
2NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
CONGRATULATIONS!
In selecting this Lennox B-Vent Gas Appliance you have chosen the finest and most
dependable fireplace to be found anywhere. A beautiful, prestigious, alternative to a
wood burning fireplace. Welcome to a Family of tens of thousands of satisfied Lennox
Fireplace Owners.
Please read and carefully follow all of the instructions found in this manual. Please pay
special attention to the safety instructions provided in this manual. The Homeowner's
Care and Operation Instructions included here will assure that you have many years of
dependable and enjoyable service from your Lennox product.
INTRODUCTION
Installation must conform to local codes. In
the absence of local codes, installation must
complywiththecurrentNationalFuel GasCode,
ANSIZ223.1(NFPA54).(InCanada,thecurrent
CAN/CGA B149 installation code). Electrical
wiring must comply with local codes. In the
absence of local codes, installation must be in
accordance with the National Electrical Code,
NFPA70-(latestedition).(InCanada,thecurrent
CSA C22.1 Canadian Electric Code).
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.
TABLE OF CONTENTS
Introduction ......................................Page 2
General Information..........................Page 2
Operation/Care of Your Appliance .....Page 3
Variable Flame Adjustment................Page 4
Outside Combustion Air Control .......Page 5
Manual Limit Switch .........................Page 5
Maintenance Schedule......................Page 6
Maintenance......................................Page 7
Front Glass Enclosure Panel,
Removal and Installation...............Page 7
Burner Adjustments..........................Page 8
Millivolt Appliance Checkout.............Page 8
Electronic Appliance Checkout..........Page 8
Logs, Rockwool, Vermiculite &
Volcanic Stone Placement.............Page 9
Wiring Diagrams...............................Page 14
Warranty ...........................................Page 14
Replacement Parts............................Page 14
Product Reference Information.........Page 14
Accessory Components ....................Page 15
Lighting Instructions – Millivolt ........Page 18
Lighting Instructions – Electronic .....Page 20
Troubleshooting Guide – Millivolt .....Page 22
Troubleshooting Guide – Electronic ..Page 22
Replacement Parts List.....................Page 24
Themillivoltappliancesaredesigned tooperate
on either natural or propane gas. A millivolt
gas control valve with piezo ignition system
provides safe, efficient operation. External
electrical power is required to operate the
optional electrically powered components, if
installed. Electricalpowermustbewiredduring
appliance installation.
The electronic appliances are designed to
operate on either natural or propane gas. An
electronic intermittent pilot system provides
safe, efficient operation. External electrical
power is required to operate these units.
These appliances comply with National Safety
Standards and are tested and listed by OMNI-
TestLaboratories,Inc.(ReportNo.116-F-__-__)
to ANSI Z21.50 (in Canada, CSA 2.22), and
CAN/CGA-2.17-M91 in both USA and Canada,
as vented gas fireplaces.
GENERAL INFORMATION
Note: Installation and repair should be
performed by a qualified service person. The
appliance should be inspected annually by a
qualified professional service technician. More
frequent inspections and cleanings may be
required due to excessive lint from carpeting,
bedding material, etc. It is imperative that the
control compartment, burnersandcirculating air
passage ways of the appliance be kept clean.
S'assurer que le brùleur et le compartiment des
commandes sont propres. Voir les instructions
d'installation et d'utilisation qui accompagnent
l'appareil.
Provide adequate clearances around air open-
ings and adequate accessibility clearance for
service and proper operation. Never obstruct
the front openings of the appliance.
Due to high temperatures the appliance should
belocatedout of trafficandaway fromfurniture
and draperies. Locate furniture and window
coverings accordingly.
Millivolt Models with
Manually-Modulated Gas Valve
Natural Gas Propane Gas
Model Input Rate
(BTU/HR) Input Rate
(BTU/HR)
MPB3328 13,500 to 17,500 13,500 to 17,500
MPB3530 16,000 to 20,000 16,500 to 20,000
MPB4035 24,000 to 30,000 22,300 to 28,000
MPB4540 24,750 to 31,000 23,000 to 29,000
Table 1
Electronic Models -
Electronic models have a fixed rate gas valve.
Input of electronic models is shown in Table 2:
Electronic Models with
Fixed-Rate Gas Valve
Natural Gas Propane Gas
Model Input Rate
(BTU/HR) Input Rate
(BTU/HR)
MPB3328 17,500 17,500
MPB3530 20,000 20,000
MPB4035 30,000 28,000
MPB4540 31,000 29,000
Table 2
These appliances are designed to operate on
natural or propane gas only.
Inputofmillivoltmodelsisvariable.These rates
are shown in Table 1:
Maximummanifoldpressureis3.5in.w.c.(0.87
kPa) for natural gas and 10 in. w.c. (2.49 kPa)
for LP/Propane gas.
Do not use these appliances if any part has been
under water. Immediately call a qualified, profes-
sional service technician to inspect the appliance
andtoreplace anypartsof the controlsystemand
any gas control which have been under water.
Table 3 shows the units' orifice size for the
elevations indicated.
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-1372 meters)
Models NaturalGas
drill size (inches) Propane Gas
drill size (inches)
MPB-3328 #47 (.0785") 1.2mm (.048")
MPB-3530 #44 (.086") #55 (.052")
MPB-4035 #37 (.104") 1/16"
(.0625")
MPB-4540 #36 (.1065") #52
(.0635")
Table 3
WARNING
Improper installation, adjustment,
alteration, service or maintenance
can cause injury or property
damage. Refer to this manual. For
assistanceoradditionalinformation
consultaqualifiedinstaller,service
agency or the gas supplier.
WARNING
These fireplaces are vented deco-
rative gas appliances. Do not burn
wood or other material in these
appliances.