Monessen Hearth NB18 User manual

81D0107 7/14 Rev. 13
Vented/Unvented Gas Log Set
Installation and Operating Instructions
Models: NB18, NB24, NB18SCR, NB24SCR
This is an unvented gas-fired heater. 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 4.
INSTALLER: Leave this manual with the appliance.
CONSUMER: Retain this manual for future reference.
This appliance may be installed in
an aftermarket, 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.
WARNINGS
If the information in this manual is not followed
exactly, a fire or explosion may result causing
propertydamage,personalinjuryorlossof life.
– Do not store or use gasoline or other
flammable 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.
• 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 fire department.
– Installation and service must be performed
by a qualified installer, service agency or
the gas supplier.

2
NB18/NB24 Gas Log Set
81D0107
CONTENTS
Important Safety Information ......................................3
Codes.......................................................................3
Product Features and Specifications ........................5
Gas Pressures .........................................................5
Ignition Controls - Millivolt ........................................5
Pilot/ODS .................................................................5
Thermal Generator...................................................5
Fireplace and Hearth Dimensions ..............................6
Placement in a Fireplace w/ Restrictive Barrier ............6
Clearances and Height Requirements .......................7
Floor Clearance .........................................................10
Fireplace Preparation ................................................11
Vented Application Installation -
NB, NBSC Models ................................................12
Gas Line Connection .................................................13
Check Gas Pressure ..................................................13
Millivolt ...................................................................13
Electrical Wiring - Millivolt.........................................14
Optional Wall Switch or Thermostat.......................14
Connect Remote Receiver.....................................15
Check System Operation .......................................15
Final Installation.........................................................16
Cast Iron Grate Installation ....................................16
Rock Wool Placement............................................17
Berkley Oak Log Placement .................................17
Ember and Rock Placement ..................................19
Stoney Creek Log Placement ................................20
Kentucky Wildwood Log.........................................23
Flame Appearance......................................................26
Operating Instructions - Millivolt ..............................26
For Your Safety Read Before Lighting ...................27
Millivolt Control Lighting Instructions......................28
To Turn Off Gas to Heater......................................28
Match Lighting Instructions ....................................29
Check Gas Pressure & Electrical Installation - SCS30
Command Center Wall Installation.........................30
Wall Switch Installation ..........................................30
Wiring Diagram - SCS............................................31
Operating Instructions - Signature Command.........32
For Your Safety Read Before Lighting ...................32
Operating Instructions............................................33
To Turn Off Gas to Appliance .................................33
Signature Command System Operation Instructions34
Touch Screen Remote Control Operation.................. 37
Cleaning & Servicing..................................................41
Troubleshooting .........................................................43
Millivolt Control System..........................................43
Signature Command System .................................45
Replacement Parts.....................................................46
Burner Assembly - Millivolt.....................................46
Burner Assembly - SCS .........................................47
Berkeley Oak Refractory Logs ...............................48
Stoney Creek Refractory Logs...............................49
Kentucky Wildwood Logs.......................................50
Massachusetts Residents Only.................................51
Warranty......................................................................52
Thank you and congratulations on your purchase of a Monessen Log Set
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 fire hazard and will void the warranty.

3
NB18/NB24 Gas Log Set
81D0107
IMPORTANT SAFETY INFORMATION
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 traffic 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 flammable 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 qualified
service person.
7. 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 fre-
quent cleaning may be required due to excessive lint
from carpeting, bedding material, etc. It is imperative
that control compartments, burners and circulating air
passageways be kept clean.
8. CARBON MONOXIDE POISONING: Early signs of
carbon monoxide poisoning are similar to the flu 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. The NB(18,24) and NB(18,24)SC units comply with
ANSI Z21.11.2 Unvented Heaters, latest edition and
also complies with ANSI Z21.60 Decorative Vented
Appliances for Solid Fuel Burning Fireplaces, latest
edition. The NB(18,24)SCR units comply with ANSI
Z21.11.2 Unvented Heaters, latest edition ONLY.
WARNING
IMPORTANT
Read these instructions carefully before installing or trying to operate this vent-free gas heater.
State and local codes may only allow operation of
this appliance in a vented configuration. Check your
state or local codes. For vented operation, see “Vented
Instructions” in this manual.
11. Do not install the heaters in a bathroom or bedroom.
12. Correct installation of the logs, proper location of the
heater, and annual cleaning are necessary to avoid
potential problems with sooting. Sooting, resulting
from improper installation or operation, can settle on
surfaces outside the fireplace. See log placement
instructions for proper installation.
13. Avoid any drafts that alter burner flame patterns. Do not
allow fans to blow directly into fireplace. Do not place
a blower inside burn area of firebox. Ceiling fans may
create drafts that alter burner flame patterns. Sooting
and improper burning will occur.
14. Caution: Candles, incense, oil lamps, etc. produce
combustion by-products including soot. Vent-free
appliances will not filter 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.
15. 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.
16. 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 NationalFuel
Gas Code, ANSI Z223.1/NFPA 54, the International
Fuel Gas Code or applicable local codes.
17. Keep room area clear and free from combustible
materials, gasoline and other flammable vapors and
liquids.
•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 fire, burns,
explosion or carbon monoxide poisoning.
•Do not allow fans to blow directly into the fireplace. Avoid any drafts that alter burner flame
patterns.
•Do not use a blower insert, heat exchanger insert or other accessory, not approved for use
with this heater where applicable.

4
NB18/NB24 Gas Log Set
81D0107
IMPORTANT SAFETY INFORMATION
18. Unvented gas heaters are a supplemental zone heater.
They are not intended to be the 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, films 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.
The initial break-in operation should last four hours to
properly cure logs and rock wool, 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 pres-
sures 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 qualified 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. This appliance must not be used with glass doors in
the closed position. This can lead to pilot outages and
severe sooting outside the fireplace.
26. Never burn solid fuels in a fireplace where a unvented
room heater is installed.
27. Always have a fireplace screen in place when the
appliance is in operation and, unless other provisions
for combustion air are provided, the screen must have
an opening(s) for induction of combustion air.
MASSACHUSSETTS RESIDENTS ONLY:
Refer to Page 46 for
additional information.
NB18, NB18SC, NB24, NB24SC
Certified To
ANSI Z21.11.2 Latest Edition
Unvented Heaters &
Z21.60 Latest Edition;
CSA 2.26 Latest Edition
WARNING
Never connect unit to private (non-utility)
gas wells. This gas is commonly known
as wellhead gas.
CODES
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
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.
NB18SCR, NB24SCR
Certified To
ANSI Z21.11.2, Latest Edition
Unvented Heaters

5
NB18/NB24 Gas Log Set
81D0107
MAKE SURE YOU HAVE RECEIVED ALL
PARTS:
Check your packing list to verify that all listed parts have
been received. You should have the following:
NB Models
•Unvented Gas Log Burner Assembly
•Two (2) Plastic Bags Containing Crushed Volcanic
Rock
•Installation/Operating Instructions
•Two (2) Anchoring Screws
•Ceramic Fiber Logs / Refractory Logs
• Rock wool & Bright Embers
•Grate Assembly
•On/Off Log Switch Assembly (MV Models Only)
•Thermostat Remote Control (SCR Models Only)
•‘AA’ Batteries (SC Models only)
The following options may be used with the millivolt con-
trolled heater. These options are not packaged with the
log set.
•Hand Held Remote with Receiver (MV)
•Wall Thermostat with 15' Wire
•Wall Switch with 15' Wire
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 should have the following items available before pro-
ceeding with installation:
•External regulator (for propane/LPG and 1/2 psi
natural gas systems only)
•Piping which complies with local codes
•Sediment trap (recommended)
•Screwdriver
•Tee joint.
•Pipe sealant approved for use with propane/LPG
(Resistant to sulfur compounds)
•Drill with 5/32 masonry bit
•Pipe wrench or appropriate size crescent wrench
set
•Manual shutoff valve
PRODUCT FEATURES
Gloves are recommended when handling
ceramic fiber logs to prevent skin irritation
from loose fibers. Logs are fragile — handle
with care.
CAUTION
NATURAL GAS
NOTE: An external regulator is required to reduce supply
pressure to a maximum of 101⁄2" w.c. on natural gas sys-
tems operating at higher pressure.
PROPANE/LPG
NOTE: An external regulator is required to reduce supply
pressure to a maximum of 13" w.c.
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. 11.0" w.c.
Pilot Regulator 3.5" w.c. n/a
MILLIVOLT IGNITION CONTROLS
Piezo ignitor allows ignition of the pilot without the use of
matches or batteries.
Millivolt control has four (4) positions:
OFF - All gas to the gas logs is shut off at the
valve.
IGN - Valve position to light/maintain a stand-
ing pilot.
ON - Valve position to turn ON/OFF log set
with remote switch/thermostat.
LOW/HI - Variable position to control flame height
(heat output).
SIGNATURE COMMAND CONTROLS
Refer to Page 28
PILOT/ODS
The gas log heater is fitted with a specially designed
safety pilot (ODS assembly) which senses the amount
of oxygen available in the room and shuts the gas log
heater off if the oxygen level begins to drop below
a satisfactory level. The pilot can only be relit when
adequate fresh air is available.
THERMAL GENERATOR
The millivolt gas log pilot is fitted with a millivolt
(thermopile) generator to provide power for remote
activation.
GAS SPECIFICATIONS
Gas Rate
Max.Input Min. Input
Model Fuel BTU/h BTU/h
NB18 Natural 28,000 19,000
NB24 Natural 37,000 25,000
NB18 LP 27,000 22,000
NB24 LP 36,000 28,000

6
NB18/NB24 Gas Log Set
81D0107
FIREPLACE AND HEARTH DIMENSIONS
WARNING
This appliance is for installation only in a
solid-fuelburningmasonry or UL127 factory-
built fireplace, vent free appliance, or in
listed ventless firebox enclosure. It has been
design certified for these installations.
Exception: DO NOT install this appliance
in a factory-built fireplace that includes
instructions stating it has not been tested
or should not be used with unvented gas
logs.
Use manufacturer's installation and clearance require-
ments as defined in their manual.
The NB and NBSC/SCR Series unvented room heaters
are approved for installation into the following unvented
fireplaces:
VF Series Fireboxes, Magnum36/42, Lo-Rider36 or
BUF
The NB and NBSC/SCR Series unvented room heaters
may also be installed into a Ventless Firebox Enclosure for
Gas Fired Decorative Type Unvented Room Heaters per
ANSI Z21.91 (typically referred to as a "Universal Firebox"),
as long as firebox hearth dimensions meet the minimum
hearth dimensions shown below.
A
C
D
B
Figure 1 -
Minimum Hearth Dimensions
Model A B C D
NB18 w/18" Log 26" 13" 18" 17"
NB24 w/24" Log 29" 13" 221⁄4" 17"
NB24 w/30" Log 33" 13" 251⁄4" 17"
NB18SC,SCR w/18" Log 28Z\x" 13" 201⁄4" 17"
NB24SC/SCR w/24" Log 31" 13" 251⁄4" 17"
NB24SC/SCR w/30" Log 35" 13" 251⁄4" 17"
IMPORTANT INFORMATION FOR THE
INSTALLATION OF THIS GAS LOG SET
PLACEMENT IN FIREPLACE WITH A
RESTRICTIVE BARRIER
The following are guidelines for placing a gas log set in
a fireplace that has a restrictive barrier along the bottom
front opening of the fireplace. Some examples of barri-
ers are glass/screen door frames and sunken/recessed
fireplaces.
Height of Minimum Depth of
Restriction (x) Fireplace/Firebox
No Restriction 13"
0" to 11⁄2" 16"
Greater than 11⁄2" to 3" 16"
Greater than 3" *
*Any barrier greater than 3" placed in front of the gas log
set is not recommended by the manufacturer.
NOTE: Non combustible material such as refractory brick
may be used to line the floor of the fireplace in order to raise
the height of the gas log set in relation to a restrictive barrier.
If the unit is raised, the minimum height dimension listed in
the homeowner’s manual must not be exceeded.
NOTE: If the log set is equipped with a remote receiver, a
restrictive barrier may reduce the battery life by increasing
the ambient temperature inside the fireplace. Placement
of the receiver outside of the fireplace will extend the
battery life.
Glass door frames
with adjustable
louvers should have
the louvers fully
open while the unit
is in operation
Height of restrictive barrier
caused by glass door frames,
recessed fireplaces, etc. from
the base or bottom surface of
the unit. (Refer to Table) Depth of Fire-
place/Firebox
Refer to Table
The log set should be
placed against or as
near as possible to the
rear wall of the fireplace/
firebox.
FP2252
Figure 2 -
Reference Drawing ofa Natural Flame Log
Set in an Enclosure
Barriers such as the bottom of a glass door
frame placed in front of a gas log set can
change the air flow characteristics of the
fireplace which in turn can cause the unit to
overheat and malfunction.
WARNING

7
NB18/NB24 Gas Log Set
81D0107
CLEARANCES AND HEIGHT REQUIREMENTS
Sidewall and ceiling clearances: The sides of the fire-
place opening must be at least 16" from any combustible
wall. The ceiling must be at least 42" from the top of the
fireplace opening.
WARNING
The dimensions shown in Figures 3 through
11 anddefinedinthefireplacemanufacturer's
instructions are minimum clearances to
maintain when installing this heater. Left
and right clearances are determined when
facing the front of the heater.
When heater is installed into a ventless
firebox, minimum clearances, as specified
by the ventless firebox manufacturer, must
be met.
Follow these instructions carefully to
ensure safe installation. Failure to follow
instructions exactly can create a fire
hazard.
Heat resistant material (minimum requirements) with
no wooden mantel or other combustible projection:
To install the gas logs into a fireplace with no wooden
mantel, shelf or other combustible projection above the
fireplace opening, measure the heat resistant material
height, according to Figure 4 and TABLE A.
Heat resistant materials such as slate and marble must be
at least 1/2" thick. Sheet metal should not be installed
onto combustible material.
IMPORTANT: If you cannot meet these minimum clear-
ances you must operate the heater with chimney flue
damper open. Refer to “Installing Vented Applications”
found on Page 17.
Heat resistant
Material
Measure
This
Distance
Heater in
Fireplace/
Firebox
FP2254
Figure 4 -
Measure Heat Resistant Material
Table A - Heat Resistant Material Requirements with No Mantel or Combustible Projection
Heat Resistant Requirements for Safe Installation
Material Measurement NB18 NB24
12" or more Hood not required Hood not required
8" or less than 12" Hood not required Extend heat resistant material to 12" or install hood. Figure 4
Less than 8" Extend heat resistant Extend heat resistant material to 8" AND install hood.
material to 8" AND Figure 5. OR, extend heat resistant material to a height of
install hood. Figure 4 at least 12"
16"
42"
Figure 3 -
Sidewall and Ceiling Clearances
FP2253

8
NB18/NB24 Gas Log Set
81D0107
CLEARANCES and HEIGHT REQUIREMENTS
Heat resistant material (minimum requirements) with
wooden mantel or other combustible projection:
To install the heater with a wooden mantel, shelf or other
combustible projection above, first measure the heat resis-
tant material shown in Figure 5, then refer to Table B.
Hood
Heater in Fireplace
or Firebox
8" or More
of Heat
Resistant
Material
FP2255
Figure 5 -
Measuring Heat Resistant Material for Mantel
Table B - Heat Resistant Material Requirements Height and Mantel Location
Requirements for Safe Installation with Wooden Mantel, Shelf or
Heat Resistant other Combustible Projection
Material Measurement NB18 NB24
12" or more Hood not required. Observe profiles Hood not required. Observe profile (side
(side elevations) shown in Figure 6 elevations shown on Figure 8
8" or less than 12" Install hood and observe profiles Install hood and observe profiles shown in
shown in Figure 7 OR Figure 7; OR extend heat resistant material
extend heat resistant material to to at least 12" and observe profiles shown in
at least 12" and observe profiles Figure 8
Less than 8" Extend heat resistant to at least 8", Extend heat resistant material to least 8", install
install hood and observe profiles hood and observe profiles shown in
shown in Figure 7; OR Figure 7; OR extend heat resistant material to at
extend heat resistant material to at least 12" and observe profiles shown in
12" and observe profiles shown in Figure 8
Figure 6

9
NB18/NB24 Gas Log Set
81D0107
10"
8"
6"
256O"
8" 1456O" 186" 2256O" 26"
12"
CLEARANCES AND HEIGHT REQUIREMENTS
Figure 7 -
Minimum Mantel
Clearance with Hood
- All Models
Example: A mantel may project from the wall a maximum
of 21⁄2" at a minimum of 8" above the opening, and a
maximum of 6" at a minimum of 141⁄2" above the opening.
10"
8"
6"
256O"
8" 14" 2056O" 246" 28"
Example: A mantel may project from the wall a maximum
of 21⁄2" at a minimum of 14" above the opening, and a
maximum of 6" at a minimum of 201⁄2" above the opening.
Figure 6 -
Minimum Mantel
Clearance with No
Hood - NB18
Heat
Resistant
Material
Heater in
Fireplace or
Firebox
FP2256
Heat
Resistant
Material
Heater in
Fireplace or
Firebox
Hood
FP2257
Figure 9 - Minimum Mantel
Clearance with Hood - NB24
(Example of Unsafe
Installation)
Figure 8 -
Minimum Mantel
Clearance with No
Hood — NB24
Example: The bottom of the mantel may project from the
wall a maximum of 10" at a minimum of 28" above the
opening.
Figure 9 is an example of an unsafe mantel installation.
This mantel projects 4" at 8" above the opening, exceeding
the maximum acceptable depth of 21⁄2" The mantel also
projects 7" at 141⁄2" above the opening, exceeding the
maximum acceptable depth of 6".
If your mantel profile is unsafe, you may either:
• Raise the mantel to an acceptable height
OR
• Remove the mantel
10" or less
12" min.
28"
Heat
Resistant
Material
Heater in
Fireplace or
Firebox
FP2260
256O"
8"
6"
7"
1456O"
4"
Mantel
Minimum
of 8" Heat
Resistant
Material
Hood
FP2259

10
NB18/NB24 Gas Log Set
81D0107
FLOOR CLEARANCE
The gas log heater must be installed at least 13⁄8" above
any combustible flooring material, such as carpeting or
tile, which is closer than 14" to the base of the fireplace.
The minimum distance must be maintained from the top
surface of carpeting, tile, etc. Figure 10
Figure 10 -
Minimum Clearance above Combustible Flooring
Heater in Fireplace
or Firebox
Combustible
Material
13⁄8" Minimum
FP2261
Figure 11 -
Minimum Clearance above Combustible Flooring with
Noncombustible Material Installed at Base of Fireplace
14” Minimum
Heater in Fireplace
or Firebox
Combustible
Material
This Distance
May Now be
Less Than 13⁄8"
FP2262
OR
The gas log heater may be installed nearer to the floor if a
minimum of 14" of noncombustible material such as slate
or marble is installed between the base of the fireplace and
the combustible flooring. Figure 11

11
NB18/NB24 Gas Log Set
81D0107
FIREPLACE PREPARATION
BEFORE FULLY INSTALLING THE UNIT:
•Turn OFF the gas supply to the fireplace or firebox.
•Seal any fresh air vents and/or ash clean-out doors
located on the floor or wall of the fireplace. If left
unsealed, drafting may cause pilot outage or soot-
ing. Use a heat resistant sealant. Do not seal the
chimney flue damper.
INSTALLING VENTED APPLICATIONS -
NB & NBSC ONLY
Manual and millivolt controlled gas logs may be installed
as a vented decorative log set in compliance with ANSI
Z21.60 and National Fuel Gas Code, Section 6.6. Since,
the gas logs are operated with the damper open, non-
combustible material and minimum mantel require-
ments do not apply.
WARNING
Before installing in a solid fuel burning
fireplace, The chimney flue and firebox
must be cleaned of soot, creosote, ashes
and loose paint by a qualified chimney
cleaner.
WARNING
Thisapplianceisforinstallationonlyinasolid
fuel burning fireplace (masonry fireplace or
manufactured fireplace) with a working
flue and constructed of noncombustible
material.
Exception: DO NOT install this appliance
in a factory-built fireplace that includes
instructions stating that it has not been
tested or should not be used with unvented
gas logs. This log set may be installed as a
vented log set.
Before installing the appliance:
•Turn off gas supply to fireplace or firebox.
•Have the fireplace floor and chimney professionally
cleaned to remove ashes, soot, creosote or other
obstructions. Have this cleaning performed annually
after installation.
•Seal any fresh air vents or ash clean-out doors
located on floor or wall of fireplace. If not, drafting
may cause pilot outage or sooting. Use a heat-resis-
tant sealant.
Install and operate the appliance as directed in this
manual.
DAMPER STOP INSTALLATION
A damper stop must be provided with the unit. Contact your
dealer to obtain one. The damper stop must be installed as
shown in Figure 12 to prevent full closure of the fireplace
damper blade and provide a minimum 29 square inch flue
opening.
Figure 12 -
Damper Stop Installation.
Damper Stop
Damper
FP2263

12
NB18/NB24 Gas Log Set
81D0107
VENTED APPLICATION INSTALLATION / SECURE APPLIANCE
WARNING
The fireplace and gas logs function as a
system. If the fireplace is spilling into the
room (check with a match or a smoke stick),
reposition the damper clamp until a positive
draft is obtained by opening the damper. If
negative pressure in home prevents having
a positive draft, contact your dealer for
assistance.
WARNING
You must secure the gas log heater to
the fireplace floor. If not, the entire unit
may move when you adjust the controls.
Movement of unit may cause shifting of
the gas logs which leads to sooting and
improper burning. Grate movement could
cause a gas leak.
Special care is required if you are installing
the unit into a sunken fireplace. You must
raisethefireplace floor toallow access to gas
logcontrols. This will insureadequate air flow
andguard againstsooting.Raise thefireplace
floor using noncombustible materials, as
described in Placement in a Fireplace with
Restrictive Barrier on Page 6.
ASSEMBLY PROCEDURE
1. Center the gas log unit on the fireplace or firebox. Make
certain the front of the burner sits inside the front edge
of the fireplace or firebox.
2.Anchor holes are located on the right and left sides of
the unit. After centering the burner correctly, mark the
hole positions on the fireplace/firebox floor. Drill two (2)
5/32" diameter holes approximately 11⁄2" deep.
3.Anchor the grate to the fireplace/firebox floor using the
screws provided. Figure 13
Proper installation of the grate is essential to prevent
any movement of the gas logs and controls during
operation. Screw
Screw
Anchor Hole
FP2264
Figure 13 -
Securing Heater to Floor of Fireplace/Firebox
VENTED APPLICATIONS ONLY

13
NB18/NB24 Gas Log Set
81D0107
GAS LINE CONNECTION
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,
providinggas meets hydrogen sulfidelimits,
and where permitted by local codes. Gas
piping system must be sized to provide
minimum inlet pressure (Listed on Data
Plate) at the maximum flow 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 14
NOTICE: A qualified gas appliance installer must connect
the heater to the gas supply. Consult all local codes.
IMPORTANT: Hold heater valve firmly with a wrench to
prevent movement when connecting to inlet pipe.
Always use an external regulator for all propane/LPG
heaters and high pressure one to two-pound systems
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.
Pipe Coupling
To Heater
Valve
Gas
Supply
Inlet
Manual Shutoff
Valve
Pipe
Stainless
Flexible Tube
Figure 14 -
Gas Connection
Locations
that the
Pressure
Tapping
Point May Be
Installed
FP2265
WARNING
CHECK GAS TYPE: The gas supply must
be the same as stated on the heater’s rat-
ing plate. If the gas supply is different, DO
NOT INSTALL THE HEATER. Contact your
dealer for the correct model.
Connecting directly to an unregulated pro-
pane/LPG tank can cause an explosion.
WARNING
The heater gas inlet connection is a 3/8" NPT at the valve.
On all control type units, the inlet connection is on the right
side of unit. To connect from the opposite side, route the
pipe around the back portion of the unit.
When tightening up 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 the gas pressure with the appliance burning and
the control set to HIGH.
MILLIVOLT VALVE CONTROL
Figure 15
The valve regulator controls the burner pressure which
should be checked at the pressure test point.
Turn captured screw counter clockwise two or three turns
and then place tubing to pressure gauge over test point
(Use test point “OUT” closest to control knob). After taking
pressure reading, be sure and turn captured screw clock-
wise firmly to re-seal. Do not over torque. Check for gas
leaks.
Figure 15 -
Pressure Test Point Location
Millivolt Control
Test Port “OUT”
FP2266

14
NB18/NB24 Gas Log Set
81D0107
ELECTRICAL WIRING - MILLIVOLT
The millivolt valve is a self-powered combination gas control
THAT DOES NOT REQUIRE 110 VAC TO OPERATE.
CONNECT OPTIONAL WALL SWITCH OR
THERMOSTAT
1. Use 18 awg, two-wire cable, 15 feet maximum length.
2. At one end of the cable, connect both wires to the wall
switch or thermostat. At the other end, connect one
wire to TP/TH and one wire to TH, or connect the wall
switch/thermostat to the two male (0.25") terminals on
the left side of the unit. The color of the wires does not
matter.
Figure 16 -
Wiring Diagram
NOTE: Log switch wires are not factory connected.
Connect log switch wires to the TH/TP and TH valve terminals as shown.
d
.
Log Switch
On/Off Switch
or Optional Wall
Switch, Remote
or T-Stat
ODS Pilot
Millivolt
Valve
TH = 3
TP = 1
TP/TH = 2
ODS
Pilot
CAUTION
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation. Verify
proper operation after servicing.

15
NB18/NB24 Gas Log Set
81D0107
ELECTRICAL WIRING - MILLIVOLT
CONNECT REMOTE RECEIVER
1. Set remote receiver. See instructions included in
receiver kit.
2. Connect the two (2) 1/4" female connectors to the TP/TH
and TH terminals on the control valve.
NOTE: Heat reduces battery life. You can protect the
receiver and extend battery life by mounting receiver
in wall or other location outside the fireplace.
CHECK SYSTEM OPERATION
The millivolt system and individual components may be
checked with a millivolt meter having a 0-1000 mV range.
Conduct each check shown in chart below by connection
meter test leads to terminals as indicated.
NOTICE
Do not allow wires touch grate or burner.
A. Complete Millivolt System Check
(“A” Reading - Thermostat contacts CLOSED -
Control Knob “ON” - Main burner should turn
ON)
a. If the reading is more than 175 millivolts and the
automatic valve still does not come on, replace the
control.
b. If the closed circuit reading (“A” reading) is less than
175 millivolts, determine cause for low reading, pro-
ceed to Section B below.
B. Thermopile Output Reading Check
(“B” Reading - Thermostat contacts OPEN - Main
burner OFF)
1. Check gas pressure to the unit. If gas pressure is
within minimum and maximum on data plate, then
check pilot voltage, 500 millivolts minimum. If the
minimum millivolt reading is not obtainable, replace
pilot.
Connect Switch or Meter
Check Meter Leads Thermostat Reading
Test To Test To Terminals Contacts Should Be
A Complete 2 & 3 Closed Minimum 175
System
B Thermopile 1 & 2 Open Minimum 500
Output
TP/TH = 2
TP = 1
TH = 3
Figure 17 -
Installing Remote Receiver Remote Receiver
Remote Wire
Connectors
Remote Wire
Connectors
Valve
FP2268

16
NB18/NB24 Gas Log Set
81D0107
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 firmly 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 and 2G-RW rock wool
(for NB18), or 3G-RW rock wool (for NB24)
supplied with the unit.
Failure to position the parts in accordance
with diagrams below or to use only parts
specificallyapprovedforthisheatermayresult
in property damage or personal injury.
Before you begin — This unit is supplied with seven (7)
ceramic fiber logs. Do not handle these logs with your bare
hands. Always wear gloves to prevent skin irritation
from ceramic fibers. After handling the logs, wash your
hands gently with soap and water to remove any traces
of fibers.
A.
Cast Iron Grate I Slot
Key
Hole Slot
Figure 18 -
Install Cast Iron Grate
CAST IRON GRATE INSTALLATION
Install the cast iron grate by inserting screw head on back
of right side of grate into the “I” shaped slot on front right
corner of unit. After moving screw head to the bottom of
the “I” slot, insert the screw head on the back of the left
side of grate into the keyhole slot on the left front of unit.
Figure 18
Cast Iron Grate
B.
FP2271
FINAL INSTALLATION

17
NB18/NB24 Gas Log Set
81D0107
LOG PLACEMENT
•Use only rock wool provided with log
set.
•Do not add additional rock wool.
WARNING
Dime-sized Pieces
of Rock Wool
FP2269
Figure 19 -
Place Rock Wool
INSTALL 18", 24" AND 30" (F,R) BERKLEY
OAK LOGS ON NATURAL BLAZE BURNER
1. Place the #1 log (the “chunk”) on the grate bar right side
of the burner adjacent to the controls. Figure 20
2. Place front right log (#2) on right pin located on burner
and right grate bar. Figure 21. slide Log #1 forward so
that it is tight against log #2.
Figure 20 -
Place Ember Chunk Log #1
Ember Chunk
Log #1
LG620
Figure 21 -
Place Right Front Log #2
Right Front
Log #2
LG630
3. Place right rear log (#3) on pin located
on rear support bracket and rest left side
of log on front right log. Figure 22.
ROCK WOOL PLACEMENT
Before installing logs, place rockwool in dime size pieces
evenly over small burner ports starting in the rear of the
burner going towards the front. Avoid placing rock wool on
slots on each side of rear burner and on large yellow flame
ports on front of burner. After covering small burner ports,
discard any excess rock wool.
Wash hands after placing rock wool. Itching may occur.
NOTE: Installation instructions are the same for 18",
24", and 30" log sets. Pictures used in this manual
illustrate the 24"set.Some variationmayexist between
the images and the set included with this manual.

18
NB18/NB24 Gas Log Set
81D0107
Figure 24 -
Place Left Front Log #5
Left Front Log #5
LG633
Figure 23 -
Place Left Rear Log #4
Left Rear
Log #4
LG632
LOG PLACEMENT
4. Place left rear log (#4) on pin located on rear
support bracket on left side. Figure 23
Figure 22 -
Place Right Rear Log #3
Right Rear
Log #3
LG631
5. Place left front log (#5) on left pin located
on burner and left grate bar. Rest top right
portion of log on right front log. Figure
24

19
NB18/NB24 Gas Log Set
81D0107
Figure 25 -
Place Middle Left Log #6
Middle Left
Log #6
LG634
Figure 27 -
Place embers
LOG PLACEMENT
6. Place top left log (#6) on unit by
placing grooved portion of log onto
left grate bar with bark facing out-
ward. Rest front part of log in groove
on left front log. Figure 25
7. Place left top log (#7) on left rear log
(#4) and left front log (#5) using locating
grooves on bottom of #7 and locating
blocks on logs #4 and #5. Figure 26
8. Place right top log (#8) onto right rear
(#3) and right front (#2) logs using locator
on bottom of right top log. Figure 26
PLACE FLICKERING EMBERS
Place flickering bright embers (FBE-.1G)
after placing logs on burner. Pull apart into
small strands and place on top of existing
rock wool in front of and between front logs
where they can be seen. Try to avoid stack-
ing these embers on top of each other. Use
smaller and stringier strands for maximum
effect. Use as much as needed until desired
effect is achieved.
Figure 26 -
Place Right Top Log #8
Left Top
Log #7
Right Top
Log #8
LG636
PLACE THE DECORATIVE ROCK
CAUTION
DO NOT sprinkle volcanic rock on the logs,
around the pilot, or on or near burners. This
may cause sooting. Place volcanic rock only
on the floor of the fireplace.
During initial operation of the new heater,
new burning logs and/or rock wool will give
off a paper burning smell and orange flames
will be present.Simply open thewindows for
a few hours to vent the odor.

20
NB18/NB24 Gas Log Set
81D0107
LOG PLACEMENT
STONEY CREEK SC18/24/30-R LOGS
PLACEMENT
1. Place bottom log (#1) on two (2) pins on rear of grate
assembly and push towards rear as far as possible.
Figure 28 Bottom Rear Log #1
LG1065
Figure 28
Ember Chunk Log #2
(Notch on both ends)
Ember Chunk
Log #3
(Notch on
one end)
LG1066
Figure 29 2. Place the ember chunk (#2)
with notch on both ends on
the grate bar right side of
the burner adjacent to the
controls. Push towards rear
as far as possible. Figure 29
3. Place the ember
chunk (#3) with notch
on one end on the
grate bar left side of
the burner with notch
towards rear. Push
towards rear as far as
possible. Figure 29
4. Place front bottom right log
(#4) on right pin located on
burner and right grate bar.
Figure 30
Front Bottom Log #4
LG1067
Figure 30