identifique el interruptor de pared que controla
la chimenea (verifique que el interruptor opera la
chimenea encendiéndola y apagándola). Limpie bien
la placa del interruptor de pared para quitar el polvo
y aceite. Pegue la etiqueta en la superficie de la placa
del interruptor que controla la chimenea (Figura A).
Seleccione el idioma que más se habla en la casa.
Si no sabe cuál es, use la etiqueta en inglés.
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 B). Seleccione
el idioma que más se habla en la casa. Si no sabe
cuál es, use la etiqueta en inglés.
3. Si no puede encontrar las etiquetas, sírvase llamar a
Lennox Hearth Products o al distribuidor de Lennox
Hearth Products más cercano para recibir etiquetas
de instrucciones de seguridad adicionales gratuitas.
Juego de etiquetas de repuesto - Nº de cat. H8024
LENNOX HEARTH PRODUCTS
1-800-655-2008
Nota: La etiqueta en inglés es transparente con texto
rojo. Las etiquetas en francés y español son negras
con texto blanco.
22
SAFETY LABEL
DIAGRAMS
Illustrations are for example only.
Your accessories may be different.
Les illustrations sont par exemple
uniquement. Vos accessoires
peuvent être différents.
Las ilustraciones son sólo ejemplos.
Tu accesorios pueden ser diferentes.
DIAGRAMMES DES ÉTIQUETTES
DE SÉCURITÉ
Figure A
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
DIAGRAMAS DE ETIQUETAS
DE SEGURIDAD
Figure B
Page 23
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
GAS CONVERSION KITS
WARNING
This conversion kit shall be installed by a qualified service agency in
accordance with the manufacturer’s instructions and all applicable codes
and requirements of the authority having jurisdiction. If the information in
these instruction is not followed exactly, a fire, explosion or production of
carbon monoxide may result causing property damage, personal injury
or loss of life. The qualified service agency is responsible for the proper
installation 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 instructions supplied with the kit. The qualified service agency
performing this installation assumes responsibility for this conversion.
AVERTISSEMENT
Cette trousse de conversion doit être installée par un technicien agréé,
selon les instructions du fabricant et selon toutes les exigences et tous les
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’explosion ou la production de monoxyde de carbone pouvant
causer des dommages matériels, des blessures ou la mort. Le tecnicien
agréé est responsable de l’installation de cette trousse. L’installation n’est
pas adéquate ni complète tant que le bon fonctionnement de l’appareil
converti n’a pas été vérifié selon les instructions du fabricant fournies avec
la trousse. Le fournisseur de service qualifié ayant réalisé l'installation
assume les responsabilités liées à la conversion.
In Canada:
THE CONVERSION SHALL BE CARRIED OUT IN ACCORDANCE WITH THE
REQUIREMENTS OF THE PROVINCIAL
AUTHORITIES HAVING JURISDICTION
AND IN ACCORDANCE WITH THE REQUIREMENTS OF THE CAN/CGA-B149.1
INSTALLATION CODE.
LA CONVERSION DEVRA ÊTRE
EFFECTUÉE CONFORMÉMENT AUX
RECOMMANDATIONS DES AUTORITÉS PROVINCIALES AYANT JURIDICTION ET CONFORMÉMENT AUX EXIGENCES DU CODE D'INSTALLATION
CAN/CGA-B149.1.
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 complete the
task including labeling that must be affixed to
ensure safe operation.
Kit part numbers are listed here and the following steps detail the conversion procedure. Refer
to the instructions provided with the conversion
kit when performing any gas conversion.
INSTALLATION INSTRUCTIONS
Step 1. TURN OFF THE GAS SUPPLY TO THE
APPLIANCE and disconnect power supply at
the circuit breaker. Ensure appliance is cold.
CAUTION: THE GAS SUPPLY SHALL BE
SHUT OFF PRIOR TO DISCONNECTING THE
ELECTRICAL POWER, BEFORE PROCEEDING
WITH THE CONVERSION.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Millivolt SIT Systems
Natural Gas To Propane Gas
Conversion Kits
Models Cat. No.
MPB33 H2009
MPB35 H2011
MPB40 H2013
MPB45 H2015
Millivolt SIT Systems
Propane Gas to Natural Gas
Conversion Kits
Models Cat. No.
MPB33 H8849
MPB35 H8850
MPB40 H8851
MPB45 H8852
Electronic SIT Systems
Natural Gas To Propane Gas
Conversion Kits
Models Cat. No.
MPB33 H8632
MPB35 H8634
MPB40 H8636
MPB45 H8638
Electronic SIT Systems
Propane Gas To Natural Gas
Conversion Kits
Models Cat. No.
MPB33 H8845
MPB35 H8846
MPB40 H8847
MPB45 H8848
ATTENTION: AVANT D’EFFECTUER
LA CONVERSION, COUPEZ D’ABORD
L’ALIMENTATION EN GAZ, ENSUITE,
COUPEZ L’ALIMENTATION ÉLECTRIQUE.
Step 2. Open the lower control compartment
door (see Figure 22 on Page 13) by pushing
on the right top corner of the door (the door is
hinged at the bottom).
[Optional] Remove the control compartment
door by sliding the hinge pin, located at the
door’s left side, to the right until it disengages
from the left corner post hole. Pull the control
compartment door diagonally to the left, away
from the fireplace.
Step 3. Remove the front glass door/frame
from the appliance (see Page 19).
Step 4. Carefully remove the logs. Exercise
care so as not to break the logs.
Step 5. Refer to Figures 28, 29, or 30.
A. Remove the grate and sub floor.
B. Remove the two (2) screws securing the
burner assembly.
C. Remove the burner assembly with attached
venturi tube.
MILLIVOLT AND ELECTRONIC IGNITION
SYSTEM APPLIANCES
Step 1. SIT Systems - Refer to Figure 38 and
the instructions provided with the SIT Regulator Conversion Kit. Using a Torx T20 driver
to remove and discard the pressure regulator
mounting screws (two screws for electronic
models, three screws for millivolt models),
pressure regulator tower, the diaphragm assembly (if applicable) and the spring. Discard
all removed components.
23
Page 24
LENNOX HEARTH PRODUCTS • MERIT PLUS® B-VENT GAS FIREPLACES (MPB33/35/40/45) • INSTALLATION INSTRUCTIONS
Pressure
Regulator
Remove
These
Components
Pilot
Orifice
Step 2. Install the new pressure regulator
assembly using the supplied screws. Tighten
the screws with a torque of 25 lb-in.
Millivolt Valve
Electronic Valve
Figure 38 - Regulator Conversion
Step 3. Install the enclosed identification label
to the valve body where it can be easily seen.
Step 4. Refer to Figure 39. Remove the pilot
hood assembly to access the hexed pilot orifice.
Remove and replace the orifice with the one
provided with the kit. Exercise extreme care to
prevent damage to or breakage of the igniter
assembly. Step 5. Remove the burner orifice
from the manifold and replace it with the one
provided in the kit. See Table 8 for orifice sizes
for natural and propane models. Figure 40
illustrates the orifice.
Figure 39 - Millivolt Pilot
Figure 40 - Orice
Use pipe joint compound or Teflon tape on all
pipe fittings before installing (ensure propane
resistant compounds are used in propane
applications, do not use pipe joint compounds
on flare fittings).
Step 6. Retrieve the burner and hold the venturi
tube above the orifice. Set the burner assem bly
into position and secure with the two screws
previously removed.
Step 7. Reassemble the remaining components
by reversing the procedures outlined in the
Steps 1 - 5.
Step 8. Attach the conversion label provided
in the conversion kit next to the rating plate on
the appliance.
Step 9. Turn on gas supply and test for gas
leaks (refer to Page 12).
Step 10. Reapply electrical power at the circuit
breaker.
Step 11. Relight the main burner. The lighting
instructions can be found on the lighting label
in the control compartment or in the Care and
Operation Manual provided with the appliance.
Verify proper burner ignition and operation.
See Burner Adjustments and Burner Flame
Appearance on Pages 19 and 20.
Step 12. Inspect the pilot system for proper
flame. The pilot flame should engulf the flame
sensor as shown in Figures 24 and 25 on
Page 14.
Step 13. Using a manometer, test the inlet and
manifold gas pressures (see Tables 2 and 3
on Page 4).
ALWAYS TEST PRESSURES WITH THE VALVE
REGULATOR CONTROL AT THE HIGHEST
SETTING.
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-1372 meters)
Model
Series
MPB33
MPB35
MPB40
MPB45
Table 8
Nat.Gas
drill size (inches)
#47 (0.0785")*
99K74 •
#44 (0.086")*
60J80 •
#38 (0.102")*
99K76 •
#37 (0.104")*
24M10 •
* Standard size installed at factory
• Part /Cat. Number
Propane
drill size (inches)
(0.048")*
99K78 •
#55 (0.052")*
19L52 •
(0.062")*
21L01 •
#52 (0.0635")*
37G00 •
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.
LENNOX®, the LENNOX design, DAVE LENNOX, the image of DAVE LENNOX and other related
LENNOX marks are registered or common law trademarks of Lennox Industries Inc. and are used
with permission.
Printed in U.S.A. © 2012 Lennox Hearth Products LLC
P/N 506015-05 Rev. D 04/2013
1508 Elm Hill Pike, Suite 108 • Nashville, TN 37210
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