
– Do not store or use gasoline or other fl ammable
vapors and liquids in the vicinity of this or any
– WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use
• Immediately call your gas supplier from a
• If you cannot reach your gas supplier, call the
– Installation and service must be performed by
WARNINGS
WARNINGS
WARNINGS

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Firebox External Dimensions
Minimum Hearth Dimensions
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the absence of local codes, with the
box enclosures for gas-fi red unvented decorative room
heater, and annual cleaning are necessary to avoid
potential problems with sooting. Sooting, resulting from
improper installation or operation, can settle on surfaces
Candles, incense, oil lamps, etc. produce
these types of products. In addition, the smoke and/or
to minimize the use of candles, incense, etc. while the
vent-free appliance is in operation.
room in which it is installed. Provisions for adequate
Please leave these instructions with the owner.
Please retain these instructions for future reference
1. Due to high temperatures, the appliance should
be located out of traffi c and away from furniture
2. Children and adults should be alerted to the hazard
to avoid burns or clothing ignition.
3. Young children should be carefully supervised
4. Do not place clothing or other fl ammable material
5. Any safety screen or guard removed for servicing
6. Installation and repair should be done by a qualifi ed
7. To prevent malfunction and/or sooting, an unvented
imperative that control compartments, burners and
headaches, dizziness and/or nausea. If you have these
for use with this heater where applicable.
WARNING

They are not intended to be a primary heating appli-
In most homes of average construction, this does not pose
harmful but may produce annoying smoke and smells
irritation. This is a normal and temporary occurrence.
The initial break-in operation should last two to three
hours with the burner at the highest setting. Provide
maximum ventilation by opening windows or doors to
initial break-in period will be slight and will disappear
piping system by closing its equipment shutoff valve
to inspect the room heater and to replace any part of the
room heater is installed.
vent the fi rebox from coming in contact with combustible
We suggest that our gas hearth
WARNING

The LCUF36 is a vent-free fi reboxe. They feature a self contained heat-circulating system. This installation manual will
Do not alter or modify the fi rebox or its components under any circumstances. Any modifi cation or alteration of the fi rebox
1. Vent-Free Gas Firebox 3. Installation and Operating Instructions
2. Canopy 4. Five (5) sheet metal screws for canopy
WHAT YOU WILL NEED FOR INSTALLATION
Piping complying with local codes
• Wall fi nishing materials
Refer to the installation instructions provided with the log sets for items required for log set installation.
WARNING
NOTICE

D
F
E
H
63/4"
13/8"
32"
321/2"
21/2"
21/2"
431/2"
40"
2" Knockout
95/8"
C
B
A
In planning the installation for the appliance it is necessary to determine where the unit is to be installed and whether optional
installation. Each installation is unique, however, and might require a different sequence.
4. Complete fi nish wall material, surround and optional hearth extension to your individual taste.

vent-free fi rebox. The following factors should be taken
• Clearance to side wall, ceiling, woodwork and
page 8. Minimum clearances to combustibles
• Location must not be affected by drafts caused by
kitchen exhaust fans, ceiling fans, return air registers
• Installation must provide adequate ventilation and
DO NOT INSTALL THIS FIREBOX IN A BED-
• Location should be out of high traffi c or windy or
DO NOT INSTALL WHERE CURTAINS, FURNITURE, CLOTHING OR OTHER FLAMMABLE OBJECTS
ARE LESS THAN 42" FROM FRONT OF HEATER.
• Never obstruct the front opening of the vent-free fi rebox or restrict the fl ow of combustion and ventilation air.
• Minimize modifi cations to existing construction. Refer to Figure 3 below for location suggestions.
• Do not install in the vicinity where gasoline or other fl ammable liquids may be stored. The vent-free fi rebox must be
kept clear and free from these combustible materials.

9"
Minimum
42"
Minimum
9"
Minimum
Ensure that minimum clearances shown in Figures 4 through 7 are maintained. Left and right clearances are determined
Follow these instructions carefully to ensure safe installation. Failure to follow these requirements may create a
The clearance from the inside of the appliance to any combustible wall should not be
The ceiling must be at least 42” from the top of the fi rebox opening.
The appliance may be placed against a combustible back wall.

The canopy supplied with the unit must be installed. If a combustible mantel is installed, it must
meet the clearance requirements as shown in
This inner chamber fi rebox fl oor must be installed at least 1
rial, such as carpeting or asphalt tile, which is closer than 14" to the base of the fi rebox.
The inner chamber fi rebox fl oor may be installed nearer to the fl oor if a minimum of 14" of noncombustible material

Firebox framing can be built before or after the appliance is set in place. Construct fi rebox framing following
The framing headers may rest on the top of the fi rebox standoffs.
The fi rebox may be installed directly on a combustible fl oor or raised on a platform of an appropriate height. When the
installed on a metal or wood panel extending the full width and depth of the enclosure.
WARNING

2. Slide the fi rebox into prepared framing or position fi rebox in its fi nal position and frame later.
3. Level the fi rebox by checking the top edge of the fi rebox. Shim if necessary.
4. Anchor fi rebox to the side framing members using 8d nails or other suitable fasteners.
5. The canopy must be installed for safe operation of the heater. See page 13 for canopy installation details.
When fi nishing a custom cabinet, mantel, or other built-in enclosure, the open-
ing size to accommodate the fi replace with trim installed is as follows:
full consideration to the clearance
WARNING
This appliance is approved for the installation of drywall or other combustible
materials against the sides or top of the black-painted fi rebox face.
Noncombustible facings will not burn when exposed to heat coming off this
mortar, stone or marble. These are safe to overlay the black-painted metal face

the latest edition of the National Fuel Gas Code ANSI Z223.1/NFPA54.
recessed fl ush into the wall or fl oor. The valve should be controlled by a removable valve key for safety.
An ANSI approved manual shut-off valve, union and plugged
A sediment trap may be upstream of the heater to prevent moisture and contaminants from passing through trap to the heater
An external regulator must be used on all propane/L.P.G. heaters, in addition to the regulator fi tted to the heater, to reduce
the supply tank pressure to 13" w.c. (maximum). Any copper tubing used to supply propane / L.P.G. from the tank must be
After completing connection, test all gas joints from the gas meter to the gas heater regulator for leaks. Using soap and
WARNING
WARNING
WARNING

A canopy is furnished with each fi rebox and
be installed for safe operation.
1. Remove the three (3) screws from the top front frame assembly. Also remove the two (2) screws on the side frames.
2. Align the canopy with the holes in the top frame.
3. Replace the screws previously removed.
4. Tighten side screws. Make sure the canopy is level and
that may be provided with the unvented
WARNING
WARNING

The optional wide canopy can be installed. See installation instructions provided with kit.
1 Standard Brass Canopy 1 BRCU36
1 Wide Brass Canopy 1 BRC36
4 Brass Trim Curved Design 1 BRTKM36
4 Pewter Trim Curved Design 1 PWTKM36
1 Standard Brass Canopy 1 BRCU36
1 Wide Brass Canopy 1 BRC36
4 Brass Trim Curved Design 1 BRTKM36
4 Pewter Trim Curved Design 1 PWTKM36

June 2004 P/N 26D4721 • Rev. 1
The following components are warranted for life to the original owner, subject of proof of purchase: Firebox,
The following components are warranted for 5 years to the original owner, subject of proof of purchase: Vent
Free Ceramic Fiber Logs, Catalytic Filter and Aluminized Burners.
Monessen Hearth Systems (MHS) warrants the components and materials in your gas appliance to be free from
manufacturing and material defects for a period of two years from date of installation. After installation, if any of
the components manufactured by MHS in the appliance are found to be defective in materials or workmanship,
MHS will, at its option, replace or repair the defective components at no charge to the original owner. MHS
two years from the date of installation. Any products presented for warranty repair must be accompanied
by a dated proof of purchase.
This Limited Lifetime Warranty will be void if the appliance is not installed by a qualifi ed installer in accordance
the installation thereof by unqualifi ed installers, (2) the costs of removal, reinstallation or transportation of
by an authorized service representative.
This warranty is expressly in lieu of other warranties, express or implied, including the warranty of merchantability
that do not allow limitations on how long an implied warranty lasts, or do not allow exclusion of indirect
MHS reserves the right to investigate any and all claims against the Limited Lifetime Warranty and decide
upon method of settlement.
For information about this warranty, contact: