NBST27NV-B 27 Natural Blaze Burner

Product Information

The product is a gas log set designed for indoor use. It comes
in two models: NBST27NV-B and NBST27PV-B. The appliance is designed
to provide warmth and ambiance in a room or living area. The
product requires installation by a licensed plumber or gas fitter
and should only be operated according to the manufacturer’s
instructions.

Safety Warnings

The product comes with important safety warnings that must be
followed to prevent injury, death, or property damage. These
include:

• 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 fire
  department.

Product Usage Instructions

Before operating the gas log set, read the owner’s manual
carefully and follow all safety warnings. The product should be
installed by a licensed plumber or gas fitter according to the
installation manual. Failure to follow installation instructions
can result in serious injury, death, or property damage.

Once installed, follow these steps to operate the product:

1. Make sure the gas supply is turned on.

2. Press and turn the control knob to the “Pilot” position.

3. Press down on the control knob to release gas to the pilot
   light.

4. Press the igniter button repeatedly until the pilot light
   ignites.

5. Hold the control knob down for 30 seconds to allow the
   thermocouple to warm up.

6. Release the control knob and turn it to the “On” position.

7. The gas log set should now be operating normally.

Regular maintenance and cleaning are required to ensure safe and
efficient operation of the product. Refer to the owner’s manual for
specific maintenance instructions and frequency.

Installation/Owner’s Manual
Appliance Setup, Care and Operation

INSTALLER: Leave this manual with party responsible for use and operation. OWNER: Retain this manual for future reference.
Contact your dealer with questions regarding installation, operation or service.

NOTICE: DO NOT discard this manual!
Models:
NBST27NV-B NBST27PV-B

WARNING: FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in serious injury, death, or property damage.
· 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.
– 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 fire department.
· Installation and service must be performed by a qualified installer, service agency, or the gas supplier.

In the Commonwealth of Massachusetts installation must be performed by a licensed plumber or gas fitter.
See appliance installation manual for additional Commonwealth of Massachusetts requirements.

· DO NOT install this unit in a bedroom or bathroom.

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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Safety Alert Key:
· DANGER! Indicates a hazardous situation which, if not avoided will result in death or serious injury. · WARNING! Indicates a hazardous situation which, if not avoided could result in death or serious injury. · CAUTION! Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury. · NOTICE: Used to address practices not related to personal injury.

Table of Contents

Installation Standard Work Checklist. . . . . . . . . . . . . . . . . . . . 3
1 Product Specific & Important Safety Information A. Appliance Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
B. BTU Specifications and Weights . . . . . . . . . . . . . . . . . . . . 4
C. High Altitude Installations . . . . . . . . . . . . . . . . . . . . . . . . . . 4 D. Non-Combustible Materials Specification. . . . . . . . . . . . . . 4
2 Getting Started
A. Design and Installation Considerations . . . . . . . . . . . . . . . 5 B. Tools and Supplies Needed . . . . . . . . . . . . . . . . . . . . . . . . 5 C. Inspect Appliance and Components. . . . . . . . . . . . . . . . . . 5 D. Check Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 E. Installation Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 F. Pilot/ODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 G. Adequate Combustion Ventilation Air . . . . . . . . . . . . . . . . . 8
3 Clearances & Height Requirements
A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 Gas Information
A. Gas Line Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 B. Millivolt Valve Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 C. Fuel Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 D. Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 E. Gas Service Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 F. Connect Optional Wall Switch or Thermostat. . . . . . . . . . 16 G. Connect Remote Receiver . . . . . . . . . . . . . . . . . . . . . . . . 17 H. Check System Operation . . . . . . . . . . . . . . . . . . . . . . . . . 17 I. Rock Wool Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5 Gas Log Sets

6 Owner’s Manual A. Congratulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
B. Limited Lifetime Warranty. . . . . . . . . . . . . . . . . . . . . . . . . 24
7 Important Safety & Operating Information A. Appliance Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 B. General Operating Parts . . . . . . . . . . . . . . . . . . . . . . . . . 28 C. Fuel Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 D. Before Lighting Appliance. . . . . . . . . . . . . . . . . . . . . . . . . 28
8 Product Specification Information A. Application Certification . . . . . . . . . . . . . . . . . . . . . . . . . . 29
B. BTU Specifications and Weights . . . . . . . . . . . . . . . . . . . 29
9 Lighting Instructions A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
10 Maintenance & Service A. Maintenance: Frequency & Tasks . . . . . . . . . . . . . . . . . 33 B. Maintenance Tasks: Qualified Service Technician . . . . . 33 C. Burner Ignition & Operation . . . . . . . . . . . . . . . . . . . . . . . 33 D. Cleaning & Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
11 Troubleshooting A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
12 Service Parts & Accessories
A. Service Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
B. Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 C. Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

A. Log Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 B. Place the Decorative Rock . . . . . . . . . . . . . . . . . . . . . . . . 21 C. Flame Appearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 D. Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

NOTE: Monessen vent free gas logs are hand painted for ultimate beauty and realism. As a result, some variation in color and shading will occur from set to set. This is intentional and designed to make each product unique, as found in nature.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

Installation Standard Work Checklist

ATTENTION INSTALLER:

Follow this Standard Work Checklist

This standard work checklist is to be used by the installer in conjunction with, not instead of, the instructions contained in this

installation manual. Customer:
Lot/Address:

Date Installed: Location of Fireplace:

Model (circle one): NBST27NV-B, NBST27PV-B

Installer: Dealer/Distributor Phone #

Serial #:

WARNING! Risk of Fire or Explosion! Failure to install appliance according to these instructions could lead to a fire or explosion.

Gas Log Install Sections 2 and 4 (Pg. 5 & 20) Verified that the chimney has been cleaned. (pg. 13) Verified clearances to combustibles. Gas Logs are leveled and secured. See page 8 for adequate provisions for combustion and ventilation air have been verified.

YES

IF NO, WHY?

Gas Section 4 (Pg 14) Proper appliance for fuel type. Leak check performed and inlet pressure verified. Verified proper air shutter setting for installation type.

Electrical Section 4 (Pg 17) Switch wires properly installed.

Embers & Logs Section 5 (Pg 19-21) All packaging and protective materials removed (inside & outside of appliance). Embers and logs installed correctly. Accessories installed properly.

Finishing Section 3 (Pg 9) Verified all clearances meet installation manual requirements. Mantels and wall projections comply with installation manual requirements.
Manual bag and all of its contents are removed and the log set given to party responsible for use and operation. Started log set and verified no gas leaks exist.

Hearth & Home Technologies recommends the following:

· Photographing the installation and copying this checklist for your file.

· That this checklist remain visible at all times on the appliance until the installation is complete.

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 ___

= Contains updated information.

(Builder / Gen. Contractor/) (Installer)

(Date)

4615-901A 07/18

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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1 Product Specific and Important Safety Information

A. Appliance Certification
MODEL: NBST27NV-B, NBST27PV-B LABORATORY: CSA TYPE: Unvented Room Heater STANDARD: ANSI Z21.11.2:19 Gas-fired
Unvented Room Heaters ANSI Z21.60-2017 – CSA 2.26-2017 Decorative Gas Appliances for Installation in Solid-Fuel Burning Fireplaces
This product is listed to ANSI standards for “Unvented Room Heaters” and applicable sections of “Gas Burning Heating Appliances for Manufactured Homes” and “Gas Fired Appliances for Use at High Altitude.”
NOTICE: This installation must conform with local codes. In the absence of local codes you must comply with the National Fuel Gas Code, ANSI Z223.1-latest edition in the U.S.A.
NOT INTENDED FOR USE AS A PRIMARY HEAT SOURCE. This appliance is tested and approved as either supplemental room heater or as a decorative appliance. It should not be factored as primary heat in residential heating calculations.

NATURAL GAS: An external regulator is required to reduce supply pressure to a maximum of 101/2″ w.c. on natural gas systems operating at higher pressure. PROPANE/LPG: An external regulator is required to reduce supply pressure to a maximum of 13″ w.c.
Millivolt 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 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.

B. BTU Specifications and Weights

Models
NBST27NV-B (0-2000 FT)

Maximum Input BTU/h
39,000

Minimum Input BTU/h
26,000

Orifice
3.20 mm

NBST27PV-B (0-2000 FT) 39,000 30,000 #48

Weight Pounds
38
38

NOTE: For LP models an external regulator is required to reduce supply pressure to a maximum of 13″ w.c.

GAS PRESSURES

NATURAL

Inlet Minimum
Inlet Maximum Gas Valve Manifold Pressure Setting Pilot Regulator

5.0″ w.c. 10.5″ w.c. 3.5″ w.c.
3.5″ w.c.

PROPANE (LP) 11.0″ w.c. 13.0″ w.c. 10″ w.c.
—

Thermal Generator The millivolt gas log pilot is fitted with a millivolt (thermopile) generator to provide power for remote activation.
C. High Altitude Installations
NOTICE: If the heating value of the gas has been reduced, these rules do not apply. Check with your local gas utility or authorities having jurisdiction.
When installing above 2000 feet elevation: Reduce input rate 4% for each 1000 feet above sea level.
Check with your local gas utility to determine proper orifice size.
D. Non-Combustible Materials Specification
Material which will not ignite and burn. Such materials are those consisting entirely of steel, iron, brick, tile, concrete, slate, glass or plasters, or any combination thereof.
Materials that are reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 ºC shall be considered non-combustible materials.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

2 Getting Started
A. Design and Installation Considerations
Installation MUST comply with local, regional, state and national codes and regulations. Consult insurance carrier, local building inspector, fire officials or authorities having jurisdiction over restrictions, installation inspection and permits. Before installing, determine the following: · Where burner assembly and log set are to be installed. · Gas supply piping. · Whether optional accessories–devices such as a wall
switch or remote control–are desired.
· Approved wood burning masonry fireplace or vent-free fireplace.
Installation and service of this appliance should be performed by qualified personnel. Hearth & Home Technologies recommends HHT Factory Trained or NFI certified professionals.

Improper installation, adjustment, alteration, service or
maintenance can cause injury or property damage. For assistance or additional information, consult a qualified service technician, service agency or your dealer.

B. Tools and Supplies Needed

Before beginning the installation be sure that the following tools and building supplies are available.

· Tape measure · Gloves · Voltmeter · Manometer

· Manual shutoff valve
· Sediment trap · Tee joint · Pipe wrench

· Phillips screwdriver

· Safety glasses

· Flat blade screwdriver

· Soapy water solution for gas leak testing

· Electric drill and bits (1/4 in. magnetic)

· External regulator (for propane/LPG only & 1/2 psi Natural gas system)
· Piping which complies with local codes · Pipe sealant approved for use with propane/LPG
(Resistant to sulfur compounds)

C. Inspect Appliance and Components
· Carefully remove the appliance and components from the packaging.
· Logs are packaged and sold separately. · Report to your dealer any parts damaged in shipment. · Read all of the instructions before starting the instal-
lation. Follow these instructions carefully during the installation to ensure maximum safety and benefit. WARNING! Risk of Fire or Explosion! Damaged parts could impair safe operation. DO NOT install damaged, incomplete or substitute components. Keep appliance dry.
Hearth & Home Technologies disclaims any responsibility for, and the warranty will be voided by, the following actions: · Installation and use of any damaged appliance. · Modification of the appliance. · Installation other than as instructed by Hearth & Home
Technologies. · Installation and/or use of any component part not approved
by Hearth & Home Technologies. Any such action may cause a fire hazard.
WARNING! Risk of Fire, Explosion or Electric Shock! DO NOT use this appliance if any part has been under water. Call a qualified service technician to inspect the appliance and to replace any part of the control system and/or gas control which has been under water.

CAUTION

Gloves are recommended when handling
refractory to prevent skin irritation from loose fibers. Logs are fragile; handle with care.

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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D. Check Parts
Verify contents to ensure you have received all parts. You should have the following:
Models
· Unvented gas log burner assembly · Three (3) bags of crushed volcanic rock · Installation/operating instructions · Two (2) anchoring brackets · Two (2) anchoring screws · Two (2) sheet metal screws · Ceramic Fiber logs (packaged and sold separately) · Two (2) bags of rock wool · On/off log switch assembly
The following options may be used with the millivolt controlled heater. These options are not packaged with the log set. · Hand-held remote with receiver (MV) · 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.
E. Installation Information
WARNING
This appliance is for installation only in a solid-fuel burning masonry or UL127 factory-built fireplace or in listed ventless firebox enclosure. It has been design certified for these installations. Exception: DO NOT install this appliance in a factorybuilt fireplace that includes instructions stating it has not been tested or should not be used with unvented gas logs.

21½”
32″ 19″
Figure 2.1 – Hearth Minimum Dimensions for Solid Fuel Burning Fireplaces and UL127 Factory Built Fireplaces

Use manufacturer’s installation and clearance requirements as defined in their manual.
This Gas-Fired Unvented Gas Log Type Room Heater is approved for installation into a CSA/ANSI Z21.91:20 listed Ventless Firebox Enclosure for Gas-Fired Unvented Gas Log Type Room Heaters, so long as the firebox hearth dimensions meet the minimum hearth dimensions listed in this manual.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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 barriers are glass/screen door frames and sunken/recessed fireplaces.

Height of Restriction (x)
No Restriction 0″ to 11/2″
Greater than 11/2″ to 3″ Greater than 3″

Minimum Depth of Fireplace/Firebox
211/2″” 251/4″ 271/4″

*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.

WARNING
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 when installed as a vented log set.

WARNING
DO NOT INSTALL ANY GLASS OR BARRIERS ON A VENTLESS FIREBOX

Glass door frames with adjustable louvers should have the louvers fully open while the unit is in operation

F. 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.
WARNING
Do not install the heater: · Where curtains, furniture, clothing, or
other flammable objects are less than 36″ from the front of the heater. · In high traffic areas. · In windy or drafty areas.

X

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 2.2 – Reference Drawing of NBST27 Log Set in an Enclosure

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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G. Adequate Combustion Ventilation Air
This heater shall not be installed in a confined space or unusually tight construction unless provisions are provided for adequate combustion and ventilation air. The National Fuel Gas Code, (ANSI Z223.1/NFPA54), defines a confined 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 unconfined 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 confined space. Unusually tight construction is defined 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 to windows and doors, and c. Caulking or sealants are applied to areas such as joints around window and door frames, between sole plates and floors, 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 maximum heater rating per the definition of unconfined 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

Counter

Fireplace

H
W
Figure 2.3
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.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

3 Clearances and Height Requirements

WARNING
The dimensions shown in Figures 3.1 through 3.7 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.
Sidewall and ceiling clearances: The sides of the fireplace opening must be at least 6″ from any combustible wall. The ceiling must be at least 42″ from the top of the fireplace opening. The wall parallel to the side of heater must be at least 36″ from the side of the heater. Refer to your firebox owner’s manual for more information.

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 3.2 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 clearances you must operate the heater with chimney flue damper open. Refer to “Installing Vented Applications” found on page 13.
Heat Resistant Material

Measure this Distance

42″

36″

Heater in Fireplace or Firebox

36″
6″
Figure 3.1 – 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, minimum clearances shown in Figures 3.1 through 3.7 must be met 3. If installing unit into a vented firebox with a damper that is always open, no minimum clearances are required.

Figure 3.2 – Measure Heat Resistant Material

Heat Resistant Material Measurement 12″ or more 8″ to less than 12″
Less than 8″

Requirements for Safe Installation
Hood not required
Extend heat resistant material to 12″ or install hood. Figure 3.2
Extend heat resistant material to at least 8″ and install hood. Figure 3.2 OR extend heat resistant material to a height of at least 12″

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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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 resistant material shown in Figure 3.3, then refer to Table B.

10″ or Less

Heat Resistant Material

28″
12″ Min.

Hood

8″ or More of Heat Resistant Material

Heater in Fireplace or Firebox

Figure 3.3 – Measure Heat Resistant Material for Mantel

Table B – Heat Resistant Material Heights and Mantel Location

Heat Resistant Material Measurement 12″ or more 8″ to less than 12″
Less than 8″

Requirements for Safe Installation
Hood not required. Observe profile (side elevations) shown in Figure 6.
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.
Extend heat resistant material to at least 8″, install hood and observe profiles shown in Figure 7; OR extend heat resistant material to at least 12″ and observe profiles shown in Figure 6.

Heater in Fireplace or Firebox
Example: The bottom of the mantel may project from the wall a maximum of 10″ at a minimum of 28″ above the firebox. Figure 3.4 – Minimum Mantel Clearance with No Hood

Heat Resistant Material

12″ 2 1/2″ 24″

13″

Hood
Heater in Fireplace or Firebox

Example: A mantel may project from the wall a maximum of 21/2″ at a minimum of 13″ above the opening, and a maximum of 12″ at a minimum of 24″ above the opening.
Figure 3.5 – Minimum Mantel Clearance with Hood

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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 3.6.
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 3.7

Vinyl Flooring
Vinyl Flooring is sensitive to heat. A 14 inch minimum depth hearth extension is recommended when using vinyl flooring up to the wall. See Figure 3.7.
NOTICE: Clearances that do not meet the minimum guidelines could result in damage or buckling to the vinyl flooring and is done at the installer’s risk.
Hearth & Home Technologies does not recommend adhesive based vinyl flooring due to thermal expansion. Floating-style flooring can be used, but will reach temperatures up to 110°F in a room with ambient temperature of 70°F. Consult flooring specifications to ensure compatibility.

Minimum Hearth Requirement – 0 in. Note: For installations with vinyl flooring, special clearance recommenda-
tions apply.

Heater in Fireplace or Firebox

Combustible Material

3/4″

Figure 3.6 – Minimum Clearance above Combustible Flooring
Minimum Hearth Requirement -14 in. Note: For installations with vinyl flooring, special clearance recommendations apply. Heater in Fireplace or Firebox
Combustible Material
This distance may now be less than 3/4″
14″ Min.
Figure 3.7 – Minimum Clearance above Combustible Flooring with
Noncombustible Material Installed at Base of Fireplace

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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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
This log set can be installed in a solid fuel burning fireplace (masonry fireplace or manufactured fireplace) with a working flue and constructed of non combustible material or in a vent-free firebox. Exception: DO NOT install this appliance in a factorybuilt 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
The use of thermostat is not allowed on vented log application. It is only allowed on unvented room heater classification.
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. Use a heat resistant sealant. Do not seal the chimney flue damper.
Vented Application Installations
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 requirements do not apply.)

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 heatresistant 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 3.9 to prevent full closure of the fireplace damper blade and provide a minimum 29 square inch flue opening.
Damper Stop
Damper
Figure 3.8 – Damper Stop Installation (Refer to WARNING at top of page)
WARNING
When this log set is installed in a vented application, the damper must be clamped to be fully open.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

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 3.9
Proper installation of the grate is essential to prevent any movement of the logs and controls during operation.

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 7.

Figure 3.9 – Secure Burner

Piezo Ignitor (Original Location)

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

13

4 Gas Information
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 sulfide 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 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.
A. Gas Line Connection
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.

WARNING
Connecting directly to an unregulated propane/ LPG tank can cause an explosion.
The heater gas inlet connection is a female 3/8″ NPT at the valve. The inlet connection is on the right side of unit. To connect from the opposite side, rotate unit 180° or route the pipe under the rear 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.
B. Millivolt Valve Control
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 clockwise 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 cycling on. Pressure gauge readings should match max/ min requirements on data plate.

Figure 4.1 Gas Connection
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.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

C. Fuel Type
· This appliance is equipped for either natural or propane gas. Field conversion is not permitted.
· Make sure the appliance is compatible with available gas types.

D. Gas Pressure
· Optimum appliance performance requires proper input pressures.
· Gas line sizing requirements will be determined in ANSI Z223.1 National Fuel Gas Code in the USA.
· Pressure requirements are:

Inlet Minimum
Inlet Maximum Gas Valve Manifold Pressure Setting Pilot Regulator

NATURAL 5.0″ w.c. 10.5″ w.c. 3.5″ w.c.
3.5″ w.c.

PROPANE (LP) 11.0″ w.c. 13.0″ w.c. 10″ w.c.
—

WARNING! Risk of Fire or Explosion! High pressure will damage valve. Low pressure could cause explosion.
· Verify inlet pressures. Verify minimum pressures when other household gas appliances are operating.
· Install regulator upstream of valve if line pressure is greater than 1/2 psig.
· Valve pressure taps are accessible prior to installing log set.

Note: Have the gas supply line installed in accordance with local codes, if any. If not, follow ANSI 223.1. Installation should be done by a qualified installer approved and/or licensed as required by the locality. (In the Commonwealth of Massachusetts installation must be performed by a licensed plumber or gas fitter).
E. Gas Service Access
Depending upon local code, a manual gas shutoff, in a readily accessible area may be required and located upstream from the appliance.
WARNING
Fire Risk. Explosion Hazard. High pressure will damage valve. · Disconnect gas supply piping BEFORE
pressure testing gas line at test pressures above 1/2 psig. · Close the manual shutoff valve BEFORE pressure testing gas line at test pressures equal to or less than 1/2 psig.
Test Port “OUT”

Figure 4.2 – Pressure Test Point Location Millivolt Control

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

15

CAUTION

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing.
The millivolt valve is a self-powered combination gas control THAT DOES NOT REQUIRE 110 VAC TO OPERATE.

F. Connect Optional Wall Switch or
Thermostat (vent free application only)
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, using fork terminal 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.

ODS Pilot

On/Off Switch or Optional Wall Switch, Remote or T-Stat

ODS Pilot

TH = 3 TP = 1 TP/TH = 2

Millivolt Valve

Log Switch

Figure 4.3 – Wiring Diagram NOTE: Log switch wires are not factory connected. Connect log switch wires to the TH/TP and TH valve terminals as shown.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

G. Connect Remote Receiver
1. Set remote receiver. See instructions included in receiver kit.
2. Unplug the two terminals for the log switch from the valve, connect the piggy back terminal of the receiver to the TH and TP/TH on the valve. Slide the terminal of the log switch onto the piggy back terminal on the receiver
NOTE: Do not allow wires touch grate or burner.
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.
H. 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.

1. 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, proceed to Section B below.
2. 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.

Check Test
A B

To Test Complete System Thermopile Output

Connect Meter Leads to Terminals 2 and 3 1 and 2

Switch or Thermostat Contacts Closed Open

Meter Should Read Minimum 175 Minimum 500

Remote Wires

Remote Wire Connectors
Valve

Remote Receiver

Figure 4.4 – Installing Remote Receiver

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

17

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 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.
I. Rock Wool Placement
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 occur.

Pilot Rockwool

Grate Tine
Horizontal Grate Bar

Before You Begin
NBST27-B logs are sold separately. 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.

Grate Tines

Rock Wool Horizontal Grate Bar

Figure 4.5 – Place Rock Wool

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

5 Gas Log Sets
WARNING
· Gloves are recommended when handling logs to prevent skin irritation from loose fibers. Logs are fragile – handle with care.
· Use only rock wool provided with log set. · DO NOT ADD ADDITIONAL ROCK WOOL.
Wash hands after placing rock wool. Itching may occur.
A. 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 surface. Figure 5.1
Log 1
Control Valve

3. Place log #3 on farthest right grate tine by aligning the V’ notch in log with grate tine. The groove in the bottom of the log should sit on the filler bracket surrounding the pilot assembly. Figure 5.3 Log #3 Figure 5.3 – Place Log #3 4. Place log #4 by aligning theV’ 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 5.4
Log #4

Figure 5.1 – 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 5.2

Figure 5.4 – Place Log #4
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 center of burner. Figure 5.5
Log #5

Log #2 Figure 5.2 – Place Log #2

Figure 5.5 – Place Log #5

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

19

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 surrounding the pilot. Place the rectangular notch in the bottom of the log onto the rectangular protrusion on the end of
log #1. Figure 5.6

Log #6

Log #1

Log #8 Figure 5.8 – Place Log #8

Figure 5.6 – Place Log #6

Control Valve

9. Place log #9 on farthest right grate tine by aligning `V’ notch in bottom of log with grate tine. Place rectangular notch in bottom of log onto rectangular protrusion on log #8. Figure 5.9
Log #9

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 5.7 Log #7 Figure 5.7 – Place Log #7 8\. Place log #8 by aligningV’ notch in bottom of log with the horizontal grate bar between tines as shown in Figure 24. Place the rectangular notch on bottom of log onto rectangular protrusion on middle of log #1. Figure 5.8

Figure 5.9 – Place Log #9
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 5.10
Log #10

Figure 5.10 – Place Log #10

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

CAUTION

B. Place Decorative Rock
The volcanic rocks are shipped with your log set. The volcanic rocks may be placed around the unit on the floor of the firebox. Be sure to avoid any areas on the burner itself
DO NOT sprinkle volcanic rocks on the logs, around the pilot, nor near the burners. This may cause sooting. Place volcanic rocks 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.
C. Flame Appearance
Flames from the pilot and 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 (refer to lighting instructions) 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 5.11 for correct pilot flame. If the pilot flame does not touch the thermocouple, then the main burner cannot function reliably. Figure 5.12 for incorrect shape of pilot flame.

In normal operation at full rate after 15 minutes, the following flame appearances should be observed: Burner will have a random pattern of yellow flames as shown in Figure 5.12. There should be glowing embers on the front burner. NOTE: The front flames and embers will be an opaque orange color during the burn off time. CAUTION: After a 15 minute pre-heat period, observe all yellow flames to ensure there is no impingement with any log. If any yellow flame is contacting any log, turn off log set and allow to cool. Remove all logs and carefully reinstall following log placement instructions precisely. Relight burner and check again for impingement of any flame on log. If flame impingement cannot be eliminated, contact your installer or dealer for assistance. Flame impingement on logs may create soot and possible property damage.
Figure 5.12 – Correct Appearance of Rear Flames

Thermocouple for Natural
Thermocouple for LP Figure 5.10 – Correct Appearance of Pilot Flame
Thermocouple for Natural
Thermocouple for LP
Figure 5.11 – Incorrect Appearance of Pilot Flame

D. 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 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 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 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.

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

21

6 Owner’s Manual Care & Operation

Owner’s Manual
Care and Operation

INSTALLER: Leave this manual with party responsible for use and operation. OWNER: Retain this manual for future reference.
Contact your dealer with questions regarding installation, operation or service.

NOTICE: DO NOT discard this manual!
Models:
NBST27NV-B NBST27PV-B

WARNING: FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in serious injury, death, or property damage.
· 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.
– 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 fire department.
· Installation and service must be performed by a qualified installer, service agency, or the gas supplier.

In the Commonwealth of Massachusetts installation must be performed by a licensed plumber or gas fitter.
See appliance installation manual for additional Commonwealth of Massachusetts requirements.

· DO NOT install this unit in a bedroom or bathroom.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

Read this manual before operating this appliance. Please retain this Owner’s Manual for future reference. Read the Installation Manual before making any installation or finishing changes.

A. Congratulations
Congratulations and thank you for selecting a Monessen vent free gas log set, an elegant and clean alternative to wood burning fireplaces. The gas log set you have selected is designed to provide the utmost in safety, efficiency, and style.
As the owner of a new vent free log set, you’ll want to read and carefully follow all of the instructions contained in this owner’s manual. Pay special attention to all cautions and warnings.

This owner’s manual should be retained for future reference. We suggest that you keep it with your other important documents and product manuals.
The information contained in this owner’s manual, unless noted otherwise, applies to all models and gas control systems noted on the cover page.
Your new Monessen gas log set will give you years of durable use and trouble- free enjoyment. Welcome to the Monessen family. We are glad you joined us!

Local Dealer Information

Dealer: Fill in your name, address, phone and email information here and appliance information below.

Dealer Name: ____ Address:

____ Phone: _____ Email:

Appliance Information: Brand: ____ Model Name: ___
Serial Number:__ Date Installed:

Listing Label Information/Location The model information regarding your specific gas log set can be found
on the rating plate usually located in the control area of the gas log set.

Type of Gas

Hearth & Home Technologies
7571 – 215th Street West Lakeville, MN 55044

ITEM NO: NBST27NV-B
GAS: Natural Gas Input Rating: Max. 39000 BTU/Hr.
Min. 26000 BTU/Hr. Manifold Pressure: 3.5″ W.C. For Purpose of Input Adjustment: Min. Supply Pressure: 5.0″ W.C. Max. Supply Pressure: 10.5″ W.C. Control Type: 11-A This unit complies with: ANSI Z21.11.2:19 Gas-fired Unvented Room Heaters ANSI Z21.60-2017 – CSA 2.26-2017 Decorative Gas Appliances for Installation in Solid-Fuel Burning Fireplaces

MODEL:NBST27NV-B

SERIAL:

BAR CODE

BAR CODE

WARNING This appliance is for installation only in a solid-fuel burning masonry or UL 127 factory-built fireplace or in a listed ventless firebox enclosure. It has been design certified for these installations. Exceptions: DO NOT install this appliance in a factory-built fireplace that includes instructions stating it has been tested or should not be used with unvented gas logs. State or local codes may only allow operation of this appliance in a vented configuration. Check your state or local codes. Approved Monessen unvented firebox enclosures, refer to installation instructions in Owner’s Manual for applicable models. If not available, contact dealer. Min. clearances: 1.75″ from side combustible wall; 42″ from top of fireplaces opening to ceiling; 36″ from side of fireplaces.

4615-203B

Model Number Serial Number

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

23

B. Limited Lifetime Warranty
Hearth & Home Technologies LLC
LIMITED LIFETIME WARRANTY
Hearth & Home Technologies LLC (“HHT”) extends the following warranty for HHT gas, wood, pellet and electric hearth appliances (each a “Product” and collectively, the “Product(s)”) and certain component parts set forth in the table below (“Component Part(s)”) that are purchased from a HHT authorized dealer or distributor. WARRANTY COVERAGE:
HHT warrants that the Products and their Component Parts will be free from defects in materials and workmanship for the applicable period of Warranty coverage set forth in the table below (“Warranty Period”). If a Product or Component Parts are found to be defective in materials or workmanship during the applicable Warranty Period, HHT will, at its option, repair the applicable Component Part(s), replace the applicable Component Part(s), or refund the purchase price of the applicable Product(s). The maximum amount recoverable under this Warranty is limited to the purchase price of the Product. This Warranty is transferable from the original purchaser to subsequent owners, but the Warranty Period will not be extended in duration or expanded in coverage for any such transfer. This Warranty is subject to conditions, exclusions, and limitations as described below. WARRANTY PERIOD: Warranty coverage begins at the date of installation. In the case of new home constructions, Warranty coverage begins on the date of first occupancy of the dwelling or six months after the sale of the Product(s) by an independent, authorized HHT dealer or distributor, whichever occurs earlier. However, the Warranty coverage shall commence no later than 24 months following the date of Product shipment from HHT, regardless of the installation or occupancy date.
The term “Lifetime” in the table below is defined as: 20 years from the beginning date of warranty coverage for gas appliances, 10 years from the beginning date of warranty coverage for wood and pellet appliances, and 5 years from the beginning of warranty coverage for standalone gas log sets. These time periods reflect the minimum expected useful lives of the designated Component Parts under normal operating conditions.

Warranty Period

Component Parts

Labor

Gas

1 Year

X

2 Years

2 years

X

X 3 years

5 years

X

X 5 years 1 year

6 years 7 years

3 years 3 years

10 years 1 year

X

Limited Lifetime

3 years

X

Pellet X

HHT Manufactured Appliances and Venting

Wood Electric Venting

Component Parts Covered by this Warranty

All parts including handles, external enameled

X

X

components and other material except as covered by Warranty Conditions, Warranty Exclusions, and

Warranty Limitations listed

X

All parts except as covered by Warranty Conditions, Warranty Exclusions, and Warranty Limitations listed

X

X

X X

X

X

X

X

X

X

X

Igniters, Auger Motors, Electronic Components, and Glass
Electrical components limited to modules, remotes/wall switches, valves, pilots, blowers, junction boxes, wire harnesses, transformers and lights (excluding light bulbs)
Molded Refractory Panels, Glass Liners
Firepots, burnpots, mechanical feeders/auger assemblies
Burners and logs for standalone gas log sets (Vented and Vent Free gas log sets not sold as
components of the fireplace or stove) Vent Free Burners and Vent Free Log components of
HHT manufactured fireplaces or stoves Castings, Medallions and Baffles
Catalysts
Manifold tubes, HHT Chimney and Terminations
Burners, logs and refractory components of HHT manufactured fireplaces or stoves
Firebox and heat exchanger, FlexBurn® System (engine, inner cover, access cover and fireback)

1 Year 4021-645M 9/21 24

None

X

X

X

X

X

All purchased replacement parts

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

Page 1 of 2

B. Limited Lifetime Warranty (continued)

WARRANTY CONDITIONS:
· Because HHT cannot control the quality of any Products sold by unauthorized sellers, this Warranty only covers Products that are purchased through an HHT authorized dealer or distributor unless otherwise prohibited by law; a list of HHT authorized dealers is available on the HHT branded websites.
· This Warranty is only valid while the applicable Product remains at the site of original installation.
· This Warranty is only valid in the country in which the HHT authorized dealer or distributor that sold the applicable Product is authorized to sell applicable Product.
· Contact your installing distributor or dealer for Warranty service. If the installing dealer or distributor is unable to provide necessary parts, contact the nearest HHT authorized dealer or supplier. Additional service fees may apply if you are seeking Warranty service from a dealer other than the dealer from whom you originally purchased the applicable Product.
· No HHT consumer should bear cost of warranty service or costs incurred while servicing warranty claims (i.e., travel, gas, or mileage) when the service is performed within the terms of this Warranty. Check with your dealer or distributor in advance for any costs to you when arranging a warranty call. Travel and shipping charges for parts are not covered by this Warranty.

WARRANTY EXCLUSIONS:
This Warranty does not cover the following: · Changes in surface finishes as a result of normal use. As a heating appliance, some changes in color of interior and exterior surface
finishes may occur. This is not a flaw and is not covered under the Warranty. · Damage to printed, plated, or enameled surfaces caused by fingerprints, accidents, misuse, scratches, melted items or other
external sources and residues left on the plated surfaces from the use of abrasive cleaners or polishes. · Repair or replacement of parts that are subject to normal wear and tear during the Warranty Period are not covered. These parts
include: paint, wood and pellet gaskets, firebricks, grates, flame guides, batteries and the discoloration of glass. · Minor expansion, contraction, or movement of certain parts causing noise. These conditions are normal and complaints related to
this noise are not covered by this Warranty. · Damages resulting from: (1) failure to install, operate, or maintain the applicable Product in accordance with the installation
instructions, operating instructions, and listing agent identification label furnished with the applicable Product; (2) failure to install the applicable Product in accordance with local building codes; (3) shipping or improper handling; (4) improper operation, abuse, misuse, continued operation with damaged, corroded or failed components, accident, or improperly/incorrectly performed repairs; (5) environmental conditions, inadequate ventilation, negative pressure, or drafting caused by tightly sealed constructions, insufficient make-up air supply, or handling devices such as exhaust fans or forced air furnaces or other such causes; (6) use of fuels other than those specified in the operation instructions; (7) installation or use of components not supplied with the applicable Product or any other components not expressly authorized and approved by HHT; (8) modification of the appliance not expressly authorized and approved by HHT in writing; and/or (9) interruptions or fluctuations of electrical power supply to the applicable Product. · Non- HHT venting components, hearth connections or other accessories used in conjunction with the applicable Product. · Any part of a pre-existing fireplace system in which an insert or a decorative gas applicable Product is installed. · HHT’s obligation under this Warranty does not extend to the Product’s capability to heat the desired space. Information is provided to assist the consumer and the dealer in selecting the proper Product for the application. Consideration must be given to the Product location and configuration, environmental conditions, insulation and air tightness of the structure.
This warranty is void if:
· The applicable Product has been over-fired, operated in atmospheres contaminated by chlorine, fluorine, or other damaging chemicals. Over-firing can be identified by, but not limited to, warped plates or tubes, deformation/warping of interior cast iron structure or components, rust colored cast iron, bubbling, cracking and discoloration of steel or enamel finishes.
· The applicable Product is subjected to prolonged periods of dampness or condensation. · There is any damage to the applicable Product due to water or weather damage which is the result of, but not limited to, improper
chimney or venting installation.

LIMITATIONS OF REMEDIES AND LIABILITY:
· EXCEPT TO THE EXTENT PROVIDED BY LAW, HHT MAKES NO EXPRESS WARRANTIES OTHER THAN THE WARRANTY SPECIFIED
HEREIN. The owner’s exclusive remedy and HHT’s sole obligation under this Warranty or in contract, tort or otherwise, shall be limited to replacement of the Component Part(s), repair of the Component Part(s), or refund of the original purchase price of the
applicable Product(s), as specified above; provided, however, that (i) if HHT is unable to provide replacement of the Component Part(s) and repair of the Component Part(s) is not commercially practicable or cannot be timely made, or (ii) the customer is willing to accept a refund of the purchase price of the applicable Product(s), HHT may discharge all such obligations by refunding the purchase price of the applicable Product. In no event will HHT be liable for any incidental or consequential damages caused by defects in the applicable Product. Some States do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you. This Warranty gives you specific legal rights and you may also have other rights which vary from State to State. THE DURATION OF ANY IMPLIED WARRANTY IS LIMITED TO DURATION OF THE
EXPRESSED WARRANTY SPECIFIED ABOVE FOR THE APPLICABLE PRODUCT. Some States do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you.

4021-645M 9/21

Page 2 of 2

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

25

7 Important Safety and Operating Information

A. Appliance Safety
WARNING! DO NOT operate gas log set before reading and understanding operating instructions. Failure to operate gas log set according to operating instructions could cause fire or injury.
WARNING! Choking Hazard! Keep media out of reach of children. · Alert children and adults to hazards of high temperatures.
High temperatures may ignite clothing or other flammable materials. · Clothing, furniture, draperies, and other flammable
materials must not be placed on or near the appliance.
Young children should be carefully supervised when they are in the same room as the appliance. Toddlers, young children and others may be susceptible to accidental contact burns.
· A physical barrier is recommended if there are at risk individuals in the house.
· To restrict access to a fireplace, install an adjustable safety gate to keep toddlers, young children, pets and other at risk individuals out of the room and away from hot surfaces.
· Install a switch lock or a wall/remote control with child protection lockout feature.
· Keep remote controls out of reach of children.
· Never leave children alone near a hot fireplace, whether operating or cooling down.
· Teach children to NEVER touch the fireplace.
· Consider not using the fireplace when children will be present.
Contact your dealer for more information, or visit: www. hpba.org/safety- information.
To prevent unintended operation when not using your fireplace for an extended period of time (summer months, vacations, trips, etc):
· Remove batteries from remote controls.
· Turn off wall controls.

Clear Space
WARNING! DO NOT place combustible objects in front of the fireplace. High temperatures may start a fire. See Figure 7.1. Avoid placing candles, electronics and other heat-sensitive objects on mantel or hearth. Heat may damage these objects.
Note: See appliance Installation Manual for hearth, mantel and finishing requirements.
O3FCFFLTIR.EIEANPRFLSRAPOCANECTE
Figure 7.1 Clear Space
Over Firing
The appliance is considered to be over firing if the flames are contacting the top of the firebox. Call a qualified service technician to service the appliance.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

Important Safety and Operating Information (continued)
OWNER
Please retain these instructions for future reference.
WARNING
· Any change to this heater or its controls can be dangerous. · Improper installation or use of the heater can cause serious injury or death from 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.

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 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. To prevent malfunction and/or sooting, an unvented gas heater should be cleaned before use and at least annually by a professional service person. More frequent cleaning may be required due to excessive lint from carpeting, bedding materials, etc. It is imperative that control compartments, burners and circulating air passageways be kept clean.
7. WARNING: Any change to this heater or its controls can be dangerous.
8. Unvented gas room heaters are a supplemental zone heater. They are not intended to be the primary heating appliance.
9. CARBON MONOXIDE POISONING: Early signs of carbon monoxide poisoning are similar to the 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.
10. The installation must conform with local codes or, in the absence of local codes, with the National Fuel Gas Code, ANSI Z223.l/NFPA54.
11. This unit complies with ANSI Z21.11.2 Unvented Heaters, latest edition and ANSI Z21.60-2012/CSA2.26-
2012.
12. Do not install the heaters in a bathroom or bedroom.

13. 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. Refer to log placement instructions for proper installation.
14. 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.
15. Caution: Candles, incense, oil lamps, etc. produce combustion by-products including soot. Vent-free room heater 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.
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 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.
18. Unvented gas room 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.
19. 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.

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27

20. Input ratings are shown in BTU per hour and are for elevations up to 4,500 feet. For elevations above 4,500 each 1,000 feet above sea level. Refer to the National Fuel Gas Code.
21. 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).
22. The appliance must be isolated from gas supply piping system by closing its equipment shutoff valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1/2 psig (3.5 kPa).
23. 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.
24. Never burn solid fuels in a fireplace 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

B. General Operating Parts
Figure 7.2 references the general operating parts of the appliance and the section of this manual in which they are discussed.
3 ft. in front of appliance
Clearance space see section 3.A
Figure 7.2 General Operating Parts
C. Fuel Specifications
WARNING! Risk of Fire or Explosion! Appliance must be set up for compatible gas type! · This appliance is designed to operate on either natural
gas or propane. Make sure the appliance is compatible with gas type selected for installation site.
WARNING! Risk of Fire! Comply with all minimum clearances to combustibles as specified in the installation instructions.
D. Before Lighting Appliance
Before operating this fireplace for the first time, have a qualified service technician: · Verify all shipping materials have been removed from
inside and/or underneath the gas log set · Review proper placement of logs · Ensure that there are no gas leaks

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

8 Product Specific Information
A. Appliance Certification
MODEL: NBST27-NV/PV-B LABORATORY: CSA TYPE: Unvented Room Heater STANDARD: ANSI Z21.11.2:19 Gas-fired
Unvented Room Heaters ANSI Z21.60-2017 – CSA 2.26-2017 Decorative Gas Appliances for Installation in Solid-Fuel Burning Fireplaces
This product is listed to ANSI standards for “Unvented Room Heaters” and applicable sections of “Gas Burning Heating Appliances for Manufactured Homes and Recreational Vehicles”, and “Gas Fired Appliances for Use at High Altitudes”.
NOTICE: This installation must conform with local codes. In the absence of local codes you must comply with the National Fuel Gas Code, ANSI Z223.1–latest edition in the U.S.A.

B. BTU Specifications and Weights

Models

Maximum Input BTU/h

NBST27NV-B (0-2000 FT) 39,000

NBST27PV-B (0-2000 FT) 39,000

Minimum Input BTU/h
26,000
30,000

Orifice
3.20 mm #48

Weight Pounds
38
38

NOT INTENDED FOR USE AS A PRIMARY HEAT SOURCE. This appliance is tested and approved as either supplemental room heat or as a decorative appliance. It should not be factored as primary heat in residential heating calculations.
Installation and service of this appliance should be performed by qualified personnel. Hearth & Home Technologies recommends HHT Factory Trained or NFI certified professionals.

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29

9 Lighting Instructions
FOR YOUR SAFETY READ BEFORE LIGHTING
WARNING
If you do not follow these instruction exactly, a fire or explosion may result causing property damage, personal injury or loss of life.
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

9.1 – Burner Controls

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

Lighting Instructions (continued)

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.

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.

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 shutting 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.

Switch

On/Off/Pilot Knob
Hi/Lo Knob

Pilot

9.2 – Piezo Ignitor

Controls

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.

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

31

Lighting Instructions (continued)
MATCH LIGHTING INSTRUCTIONS
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.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

10 Maintenance and Service
Any safety screen removed for servicing must be replaced prior to operating the unvented room heater.
When properly maintained, your fireplace will give you many years of trouble- free service. Contact your dealer to answer questions regarding proper operation, troubleshooting and service for your appliance. Visit www.monessenhearth.com to locate a dealer. We recommend annual service by a qualified service technician.
A. Maintenance: Frequency and Tasks
The matrix below is an overview of maintenance tasks to be performed on the appliance. Section B gives details and instructions needed to assist the appropriate person in performing the tasks.

Task
Pilot Inspection & Cleaning
Log Inspection
Firebox Inspection
Burner Ignition & Operation

Frequency Annually Annually Annually
Annually

To be completed by
Qualified Service Technician

B. Maintenance Tasks: Qualified Service Technician
The following tasks must be performed by a qualified service technician.
Pilot
Frequency: Annually
By: Qualified Service Technician Tools needed: Small soft brush, pipe cleaner
· Inspect and remove dust, spider webs and lint
· Gently run pipe cleaner through air intake port
Firebox
Frequency: Annually
By: Qualified Service Technician Tools needed: Protective gloves, sandpaper, steel wool, cloths, mineral spirits, primer and touch-up paint. · Inspect for paint condition, warped surfaces, corrosion
or perforation. Sand and repaint as necessary. · Replace fireplace if firebox has been perforated.

C. Burner Ignition and Operation
Frequency: Annually
By: Qualified Service Technician
Tools needed: Protective gloves, vacuum cleaner, whisk broom, flashlight, voltmeter, indexed drill bit set, and a manometer.
· Verify burner is properly secured and aligned with pilot or igniter.
· Clean off burner top, inspect for plugged ports, corrosion or deterioration. Replace burner if necessary.
· Inspect for lifting or other flame problems.
· Inspect orifice for soot, dirt and corrosion. Verify orifice size is correct. See Service Parts List for proper orifice sizing.
· Verify manifold and inlet pressures. Adjust regulator as required.
· Inspect pilot flame pattern and strength. See Figure 10.1 and 10.2 for proper pilot flame pattern. Clean or replace orifice spud as necessary.

Thermocouple for Natural Gas

Thermocouple for LP

Figure 10.1 Correct Pilot Flame Appearance

Thermocouple for Natural Gas

Thermocouple for LP

Figure 10.2 Incorrect Pilot Flame Appearance

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33

D. Cleaning and Servicing
Annual inspection and cleaning by your dealer or qualified service technician is recommended to prevent malfunction and/or sooting.
WARNING
Turn off heater and allow to cool before cleaning.
Remove logs, handling carefully by holding gently at each end. Gloves are recommended to prevent skin irritation from logs. 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
rear burner, control and piezo covers and grate weldment.
· Inspect and clean burner air intake holes. Remove
lint or particles with vacuum, brush, or pipe cleaners. 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 cleaners. 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.
· Verify smooth and responsive ignition of main burner
and rear burner.
· Replace battery in remote control device.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

11 Troubleshooting

WARNING
Turn appliance OFF and allow to cool before servicing. Only a qualified service person should service and repair the heater.

MILLIVOLT CONTROL SYSTEM
NOTE: All troubleshooting items are listed in order of operation.

PROBLEM When ignitor button is pressed, there is no spark at ODS/pilot.
Appliance produces unwanted odors.
Appliance shuts off during use.
Gas odor even when control knob is in OFF position.
When ignitor button is pressed, there is spark at ODS pilot, but no ignition.

POSSIBLE CAUSE Ignitor electrode positioned wrong. Ignitor electrode is broken. Ignitor electrode not connected to ignitor cable. Ignitor cable pinched or wet. Keep ignitor cable dry. Broken ignitor cable. Bad piezo ignitor. Appliance burning vapors from paint, hair spray, glues, etc. Gas leak.
Initial burn off.
Not enough fresh air is available for ODS/pilot to operate. Low line pressure. ODS/pilot is partially clogged.
Defective thermopile.
Restrictions in incoming air flow.
Gas leak. Control valve defective. Gas supply turned off or manual shutoff valve closed. Control knob not in PILOT position. Control knob not pressed in while in PILOT position.
Air in gas lines when installed.
ODS/pilot is clogged.
Gas regulator setting is not correct.

SOLUTION
Replace ignitor. Replace ignitor.
Reconnect ignitor cable.
Free ignitor cable if pinched by any metal or tubing. Replace ignitor cable. Replace piezo ignitor. Ventilate room. Stop using odor causing products while heater is running. Locate and correct all leaks. Ventilate room and turn unit on high until odor is gone. Odor should be gone after six hours of continuous use.
Open window and/or door for ventilation.
Contact local gas company. Clean ODS/pilot. Check wire connections. Check output should be 500 millivolts across TH/TP and TP Terminals with ON/OFF switches off.
Check for bottom riser on glass door, sunken fireplace, excessive lava rock/ cinders densely packed against grate. Locate and correct all leaks. Replace control valve. Turn on gas supply or open manual shutoff valve. Turn control knot to PILOT position. Press in control knob while in PILOT position. Continue holding down control knob. Repeat igniting operation until air is removed. Replace ODS/pilot assembly or get it serviced. Check incoming pressure. Replace gas regulator.

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35

Troubleshooting

PROBLEM

POSSIBLE CAUSE

SOLUTION

Control knob not fully pressed in.

Press in control knob fully.

Control knob not pressed in long enough.

After ODS/pilot lights, keep control knob pressed in for 30 seconds.

Manual shutoff valve not fully open.

Fully open manual shutoff valve.

ODS/pilot lights, but flame goes out when control knob is released.

Thermocouple connection loose at control valve.
Pilot flame not touching thermocouple, which allows thermocouple to cool, causing pilot flame to go out. This problem could be caused by either low gas pressure, or a dirty or partially clogged ODS/ pilot.

Hand tighten thermocouple connection until snug, then tighten 1/4 turn more.
Contact local gas company.

Thermocouple damaged.

Replace thermocouple.

Control valve damaged.

Replace control valve.

Burner orifice is clogged.

Clean burner or replace burner orifice

Burner does not light after ODS/pilot is lit. Burner orifice diameter is too small.

Replace orifice.

Inlet gas pressure is too low.

Contact local gas company.

Burner backfires during combustion.

Manifold Pressure is too low. Burner orifice is clogged.

Contact local gas company. Clean burner or replace burner orifice.

Slight smoke or odor during initial operation.

Burner orifice is clogged or damaged. Burner is damaged. Gas regulator is defective.

Clean burner or replace burner orifice. Replace burner. Replace gas regulator.

Logs appear to smoke after initial opera- Vapors from paint or curing process of

tion.

logs.

1. Problem will stop after a few hours of operation. Run the heater with the damper open if you have one, or open a
window for the first few hours.
OR
2. Log heater is intended to be smokeless. Turn OFF heater and call qualified service person.

Turning control knob to HIGH position when burner is cold.

Turn control knob to LOW position and let warm up for a minute.

Heater produces a whistling noise when

burner is lit.

Air in gas line.

Operate burner until air is removed from line. Have gas line checked by local gas company.

Dirty or partially clogged burner orifices. Clean burner or replace burner orifice.

No gas to pilot.

LP regulator shut down due to inlet pressure too high.

1. Verify LP tank regulator is installed and set at 11″ to 13″ w.c. OR 2. Replace regulator on heater.

WARNING
If the gas quality is bad, your pilot may not stay lit, the burners may produce soot and the heater may backfire when lit. If the gas quality or pressure is low, contact your local gas supplier immediately.

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

12 Service Parts
A. Service Parts

Service Parts

NBST27NV-B, NBST27PV-B

Natural Blaze 27″ See-Through Hearth Kit

Beginning Manufacturing Date: Jun 2018 Ending Manufacturing Date: Active

1

2 8
7

5

6

3

4

IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or distributor. Hearth and Home Technologies does not sell directly to consumers. Provide model number and serial number when requesting service parts from your dealer or distributor.

ITEM

DESCRIPTION

1 Control Valve

2 Pilot Regulator

3 Pilot Assembly

4 Piezo Ignitor 5 Piezo Wire 6 On/Off Switch

7 Burner Assembly

8 Grate Assembly Tubing, Regulator to Pilot Tubing, Regulator to Valve Tubing, Valve to Venturi Tubing, Pilot to Valve Wiring Harness Lava Rock Rock Wool

COMMENTS NG
Propane NG Only
NG Propane
NG Propane Qty 2 req
NG NG
Propane
2.5lb 4 grams

PART NUMBER SRV14D0467 SRV14D0468 SRV14D0469 20303785K 20303786K SRV14D0503 SRV00K0632 SRV32D0232 SRV81D3016 SRV81D3028 SRV4615-005 SRV81D3009 SRV81D3010 SRV81D3008 SRV81D3011 SRV70D0050 SRV00F0540 SRV59D0096

Stocked at Depot
Y Y Y Y Y Y Y Y Y Y
Y
Y 11/21

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

37

Service Parts
Natural Blaze 27″ See-Through Log Set

NBST27-F
Beginning Manufacturing Date: Jun 2018 Ending Manufacturing Date: Active

1
2 4
5
6 10

8 3
7
9

IMPORTANT: THIS IS DATED INFORMATION. Parts must be ordered from a dealer or distributor. Hearth and Home Technologies does not sell directly to consumers. Provide model number and serial number when requesting service parts from your dealer or distributor.

ITEM 1 2 3 4 5 6 7 8 9 10

Log # 1 Log # 2 Log # 3 Log # 4 Log # 5 Log # 6 Log # 7 Log # 8 Log # 9 Log # 10

DESCRIPTION

COMMENTS

PART NUMBER SRV4615-701 SRV4615-702 SRV4615-703 SRV4615-704 SRV4615-705 SRV4615-706 SRV4615-707 SRV4615-708 SRV4615-709 SRV4615-710

Stocked at Depot
11/21

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Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

B. Accessories
DESCRIPTION Flex Connector Wall Switch and Wire Wall Thermostat Kit On/Off Remote Thermostat Remote Remote Receiver Cover Ember Remote Receiver Cover Metal Log Switch with Wires Universal Andirons Rock Wool Flickering Bright Embers

PART NUMBER Flexcon 30 MVWS WT RCB, RCMT, TLM, WMTD RCST, RCT, TLT, WWTD RRCE RRCM ELSK UAI9 EB-RW FBE-.1G

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39

MASSACHUSETTS RESIDENTS ONLY

Please read and follow these special requirements

NOTE REGARDING VENTED PRODUCTS
This product must be installed by a licensed plumber or gas fitter when installed within the Commonwealth of Massachusetts.

2. Approved Carbon Monoxide Detectors. Each carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certified.

Any residence with a direct vent product must have a carbon monoxide (CO) detector installed in the residence.
Installation of the fireplace or vented gas log in the State of Massachusetts requires the damper to be permanently removed or welded in the fully open position.
In addition, a naturally vented gas log may not be installed in a bedroom or bathroom in the State of Massachusetts.
Flex line installation must not exceed 36 inches and must have a T shutoff valve.
NOTE REGARDING VENT FREE PRODUCTS This product must be installed by a licensed plumber or gas fitter when installed within the Commonwealth of Massachusetts.
In addition, vent free products may not be installed in a bedroom or bathroom regardless of size or type in the State of Massachusetts.
Flex line installation must not exceed 36 inches and must have a T shutoff valve.
CARBON MONOXIDE DETECTOR REQUIREMENTS (2) Revise 10.8.3 by adding the following additional requirements:
(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:
1. Installation of carbon monoxide detectors. At the time of installation of the side wall horizontal vented gas fueled equipment, the installing plumber or gas fitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back-up is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gas fitter shall observe that a battery operated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or structure served by the side wall horizontal vented gas fueled equipment. It shall be the responsibility of the property owner to secure the services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors
a. In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, the hard wired carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision can not be met at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery operated carbon monoxide detector with an alarm shall be installed.

3. Signage. A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, “GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS.”
4. Inspection. The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR 5.08(2)(a)1 through 4.
(b) Exemptions: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled “Equipment Not Required To Be Vented” in the most current edition of NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the dwelling, building or structure used in whole or in part for residential purposes.
(c) Manufacturer requirements — Gas Equipment Venting System Provided. When the manufacturer of Product Approved side wall horizontally vented gas equipment provides a venting system design or venting system components with the equipment, the instructions provided by the manufacturer for installation of the equipment and the venting system shall include:
1. Detailed instructions for the installation of the venting system design or the venting system components; and
2. A complete parts list for the venting system design or venting system.
(d) Manufacturer requirements — Gas Equipment Venting System Not Provided. When the manufacturer of a Product Approved side wall horizontally vented gas fueled equipment does not provide the parts for venting the flue gases, but identifies “special venting systems,” the following requirements shall be satisfied by the manufacturer:
1. The referenced “special venting system” instructions shall be included with the appliance or equipment installation instructions; and
2. The “special venting systems” shall be Product Approved by the Board, and the instructions for that system shall include a parts list and detailed installation instructions.
(e) A copy of all installation instructions for all Product Approved side wall horizontally vented gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all venting design

40

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

C. Contact Information

Monessen, a brand of Hearth & Home Technologies 7571 215th Street West, Lakeville, MN 55044 www.monessenhearth.com
Please contact your dealer with any questions or concerns. For the location of your nearest dealer, please visit www.monessenhearth.com

– NOTES

· Important operating and maintenance instructions included.

NOTICE

DO NOT DISCARD THIS MANUAL

· Read, understand and follow these instructions for safe installation and operation.

· Leave this manual with party responsible for use and operation.

This product may be covered by one or more of the following patents: (United States) 5613487, 5647340, 5890485, 5941237, 6006743, 6019099, 6053165, 6145502, 6374822, 6484712, 6601579, 6769426, 6863064, 7077122, 7098269, 7258116, 7470729, 8147240 or other U.S. and foreign patents pending.
2000-945C

Printed in U.S.A. – Copyright 2016

Monessen · NBST27-B Gas Log Set Owner’s /Installation Manual · 4615-900 Rev. H · 01/22

41

References

• Monessen Hearth | Vent Free Fireplaces, Fireboxes & Gas Logs

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