Monessen Hearth AVFLST Series Manual

This is an unvented replace. It uses air (oxygen)
from the room in which it is installed. Provisions
for adequate combustion and ventilation 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.
AVFLST Vent Free See Through
Fireplace System
Installation & Operating Instructions
Models: AVFLST42NIP and AVFLST42PIP
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020

2
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
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
AVFLST42 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 for installation ............................... 8
Planning the installation .............................................. 8
Adequate combustion and ventilation air .................... 8
Fireplace location ........................................................ 9
Clearances and height requirements ........................ 10
FIREPLACE INSTALLATION ...................................... 12
Secure replace to framing ....................................... 12
Finishing material ...................................................... 12
Noncombustible facing installation ............................ 12
Connect the gas ........................................................ 13
Check gas pressure .................................................. 14
Gas pressures ........................................................... 14
ELECTRICAL INSTALLATION.................................... 15
Wiring junction box .................................................... 15
Wiring Requirements ................................................. 16
FINAL INSTALLATION ................................................ 18
Installation of air deection glass .............................. 18
Fireglass only placement .......................................... 18
Glass and optional stone kit placement .................... 18
OPERATING INSTRUCTIONS .................................... 19
For your safety read before lighting .......................... 19
Heat Management ..................................................... 20
Operation During a Power Outage ............................ 20
Intellire™ Plus ODS SYSTEM OPERATION............ 21
FLAME APPEARANCE & LED CONTROL................. 28
Flame appearance .................................................... 28
Check the pilot ame ................................................. 28
Check the burner ame ............................................. 28
LED Control ............................................................... 28
MAINTENANCE and CLEANING................................ 29
Cleaning and servicing .............................................. 29
Replacing top light bulb ............................................. 29
Replacing led strips ................................................... 29
Porcelain Panel Removal .......................................... 30
OPERATION AND OPTIONAL ACCESSORIES ......... 31
Operating information ................................................ 31
Optional accessories ................................................. 31
TROUBLESHOOTING................................................. 32
Intellire™ Plus ODS System ................................... 34
SERVICE PARTS......................................................... 36
LIMITED LIFETIME WARRANTY ................................ 38
►
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3
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
Customer:
Lot/Address:
Model (circle one): AVFLST42NIP, AVFLST42PIP
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
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
___________________________
4118-982A 04/20
= Contains updated information.
• 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
Appliance Install (Pg. 7-12)
Verified that the chase is insulated and sealed.
Required non-combustible board is installed.
Fireplace is leveled and secured.
Adequate provisions for combustion and ventilation air have been verified.
Verified clearances to combustibles.
Gas (Pg 13-14)
Proper appliance for fuel type.
Leak check performed and inlet pressure verified.
Verified proper air shutter setting for installation type.
Electrical (Pg 15)
Unswitched power (110-120 VAC) provided to the appliance.
Switch wires properly installed.
Media & Accessories (Pg 18)
All packaging and protective materials removed (inside & outside of
appliance). Media installed correctly.
Accessories installed properly.
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.
Hearth & Home Technologies recommends the following:
STANDARD WORK CHECKLIST

4
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
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 tra󰀩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 soot-
ing, an unvented replace 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 mate-
rials, etc. It is imperative that control compartments,
burners and circulating air passageways be kept
clean.
7. WARNING! Any change to this heater or its controls
can be dangerous.
8. Unvented fireplaces 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 Z21.11.2:19 Unvented
Heaters.
12. Do not install the heaters in a bathroom or bedroom.
13. Proper location of the heater, and annual cleaning are
necessary to avoid potential problems with sooting.
Sooting, resulting from improper installation or opera-
tion, can settle on surfaces outside the replace.
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 re-burned 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 replace. It uses air (oxygen) from
the room in which it is installed. Provisions 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 replaces emit moisture into the living area.
In most homes of average construction, this does not
pose a problem. In houses of extremely tight con-
struction, additional mechanical ventilation is recom-
mended.
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

5
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
IMPORTANT SAFETY INFORMATION
as they are burned o󰀨 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 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 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 shuto󰀨 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
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
PRODUCT FEATURES
NOTE: For LP models an external regulator is required
to reduce supply pressure to a maximum of 13" w.c.
GAS SPECIFICATIONS & ORIFICE SIZE
AVFLST42 CONTROLS
MODEL FUEL
MAX. INPUT
(BTU/h)
MIN. INPUT
(BTU/h)
ORIFICE
SIZE
AVFLST42NIP N AT. 37,000 24,500 2.20 mm
AVFLST42PIP L P. 36,000 28,500 #55
GAS PRESSURES
NATURAL PROPANE (LP)
Inlet Minimum 5.0" w.c. 11.0" w.c.
Inlet Maximum 10.5" w.c. 13.0" w.c.
Regulator Pressure
Setting
3.5" w.c. 10" w.c.
Pilot Regulator 3.5" w.c. —
Control Module
Thermocouple Module
Aux Module
LED Switches
Figure 1. AVFLST42 Controls (Control Access Door Shown Open)

7
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
FIREPLACE AND FRAMING DIMENSIONS
13⁄"
[333mm]
32"
[813mm]
43"
[1092mm]
48½"
[1232mm]
39¾"
[1010mm]
37½"
[953mm]
6⁄"
[154mm]
28"
[711mm]
15⁄"
[386mm]
½"[13mm]
or
⁄"[16mm]
½"[13mm]
or
⁄"[16mm]
33 ½" *
[851mm]
Minimum rough
opening depth
for 5/8" wall thickness
12"
[305mm]
Interior wall
installation
Exterior wall
installation
Minimum Rough
Framing Width
44"
[1118mm]
44"
[1118mm]
Wall cover
thickness
Wall cover
thickness
Minimum rough
opening depth
for 5/8" wall thickness
14⁄"
[378mm]
Minimum
Rough
Framing
Height
32"
[813mm]
*NOTE: The AVFLST42 unit must be raised at least 1.5 inches above the top surface of the nished oor when
using the AVFL42WFBT-A or AVFL42WCSS-A wide contemporary face.
Figure 2. Fireplace dimensions
Figure 3. Framing dimensions with outdoor kit installed (AVFLSTSSODK)

8
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
GETTING STARTED
Check to verify that all listed parts have been received.
You should have the following:
• One (1) Unvented replace
• Two (2) Anchoring screws
• One (1)Installation/operating instructions
• Two (2) 5" noncombustible board
• Two (2) 2" x 32" deector glass
• Two (2) Bags reglass
• One (1) 90 watt bulb
• One (1) RC300 remote control
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 FOR INSTALLATION
You must have the following items available before pro-
ceeding with installation:
• External regulator (for propane/LPG only)
• Manual shuto󰀨 valve
• Piping which complies with local codes
• Sediment trap
• Phillips head screwdriver
• Tee joint.
• Pipe sealant approved for use with propane/LPG
(Resistant to sulfur compounds)
• Pipe wrench
PRE-INSTALLATION INFORMATION
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 di󰀨erent sequence.
1. Position fireplace in desired location. Refer to the
Fireplace and Framing Dimensions (page 7, Figures 2
and 3,) Fireplace Location (page 9, Figure 5) and
Clearances and Height Requirements (page 10, Figures
6 and 7.)
NOTE: Be sure all cardboard 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 10) 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
VENTILATION 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 (4.8m3 per kw)
of the aggregate input rating of all appliances installed in
that space, 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 m3 per 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 tra󰀩c areas.
• In windy or drafty areas.

9
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
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 replace requires no outside venting and
burns cleanly and e󰀩ciency. As a zero-clearance unvented
replace, it can be installed recessed into any wall that is
accessible to a gas line, except in a bedroom or bathroom.
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 a󰀨ected 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 tra󰀩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 5 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
Figure 4.
Fireplace locations
Indoor application
Exterior wall application
with AVFLSTSSODK installed
Figure 5. Possible Fireplace Locations

10
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
PRE-INSTALLATION INFORMATION
CLEARANCES AND HEIGHT
REQUIREMENTS
Ensure that minimum clearances shown in Figures 6 and
7 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 Clearances — The clearance from the inside of
the appliance to any combustible adjacent wall should not
be less than 6". Figure 6
Ceiling Clearance — The ceiling must be at least 36" from
the rebox opening. Figure 6
WARNING!
The dimensions shown in Figures 6 and 7
are 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 re 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 Figures 6 and 7.
36"Minimum
From Opening
12"Max.
Depth
21/2"Max
Depth
18"Min.
From Opening
28"Min.
From Opening
6"Min.
FP3006
mantel clearances
Figure 6. Sidewall and Ceiling Clearances
FP3006
Figure 7. Mantel Clearances
23"
28"
12"
6"
21/2"
mantel clearances
18"
Top of Fireplace
Opening
FP3007
SIDE VIEW
Wall
Insulation
Board
Stud
Stando󰀨
6"
5"
3"4¹⁄₂"45°
1"
3¹⁄₂"
FP3008
mantel leg
1¹⁄₂"
2¹⁄₂"
Fireplace
Opening
FP3008
TOP VIEW
Mantel Clearances shown apply to both sides
of the See Through Unit.

11
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
Good Faith Guidelines for TV Installa ons above a Typical Gas Fireplace
Item Minimum Dimensions
A 6 inches
B4 inches
C 28 inches
D 12 inches
BB
D
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
PRE-INSTALLATION INFORMATION
Mantel and TV Clearances shown apply to both
sides of the See Through Unit.

12
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
FIREPLACE INSTALLATION
SECURE FIREPLACE TO FRAMING
The replace must be secured to the framing studs as
shown in Figure 8. Use eight (8) screws to attach replace
to framing. The side nailing anges are 1⁄2" or 5⁄8" to accom-
modate di󰀨erent wall thickness.
WARNING!
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 stando󰀨s on the top and to the wall board stand-o󰀨s
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.
NONCOMBUSTIBLEFACINGINSTALLATION
CAUTION: The noncombustible wall board supplied with
this unit can be damaged if dropped or struck. Handle
with care.
1. Using drywall screws, secure the noncombustible board
to the two brackets on top of the 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
Supplied noncombustible board
5”
Framing
Members
Nailing
Flange
Screws
Noncombustible Material
Nailing
Flange
Nailing
Flange
Screws
Figure 8. Secure Fireplace to Framing Studs
Figure 9. Noncombustible board installation

13
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
FIREPLACE INSTALLATION
CONNECT THE GAS
NOTICE: A qualied gas appliance installer must connect
the heater to the gas supply. Consult all local codes.
Note: Gas line may be installed on the left or right side of
the appliance.
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
10
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 reliably. Figure 10
IMPORTANT: Loosen the pipe adapter on the ex tube
before installing to the system piping.
Always use an external regulator for all propane/LPG heat-
ers only, to reduce the supply tank pressure to a maximum
of 13" w.c. This is in addition to the internal regulator in the
heater valve.
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.
WARNING!
CHECK GAS TYPE: The gas supply must be the
same as stated on the heater’s rating plate. If the
gas supply is di󰀨erent, DO NOT INSTALL THE
HEATER. Contact your dealer for the correct
model.
WARNING!
Connecting directly to an unregulated
propane/LP tank can cause an explosion.
FP2447
gas connection
3” Min.
To Fireplace
Pipe
Coupling
Stainless
Flexible Tube
Pipe
Locations Pressure Tapping
Point Installation
Manual Shuto󰀨
Valve
Gas Supply Inlet
Tee Joint
Pipe Nipple
Cap
Sediment
Trap
WARNING!
DO NOT USE OPEN FLAME TO CHECK FOR
GAS LEAKS.
WARNING!
This appliance is equipped for either natural or propane
gas. Field conversion is not permitted.
Figure 10. Gas Connection
►

14
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
FIREPLACE INSTALLATION
CHECK GAS PRESSURE
Figure 11
Check the gas pressure with the appliance burning and
the control set to HIGH.
The valve regulator controls the burner pressure which
should be checked at the pressure test point.
Open control access door at bottom front of unit to nd
valve and regulator.
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. If the pressure is not
within the range listed for your gas type turn the valve reg-
ulator until it is within range. After taking pressure reading,
be sure and turn captured screw clockwise rmly to reseal.
Do not over torque. Check for gas leaks.
GAS PRESSURES
NATURAL PROPANE (LP)
Inlet Minimum 5.0" w.c. 11.0" w.c.
Inlet Maximum 10.5" w.c. 13.0" w.c.
Regulator Pressure
Setting
3.5" w.c. 10" w.c.
Pilot Regulator 3.5" w.c. —
Figure 11. Pressure Test Point Location
TEST PORT 'A'

15
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
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 cover plate located on the outer shell-
right side.
3. Loosen two screws on the Romex connector, feed the
necessary length of wire through the connector and
tighten the screws.
4. Make all necessary wire connections and reattach the
cover plate to the outer shell.
WARNING!
Electrical connections should only be performed by
a qualied licensed electrician. Main power supply
must be turned o󰀨 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 receptacle.
WARNING!
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation. Verify
proper operation after servicing.
Figure 12. Junction Box Wiring Diagram
FP1912
Junction box wiring
8/08
Junction Box
Factory Supplied
Not Supplied
120V AC
60Hz
►

16
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
ELECTRICAL INSTALLATION
Wiring Requirements
Intellire™Plus ODS Ignition System Wiring
NOTICE: Batteries should only be used as a power source
in the event of an emergency power outage. Batteries
should not be used as a primary long-term power source.
Battery polarity must be correct when installing batteries.
When using batteries as a power source, the 6-volt
transformer must be unplugged from the receptacle.
Do not store batteries in the battery pack when the
appliance is powered by the 6 volt transformer connected
to permanent electrical service.
• Wire the appliance junction box to 110-120 VAC for
proper operation of the appliance.
WARNING! Risk of Shock or Explosion! DO NOT wire
IFP ODS controlled appliance junction box to a switched
circuit. Incorrect wiring will override IFP ODS safety lock-
out.
• Refer to Figure 13 and 14, IFP ODS Wiring Diagram.
• This appliance is equipped with an Intellire™ Plus
control valve which operates on a 6 volt/1.5 AMP system.
• Plug the 6 volt transformer plug into the appliance junction
box to supply power to the unit OR install 4 AA cell
batteries (not included) into the battery pack before use.
Accessories Requirements
• This appliance ships standard with a remote control.
Wiring for optional Hearth & Home Technologies approved
accessories should be done now to avoid reconstruction.
Follow instructions that come with those accessories.
Figure 13. IntelliFire™ Plus ODS Wiring Diagram
TO Y CORD
(120VAC) SEE
FIGURE 14 ON
NEXT PAGE
I
S
RC300 4.5V DC
(AAA X 3)
TO JUNCTION
BOX 120VAC
GROUND
ORANGE
(PILOT)
GREEN
(MAIN)
BROWN
BLACK
RED
BROWN/RED
OPTIONAL ON/OFF
SWITCH
BATTERY PACK
6V DC
FLAME
MODULATION
AUX300 MODULE
AUX 1 AUX 2
FAN
WHITE
ORANGE
CONTROL MODULE
6V DC
SUPPLY
PILOT
THERMOCOUPLE MODULE
ODS to Adapter Box Wire Assembly
Thermocouple Module Wire Assembly
8K-1 Adapter Box Wire Assembly
ODS Adapter Box
THERMOCOUPLE
THERMOCOUPLE
SENSOR
SENSOR
TO TOP DOME
LIGHT
►

17
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
Figure 14. LED Wiring Diagram
LED STRIP LED STRIP
TRANSFORMER
CONTROL
MODULE
TOP BUTTON
ON/HI/MED/LO/OFF
BOTTOM BUTTON
Color Selection
RED
BLUE
YELLOW
GREEN
RED BLACK
BLACK BLACK BLACK
GREEN
Use Y cord supplied in install bag to plug in 6V
DC supply for control module and LED
transformer.
To Junction
Box 120VAC
6V DC Supply
(See Figure 13 on previous
page)

18
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
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. Repeat for the second glass deector
installation.
FIREGLASS ONLY PLACEMENT
NOTE: Two (2) bags of reglass are supplied with the
replace. Both bags may be used to cover the entire oor
and burner. We advise against using additional reglass
as too much can cut o󰀨 the proper amount of air the burner
needs to burn cleanly. This may cause sooting.
1. Spread reglass evenly in one layer over the entire oor
and burner. It is important to not have the reglass too
thick on ported area (single layer only).
2. Turn burner on and adjust reglass over ported areas
to achieve an even, clean ame.
GLASS AND OPTIONAL STONE KIT
PLACEMENT
1. For best results, spread reglass evenly over the entire
oor and burner making sure the reglass is not too
thick over the burner ports (single layer only).
2. Place the stones randomly in front of and behind the
air deection glass. CAUTION: Do not allow stones to
sit directly on burner or in ame. Figure 17.
3. Turn burner on and adjust reglass over the ported area
to achieve an even, clean ame. (page 28, Figure
22.)
Figure 15. Air Deection Glass Placement (before) Figure 16. Air Deection Glass Placement (after)
Figure 17. Air Deection Glass and Stone Placement
Burner Surface
Examples of
Stone Placement

19
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
IPI LIGHTING INSTRUCTIONS
4604-200
FOR YOUR SAFETY READ BEFORE LIGHTING
TO TURN OFF GAS TO APPLIANCE
1. Equipped with wall switch: Turn ON/OFF switch to OFF.
Equipped with remote or wall control: Press OFF button.
Equipped with thermostat: Set temperature to lowest setting.
WARNING: If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.
GAS
VALVE
A. This appliance is equipped with an intermittent pilot ignition (IPI) device which
automatically lights the burner. DO NOT try to light the burner by hand.
B. BEFORE LIGHTING, smell all around the appliance area for gas. Be sure to smell
next to the floor because some gas is heavier than air and will settle on the floor.
WHAT TO DO IF YOU SMELL GAS
•DO NOT try to light any appliance.
•DO NOT touch any electric switch; do not use any phone in your building.
• Immediately call your gas supplier from a neighbor’s phone. Follow the gas sup-
plier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
C. DO NOT use this appliance if any part has been under water. Immediately call
a qualified service technician to inspect the appliance and to replace any part of
the control system and any gas control which has been under water.
LIGHTING INSTRUCTIONS (IPI)
2. Wait five (5) minutes to clear out any gas. Then smell for gas, including near the
floor. If you smell gas, STOP! Follow “B” in the Safety Information located on the
top of this label. If you do not smell gas, go to next step.
3. To light the burner:
Equipped with wall switch: Turn ON/OFF switch to ON.
Equipped with remote or wall control: Press ON or FLAME button.
Equipped with thermostat: Set temperature to desired setting.
4. If the appliance does not light after three tries, call your service technician or gas
supplier.
2. Service technician should turn off electric power to the control when performing
service.
1. This appliance is equipped with an ignition device which automatically
lights the burner. DO NOT try to light the burner by hand.
4604-201
.
WARNING:
NOT FOR USE WITH SOLID FUEL
DO NOT CONNECT LINE VOLTAGE (110/120 VAC OR 220/240 VAC) TO THE CON-
TROL VALVE.
Improper installation, adjustment, alteration, service or maintenance can cause
injury or property damage. Refer to the owner’s information manual provided with
this appliance. For assistance or additional information, consult a qualified installer,
service agency or the gas supplier.
This appliance needs fresh air for safe operation and must be installed so there are
provisions for adequate combustion and ventilation air.
Keep burner and control compartment clean. See installation and operating instruc-
tions accompanying appliance.
Hot while in operation. DO NOT touch. Keep children, clothing, furniture, gasoline
and other liquids having flammable vapors away.
,enonfi;ynafi,sedoclacolhtiwecnadroccanidellatsniebtsumecnailppasihT
follow the National Fuel Gas Code, ANSIZ223.1/ NFPA 54, or the National Gas and
Propane Installation code, CSA B149.1.
CAUTION:
For additional information on operating your
Hearth & Home Technologies fireplace, please refer to www.fireplaces.com.

20
AVFLST Vent Free Fireplace
Monessen • AVFLST42 Installation Instructions • 4118-900 Rev. B • 05/2020
OPERATING INSTRUCTIONS
Initial Use
Initial Break-in Procedure
• The replace should run three to four hours continuously
on high.
• Turn the replace o󰀨 and allow it to completely cool.
This cures the materials used to manufacture the re-
place.
• Some people may be sensitive to smoke and odors.
• Smoke detectors may activate.
NOTICE: Some functionality will be lost when using
battery backup including remote control, lights, or any
other auxiliary functions that require household 110-120
VAC power.
Operation During A Power Outage
NOTICE: Batteries should only be used as a power source
in the event of an emergency power outage. Batteries
should not be used as a primary long-term power source.
Figure 18. Control Cavity Location
The IntelliFire™ Plus ODS intermittent pilot ignition system
comes with a battery backup system that enables the
system to operate in a power outage. The system o󰀨ers
seamless transition from household AC power to battery
backup. A factory-installed battery pack is located in the
control cavity of the appliance. See Figure 18. Battery
longevity and performance will be a󰀨ected by long term
exposure to the service temperatures of this appliance.
To Operate Fireplace Using Battery Power (DC):
1. Access the control cavity of the appliance. See Figure 18
for location. Lift the barrier screen o󰀨 of the appliance.
2. Locate the battery tray and insert four AA cell batteries.
See Figure 18. Battery polarity must be correct or
module damage will occur. A complete wiring diagram
is included in the electrical section of the appliance
installation manual.
3. Turn the appliance on according to the instructions
below for the appropriate type of control:
Standard Wall Switch or Factory-Installed ON/OFF
Switch:
• Toggle the switch as you would under normal
circumstances.
Wireless Remote:
To Return to Operation Using Electrical (AC) Power
Standard Wall Switch or Factory-Installed ON/OFF
Switch:
• Toggle the switch to OFF.
• Remove the batteries from the battery tray.
Wireless Remote:
• Slide the ON/REMOTE/OFF switch to the REMOTE
position.
• Remove the batteries from the battery tray.
Ignition Module:
• Slide the ON/REMOTE/OFF switch to the REMOTE
position.
• Remove the batteries from the battery tray.
• Remote receiver is integrated into the ignition module
• Use the remote to turn the appliance on.
• To preserve battery life, do not use the HI/LO ame or
THERMOSTAT options.
Ignition Module:
• Locate the ignition module in the control cavity.
• Slide the ON/REMOTE/OFF switch to the ON position.
Heat Management
Burn Rate
The Artisan model has a variable burn rate which is con-
trolled by the remote control. Therefore the ame height
is adjustable.
The ame height may be adjusted as desired by locating
the ame option on the remote control and adjusting up or
down to desired ame height.
Control Module
Battery Tray
Gas Valve