Monessen Hearth LSTF36-B Operating instructions

Installation & Owner’s Manual
Installation, Care, and Operation
INSTALLER: Leave this manual with party responsible for use and operation.
OWNER: Retain this manual for future reference.
VENT FREE FIREBOX
Model(s):
LSTF36-B
NOTICE: DO NOT discard this manual!
• DO NOT store or use gasoline or other am-
mable vapors and liquids in the vicinity of this
or any other appliance.
• DO NOT overre. Overring will void your
warranty.
• Comply with all minimum clearances to com-
bustibles as specied. Failure to comply may
cause house re.
WARNING: If the information in these
instructions is not followed exactly, a re
or explosion may result causing property
damage, personal injury, or death.
WARNING
HOT SURFACES!
Glass and other surfaces are hot during
operation AND cool down.
Hot glass will cause burns.
• DO NOT touch glass until it is cooled
• NEVER allow children to touch glass
• Keep children away
• CAREFULLY SUPERVISE children in same room as
replace.
• Alert children and adults to hazards of high temperatures.
High temperatures may ignite clothing or other ammable
materials.
• Keep clothing, furniture, draperies and other ammable
materials away.
Carefully review the instructions supplied
with the decorative type unvented room
heater for the minimum fireplace size
requirement.
DO NOT INSTALL AN APPLIANCE IN THIS
FIREBOX UNLESS THIS FIREBOX MEETS
THE MINIMUM DIMENSIONS REQUIRED
FOR THE INSTALLATION.
Installation and service of this appliance should be performed by
qualied personnel. Hearth & Home Technologies recommends
HHT Factory Trained or NFI certied professionals.
For use with a listed gas-red unvented
decorative room heater not to exceed 40,000
BTU/hr. Do not build a wood re.
1
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

Safety Alert Key:
• DANGER! Indicates a hazardous situation which, if not avoided will result in death or serious injury.
• WARNING! Indicates a hazardous situation which, if not avoided could result in death or serious injury.
• CAUTION! Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.
• NOTICE: Indicates practices which may cause damage to the replace or to property.
Table of Contents
Installation Standard Work Checklist 3
1 Welcome
A. Congratulations 4
B. LIMITED LIFETIME WARRANTY 5
2 Important Safety and Operating Information 7
3 General Installation Information
Before You Start 9
Check Parts 9
Tools Needed for Installation 9
4 Firebox and Framing Dimensions
Dimensions 10
5 Hearth Dimensions and Firebox Locations
Hearth Dimensions 12
Firebox Locations 12
6 Clearances 13
7 Fireplace, Canopy and Gas Line Installation
Securing and Leveling the Appliance 15
Canopy Installation 15
Gas Connections 16
8 Combustion Air
Install Model AK22 Combustion Air Assembly 17
9 Optional Equipment
Forced AIr Kit 19
Refractory 19
Accent Light Kit 19
Optional Door Kit 19
10 Service Parts
Service Parts Lists 20
2Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

Customer:
Lot/Address
Model (circle one): LSTF36-B
YES IF NO, WHY?
Dealer/Distributor Phone #
Serial #:
Fireplace Install
ATTENTION INSTALLER:
Follow this Standard Work Checklist
This standard work checklist is to be used by the installer in conjuction with, not instead of, the instructions contained in this installation
manual.
Date Installed:
Location of Fireplace:
Installer:
WARNING! Risk of Fire or Explosion! Failure to install fireplace acording to these instructions can lead to a fire or
explosion.
Wiring has been installed if necessary. Verified
clearances to combustibles. (Pg. 12)
Fireplace is leveled and secured. (Pg. 14)
Hearth extension size/height decided. (Pg. 12)
Outside air kit installed. (Pg 16) Optional
Comments communicated to party responsible
4613-902 • Rev A• 4/18
• Photographing the installation and copying this checklist for your file.
Combustible materials not installed in non-combustible areas.
(Builder/Gen. Contractor) (Installer) (Date)
Comments: Further description of the issues, who is responsible (Installer/Builder/Other Trades, etc.) and corrective action needed:
• That this checklist remain visible at all times on the fireplace until the installation is complete.
__________________________ by ______________________on _________
Hearth extension installed per manual requirements.
Verified all clearances meet installation manual requirements.
Mantels and wall projections comply with installation manual requirements.
Hearth & Home Technologies recommends the following:
Finishing
Fireplace Setup
All packaging and protective materials removed.
Refractory installed correctly.
Firescreen installed properly.
Manual bag and all of its contents are removed from the fireplace and given to the party
responsible for use and operation.
Blower kit installed properly. (Optional)
Light kit installed properly. (Optional)
Door kit installed properly. (Optional)
3
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

Read this manual before installing or operating this replace.
Please retain this manual for future references.
A. Congratulations
Congratulations on selecting a Monessen Hearth gas re-
box. It is designed to provide the utmost in safety, reliability,
and efciency.
As the owner of a new replace, you'll want to read and
carefully follow all of the instructions contained in this man-
ual. Pay special attention to all Cautions and Warnings.
This manual should be retained for future reference. We
suggest that you keep it with your other important docu-
ments and product manuals.
Your new Monessen vent free replace will give you years
of durable use and trouble-free enjoyment. Welcome to the
Monessen family of replace products!
Monessen is a registered trademark of Hearth & Home
Technologies.
Brand: ________________________________________________ Model Name: ___________________________
Serial Number:__________________________________________ Date Installed: __________________________
Fireplace Information:
Local Dealer Information
DEALER: Fill in
your name, address,
phone and email
information here and
replace information
below.
Dealer Name: ________________________________________________________
Address: ____________________________________________________________
____________________________________________________________
Phone: _____________________________________________________________
Email: _____________________________________________________________
1 Welcome
4Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

B. LIMITED LIFETIME WARRANTY
X Molded refractory panels
4021-645H 10/15 Page 1 of 2
Hearth & Home Technologies
LIMITED LIFETIME WARRANTY
Hearth & Home Technologies, on behalf of its hearth brands (“HHT”), extends the following warranty for HHT
gas, wood, pellet, coal and electric hearth appliances that are purchased from an HHT authorized dealer.
WARRANTY COVERAGE:
HHT warrants to the original owner of the HHT appliance at the site of installation, and to any transferee taking ownership
of the appliance at the site of installation within two years following the date of original purchase, that the HHT appliance
will be free from defects in materials and workmanship at the time of manufacture. After installation, if covered compo-
nents manufactured by HHT are found to be defective in materials or workmanship during the applicable warranty period,
HHT will, at its option, repair or replace the covered components. HHT, at its own discretion, may fully discharge all of its
obligations under such warranties by replacing the product itself or refunding the verified purchase price of the product
itself. The maximum amount recoverable under this warranty is limited to the purchase price of the product. This warranty
is subject to conditions, exclusions and limitations as described below.
WARRANTY PERIOD:
Warranty coverage begins on the date of original purchase. In the case of new home construction, warranty coverage
begins on the date of first occupancy of the dwelling or six months after the sale of the product by an independent,
authorized HHT dealer/ distributor, whichever occurs earlier. The warranty shall commence no later than 24 months
following the date of product shipment from HHT, regardless of the installation or occupancy date. The warranty period for
parts and labor for covered components is produced in the following table.
The term “Limited Lifetime” in the table below is defined as: 20 years from the beginning date of warranty coverage for
gas appliances, and 10 years from the beginning date of warranty coverage for wood, pellet, and coal appliances. These
time periods reflect the minimum expected useful lives of the designated components under normal operating conditions.
See conditions, exclusions, and limitations on next page.
Parts Labor Gas Wood Pellet EPA
Wood
Coal Electric Venting
XXXXXXX
All parts and material except as
covered by Conditions,
Exclusions, and Limitations
listed
XXX
Igniters, electronic components,
and glass
X X X X X Factory-installed blowers
X Firepots and burnpots
5 years 1 year X X Castings and baffles
7 years 3 years X X X Manifold tubes,
HHT chimney and termination
10
years
1 year X Burners, logs and refractory
Limited
Lifetime
3 years X X X X X Firebox and heat exchanger
XXXXXXX
All replacement parts
beyond warranty period
Warranty Period HHT Manufactured Appliances and Venting
1 Year
Components Covered
3 years
2 years
90 Days
XIgnition Modules
5
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

WARRANTY CONDITIONS:
• This warranty only covers HHT appliances that are purchased through an HHT authorized dealer or distributor. A list of
HHT authorized dealers is available on the HHT branded websites.
• This warranty is only valid while the HHT appliance remains at the site of original installation.
• This warranty is only valid in the country in which the HHT authorized dealer or distributor that sold the appliance
resides.
• Contact your installing dealer for warranty service. If the installing dealer is unable to provide necessary parts, contact
the nearest HHT authorized dealer or supplier. Additional service fees may apply if you are seeking warranty service
from a dealer other than the dealer from whom you originally purchased the product.
• Check with your dealer in advance for any costs to you when arranging a warranty call. Travel and shipping charges
for parts are not covered by this warranty.
This warranty is void if:
• The appliance has been over-fired or operated in atmospheres contaminated by chlorine, fluorine, or other damaging
chemicals. Over-firing can be identified by, but not limited to, warped plates or tubes, rust colored cast iron, bubbling,
cracking and discoloration of steel or enamel finishes.
• The appliance is subjected to prolonged periods of dampness or condensation.
• There is any damage to the appliance or other components due to water or weather damage which is the result of, but
not limited to, improper chimney or venting installation.
LIMITATIONS OF LIABILITY:
• The owner’s exclusive remedy and HHT’s sole obligation under this warranty, under any other warranty, express or
implied, or in contract, tort or otherwise, shall be limited to replacement, repair, or refund, as specified above. In no
event will HHT be liable for any incidental or consequential damages caused by defects in the appliance. Some states
do not allow exclusions or limitation of incidental or consequential damages, so these limitations may not apply to you.
This warranty gives you specific rights; you may also have other rights, which vary from state to state. EXCEPT TO
THE EXTENT PROVIDED BY LAW, HHT MAKES NO EXPRESS WARRANTIES OTHER THAN THE WARRANTY
SPECIFIED HEREIN. THE DURATION OF ANY IMPLIED WARRANTY IS LIMITED TO DURATION OF THE
EXPRESSED WARRANTY SPECIFIED ABOVE.
WARRANTY EXCLUSIONS:
This warranty does not cover the following:
• Changes in surface finishes as a result of normal use. As a heating appliance, some changes in color of interior and
exterior surface finishes may occur. This is not a flaw and is not covered under warranty.
• Damage to printed, plated, or enameled surfaces caused by fingerprints, accidents, misuse, scratches, melted items,
or other external sources and residues left on the plated surfaces from the use of abrasive cleaners or polishes.
• Repair or replacement of parts that are subject to normal wear and tear during the warranty period. These parts
include: paint, wood, pellet and coal gaskets, firebricks, grates, flame guides, batteries and the discoloration of glass.
• Expansion, contraction, or movement of certain parts causing noise. These conditions are normal and complaints
related to this noise are not covered by this warranty.
• Damages resulting from: (1) failure to install, operate, or maintain the appliance in accordance with the installation
instructions, operating instructions, and listing agent identification label furnished with the appliance; (2) failure to
install the appliance in accordance with local building codes; (3) shipping or improper handling; (4) improper opera-
tion, abuse, misuse, continued operation with damaged, corroded or failed components, accident, or improperly/
incorrectly performed repairs; (5) environmental conditions, inadequate ventilation, negative pressure, or drafting
caused by tightly sealed constructions, insufficient make-up air supply, or handling devices such as exhaust fans or
forced air furnaces or other such causes; (6) use of fuels other than those specified in the operating instructions; (7)
installation or use of components not supplied with the appliance or any other components not expressly authorized
and approved by HHT; (8) modification of the appliance not expressly authorized and approved by HHT in writing;
and/or (9) interruptions or fluctuations of electrical power supply to the appliance.
• Non-HHT venting components, hearth components or other accessories used in conjunction with the appliance.
• Any part of a pre-existing fireplace system in which an insert or a decorative gas appliance is installed.
• HHT’s obligation under this warranty does not extend to the appliance’s capability to heat the desired space. Informa-
tion is provided to assist the consumer and the dealer in selecting the proper appliance for the application. Consider-
ation must be given to appliance location and configuration, environmental conditions, insulation and air tightness of
the structure.
4021-645H 10/15 Page 2 of 2
LIMITED LIFETIME WARRANTY (con't)
6Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

Continued on page 8
INSTALLER
Please leave these instructions with the appliance.
OWNER
Please retain these instructions for future reference .
WARNING!
• Any change to this heater or its controls can be dangerous.
• Improper installation or use of the heater can cause serious injury or death from re, burns,
explosion or carbon monoxide poisoning.
• Do not allow fans to blow directly into the replace. Avoid any drafts that alter burner ame patterns.
• Do not use a blower insert, heat exchanger insert or other accessory, not approved for
use with this heater where applicable.
1. Due to high temperatures, the rebox should be
located out of trafc and away from furniture and
draperies.
2. Children and adults should be alerted to the hazard
of high surface temperature and should stay away
to avoid burns or clothing ignition.
3. Young children should be carefully supervised when
they are in the same room with the rebox.
4. Do not place clothing or other ammable material
near the replace when the rebox is in use.
5. Any safety screen or guard removed for servicing,
must be replaced prior to operating a heater within
the rebox.
6. Installation and repair should be done by a qualied
service person.
7. To prevent malfunction and/or sooting, an unvented
gas heater/rebox should be cleaned at least annu-
ally by a professional service person. More frequent
cleaning may be required due to excessive lint from
carpeting, etc. It is imperative that control compart-
ments, burners and circulating air passageways be
kept clean.
8. CARBON MONOXIDE POISONING: Early signs of
carbon monoxide poisoning are similar to the u with
headaches, dizziness and/or nausea. If you have these
signs, obtain fresh air immediately. Have the heater
serviced as it may not be operating properly.
9. The installation must conform with local codes or, in
the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.l/NFPA54.
10. This unit complies with ANSI Z21.91-2017 ventless
rebox enclosures for gas-red unvented decorative
room heaters.
11. Do not install the unvented heater in a bathroom.
12. Do not install the unvented heater in a bedroom unless
the maximum input rating is equal to or less than
10,000 Btu/hr.
13. Correct installation of the ceramic ber logs, proper
location of the heater, and annual cleaning are neces-
sary to avoid potential problems with sooting. Sooting,
resulting from improper installation or operation, can
settle on surfaces outside the replace. See log place-
ment instructions for proper installation.
14. Avoid any drafts that alter burner ame patterns. Do not
allow fans to blow directly into replace. Do not place
a blower inside burn area of rebox. Ceiling fans may
create drafts that alter burner ame patterns. Sooting
and improper burning will occur.
15. CAUTION: Candles, incense, oil lamps, etc. produce
combustion by-products including soot. Vent free
appliances will not lter or clean soot produced by
these types of products. In addition, the smoke and/
or aromatics (scents) may be re-burnt in the vent free
appliance which can produce odors. It is recommended
to minimize the use of candles, incense, etc. while the
vent free appliance is in operation.
16. An unvented gas-red heater uses air (oxygen) from
the room in which it is installed. Provisions for adequate
combustion and ventilation air must be provided. See
installation guidelines.
17. Keep room area clear and free from combustible mate-
rials, gasoline and other ammable vapors and liquids.
18. Unvented gas heaters are a supplemental zone heater.
They are not intended to be a primary heating appli-
ance.
19. Unvented gas heaters emit moisture into the living
area. In most homes of average construction, this
does not pose a problem. In houses of extremely
tight construction, additional mechanical ventilation is
recommended.
20. During manufacturing, fabricating and shipping, various
components of this appliance are treated with certain
oils, lms or bonding agents. These chemicals are not
harmful but may produce annoying smoke and smells
as they are burned off during the initial operation of the
appliance; possibly causing headaches, or eye or lung
irritation. This is a normal and temporary occurrence.
2 Important Safety and Operating Information
7
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

WARNING!
Do not attempt to burn solid wood fuels, vented
gas log sets, or any other combustible in this
unvented rebox. Also, do not install a vent
free gas log set in this rebox if the minimum
clearance and height requirements of the log
set are too large for the rebox.
Continued from page 7
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
allow odors to dissipate. Any odors remaining after this
initial break-in period will be slight and will disappear
with continued use.
21. Input ratings are shown in BTU per hour and are for
elevations up to 2,000 feet. For elevations above 2,000
feet, input ratings should be reduced 4 percent for each
1,000 feet above sea level. Refer to the National Fuel
Gas Code.
22. The appliance and its main gas valve must be discon-
nected from the gas supply piping system during any
pressure testing of that system at test pressures in
excess of 1/2 psig (3.5 kPa).
23. 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 psig
(3.5 kPa).
24. Do not use this room heater if any part has been under
water. Immediately call a qualied service technician
to inspect the room heater and to replace any part of
the control system and any gas control which has been
under water.
25. Never burn solid fuels in a replace where a unvented
room heater is installed.
26. Always have a replace screen in place when the
appliance is in operation, and unless other provisions
for combustion air are provided, the screen shall have
an opening(s) for induction of combustion air.
27. Do not ll spaces around the rebox with insulation or
other materials. These spaces must be maintained to
prevent the rebox from coming in contact with com-
bustible materials.
Notice: Illustrations shown in this manual reect
“typical” installations with nominal dimensions and
are for design and framing reference only. Actual
installations may vary due to individual design
preferences. However, always maintain minimum
clearances to combustible materials and do not
violate any specic installation requirements.
WARNING!
Never connect unit to private (non-utility)
gas wells. This gas is commonly known as
wellhead gas.
Nous recommandons que nos
appareils de chauffage au gaz
soient installés et entretenus par
des professionnels qui ont été
accrédités aux È.U. par le National
Fireplace Institute ® (NFI) comme
étant des spécialistes du NFI en
matièred’appareils de chauffage
au gaz.
IMPORTANT:
Please Read the Following Carefully
It is normal for replaces fabricated of steel
to give off some expansion and/or contrac-
tion noises during the startup and cool down
cycle. Similar noises are found with your fur-
nace heat exchanger or car engine.
8Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

3 General Installation Information
The new LSTF36-B is a vent free rebox. It features a self
contained heat circulating system.
This installation manual will enable you to obtain a safe,
efcient and dependable installation of this vent free re-
place system.
Do not alter or modify the rebox or its components under
any circumstances. Any modication or alteration of the
rebox system, including but not limited to the rebox and
accessories, may void the warranty, listings and approvals
of this system and could result in an unsafe and potentially
dangerous installation.
BEFORE YOU START
Carefully inspect the contents for shipping damage. If any
parts are missing or damaged, immediately inform the
dealer from whom you purchased the appliance. Do not
attempt to install any part of the appliance unless you have
all the parts in good condition.
Note: If using a blower or light kit, electrical
connections should be made prior to the rebox being
enclosed by the nished walls.
MAKE SURE YOU HAVE RECEIVED ALL
PARTS
Verify contents to ensure all parts have been received.
The following should be included:
1. Vent Free Gas Firebox
2. Canopy (2)
3. Installation and Operating Instructions
WHAT YOU WILL NEED FOR INSTALLATION
TOOLS and BUILDING SUPPLIES
• Phillips screwdriver • Square
• Framing materials • Hammer
• Saw and / or saber saw • Tee joint
• Level • Pipe wrench
• Measuring tape • Pliers
• Electric drill and bits
• Fireplace surround materials (noncombustible)
• Caulking material (noncombustible)
• Wall nishing materials
• Piping complying with local codes
• Pipe sealant approved for use with propane/L.P.G.
(resistant to sulfur compounds)
Refer to the installation instructions provided with the log
sets for items required for log set installation.
9
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

4 Firebox and Framing Dimensions
PLANNING THE INSTALLATION
In planning the installation for the appliance it is necessary
to determine where the unit is to be installed and whether
optional accessories are desired. Gas supply piping should
also be planned. The following steps represent the normal
sequence of installation. Each installation is unique, how-
ever, and might require a different sequence.
1. Position rebox prior to framing or into prepared fram-
ing.
2. The canopy supplied with the unit must be installed.
See Canopy Installation on page 15.
3. Field wire main power supply to circulating models with
fan kit or accent light kit. (Electrical connections should
only be performed by an experienced, licensed/certi-
ed tradesman.)
4. Plumb gas line. (Gas connections should only be per-
formed by an experienced, licensed/certied trades-
man.)
5. Install vent free gas log heater per the instructions pro-
vided with the vent free gas log heater.
6. Complete nish wall material and surround to your in-
dividual taste.
45”
42”
18-3/4”
24”
Top
12”12”
2-3/8”
8-3/8”
3-1/4”
8-3/4” 42”
30-3/4”
1-1/4”
5-1/4”
3”
3” 36” 3”
37-1/4”
Left
Front Right
Figure 4.1 Framing Dimensions
Notice: Illustrations displayed in this manu-
al reect "typical" installations with nominal
dimensions and are for design and framing
reference only. Actual installations may vary
due to individual design preferences. Howev-
er, always maintain minimum clearances to
combustible materials and do not violate any
specic installation requirements.
10 Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

FIREPLACE FRAMING
WARNING!
The fireplace must be installed giving full
consideration to the clearance and height
requirements identied in this manual.
11-1/2” 11-1/2”
23”
24”
21”
46”
Gas Connection
2x4 section to be in-
stalled after replace
is set in place to attach
nailing anges and end
2x4.
Figure 4.2 Top View of Framing Specications
23”
37-1/2”
42-1/2”
Figure 4.3 Framing Specications
11
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

5 Hearth Dimensions and Firebox Locations
FIREBOX LOCATION
Carefully select the best location for installation of your
vent free rebox. The following factors should be taken
into consideration:
• Clearance to side wall, ceiling, woodwork and windows.
See “Clearances/Height Requirements on page 12.
Minimum clearances to combustibles must be main-
tained.
• Location must not be affected by drafts caused by
kitchen exhaust fans, ceiling fans, return air registers for
forced air furnaces / air conditioners, windows or doors.
• Installation must provide adequate ventilation and com-
bustion air.
• Location should be out of high trafc or windy or drafty
areas.
• 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 rebox
or restrict the ow of combustion and ventilation air.
• Do not install in the vicinity where gasoline or other
ammable liquids may be stored. The vent free rebox
must be kept clear and free from these combustible
materials.
Figure 5.1 Minimum Hearth Dimensions
Ref. LSTF36-B
A 33½"
B19"
C27¾"
A
B
C
12 Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

6 Clearances
Ensure that minimum clearances shown in Figures 6.1
through 6.4 are maintained. Left and right clearances are
determined when facing the front of the rebox.
Follow these instructions carefully to ensure safe instal-
lation. Failure to follow these requirements may create a
re hazard.
1. Sidewall clearances: The clearance from the inside
of the appliance to any combustible wall should not be
less than 6". See Figure 6.1.
2. Ceiling clearance: The ceiling must be at least 42"
from the top of the rebox opening. See Figure 6.1.
3. Back wall clearance: The appliance may be placed
against a combustible back wall.
4. Parallel wall clearances: The clearance from the
opening of the rebox to any wall that is parallel to the
opening should not be less than 36". See Figure 6.2.
NOTE: The canopy supplied with the unit must be installed
for correct mantel clearances.
Figure 6.3 Mantel Clearances
Figure 6.4 Mantel Leg Clearance
12”
10”
8”
6”
2½”
12”
14”
15½”
16¾”
18”
Combustible
Material Can
Contact Top
of Fireplace
Noncombustible Material
Only if Needed to Cover
Radiant Top Face
42"
Minimum
6"
Minimum
6"
Minimum
Figure 6.1 Clearance and Height Requirements
36”
(914 mm)
FP2320
wall clearance
Figure 6.2 Wall Clearance
Finish Wall
Combustible
Material Area
45°
1”
2¹⁄₂”
3”
5”
6”
1¹⁄₂”
3¹⁄₂”
4¹⁄₂”
Fireplace
Hood
Top View
13
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

Firebox framing can be built before or after the appliance is
set in place. Construct rebox framing following Figure 4.1
for your specic installation requirements. Refer to Figure
4.1 on page 9 for rebox dimensions. The framing headers
may rest on the top of the rebox standoffs.
The rebox may be installed directly on a combustible oor
or raised on a platform of an appropriate height. When
the rebox is installed directly on carpeting, tile, or other
combustible material, other than wood ooring, the rebox
shall be installed on a metal or wood panel extending the
full width and depth of the enclosure.
WARNING!
Do not ll spaces around rebox with insulation
or other materials. This could cause a re.
WARNING!
The fireplace must be installed giving full
consideration to the clearance and height
requirements identied in this manual.
5. Mantel clearances: If a combustible mantel is installed,
it must meet the clearance requirements as shown in
Figures 6.3 & 6.4.
6. Floor clearance: This inner chamber rebox oor must
be installed at least 1" above any combustible ooring
material, such as carpeting or asphalt tile, which is
closer than 14" to the base of the rebox. See Figure 6.5.
Or
The inner chamber rebox oor may be installed nearer to
the oor if a minimum of 14" of noncombustible material
such as slate or marble is installed between the base of
the rebox and the combustible ooring. See Figure 6.6..
1” Min.
Combustible
Material
Figure 6.5 Floor Clearance Above Combustible Flooring Material
14”
Min.
Noncombustible
Material
Figure 6.6 Floor Clearance Above Noncombustible Flooring
Material
The classication "non-combustible material includes, but
is not limited to stone, brick, and mortar. Non-combus-
tibles are safe to overlay the black-painted metal face,
including radiant plates, and do not pose a re hazard.
Any non-combustible nish material must not extend past
or interfere with the replace opening.
The classication "combustible material," includes, but
is not limited to: plywood, drywall, and particle board.
Combustible materials may contact the sides, bottom,
or back of the rebox. Do not overlay the black-painted
face with combustible.
14 Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

SECURING AND LEVELING THE APPLIANCE
1. Bend out the nailing anges located on each side of the
rebox.
2. Slide the rebox into prepared framing or position rebox
in its nal position and frame later.
3. Level the rebox by checking the top edge of the rebox.
Shim if necessary.
4. Anchor rebox to the side framing members using 8d
nails or other suitable fasteners. Figure 7.1
5. The canopy must be installed for safe operation of the
rebox.
CANOPY INSTALLATION
A canopy is furnished with each rebox and MUST be
installed for safe operation.
1. Locate three (3) screws at the front edge of the face (one
at each end and one in center). Loosen screws slightly,
slide canopy slots against screws and tighten in place.
Repeat for the other side. Figure 7.2.
WARNING!
The rebox canopy must not be modied or
replaced with a canopy that may be provided
with the vent free decorative room heater.
WARNING!
Close replace screen panel before operating a
decorative type vent free room heater.
7 Fireplace, Canopy and Gas Line Installation
Nail Sides Through Nailing Flanges
Figure 7.1 Location of Nailing Flanges
Screws
Front Face Canopy
Figure 7.2 Canopy Installation
15
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

Consult all local codes. All gas piping must be installed to
comply with local codes, or in the absence of local codes,
with the latest edition of the National Fuel Gas Code ANSI
Z223.1/NFPA54.
The 1/2" gas line may enter either from the left side or right
side of the rebox. Gas access holes are provided on both
sides of the rebox.
A listed manual shutoff valve must be installed upstream of
the appliance. A union tee and plugged 1/8" NPT pressure
tapping point should be installed upstream of the appliance.
IMPORTANT: Install main gas valve (equipment shutoff
valve) in an accessible location. The main gas valve is
for turning on or shutting off the gas to the replace.
A sediment trap may be upstream of the heater to prevent
moisture and contaminants from passing through trap to
the heater controls and burners. Failure to do so could
prevent the heater from operating reliably. Consult appli-
cable codes.
An external regulator must be used on all propane/L.P.G.
heaters, in addition to the regulator 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 internally tinned.
NOTE: When connecting propane / L.P.G. vent free
room heaters, you must use pipe sealant resistant to
propane / L.P.G.
IMPORTANT: Hold heater regulator with a wrench to
prevent movement when connecting to inlet piping.
Check gas type: The gas supply must be the same as
stated on the heater’s rating plate. If the gas supply
is different, DO NOT INSTALL THE HEATER. Contact
your dealer for the correct model.
Notice: After completing connection, test all gas joints
from the gas meter to the gas heater regulator for leaks.
Using soap and water solution or a gas sniffer. DO NOT
USE AN OPEN FLAME.
WARNING!
Plumbing connections should only be
performed by a qualied, licensed plumber.
Main gas supply must be off when plumbing
gas line to replace or performing service.
WARNING!
Connecting directly to an unregulated propane/
L.P.G. tank can cause an explosion.
WARNING!
Do not connect directly to natural gas 1/2 PSI or
2 PSI systems. Always make sure natural gas
pressure is regulated 10.5 w.c. (maximum before
operating the unit).
GAS CONNECTIONS
16 Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

8 Combustion Air
AK22 INSTALLATION
Note: The AK22 is an optional accessory that can be used
to bring in fresh air. Use of the AK22 is not required for
operation unless specied by local codes.
1. Locate combustion air assembly at an exterior location
which is not likely to be accidentally blocked in any man-
ner. Locate assembly a min. of 12" above the snow line
to prevent blockage by snow accumulation.
2. Never mount the combustion air inlet assembly in a ga-
rage or storage area where combustible fumes such as
gasoline might be drawn into the replace.
3. Combustion air can be drawn from the crawl space under
a house when an adequate supply of air is provided by
open ventilation.
4. CAUTION: Do not take combustion air from attic space
or garage space.
5. Locate air supply inlet at least 3' away from any appliance
vent terminal.
6. Avoid extremely long runs and numerous turns in the duct
leading from the replace to the combustion air assembly.
These conditions increase the resistance to the free ow
of air through the duct. Refer to Figures 8.1 through 8.4
for methods of installing the outside air for combustion
assemblies.
FP2459
OA basement install
Above
Snow
Level
Ground
Level
15' Max.
FP2460
OA slab install
Inlet Grille
in Soft
(Overhang)
FP2461
above basement
Duct
Extended
to Miss
Joist
To Outside Wall
NOTE: Fireplace model in illustrations may not be
representative of your appliance.
Figure 8.1 Basement Installation
Figure 8.2 Concrete Slab Installation (Optional Outside Air Runs)
Figure 8.3 Installation Above Basement or Crawl Space
17
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

FP2462
OA corner install
Outside
Wall Inside Wall
Figure 8.4 45° Corner Installation on Slab Floor
WARNING!
DO NOT remove the cover on side of rebox if
the outside air will not be connected.
Step by Step Installation
1. Attach the collar to the side of the replace by aligning the
four holes in the collar with the four holes on the replace
side. Attach with the screws provided. See Figure 8.6.
2. Mark and cut out a 4 in. (102 mm) hole in the building
side for air entry. This hole should allow for some framing
(two sides) so the hooded air inlet may be nailed into
position, ush with the building’s outside.
3. Install hooded air inlet in the sidewall of the structure.
4. Assemble the exible duct ID4 or UD4 (not supplied)
between the collar and the hooded air inlet. Secure it
into position with the supplied wire ties.
Outlet placed
higher than 3 ft
below the
termination cap
Attic space
Garage or
combustible
liquids storage
Outlet blocked by
snow, leaves, etc.
Clear area
outside
house or in
ventilated
crawl space
YES
NO
NO
NO
NO
Factory-built
fireplace
• Use UL181 Class 1 or Class 0 rigid or flexible ducting.
• Install with short run or mainly straight duct, except small
dip for cold air trap which will help prevent flow of cold air.
• Secure flex duct with screws or wire ties.
Figure 8.5
Figure 8.6
18 Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

9 Optional Equipment
FORCED AIR KIT (BLOTDL)
If you are installing the forced air kit, Model BLOTDL, see
the installation instructions provided with the kit for electri-
cal wiring requirements. The rebox must be connected to
main power supply at time of rebox installation. The blower
must be installed prior to the installation of the vent free
heater. The electrical connections must be made before
the rebox is framed and enclosed in the nished walls.
WARNING!
Electrical connections should only be performed
by a qualied, licensed electrician, main power
must be off when connecting to main electrical
power supply or performing service.
When installed, the blower must be electrically
grounded in accordance with local codes or in
the absence of local codes, with the National
Electrical Code ANSI/NFPA 70.
REFRACTORY
The LSTF36-B is shipped with factory installed refractory
panels. Once unit is in place, remove the shipping brackets
at the four corners of the oor brick.
NOTE: Brackets located at the top corners of the side panels
remain in place. If preferred, the re brick can be removed
and the unit operated without any refractory panels.
ACCENT LIGHT KIT (MONALST)
If you are installing the accent light kit, Model MONALST,
see the installation instructions provided with the kit for
electrical wiring requirements. The rebox must be con-
nected to the main power supply at the time of rebox in-
stallation. The accent light must be installed prior to the in-
stallaton of the vent free heater. The electrical connections
must be made before the rebox is framed and enclosed
in the nished wall.
OPTIONAL DOOR KIT (DLR36B)
If you are installing the optional door kit, see the installa-
tions instructions provided with the kit.
Brackets to be removed before operation
Figure 9.1 Remove Brackets
19
Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18

10 Service Parts
Service Parts LSTF36-B
Beginning Manufacturing Date: July 2018
Ending Manufacturing Date: Active
IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or distributor.
Hearth and Home Technologies does not sell directly to consumers. Provide model number
and serial number when requesting service parts from your dealer or distributor.
Stocked
at Depot
ITEM DESCRIPTION COMMENTS PART NUMBER
1 Plate, Socket Qty 2 req SRV4607-144
2 Plate, Firebox Outer Top SRV4613-111
3 Plate, Light Box Qty 2 req SRV4613-109
4 Firebox, Access Panel SRV4613-105
5 Junction Box Cover Plate SRV26548
6 Clamp Connector SRV230-1670
7 Junction Box Cover SRV4604-103
8 Junction Box Plastic SRV4021-013 Y
9 Canopy Qty 2 req SRV4607-107
10 Firescreen Rod Qty 4 req SRV12052
11 Screen, Panel (24” W x 30” H) Qty 4 req SRV26D4563
12 Retainer, Brick (Top) Qty 4 req 79D0098K
Refractory
13 Refractory, Side Qty 2 req SRV4608-708
14 Refractory, Hearth SRV4608-709
15 Bracket, Brick Front Qty 4 req 71D0124K
16 Nailing Flange Qty 8 req 31190
Firebox Touch Up Paint SRV4021-110
Gloss Black Corvel Aerosol 71479
5/18
36” Vent Free See Through Fireplace
Lo-Rider
8
9
10
13
11
7
4
3
2
16
15
14
1
12
6
5
20 Monessen • LSTF36-B Installation and Operating Manual • 4613-900 • Rev A • 01/18