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LENNOX HEARTH PRODUCTS • MERIT
®
PLUS DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • CARE AND OPERATION INSTRUCTIONS
Safety and
Your Fireplace
To prevent severe burns and injuries, install
a screen or physical barrier to prevent direct
contact with the glass.
To order a FREE Lennox
®
SAFETY GUARD
for your fireplace, see details at left.
Follow the safety instructions below
and be sure everyone in your household
understands this burn hazard:
• The surfaces on your fireplace get
EXTREMELY HOT!
• The glass on the front
of the fireplace reaches
EXTREMELY HIGH
temperatures and can
cause severe burns if touched.
• Keep children away from an operating
fireplace. Closely supervise children in
any room where a fireplace is operating
to prevent contact with glass.
• Keep clothing, furniture,
gasoline, and other
flammable liquids away
from the fireplace.
• Even after the gas is turned off, fireplace
surfaces remain extremely hot.
Be sure to attach the enclosed Safety-in-
Operation Warnings where you turn on your
fireplace, to help remind everyone of the
dangers associated with high temperatures
(see page 5).
Read Important Safety Information on
page 4.
All parts of your Lennox
Hearth Products fireplace
get EXTREMELY HOT!
Table of Contents
Safety and Your Fireplace. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Important Safety Information .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Attaching the Safety-in-Operation Warnings . . . . . . . . . . . . . . . . . . . . . . . . . 5
Appliance Installation, Service, and Maintenance Notices . . . . . . . . . . . . . . . . . 6
Appliance Operation Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
BTU Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Gas Pressure Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Orifice Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Burn-In Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Operation/Care of Your Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Gas Controls Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Variable Flame Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Front Glass Enclosure Panel, Removal and Installation . . . . . . . . . . . . . . . . . . 11
Install Volcanic Stone, Embers and Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Burner Flame Appearance/Sooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Burner Flame Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Millivolt Appliance Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Electronic Appliance Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Ordering Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Product Reference Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Fireplace Shipping Weights/Volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Accessory Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Maintenance Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Lighting Instructions – Millivolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Lighting Instructions – Electronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Troubleshooting Guide – Millivolt Gas Control System . . . . . . . . . . . . . . . . . . 30
Troubleshooting Guide – Electronic Gas Control System . . . . . . . . . . . . . . . . . 31
Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
•
FREE
SAFETY GUARD
OFFER
•
The Lennox
®
SAFETY GUARD protects against
severe burns and injuries by preventing direct contact
with the front glass surface of your fireplace.
To receive your FREE SAFETY GUARD, call 1-800-786-7976
or visit
www.lennox.com (Hearth / Owner Resources).
Note: Safety Guards may not be available for some
older models that are no longer in production.
Thank you for your purchase. We appreciate your business!
Please carefully read and follow all instructions in this manual.
Pay special attention to all warnings and safety information.
Following these safety, care, and operation instructions will help ensure
many years of dependable and enjoyable service from your fireplace.
Register your product online today!
To help us keep you up-to-date on product information and offers,
please take a few moments to register your product online at
www.lennox.com (Hearth / Owner Resources)
.