Monessen Hearth AVFL42NTSC-SR Manual

AVFL Vent Free Fireplace System
Installation & Operating Instructions
Models: AVFL42NTSC-SR
This is an unvented gas-red heater. It uses air
(oxygen) from the room in which it is installed.
Provisions for adequate combustion and ventil-
ation air must be provided. Refer to Page 8.
INSTALLER: Leave this manual with the appliance.
CONSUMER: Retain this manual for future
reference.
• Do not store or use gasoline or other
ammable 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.
– Leave the building immediately.
– 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 re department.
• Installation and service must be performed
by a qualied installer, service agency or
the gas supplier.
WARNING: If the information in this manual
is not followed exactly, a re or explosion may
result causing property damage, personal
injury or loss of life.
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19

2
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
CONTENTS
Thank you and congratulations on your purchase of a Monessen replace.
PLEASE READ THE INSTALLATION AND OPERATION INSTRUCTIONS BEFORE USING THE APPLIANCE!
IMPORTANT: Read all instructions and warnings carefully before starting installation.
Failure to follow these instructions may result in a possible re hazard and will void the warranty.
Standard Work Checklist........................................... 3
Important Safety Information .................................... 4
Building Code Information ......................................... 5
Product Features......................................................... 6
AVFL42 Controls ...................................................... 6
Gas Specications & Orice Size ............................. 6
Gas Pressures .......................................................... 6
Fireplace and Framing Dimensions .......................... 7
Pre-installation Information........................................ 8
Getting Started ......................................................... 8
What You Will Need .................................................. 8
Planning the Installation ........................................... 8
Adequate Combustion and Ventilation Air ................ 8
Fireplace Location .................................................... 9
Clearances & Height Requirements ....................... 10
Good Faith Guidelines for TV Installations ............. 11
Fireplace Installation................................................. 12
Secure Fireplace to Framing .................................. 12
Finishing Material ................................................... 12
Noncombustible Facing Installation ........................ 12
Connect the Gas .................................................... 13
Check Gas Pressure .............................................. 14
Electrical Installation................................................. 15
Wiring Junction Box ............................................... 15
Signature Command®Wiring Diagram ................... 16
Final Installation ........................................................ 17
Bulb Installation ...................................................... 17
Installation of Air Deection Glass .......................... 19
Glass Only Placement ............................................ 19
Glass & Optional Stone Kit Placement ................... 19
Placement of Optional Logs ................................... 20
Operating Instructions.............................................. 21
For Your Safety Read Before Lighting .................... 21
Turning On Unit ...................................................... 22
To Turn Off Gas to Appliance .................................. 22
Signature Command®System Operation ................ 23
Features ................................................................. 23
Battery Installation .................................................. 23
System Conguration/Setup ................................... 23
Cold Climate Option ............................................... 23
Functions/Operation ............................................... 25
Touch Screen Remote Control Operation ............... 26
Troubleshooting ...................................................... 31
Maintenance and Cleaning ....................................... 32
Flame Appearance ................................................. 32
Check the Pilot Flame ............................................ 32
Check Burner Flame Appearance .......................... 32
Cleaning and Servicing .......................................... 33
Replacing Light Bulbs ............................................. 33
Operation and Optional Accessories ...................... 35
Operating Information ............................................. 35
Optional Accessories .............................................. 35
Troubleshooting ........................................................ 36
Signature Command®System ................................ 37
Service Parts.............................................................. 38
Firebox ................................................................... 38
Logs ........................................................................ 39
Signature Command®System ................................ 40
Limited Lifetime Warranty Policy............................. 41
►
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3
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
Gas (Pg 13-14)
Proper appliance for fuel type.
Leak check performed and inlet pressure verified.
Verified proper air shutter setting for installation type.
Customer:
Lot/Address:
Model (circle one): AVFL42NTSC-SR
Date Installed:
Location of Fireplace:
Installer:
Dealer/Distributor Phone #
Serial #:
Comments: Further description of the issues, who is responsible (Installer/ Builder/ Other Trades, etc) and corrective
action needed _____________________________________________________________________________________
Comments Communicated to party responsible ____________________ by ______________________on ___________
(Builder / Gen. Contractor/) (Installer) (Date)
?YHW , ON F I SEY
___________________________
___________________________
___________________________
___________________________
___________________________
Appliance Install (Pg. 8-12)
Verified that the chase is insulated and sealed.
Required non-combustible board is installed.
Verifi ed clearances to combustibles.
Fireplace is leveled and secured.
Adequate provisions for combustion and ventilation air have been verified.
___________________________
___________________________
___________________________
___________________________
___________________________
Finishing (Pg 10-12)
Verifi ed all clearances meet installation manual requirements.
Mantels and wall projections comply with installation manual requirements.
___________________________
___________________________
___________________________
___________________________
___________________________
Manual bag and all of its contents are removed from inside/
under the appliance and given to party responsible for use and
operation. Started appliance and veried no gas leaks exist.
___________________________
___________________________
4116-982A 08/19
 = Contains updated information.
Hearth & Home Technologies recommends the following:
• Photographing the installation and copying this checklist for your file.
• That this checklist remain visible at all times on the appliance until the installation is complete.
This standard work checklist is to be used by the installer in conjunction with, not instead of, the instructions contained in this
installation manual.
WARNING! Risk of Fire or Explosion! Failure to install appliance according to these instructions could
lead to a fire or explosion.
ATTENTION INSTALLER:
Follow this Standard Work Checklist
Media & Accessories (Pg 17-21)
All packaging and protective materials removed (inside & outside of appliance).
Media installed correctly.
Accessories installed properly.
Electrical (Pg 15)
Unswitched power (110-120 VAC) provided to the appliance.
Switch wires properly installed.
STANDARD WORK CHECKLIST

4
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
IMPORTANT SAFETY INFORMATION
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.
INSTALLER
Please leave these instructions with the appliance.
OWNER
Please retain these instructions for future reference .
1. Due to high temperatures, the appliance 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 appliance.
4. Do not place clothing or other ammable material
on or near the appliance.
5. Any safety screen or guard removed for servicing
an appliance, must be replaced prior to operating
the heater.
6. Installation and repair should be done by a quali-
ed service person. To prevent malfunction and/or
sooting, an unvented gas heater should be cleaned
before use and at least annually by a professional
service person. More frequent cleaning may be
required due to excessive lint from carpeting,
bedding materials, etc. It is imperative that control
compartments, burners and circulating air passage-
ways be kept clean.
7. WARNING: Any change to this heater or its controls
can be dangerous.
8. Unvented gas heaters are a supplemental zone
heater. They are not intended to be the primary
heating appliance.
9. 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.
10. The installation must conform with local codes or, in
the absence of local codes, with the National Fuel
Gas Code, ANSI Z223.l/NFPA54.
11. This unit complies with ANSI Z21.11.2 Unvented
Heaters, latest edition.
12. Do not install the heaters in a bathroom or bedroom.
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. Refer to log
placement 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 byproducts 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 reburned 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. This is an unvented gas-fired heater. It uses air
(oxygen) from the room in which it is installed. Provi-
sions for adequate combustion and ventilation air must
be provided. Refer to Page 8.
17. This heater shall not be installed in a room or space
unless the required volume of indoor combustion air is
provided by the method described in the National Fuel
Gas Code, ANSI Z223.1/NFPA 54, the International
Fuel Gas Code or applicable local codes.
18. Keep room area clear and free from combustible mate-
rials, gasoline and other ammable vapors and liquids.
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

5
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
IMPORTANT SAFETY INFORMATION
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.
The initial break-in operation should last two to three
hours. Provide maximum ventilation by opening win-
dows 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 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 psig (3.5 kPa).
23. The appliance must be isolated from 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.
BUILDING CODE INFORMATION
Adhere to all local codes or, in their absence, the latest
edition of THE NATIONAL FUEL GAS CODE ANSI Z223.1
or NFPA54 which can be obtained from:
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
or
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
This appliance may be installed in an after-
market, permanently located, manufactured
(mobile) home, where not prohibited by local
codes.
This appliance is only for use with the type of
gas indicated on the rating plate. This appliance
is not convertible for use with other gases.
WARNING: This product and the
fuels used to operate this product (liquid
propane or natural gas), and the products
of combustion of such fuels, can expose
you to chemicals including benzene, which
is known to the State of California to cause
cancer and reproductive harm. For more
information go to: www.P65Warnings.
ca.gov.

6
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
PRODUCT FEATURES
GAS PRESSURES
GAS SPECIFICATIONS & ORIFICE SIZE
AVFL42 CONTROLS
MODEL FUEL
INPUT
(BTU/h)
ORIFICE
SIZE
AVFL42NTSC-SR N AT. 24,500 #50
NATURAL
Inlet Minimum 5.0" w.c.
Inlet Maximum 10.5" w.c.
Regulator Pressure
Setting 3.5" w.c.
Pilot Regulator 3.5" w.c.
FP3020
AVFL controls
Control Board FP3020
Thermocouple
Module
Command Center
AC Module
Figure 1 –
AVFL42 Controls (Control Access Door Shown Open)

7
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FIREPLACE AND FRAMING DIMENSIONS
48 3/4" (1238 mm)
48 3/4" (1238 mm)
34 1/2"
(876 mm)
68 15/16" (1751 mm)
13 1/8"
(333 mm)
13 1/2"
(343 mm)
Minimum
Rough
Depth
44" (1118 mm)
Rough Opening Width
1/2"(13 mm)
or 5/8"(16 mm)
43" (1092 mm)
37 1/2" (953 mm)
32"
(813 mm)
Minimum
Rough
Height
32"
(813 mm)
28"
(711 mm)
15 3/16"
(386 mm)
13 1/2"
(343 mm)
5467
AVFL dims
2 1/4"
(57 mm)
4 5/8"
(118 mm)
6 1/16"
(154 mm)
39 3/4" (1010 mm)
Figure 2 –
Fireplace and Framing Dimensions

8
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
GETTING STARTED
Check your packing list to verify that all listed parts have
been received. You should have the following:
• Unvented gas heater
• Two (2) anchoring screws
• Installation/operating instructions
• 5" non-combustible board
• 2" x 32" deector glass
• Two (2) bags reglass
• Twelve (12) 15 watt bulbs
• One (1) 90 watt bulb
• TSFSC remote control
• One (1) 1-1/8" eyebrow
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 parts in good condition.
WHAT YOU WILL NEED
You must have the following items available before pro-
ceeding with installation:
• Manual shutoff valve
• Piping which complies with local codes
• Sediment trap
• Phillips head screwdriver
• Tee joint.
• Pipe sealant approved for use with Natural Gas
(Resistant to sulfur compounds)
• Pipe wrench
PRE-INSTALLATION INFORMATION
WARNING
Gloves are recommended when handling
ceramic ber logs to prevent skin irritation
from loose bers. Logs are fragile — handle
with care.
PLANNING THE INSTALLATION
In planning the installation for the replace 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 replace in desired location. Refer to the Fire-
place Location (page 9, Figure 3) and Clearances and
Height Requirements (page 10, Figure 5) sections and
Fireplace and Framing Dimensions (page 7, Figure 2)
illustration found in this manual.
NOTE: Be sure all packing material has been removed
from under the unit.
2. Install following the instructions found in this manual.
3. Field wire main power supply to junction box. Refer to
the Electrical Installation section (page 15). (Electrical
connections should only be performed by an experi-
enced, licensed certied service person).
4. Plumb gas line. Refer to the Connect the Gas (page
13, Figure 7) section found in this manual. (Gas
connections should only be performed by an experi-
enced, licensed/certied service person).
5. Complete nish wall material and/or surround.
ADEQUATE COMBUSTION AND VENTILA-
TION AIR
This heater shall not be installed in a conned space or
unusually tight construction unless provisions are provided
for adequate combustion and ventilation air.
The National Fuel Gas Code, (ANSI Z223.1/NFPA54),
denes a conned space as a space whose volume is less
than 50 cubic feet per 1,000 BTU per hour (4.8m3per kw) of
the aggregate input rating of all appliances installed in that
pace, and an unconned space as a space whose volume
is not less than 50 cubic feet per 1,000 BTU per hour (4.8
m3per kw) of the aggregate input rating of all appliances
installed in that space. Rooms communicating directly with
the space in which the appliances are installed, through
openings not furnished with doors, are considered a part
of a conned space.
Unusually tight construction is dened as construction
where:
a. Walls and ceilings exposed to the outside atmosphere
have a continuous water vapor retarder with a rating of
1 perm (6 x 1011 kg per pa/sec-m2) or less with openings
gasketed or sealed, and
b. Weather stripping has been added on openable win-
dows and doors, and
WARNING
Do not install the heater:
•Where curtains, furniture, clothing, or
other ammable objects are less than
36" from the front of the heater.
• In high trafc areas.
• In windy or drafty areas.

9
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
PRE-INSTALLATION INFORMATION
FP3029
c. Caulking or sealants are applied to areas such as joints
around window and door frames, between sole plates
and oors, between wall-ceiling joints, between wall
panels, at penetrations for plumbing, electrical and gas
lines and other openings.
The following formula can be used to determine the maxi-
mum heater rating per the denition of unconned space:
BTU/Hr = (L1+ L2) Ft x (W) Ft x (H) Ft
50
Consider two connecting rooms with an open area
between, with the following dimensions:
L1 = 151/2 Ft., L2 = 12 Ft., W = 12 Ft., H = 8 Ft.
BTU/Hr = (151/2 + 12) x (12) x (8)
50
If there were a door between the two rooms the calculation
would be based only on the room with the heater.
BTU/Hr = (151/2) x (12) x (8)
50
FIREPLACE LOCATION
This unvented gas heater requires no outside venting and
burns cleanly and efciency. As a zero-clearance unvented
gas heater, it can be installed against (or recessed into)
any wall that is accessible to a gas line.
Carefully select the best location for installation of your
unvented replace. The following factors should be taken
into consideration.
• Clearance to side wall, ceiling, woodwork and window
or other combustibles. Refer to Clearance and Height
Requirements section on Page 10. Minimum clear-
ances to combustibles must be maintained.
• 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
combustion air.
• DO NOT INSTALL THIS MODEL IN A BEDROOM
OR BATHROOM.
• Location should be out of high trafc areas and
away from furniture and draperies due to heat from
rebox.
• Never obstruct the front opening of the unvented re-
place or restrict the ow of combustion and ventilation
air.
• Minimize modications to existing construction. Refer
to Figure 3 below for location suggestions.
• Do not install in the vicinity where gasoline or other
ammable liquids may be stored. The unvented re-
box must be kept clear and free from the combustible
materials.
WARNING
If the area in which the heater may be
operated does not meet the required volume
for indoor combustion air, combustion and
ventilation air shall be provided by one
of the methods described in the National
Fuel Gas Code, ANSI Z223.1/NFPA 54, the
International Fuel Gas Code or applicable
local codes.
W
H
Counter
Fireplace
FP3029
replace locations
Figure 3 –
Possible Fireplace Locations

10
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
PRE-INSTALLATION INFORMATION
CLEARANCES AND HEIGHT REQUIREMENTS
Ensure that minimum clearances shown in Figures 4 and
5 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.
Sidewall & Mantel Leg Clearances — The clearance from
the inside of the appliance to any combustible adjacent
wall should not be less than 6". Mantel leg clearances are
projected out at a 45° angle. Figure 5
Ceiling Clearance — The ceiling must be at least 36" from
the rebox opening. Figure 5
Back Wall Clearance — The appliance may be placed
against a combustible back wall.
WARNING
The dimensions shown in Figures 4 and
5are minimum clearances to maintain
when installing this heater. Left and right
clearances are determined when facing the
front of the heater.
Follow these instructions carefully to
ensure safe installation. Failure to follow
instructions exactly can create a fire
hazard.
Floor Clearance — The replace may be installed directly
on a combustible oor or a raised platform of an appropriate
height. Do not place replace on carpeting, vinyl, tile or
other soft oor coverings. It may, however, be placed on at
wood, plywood, particle board or other hard surfaces. Be
sure replace rests on a solid continuous oor or platform
with appropriate framing for support so that no cold air can
enter from under the rebox. See note below regarding
oor installation with wide contemporary faces.
Mantel clearances — Must meet the clearance require-
ments detailed in Figure 5. This is for combustible and
non-combustible mantels.
NOTE: When installing at oor level and using the wide
contemporary face, the replace must be raised up a
minimum of 3/4" to allow clearance for ooring material.
Eyebrow
Screws
Eyebrow must be installed with the three (3) screws
provided. Figure 4.
Figure 4 –
Eyebrow Installation
Figure 5 –
Sidewall, Mantel Leg and Ceiling Clearances
14"
18"
12"
6"
FP3007
mantel clearances
36"
Top of Fireplace
Opening
SIDE VIEW
Wall
Insulation
Board
Stud
Standoff
6"
5"
3"
4¹⁄₂"
45°
1"
3¹⁄₂"
FP3008
mantel leg
1¹⁄₂"
2¹⁄₂"
Fireplace
Opening
TOP VIEW
Ceiling
Sidewall

11
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
PRE-INSTALLATION INFORMATION
Good Faith Guidelines for TV Installa ons above a Typical Gas Fireplace
Item Minimum Dimensions
A 4 inches
B4 inches
C 14 inches
D 6 inches
BB
A
Fireplace
TV
Mantel
A
C
Notes:
1. These are good faith recommended clearances only and not a guarantee of compliance with all TV
manufacturers’ maximum allowable opera ng temperatures.
2. Since every home has unique air ow characteris cs and maximum allowable opera ng temperatures
can vary from manufacturer to manufacturer and from model to model, actual TV temperatures should
be validated at the me of each installa on. TVs should not be used in situa ons where the actual TV
temperature exceeds the manufacturers’ maximum allowable opera ng temperatures iden ed in the
TV’s technical speci ca ons. Contact the TV’s manufacturer directly if you cannot locate this
informa on or have ques ons regarding the informa on.
3. Mantel height and depth must conform to mantle requirements specified in the replace installa on
manual.
4. “C” dimension taken from the top of the hood or fireplace opening.
5. Sugges ons on how to further reduce TV temperatures:
a. Increase “A” dimension.
b. Increase “C” dimension, however, increasing “B” dimension beyond maximum recommended
typically results in higher temperatures.
TV Wall
Bracket
Fireplace
C
TV on the wall TV recessed into the wall
D

12
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FIREPLACE INSTALLATION
SECURE FIREPLACE TO FRAMING
The replace must be secured to the framing studs as
shown in Figure 6. Use four (4) screws to attach replace
to framing. The side nailing anges are 1⁄2" or 5⁄8" to accom-
modate different wall thickness.
NOTE
Never install combustible materials over
front face of replace.
FINISHING MATERIAL
NOTE: Any remote wiring (i.e. remote control, wall
switch), must be done prior to nal nishing to avoid costly
reconstruction.
Only noncombustible materials (i.e. brick, tile, slate, steel,
or other materials with a UL re rating of Zero) may be
used to cover the black painted face of the appliance. It is
permissible to bring combustible wall board to the top of
the standoffs on the top and to the wall board stand-offs
on the sides of the unit. A 300°F minimum adhesive may
be used to attach facing materials to the black surface. If
joints between the nished wall and the replace surround
are sealed, a 300°F minimum sealant material (General
Electric RTV103 or equivalent) must be used.
NOTE: Fireplace may be installed on top of framing or
platform constructed of combustible materials which do
not protrude beyond the face.
NONCOMBUSTIBLE FACING INSTALLATION
CAUTION: The noncombustible wall board supplied with
this unit can be damaged if dropped or struck. Handle
with care.
1. Using drywall screws secure noncombustible board to
the two brackets on top of unit. IMPORTANT: To avoid
cracking the board, pre-drill holes prior to securing to the
unit/framing.
2. Wipe any debris or dust from the noncombustible board
and drywall.
3. It is highly recommended to prime the facing using a
quality primer prior to taping and mudding. This will
ensure proper adhesion of both the tape and mud. The
supplied board is very porous.
4. Tape the seams using a mesh type tape.
5. Mud seams as normal. We recommend using a product
called Durabond high strength compound for the rst
coat. This product can be purchased at any hardware
store. Follow manufacturer's recommendations for curing
the mud. NOTE: Depending upon the nal nishing
method, use a minimum rated 300 degree sealant, dry-
wall compound or thin set to seal the side and top joints.
6. Prime wall for a second time for proper adhesion of paint.
5"
43"
44"
32"
MOUNTING POINTS
FP3009
Framing
Members
Nailing
Flange
Screws
Noncombustible Material
FP3009
secure fireplace
5”
Nailing
Flange
Nailing
Flange
Screws
Noncombustible board
Figure 6 –
Secure Fireplace to Framing Studs
Figure 6A –
Noncombustible facing installation

13
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FIREPLACE INSTALLATION
CONNECT THE GAS
NOTICE: A qualied gas appliance installer must connect
the heater to the gas supply. Consult all local codes.
WARNING
Use new black iron or steel pipe. Internally
tinned copper or copper tubing can be
used per National Fuel Code, section 2.6.3,
providing gas meets hydrogen sulde limits,
and where permitted by local codes. Gas
piping system must be sized to provide
minimum inlet pressure (Listed on Data
Plate) at the maximum ow rate (BTU/hr).
Undue pressure loss will occur if the pipe
is too small.
A manual shutoff valve must be installed
upstream of the appliance. Union tee
and plugged 1⁄8" NPT pressure tapping
point should be installed upstream of the
appliance. Figure 7
A sediment trap should be installed upstream
to prevent moisture and contaminants from
passing through the pipe to appliance
controls and burners. Failure to do so
could prevent the appliance from operating
reliable. Figure 7
IMPORTANT: Loosen the pipe adapter on the ex tube
before installing to the system piping.
When tightening the joint to the valve, hold the valve
securely to prevent movement.
Test all gas joints from the gas meter to the heater valve for
leaks using a gas analyzer or soap and water solution after
completing connection. DO NOT USE AN OPEN FLAME.
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.
WARNING
FP2447
gas connection
To Fireplace
Pipe
Coupling
Stainless
Flexible Tube
Pipe
Locations Pressure Tapping
Point Installation
Manual Shutoff
Valve
Gas Supply
Inlet
FP2447
Tee Joint
Pipe Nipple
Cap
Sediment
Trap
3" minimum
WARNING
DO NOT USE OPEN FLAME TO CHECK
FOR GAS LEAKS.
WARNING
This appliance is equipped for either natural gas. Field
conversion is not permitted.
Figure 7 –
Gas Connection

14
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FIREPLACE INSTALLATION
CHECK GAS PRESSURE
Figure 8
Check the gas pressure with the appliance burning.
Open control access door at bottom front of unit to nd
valve and regulator referred to below.
The valve regulator controls the burner pressure which
should be checked at the pressure test point.
Turn captured screw counterclockwise two or three turns
and then place tubing to pressure gauge over test point.
Use test point “A” closest to gas inlet. After taking pressure
reading, be sure and turn captured screw clockwise rmly
to reseal. Do not over torque. Check for gas leaks.
Figure 8 –
Pressure Test Point Location
Test Port ‘A’
(Inlet Test Port)
Outlet Test Port

15
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
ELECTRICAL INSTALLATION
IMPORTANT: Always check local building codes. This in-
stallation must comply with local regulations as well as
the National Electric Code.
WIRING JUNCTION BOX
1. Before installing, wire the receptacle into an electrical
circuit. This should be done before framing the re-
place. Wire with minimum 60° C wire in accordance
with prevailing codes.
2. Remove the external junction box cover by removing
the screw from the right side of the outside rebox wall.
Junction box was installed at the factory.
3. The junction box cover has a factory installed “romex”
style strain relief connector. After connecting the wires,
route the wire leads through this connector.
CAUTION
Electrical connections should only be performed
by a qualied licensed electrician. Main power
supply must be turned off before connecting to
the main electrical power supply or performing
service.
WARNING
Electrical Grounding Instructions:
This appliance is equipped with a three-prong
(grounding) plug for your protection against
shock hazard and should be plugged directly
into a properly grounded three prong recepta-
cle.
WARNING
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation. Verify
proper operation after servicing.
For vent free SC System, the unit will continue to burn
during power loss to AC only with batteries installed.
Without power, the unit will shut down without batteries
installed but can be started with fresh batteries installed
from the Command Center.
Figure 9 –
Junction Box Wiring Diagram
FP1912
Junction box wiring
8/08
Junction Box
Factory Supplied
Not Supplied
120V AC
60Hz

16
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
ELECTRICAL INSTALLATION
NOTE: Wall switch wires must
be connected together if a wall
switch is not being used.
Figure 9 –
Signature Command®Wiring Diagram
SIGNATURE COMMAND WIRING DIAGRAM
wiring diagram
Control Board
RF Receiver
ON/OFF Button
Black / Thermopile
Red / Thermopile
Sensor
Ignitor / Sparker
Plug-in Connector
Control Board to Command Center
OFF/LO LED ON/HI
Master Switch
Command Center Optional
Wall Switch
DC Power/Green
Ground
Plug-in Connector
Control Board to
Solenoid
Gas In
Gas Out
Pilot Gas Tubing
Valve
Black
Yellow
Thermocouple
Pilot
Thermocouple
Module
Orange
Red
Plug in
Connector “A”
A/C MODULE
TO JUNCTION BOX
IN FIREPLACE
PLUG-IN
CONNECTOR “A”
WHITE
BLACK
GREEN
Opt. Blower
WHITE
BLACK
Top Lamp
90w
WHITE
BLACK
Back Row
15W x 6 Lamps
Front Row
15W x 6 Lamps
BLACK
WHITE
BLACK
WHITE
BLACK
WHITE
Optional
Blower
Hearth
Light
Top Light
Green

17
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FINAL INSTALLATION
BULB INSTALLATION
NOTE: This unit is shipped without bulbs installed to pre-
vent any damage to the bulb lament during transport.
This unit is shipped with a total of 13 bulbs (twelve 15W
bulbs and one 90W bulb). These instructions apply to
new installations only. If replacing bulbs after the installa-
tion is complete, see page 33 for instructions.
LOWER LIGHT BAR BULB INSTALLATION
1. Remove air deection glass from the unit and place
on a at, clean surface.
2. Using a Phillips screwdriver remove the screws (one
each) holding the left and right porcelain panels in
place.
3. Carefully remove the panels from the unit plac-
ing them on a clean level surface. NOTE: The rear
porcelain panel is held in place by the left and right
panel and could fall forward if not supported during
removal of the side panels.
CAUTION
Turn OFF the main power supply before perform-
ing any service work on the unit, including install-
ing or replacing light bulbs.
TOP LIGHT BULB INSTALLATION
1. Remove three screws holding light cover in place
(as shown in Figure 11)
2. Insert (1) 90W bulb provided into socket
3. Replace top light cover with three screws
4. With side panels removed the rear porcelain panel
can be removed from the unit and placed on a clean,
level surface.
5. Remove nine screws that secure the front hearth in
place and remove from unit. Figure 13
Top light
location Porcelain
panel screw
Porcelain
panel screw
Light cover
screws
Figure 10–
Top Light Position; Porcelain Panel Screw Location
Figure 11–
Top Light Screws
Figure 12–
Porcelain Panel Screw Location

18
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
6. Remove ve screws that secure the rear hearth in
place and remove from unit. Figure 13
7. Figure 14 shows bulb placement for front and rear
light bars. Insert bulbs in sockets.
8. With (twelve 15W) bulbs installed in front and rear
light bar, reinstall the rear hearth rst with ve
screws that were removed earlier. Figure 13
9. Reinstall the front hearth with nine screws removed
earlier. Figure 13
10. Place the rear porcelain panel back in place and
reinstall the left and right side using same screws
that were removed earlier.
11. Re-install the air deection glass before proceeding
to add decorative media (next page).
FINAL INSTALLATION
Nine Front Hearth Screws
Five Rear Hearth Screws
Front Lower Light Bulbs
Rear Lower Light Bulbs
Figure 13–
Hearth Screw Locations
Figure 14–
Lower Light Bulb Location

19
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FINAL INSTALLATION
INSTALLATION OF AIR DEFLECTION
GLASS
NOTE: The 32" deector glass must be installed prior
to placing any reglass or stone media on the burner.
To install the air deection glass simply place the tabs
located at the bottom of the glass into the slots at either
end of the burner oor, in front of the burner ports. The
glass should stand upright, neither leaning forward nor
backward.
GLASS ONLY PLACEMENT
NOTE: Two (2) bags of glass are supplied with the replace.
Both bags may be used to cover the entire oor and burner.
We advise against using additional glass as too much can
cut off the proper amount of air the burner needs to burn
cleanly. This may cause sooting.
1. Spread glass evenly in one layer over the entire oor
and burner. It is important to not have the glass too thick
on ported area (single layer only).
2. Turn burner on and adjust glass over ported areas to
achieve an even, clean ame.
GLASS AND OPTIONAL STONE KIT PLACEMENT
1. For best results, spread glass evenly over the entire
oor and burner making sure the glass is not too thick
over the burner ports (single layer only).
2. Place the stones randomly in front of and behind the
burner. CAUTION: Do not allow stones to sit directly
on burner or in ame. Figure 15 and 16.
3. Turn burner on and adjust glass over the ported area
to achieve an even, clean ame. Page 32, Figure 37
Figure 15 –
Air Deection Glass and Stone Placement
Rear VentBurner Surface
Examples of
Stone Placement
Air Deection Glass Placement (before) Air Deection Glass Placement (after)

20
AVFL Vent Free Fireplace
Monessen • AVFL42NTSC-SR Installation Instructions • 4116-900 Rev. B • 10/19
FINAL INSTALLATION
PLACEMENT OF OPTIONAL LOGS
WARNING: Turn off replace and allow to cool com-
pletely before beginning installation.
Kit Contents:
• Two (2) ceramic ber driftwood logs
• Four (4) log support pin brackets
• Eight (8) #8 bracket mounting screws
NOTE — Do not handle logs with your bare hands. Always
wear gloves to prevent skin irritation from ceramic -
bers. After handling the logs, wash your hands with soap
and water to remove any traces of bers.
NOTE: Prior to installing the log set, you must rst install the
pin brackets on the burner. Fireglass and the air deection
glass should only be installed after the pin brackets are in
place. The logs must then be placed in the unit after the
reglass and air deection glass. If the optional logs are
added after the air deection glass and reglass are in use,
move the reglass away from the areas in Figure 17 and
WARNING
The positioning of the logs is critical to
the safe and clean operation of this heater.
Sooting and other problems may result if the
logs are not properly and rmly positioned
in the appliance. Never add additional logs
or embellishments such as pine cones,
vermiculite or rock wool to the heater. Only
use the logs supplied with the optional log
kit (AVFL42DLS).
Failure to position the parts in accordance
with diagrams below or to use only
parts specifically approved for this
heater may result in property damage or
personal injury.
install the support brackets, then arrange reglass evenly
across burner again.
1. Mount the four log support
pin brackets using mount-
ing holes and screws pro-
vided in locations indicated
in Figure 18. Note that the
front log can be mounted
in two different positions.
The pin brackets can be
moved to accommodate
the preferred log place-
ment.
2. Place the large rear log
(#1) by aligning the holes
in the bottom of the log
with the two pins at the
back of the burner. Figure 19.
Figure 16–
Stone Placement
Figure 18 –
Alternative Log Placement
Figure 17 –
Log Pin Assembly
Pin placement
Log #1 (Rear)
Pin placement
Log #2 (Front)
Option 1
Pin placement
Log #2 (Front)
Option 2
Air Deection
Glass