Vermont Castings NBST27 User manual

81D3032 10/15 Rev. 7
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.
Vented/Unvented Gas Log Set
Installation and Operating Instructions
Models: NBST27
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.
If theinformationin thismanual is notfollowed
exactly, a fire or explosion may result causing
property damage, personal injury or loss of
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.
WARNING

281D3032
NBST27 Unvented Gas Log Set CONTENTS
Important Safety Information .............................3
Codes.............................................................4
Features and Specifications...............................5
Check Parts....................................................5
Items Needed for INstallation.........................5
Gas Pressures................................................5
Gas Specifications..........................................5
Pilot/ODS........................................................5
Thermal Generator.........................................5
Product Features and Specifications ...............5
Gas Pressures................................................5
Gas Specifications..........................................5
Ignition Controls..............................................5
Pilot/ODS........................................................5
Thermal Generator.........................................5
Fireplace and Hearth Dimensions .....................6
Placement in Fireplace with a Restrictive
Barrier.............................................................6
Clearances and Height Requirements ..............7
Floor Clearances ................................................9
Fireplace Preparation .......................................10
Before Fully Installing the Unit......................10
Installing in Vented Applications ...................10
Before Installing the Appliance .....................10
Damper Stop Installation..............................10
Place and Secure Appliance.............................11
Gas and Valve Connection ...............................12
Millivolt Valve Control....................................12
Electrical Wiring (Millivolt)................................13
Connecting Optional Wall Switch
or Thermostat ...............................................13
Connect Remote Receiver ...........................14
Checking System Operation.........................14
Log Placement...................................................15
Rockwool Placement....................................15
Log Placement..............................................15
Flame Appearance.............................................17
Check the Pilot Flame ..................................17
Check Burner Flame Appearance ................17
Operating Instructions......................................18
For Your Safety Read Before Lighting..........18
Millivolt Control Lighting Instructions............19
To Turn Off Gas to Heater.............................19
Match Lighting Instructions...........................20
Maintenance.......................................................20
Cleaning and Servicing.................................20
Troubleshooting ................................................21
Replacement Parts............................................23
Accessories .......................................................24
Requirements in Massachusetts......................25
Warranty.............................................Back Cover

3
81D3032
NBST27 Unvented Gas Log Set
IMPORTANT SAFETY INFORMATION
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. Youngchildrenshould be carefully supervisedwhen
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. Installationand repair shouldbe done by a qualified
service person.
7. To preventmalfunction 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
excessivelint 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,dizzinessand/ornausea.Ifyouhavethese
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. Thisunit complies withANSIZ21.11.2 Unvented Heat-
ers, latest edition and also complies withANSI Z21.60
Decorative Vented Appliances for Solid Fuel Burning
Fireplaces, latest edition. State and local codes may
only allow operation of this appliance in a vented con-
figuration.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 ceramic fiber logs, proper
location of the heater, and annual cleaning are neces-
saryto avoid potential problems with sooting. Sooting,
resulting from improper installation or operation, can
settleon surfaces outside the fireplace.See log place-
ment instructions for proper installation.
13. Avoidanydraftsthatalterburnerflamepatterns.Donot
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 reburnt in the vent-free
appliancewhichcanproduceodors.Itisrecommended
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-
sionsforadequate combustion and ventilationair must
be provided. Refer to Page 5
16. This heater shall not be installed in a room or space
unlessthe required volume of indoor combustion air is
providedby the method described in the National Fuel
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.
INSTALLER
Please leave these instructions with the appliance. OWNER Please retain these instructions for future reference .
IMPORTANT: Read these instructions carefully before installing or trying to operate this vent-free gas heater.
• 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.
WARNING:

481D3032
NBST27 Unvented Gas Log Set
18. Unventedgasheatersareasupplemental 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. Duringmanufacturing,fabricatingandshipping,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
asthey are burnedoffduringthe 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
elevationsupto2,000 feet. For elevationsabove2,000
feet,inputratingsshouldbereduced 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
duringany pressure testingof that system at testpres-
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. Donot use this room heaterif any part has beenunder
water. Immediately call a qualified service technician
to inspect the room heater and to replace any part of
thecontrolsystem and any gascontrolwhich 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.
IMPORTANT SAFETY INFORMATION
NBST27 is certified to ANSI Z21.11.2
Latest Edition Unvented Heaters
& Z21.60 Latest Edition;
CSA 2.26 Latest Edition
CODES
Adhere to all local codes or, in their absence, the latest
editionofTHENATIONALFUELGAS CODEANSIZ223.1
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
Never connect unit to private (non-utility) gas wells.
This gas is commonly known as wellhead gas.
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.
WARNING
MASSACHUSSETTS RESIDENTS ONLY:
Refer to page 25 for additional information.

5
81D3032
NBST27 Unvented Gas Log Set
FEATURES AND SPECIFICATIONS
CHECK PARTS:
Verify contents to ensure you have received all parts. You
should have the following:
•Unvented Gas Log Burner Assembly
• Crushed Volcanic Rock, 3 bags
•Anchoring Screws, 2
•Ceramic Fiber Logs
•Rock wool
•Flickering Bright Embers, 1 bag
•On/Off Log SwitchAssembly
• Installation/Operating Instructions
The following options may be used with the milli-volt con-
trolled heater. These options are not packaged with the
log set.
• Hand Held Remote with Receiver
• Wall Thermostat with 15' Wire
• Wall Switch with 15' Wire
• Hand held Thermostat Remote with Receiver
• Andirons
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.
ITEMS NEEDED FOR INSTALLATION:
You should have the following items available before pro-
ceeding with installation:
• External regulator (for propane/LPG and 1/2 lb.
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
Gloves are recommended when handling
ceramic fiber logs to prevent skin irritation
from loose fibers. Logs are fragile; handle
with care.
CAUTION
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
NATURALGAS:Anexternalregulatorisrequiredtoreduce
supplypressure to a maximum of 101⁄2" w.c.on natural gas
systems operating at higher pressure.
PROPANE/LPG:Anexternalregulatoris required to reduce
supply pressure to a maximum of 13" w.c.
IGNITION CONTROLS
The 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 standing pilot.
ON: Valve position to turn ON/OFF log set with remote
switch/thermostat.
LOW/HI: Variable position to control flame height (heat
output).
PILOT/ODS
Thegas log heateris fitted with a specially designedsafety
pilot (ODS assembly) which senses the amount of oxygen
available in the room and shuts the gas log heater off if the
oxygenlevel begins to drop below a satisfactory level.The
pilot can only be relit when adequate fresh air is available.
THERMAL GENERATOR
Themillivoltgaslog 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
NBST27NV Natural 39,000 26,000
NBST27PV LP 39,000 30,000

681D3032
NBST27 Unvented Gas Log Set FIREPLACE AND HEARTH DIMENSIONS
Use the fireplace manufacturer's installation and clear-
ance requirements as defined in their manual.
TheNBST27unventedroomheaterisapprovedforinstalla-
tionintothe following unventedfireboxes:LSTF36, LPF36,
LRF36, LLF36
The NBST27 unvented room heater may also be installed
intoaVentless FireboxEnclosurefor Gas FiredDecorative
Type Unvented Room Heaters per IAS Requirement No.
2-97ANSI Z21.91-2001 (typically referred to as a "Univer-
sal Firebox"), as long as firebox hearth dimensions meet
the minimum hearth dimensions shown below.
32”
2156O”
2156O”
Figure 1 -
Hearth Minimum Dimensions for Solid Fuel Burning Fire-
places and UL127 Factory Built Fireplaces
X
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)
Refer to
Table
Figure 2 -
Reference Drawing of NBST27 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
flowcharacteristicsofthefireplacewhich in turn can
cause the unit to overheat and malfunction.
WARNING
This appliance is for installation only in a solid-fuel
burning masonry or UL127 factory-built fireplace,
vent free appliance, or in listed ventless firebox
enclosure. It has been design certified for these
installations.
Exception:DONOTinstallthisapplianceinafactory-
built fireplace that includes instructions stating
it has not been tested or should not be used with
unvented gas logs.
WARNING PLACEMENT IN FIREPLACE WITH A
RESTRICTIVE BARRIER
The following are guidelines for placing a gas log set in a
fireplacethathasa restrictive barrier alongthe bottom front
opening of the fireplace. Some examples of barriers are
glass/screendoorframes and sunken/recessed fireplaces.
Height of Restriction
(x) Minimum Depth of Fireplace/Firebox
No Restriction 211⁄2”"
0" to 11⁄2"25
1⁄4"
Greater than 11⁄2" to 3" 271⁄4"
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.

7
81D3032
NBST27 Unvented Gas Log Set
CLEARANCE AND HEIGHT REQUIREMENTS
Sidewall and ceiling clearances: The sides of the fire-
place opening must be at least 13⁄4"from any combustible
wall. The ceiling must be at least 42" from the top of the
fireplaceopening.Thewallparallelto the sideof the heater
must be at least 36" from the side of the heater. Refer to
your firebox owners manual for more information.
42” 36”
36”
16M”
Figure 3 -
Sidewall and Ceiling Clearances
IMPORTANT:
1. If installing unit into an unvented firebox, minimum
required clearances listed in the firebox installation
manual must be met.
2. If installing unit into a vented firebox with a working
damper,minimumclearancesshowninFigure8through
10 must be met
3. If installing unit into a vented firebox with a damper that
is always open, no minimum clearances are required.
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, per Figure 4, then see 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 the unit is installed in a vented fireplace
and cannot meet these minimum clearances you must
operate the heater with chimney flue damper open. Refer
to “Installing Vented Applications” on Page 11.
Measure this Distance
Heat Resistant
Material
Heater in Fireplace or
Firebox
Figure 4 -
Measure Heat Resistant Material
Table A — Heat Resistant Material Requirements
with no Mantel or Combustible Projection
The dimensions shown in Figures 3 through 9 and
defined in the fireplace manufacturer'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.
WARNING
Heat Resistant
Material Mea-
surement Requirements for Safe Installation
12" or more Hood not required
8" to less than 12" Extend heat resistant material to 12" or
install hood. Figure 4
Less than 8" Extend heat resistant material to at
least 8" and install hood. Figure 4 OR
extend heat resistant material to a
height of at least 12"

881D3032
NBST27 Unvented Gas Log Set CLEARANCE 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
combustibleprojection above, firstmeasurethe heat resis-
tant material shown in Figure 5, then refer to Table B.
8" or More of
Heat Resistant
Material
Hood
Heater in Fireplace or Firebox
Figure 5 -
Measure Heat Resistant Material for Mantel
Table B -
Heat Resistant Material Heights and Mantel Location
12"
Min.
28"
10" or Less
Heat Resistant
Material
Heater in
Fireplace
or Firebox
FP2366
Example:
The bottom of the mantel may project from the wall a maximum
of 10" at a minimum of 28" above the firebox.
Figure 6 -
Minimum Mantel Clearance with No Hood
2 1/2"
12"
13"
24"
Heat Resistant
Material
Heater in Fireplace or
Firebox
Hood
Example:
A mantel may project from the wall a maximum of 21⁄2" at a min-
imum of 13" above the opening, and a maximum of 12" at a
minimum of 24" above the opening.
Figure 7 -
Minimum Mantel Clearance with Hood
Heat Resistant
Material Mea-
surement Requirements for Safe Installation
12" or more Hood not required. Observe profile
(side elevations) shown in Figure 6.
8" to less than 12" Install hood and observer profiles
shown in Figure 7; OR extend heat
resistant material to at least 12" and
observe profiles shown in Figure 6.
Less than 8" Extend heat resistant material to at
least 8", install hood and observe pro-
files shown in Figure 7; OR extend heat
resistant material to at least 12" and
observe profiles shown in Figure 6.

9
81D3032
NBST27 Unvented Gas Log SetFLOOR CLEARANCES
The gas log heater must be installed at least 3/4" 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 8
OR
The gas log heater may be installed nearer to the floor if a
minimum of 14" of noncombustible material such as slate
ormarble is installed betweenthe base ofthe fireplace and
the combustible flooring. Figure 9
3/4"
Combustible
Material
Heater in Fireplace
or Firebox
Figure 8 -
Minimum Clearance above Combustible Flooring
14" Min.
Heater in Fireplace
or Firebox
Combustible
Material
This distance may now
be less than 3/4"
Figure 9 -
Minimum Clearance above Combustible Flooring with Noncombus-
tible Material Installed at Base of Fireplace

10 81D3032
NBST27 Unvented Gas Log Set 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 sooting.
Usea heat resistant sealant. Do not seal the chimney
flue damper.
INSTALLING IN VENTED APPLICATIONS
Milli-volt controlled gas logs may be installed as a vented
decorative log set in compliance with ANSI Z21.60 and
NationalFuel Gas Code, Section 6.6. Since, the gas logs
are operated with the damper open, noncombustible
material and minimum mantel requirements do not
apply.
Damper Stop
Damper
FP2370
Figure 10 -
Damper Stop Installation
(Refer to WARNING at top of page)
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-resistant sealant.
Do not seal chimney flue damper.
Install and operate the appliance as directed in this
manual.
DAMPER STOP INSTALLATION:
A damper stop must be provided with the unit when used
for vented applications. Contact your dealer to obtain one.
The damper stop must be installed as shown in Figure 10
to prevent full closure of the fireplace damper blade and
provide a minimum 29 square inch flue opening.
Refer to Page 27 for installations in the Commonwealth
of Massachusetts.
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
This appliance is for installation only in a solid
fuel burning fireplace (masonry fireplace or
manufactured fireplace) with a working flue and
constructed of noncombustible material.
Exception:DONOTinstallthisapplianceinafactory-
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.
WARNING

11
81D3032
NBST27 Unvented Gas Log Set
SECURE APPLIANCE
PLACE AND SECURE APPLIANCE
1. Center the gas log unit in the fireplace or firebox. Make
certain the front feet of the grate sit 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 grate correctly, mark the
hole locations on the fireplace/firebox floor. Drill two (2)
5/32” diameter holes approximately 11⁄4" deep.
3. Anchor the unit to the fireplace/firebox floor using the
screws provided. Figure 11
Proper installation of the grate is essential to prevent
any movement of the logs and controls during oper-
ation.
NOTE
RIGHT CORNER APPLICATIONS
For right corner installations, the piezo ignitor
can be moved to the opposite corner of the ap-
pliance:
1. Remove wire from back of ignitor.
2. Remove two (2) screws holding piezo brack-
et.
3. Reattach bracket on the opposite corner
(where inlet fuel comes into the valve) by us-
ing two clearance holes on burner base.
4. Reattach wire to ignitor. Figure 11 -
Secure Burner
Piezo Ignitor
(Original Location)
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 raise the fireplace
floor to allow access to gas log controls. This will
insure adequate air flow and guard against sooting.
Raise the fireplace floor using noncombustible
materials, as described in Placement in a Fireplace
with Restrictive Barrier on Page 6.
WARNING

12 81D3032
NBST27 Unvented Gas Log Set GAS AND VALVE CONNECTION
NOTICE: Aqualified 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.
To
Heater Valve
Pipe
Possible Locations
for Pressure Tapping
Point
Gas
Supply
Inlet
Manual Shut-off Valve
Pipe Coupling
Stainless Flexible
Tube, Pipe or
Metal Tube
Figure 12 -
Gas Connection
The heater gas inlet connection is a female 3/8" NPT at
the valve. The inlet connection is on the right side of unit
whenfacing the control.Toconnectfromthe opposite side,
rotate unit 180° or route the pipe under the rear portion of
the unit.
When tightening the joint to the valve, hold the valve
securely to prevent movement.
Test all gas connection 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 13
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.
Repeat process for “IN” port. Check “IN” port with unit set
on high with any other gas appliances in the house on or
cyclingon.Pressuregaugereadings should match max/min
requirements on data plate.
Test Port “OUT”
Figure 13 -
Pressure Test Point Location Millivolt Control
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
hydrogensulfidelimits, and where permittedby 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
WARNING Connecting directly to an unregulated propane/
LPG tank can cause an explosion.
WARNING
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

13
81D3032
NBST27 Unvented Gas Log Set
ELECTRICAL WIRING — MILLIVOLT
The Millivolt valve is a self-powered combination gas con-
trol THAT DOES NOT REQUIRE 110VAC TO OPERATE.
Figure 14 -
Wiring Diagram
TH = 3
TP = 1
TP/TH = 2
ON/OFF Switch or
Optional Wall Switch,
Remote or T-Stat
Log
Switch
Millivolt Valve
ODS Pilot
ODS Pilot
FP2267
NOTE: Log switch wires are not fac-
tory connected. Connect log switch
wires to the TH/TP and TH valve
terminals.
CONNECTING 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.
Label all wires prior to disconnection when servic-
ing controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after
servicing.
WARNING

14 81D3032
NBST27 Unvented Gas Log Set ELECTRICAL WIRING — MILLIVOLT
CONNECT REMOTE RECEIVER
1. Set remote receiver. Refer to instructions included in
the receiver kit.
2. Connect the two (20 1⁄4" female connectors to the TP/
TH and TH terminals on the control valve.
NOTE: Do not allow wires touch grate or burner.
NOTE: Heat reduces battery life. Protect the receiver and
extend battery life by mounting receiver in wall or other
location outside the fireplace.
CHECKING SYSTEM OPERATION
The millivolt system and individual components may be
checked with a millivolt meter having a 1-1000 mV range.
Conduct each check shown in chart by connecting meter
test leads to terminals as indicated.
Check
Test To Test Connect Meter Leads to Terminal Switch or Thermostat Contacts Meter Should Read
A Complete System 2 & 3 Closed Minimum 175
B Thermopile Output 1 & 2 Open Minimum 500
A. Complete Millivolt System Check
(“A” Reading - Thermostat contacts CLOSED - Control
knob “ON” - Main burner should turn ON)
1. If reading is more than 175 millivolts and the au-
tomatic valve still does not come on, replace the
control.
2. If the closed circuit reading (“A” reading) is less
than 175 millivolts, determine cause for low read-
ing, proceed to Section B.
B. Thermopile Output Reading Check
(“B” Reading - thermostat contacts OPEN - Main burn-
er 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.
Remote
Wires
Remote
Receiver
Remote Wire
Connectors
Valve
FP2376
Figure 15 -
Install Remote Receiver

15
81D3032
NBST27 Unvented Gas Log Set
LOG PLACEMENT
NOTE: This unit is supplied with 10 ceramic fiber logs. Do
not handle the logs with bare hands. Always wear gloves
to prevent skin irritation from ceramic fibers. After han-
dling the logs, wash your hands gently with soap and wa-
ter to remove any traces of fibers.
CAUTION
DO NOT sprinkle volcanic rock on the logs,
around the pilot, or on or near burners. This
may cause sooting.Place volcanicrock 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 the windows
for a few hours to vent the odor.
ROCK WOOL PLACEMENT
1. Place dime size pieces of rock wool evenly over small
burner ports starting at pilot and down each side of
burner. Avoid placing rock wool on slots on either side
of burner between the air defectors. Figure 16. Wash
hands after placing rock wool. Skin irritation may oc-
cur.
LOG PLACEMENT
Begin on Side A, valve on left as you face the fireplace.
1. Place log #1 on burner by aligning two (2) holes on
bottom of log with two (2) pins on burner. The tallest
part of the log is on the valve side of burner. Gently
push log down until it comes in contact with burner sur-
face. Figure 17
Figure 16 -
Place Rock Wool
Pilot Rockwool
Rock Wool
Horizontal
Grate Bar
Grate Tine
Grate Tines
Horizontal Grate Bar
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 specifically
approved for this heater may result in property
damage or personal injury.
WARNING
Log 1
Control
Valve
Figure 17 -
Place Log #1
2. Place log #2 on left grate tines by aligning the ‘V’
notches in the log with grate tines. The groove on the
bottom of the log should be firmly seated on the grate
bar. Figure 18
Log #2
Figure 18 -
Place Log #2

16 81D3032
NBST27 Unvented Gas Log Set
Log #4
Figure 20 -
Place Log #4
3. Place log #3 on farthest right grate tine by aligning the
‘V’ notch in log with grate tine. The groove in the bot-
tom of the log should sit on the filler bracket surround-
ing the pilot assembly. Figure 19
LOG PLACEMENT
Log #3
Figure 19 -
Place Log #3
4. Place log #4 by aligning the ‘V’ notch on bottom of log
with horizontal grate bar between tines as shown in
Figure 20. Place the rectangular notch on bottom of
log onto the matching rectangular protrusion on log #1.
Figure 20
5. Place log #5 by placing rectangular notch on bottom
of log onto matching rectangular protrusion on log #2.
Make sure ember or ‘burnt’portion of log is facing cen-
ter of burner. Figure 21
Log #5
Figure 21 -
Place Log #5
Continue on Side B, valve on right as you face the
fireplace.
6. Place log #6 on pilot end of burner by aligning the ‘V’
notch in bottom of log with the filler bracket surround-
ing the pilot. Place the rectangular notch in the bottom
of the log onto the rectangular protrusion on the end of
log #1. Figure 22
7. Place log #7 on left two (2) grate tines by aligning the
‘V’ notch in log with grate tines. Make sure groove on
bottom of log is firmly seated on grate bar. Figure 23
Log #6 Log #1
Control Valve
Figure 22 -
Place Log #6
8. Place log #8 by aligning ‘V’ notch in bottom of log with
the horizontal grate bar between tines as shown in Fig-
ure 24. Place the rectangular notch on bottom of log
onto rectangular protrusion on middle of log #1. Figure
24
Log #7
Figure 23 -
Place Log #7

17
81D3032
NBST27 Unvented Gas Log Set
FLAME APPEARANCE
9. Place log #9 on farthest right grate tine by aligning ‘V’
notch in bottom of log with grate tine. Place rectangu-
lar notch in bottom of log onto rectangular protrusion
on log #8. Figure 25
Log #8
Figure 24 -
Place Log #8
Log #9
Figure 25 -
Place Log #9
Log #10
Figure 26 -
Place Log #10
10. Place log #10 by aligning two (2) rectangular notches
on bottom of log with rectangular protrusions on logs
#6 & #7. Make sure the ember or ‘burnt’ area of log is
facing center of burner. Figure 26
FLAME APPEARANCE
Flames from the pilot, front and rear burner should be
visually checked as soon as the heater is installed.
In addition, periodically check the flames visually during
operation.
CHECK THE PILOT FLAME
The pilot flame must always be present when the
heater is in operation. It should just touch the top of the
thermocouple tip for natural. Refer to Figure 27 for correct
pilot flame.
Ifthe pilot flamedoesnot touch thethermocouple, then the
mainburnercannot function reliably. Figure 28 forincorrect
shape of pilot flame.
Figure 27 -
Correct Pilot Flame
Appearance
Thermo-
couple for
Natural Gas
Thermo-
couple
for LP
Figure 28 -
Incorrect Pilot Flame
Appearance
CHECK BURNER FLAME APPEARANCE
Innormal operation at full rateafter 15minutes, the flames
should appear as shown in Figure 29.
The flames should be yellow and extend 3-4” above the
log top surfaces. The yellow flames should not impinge
on the logs.
Figure 29 -
Correct Burner Flame Appearance
Thermo-
couple
for LP
Thermo-
couple
for
Natural
Gas

18 81D3032
NBST27 Unvented Gas Log Set OPERATING INSTRUCTIONS
OPERATING INSTRUCTIONS
Avoid any drafts that alter burner flame patterns. Do
not allow fans to blow directly into the fireplace. Do not
place a blower inside the burn area of the firebox. Ceiling
fans may create drafts that alter flame patterns. Sooting
and improper burning will result.
During manufacturing, fabricating and shipping, various
components of this appliance are treated with certain oils,
films or bonding agents. These chemicals are not harm-
ful, 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.
FOR YOUR SAFETY, READ BEFORE LIGHTING
A. This appliance is equipped with a piezo ignition device which lights the pilot. If piezo is not working properly
see Match Lighting Instructions.
B. BEFORE OPERATING 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 attempt 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 supplier's instructions.
•If you cannot reach your gas supplier, call the fire department.
C. Use only your hand to push in, or turn the gas control knob. Never use tools. If the knob will not push in or turn
by hand, don't try to repair it. Call a qualified service technician. Force or attempted repair may result in a fire
or explosion.
D. Do not use this appliance if any part of it 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 that has been under
water. Control Knobs
Piezo Ignitor
Figure 30 -
Burner Controls
Theinitialbreak-in operation should lastfourhours with the
burnerat the highest setting. Providemaximum ventilation
by opening windows or doors to allow odors to dissipate.
Any odors remaining after this initial break-in will be slight
and will disappear with continued use.
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.
If you do not follow these instruction exactly, a fire or explosion may result causing property damage,
personal injury or loss of life.
WARNING

19
81D3032
NBST27 Unvented Gas Log Set
OPERATING INSTRUCTIONS
MILLIVOLT CONTROL LIGHTING INSTRUCTIONS
1. STOP! Read the safety information label.
2. Make sure the manual shutoff valve is fully open.
3. This gas log set is equipped with an ignition device (piezo) which automatically lights the pilot. If piezo
ignitor does not light the pilot, refer to instructions for Match Lighting Instructions, Page 22.
4. Turn gas control knob clockwise to the OFF position and turn ON/OFF switch to OFF position.
5. Wait (5) minutes to clear out any gas. Then smell for gas, including near the floor. If you smell gas,
STOP! Follow the instructions under What To Do If You Smell Gas, Page 20.
6. From OFF position, turn the gas control knob counterclockwise to IGN position. Push in control
knob for 5 seconds. NOTE: If you are running the heater for the first time, it may be necessary to
press in the control knob for 30 seconds or longer to allow air to bleed out of the gas piping.
7. With the control knob pushed in, push in and release the piezo ignitor button to light the pilot.
8. Continue pushing the control knob in for a further 60 seconds to prevent the flame detector from shut-
ting off the gas while the probe is warming up. Release the control knob.
9. Turn gas control knob counterclockwise to the ON position.
10. After the pilot has been lit for one minute, the burners can be turned on. Turn the ON/OFF switch to
ON position.
11. If the gas logs will not operate, follow the instructions To Turn Off Gas To Heater below and call your
service technician or gas supplier.
Figure 31 -
Pilot
On/Off/Pilot
Knob
Switch
Hi/Lo
Knob
Piezo Ignitor
TO TURN OFF GAS TO HEATER
1. Turn control knob clockwise to OFF position to completely shut off the heater.
2. If applicable: Turn ON/OFF switch to OFF position and/or set thermostat (if present) to lowest setting.
3. If applicable: Turn off all electric power to the heater.
Figure 32 -
Controls

20 81D3032
NBST27 Unvented Gas Log Set
MATCH LIGHTING INSTRUCTIONS
MAINTENANCE
1. Remove any items necessary for easy access to the pilot (for example: logs, screens, etc.).
2. Follow appropriate lighting instructions found previously. Instead of pushing and releasing the piezo
button, light a match and hold the flame to the end of the pilot and ignite the pilot.
3. After control knob has been released and pilot stays lit, reinstall any items that were removed for pilot
access.
4. Call a qualified service technician for repair or replacement of the piezo ignitor.
CLEANING AND SERVICING
Annual inspection and cleaning by your dealer or qualified service technician is recommended
to prevent malfunction and/or sooting.
Remove logs, handling carefully by holding gently at each end. Gloves are recommended to prevent
skin irritation from ceramic fibers. If skin becomes irritated, wash gently with soap and water. Refer to
manual for correct log placement.
PERIODIC CLEANING - Refer to parts diagram for
location of items discussed below.
•Do not use cleaning fluid to clean logs or any part of
heater.
•Brush logs with soft bristle brush or vacuum with
brush attachment.
•Vacuum loose particles and dust from the front and
rearburner,control and piezo covers andgrateweld-
ment.
•Inspect and clean burner air intake holes. Remove
lint or particles with vacuum, brush, or pipe clean-
ers. Failure to keep air intake holes clean will
result in sooting and poor combustion.
•External case should be dusted and wiped with a
wet soapy cloth.
ANNUAL CLEANING/INSPECTION - Refer to parts
diagram for location of items discussed below.
•Inspect and clean burner air intake holes. Remove
lint or particles with vacuum, brush or pipe clean-
ers.
Failure to keep air intake holes clean will result
in sooting and poor combustion.
•Inspect and clean all burner ports.
•Inspect ODS pilot for operation and accumulation of
lint at air intake holes.
•Verify flame pattern and log placement for proper
operation.
•Verifysmooth and responsive ignitionofmain burner
and rear burner.
•Replace battery in remote control device.
Turn off heater and allow to cool before cleaning. Disconnect electrical power before cleaning or
servicing.
WARNING