Monessen Hearth DFS36NVC User manual

This is an unvented gas-fired
heater. It uses air (oxygen) from
the room in which it is installed.
Provisions for adequate combustion
and ventilation air must be provided.
Refer to page 10.
READ AND SAVE THESE INSTRUCTIONS
VENT-FREE FIREPLACE
SYSTEMS
INSTALLATION AND OPERATING
INSTRUCTIONS
MODELS:
DFS32NVC, DFS32PVC
DFS36NVC, DFS36PVC
DFS42NVC, DFS42PVC
WARNINGS
If the information in this manual is not followed
exactly, a fire or explosion may result causing
property damage, personal injury or loss of life.
– Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any
other appliance.
– WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use
any phone in your building.
• Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call the
fire department.
– Installation and service must be performed by
a qualified installer, service agency or the gas
supplier.
WARNINGS

2 71D0532
CONTENTS
Important Safety Information ................................ 3
Product Features.....................................................5
Operation ..............................................................5
Specifications..........................................................7
Ignition Controls....................................................7
Pilot.......................................................................7
Thermal Generator................................................7
Getting Started.........................................................8
General Installation Information ............................9
Firebox Dimensions .............................................. 9
Codes..................................................................10
Adequate Combustion and Ventilation Air...........10
Removing Screen ............................................... 12
Installing Canopy ................................................ 12
Location of Fireplace ............................................13
Clearances and Height Requirements.................14
Fireplace Framing..................................................15
Connecting the Gas...............................................17
Checking Gas Pressure........................................18
Milli-Volt Control .................................................. 18
Electrical Wiring (Milli-Volt) ..................................19
Connecting Optional Wall Switch........................19
Connecting Remote Receiver.............................20
Checking System Operation ...............................20
Log Placement.......................................................21
Flame Appearance.................................................25
Checking the Burner Flame .................................26
Operating Instructions..........................................27
For Your Safety Read Before Lighting ................27
Milli-Volt Control Lighting Instructions ................. 28
Match Lighting Instructions .................................29
Cleaning and Servicing.........................................29
Blower and Other Optional Equipment ...............30
Illustrated Parts Breakdown.................................31
Logs ....................................................................31
Heater .................................................................32
Cabinet................................................................34
Troubleshooting ....................................................36
Trim Installation.....................................................38
Using Optional Outside Air Kit.............................40
Warranty.................................................Back Cover

71D0532 3
10. This unit complies with ANSI Z21.11.2 Unvented
Heaters.
11. Do not install the heaters in a bathroom or bedroom.
12. Correct installation of the ceramic fiber logs, proper
location of the heater, and annual cleaning are necessary
to avoid potential problems with sooting. Sooting,
resulting from improper installation or operation,
can settle on surfaces outside the fireplace. See log
placement instructions for proper installation.
13. Avoid any drafts that alter burner flame patterns. Do not
allow fans to blow directly into fireplace. Do not place
a blower inside burn area of firebox. Ceiling fans may
create drafts that alter burner flame patterns. Sooting
and improper burning will occur.
14. Caution: Candles, incense, oil lamps, etc. produce
combustion byproducts including soot. Vent-free
appliances will not filter or clean soot produced by
these types of products. In addition, the smoke and/or
aromatics (scents) may be reburnt in the vent-free
appliance which can produce odors. It is recommended
to minimize the use of candles, incense, etc. while the
vent-free appliance is in operation.
15. This is an unvented gas-fired heater. It uses air (oxygen)
from the room in which it is installed. Provisions
for adequate combustion and ventilation air must be
provided. See page 10.
16. Keep room area clear and free from combustible
materials, gasoline and other flammable vapors and
liquids.
INSTALLER
Please leave these instructions with the appliance. OWNER
Please retain these instructions for future reference .
IMPORTANT
Read these instructions carefully before installing or trying to operate this vent-free gas heater.
IMPORTANT SAFETY INFORMATION
1. Due to high temperatures, the appliance should
be located out of traffic and away from furniture
and draperies.
2. Children and adults should be alerted to the hazard
of high surface temperature and should stay away to
avoid burns or clothing ignition.
3. Young children should be carefully supervised when
they are in the same room with the appliance.
4. Do not place clothing or other flammable material
on or near the appliance.
5. Any safety screen or guard removed for servicing
an appliance, must be replaced prior to operating
the heater.
6. Installation and repair should be done by a qualified
service person.
7. To prevent malfunction and/or sooting, an unvented
gas heater should be cleaned before use and at least
annually by a professional service person. More
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.
8. CARBON MONOXIDE POISONING: Early signs of
carbon monoxide poisoning are similar to the flu with
headaches, dizziness and/or nausea. If you have these
signs, obtain fresh air immediately. Have the heater
serviced as it may not be operating properly.
9. The installation must conform with local codes or, in
the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.l/NFPA54. Continued on page 4
• Any change to this heater or its controls can be dangerous.
• Improper installation or use of the heater can cause serious injury or death from fire,
burns, explosion or carbon monoxide poisoning.
• Do not allow fans to blow directly into the fireplace. Avoid any drafts that alter
burner flame patterns.
• Do not use a blower insert, heat exchanger insert or other accessory, not approved
for use with this heater where applicable.
WARNING

4 71D0532
IMPORTANT SAFETY INFORMATION
THIS APPLIANCE MAY BE
INSTALLED IN AN AFTERMAR-
KET, PERMANENTLYLOCATED,
MANUFACTURED (MOBILE)
HOME, WHERE NOT PROHIB-
ITED BY LOCAL CODES.
THIS APPLIANCE IS ONLY FOR
USE WITH THE TYPE OF GAS
INDICATED ON THE RATING
PLATE. THIS APPLIANCE IS
NOT CONVERTIBLE FOR USE
WITH OTHER GASES.
Continued from page 3
17. Unvented gas heaters are a supplemental zone heater.
They are not intended to be the primary heating appli-
ance.
18. Unvented gas heaters emit moisture into the living
area. In most homes of average construction, this
does not pose a problem. In houses of extremely tight
construction, additional mechanical ventilation is
recommended.
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.
The initial break-in operation should last two to three
hours with the burner at the highest setting. Provide
maximum ventilation by opening windows or doors to
allow odors to dissipate. Any odors remaining after this
initial break-in period will be slight and will disappear
with continued use.
20. Input ratings are shown in BTU per hour and are for
elevations up to 2,000 feet. For elevations above 2,000
feet, input ratings should be reduced 4 percent for
each 1,000 feet above sea level. Refer to the National
Fuel Gas Code.
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.
25. Always have a fireplace screen in place when the
appliance is in operation and, unless other provisions
for combustion air are provided, the screen must have
an opening(s) for induction of combustion air.

71D0532 5
PRODUCT FEATURES
Figure 1 - Access to Controls
This vent-free fireplace must be mounted on the floor or on the optional fireplace hearth.
OPERATION
This unvented gas heater requires no outside venting and burns cleanly with high heating efficiency.
This zero-clearance unvented gas heater can be installed against (or recessed into) any wall that is accessible to
a gas line.
Screen
Control
Knobs
On/Off Switch
Piezo

6 71D0532
NATURAL GAS
Milli-Volt Pressure
Regulator Pressure Setting: 3.5" w.c.
Pilot Regulator: 3.5" w.c.
Gas Inlet Pressure: Max. 10 1/2" w. c.
Min. 5" w.c.
PRODUCT FEATURES
PROPANE/LPG
Note: An external regulator is required to reduce supply pressure to a maximum of 13" w.c.
Milli-Volt Pressure
Regulator Pressure Setting: 10" w.c.
Gas Inlet Pressure: Max. 13" w.c.
Min. 11" w.c.
Gas Rate
Model Number Control Max BTU/Hr Min BTU/Hr
DFS32NVC MILLI-VOLT 38,000 26,000
DFS36NVC MILLI-VOLT 38,000 26,000
DFS42NVC MILLI-VOLT 38,000 26,000
Gas Rate
Model Number Control Max BTU/Hr Min BTU/Hr
DFS32PVC MILLI-VOLT 34,000 26,000
DFS36PVC MILLI-VOLT 34,000 26,000
DFS42PVC MILLI-VOLT 34,000 26,000

71D0532 7
SPECIFICATIONS
IGNITION CONTROLS
Piezo ignitor allows ignition of the pilot without the use of matches or batteries.
Milli-Volt 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). Both front and rear burners are in operation
to provide realistic glow and yellow flame.
PILOT
The gas log heater is fitted with a specially designed safety pilot light (ODS assembly) which senses the amount of oxygen
available in the room and shuts the gas log heater off if the oxygen level begins to drop below a satisfactory level. The pilot
can only be relit when adequate fresh air is available.
THERMAL GENERATOR
The milli-volt gas log pilot is fitted with a milli-volt generator to provide power for remote activation.

8 71D0532
MAKE SURE YOU HAVE RECEIVED ALL PARTS:
Check your packing list to verify that all listed parts have been received. You should have the following:
• Unvented gas log grate/burner assembly
• Installation/operating instructions
• Ceramic fiber logs
• Rock wool
• Plastic bag containing crushed volcanic rock
• Trim kit
• Canopy and five (5) mounting screws
The milli-volt controlled version of this heater is the only style designed to be operated with optional devices for ON/OFF
functions. The following options may be used with the milli-volt controlled heater. These options are not packaged with
the log set.
• Hand held remote with receiver
• Wall switch with 15' wire
• Wall thermostat with 15' wire
• Hand held thermostat remote with receiver
• Gloves are recommended when handling ceramic fiber logs to prevent skin irritation
from loose fibers. Logs are fragile — handle with care.
WARNING
Carefully inspect the contents for shipping damage. If any parts are missing or damaged, immediately inform the
dealer from whom you purchased the appliance. Do not attempt to install any part of the appliance unless you
have all parts in good condition.
WHAT YOU WILL NEED FOR INSTALLATION:
You must have the following items available before proceeding with installation:
• External regulator (for propane/LPG and 1/2 lb. natural gas systems only)
• Piping which complies with local codes
• Pipe wrench or appropriate size crescent wrench set
• Pipe sealant approved for use with propane/LPG (Resistant to sulfur compounds)
• Sediment trap
• Manual shutoff valve
• Tee joint.
• Phillips head screwdriver
GETTING STARTED

71D0532 9
L
J
K
5 7/16"
G
F
D
E
C
34 1/2"
H
A
B
I
1 1/4"
21 3/4"
6"
1 5/16"
2 1/2"
GENERAL INSTALLATION INFORMATION
In planning the installation for the fireplace it is necessary to determine where the unit is to be installed and whether optional
accessories are desired. Gas supply piping should also be planned. The following steps represent the normal sequence of
installation. Each installation is unique, however, and might require a different sequence.
1. Position fireplace in desired location. Refer to the “Loca-
tion of Fireplace” and “Clearances and Height Require-
ments,” and “Firebox Framing” sections found in this
manual. Note: Be sure all packing material has
been removed from underside of the unit.
2. Install canopy and logs per instructions found in
this manual. The canopy MUST be installed for safe
operation of the unit.
3. Field wire main power supply to units with fan kit.
Refer to the “Electrical Section” found in this manual.
(Electrical connections should only be performed by an
experienced, licensed certified tradesman).
4. Install optional ON/OFF kit on units with milli-volt
control. Refer to installation instructions included with
the kit and also refer to the “Electrical Wiring” section
found in this manual.
5. Plumb gas line. Refer to the “Connecting the Gas”
section found in this manual. (Gas connections should
only be performed by an experienced, licensed / certified
tradesman).
6. Complete finish wall material and/or surround.
Figure 2 - Firebox Dimensions with Screen and Log Sets
DFS32NVC DFS36NVC DFS42NVC
DFS32PVC DFS36PVC DFS42PVC
A 37" 41" 47"
B 32" 36" 42"
C 16" 18" 18"
D 29" 32" 38"
E 18⅝" 20⅝" 20⅝"
F 23⅜" 27⅜" 33⅜"
G13¼" 15¾" 15¾"
H18" 17⅝" 17⅝"
I 29⅞" 34" 40"
J7⅛" 9¾" 9¾"
K8" 8¼" 8¼"
L 2¾" 2¼" 2¼"
1 ¼"
5 7/16"
21 ¾"
2 ½"
1 5/16"
6"
34 ½"

10 71D0532
GENERAL INSTALLATION INFORMATION
CODES
Adhere to all local codes or, in their absence, the latest edition of THE NATIONAL FUEL GAS CODE ANSI Z223.1 or
NFPA54 which can be obtained from:
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
or
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
ADEQUATE COMBUSTION AND 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 (4.8 m3per 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
m3per kw) of the aggregate input rating of all appliances installed in that space. Rooms communicating directly
with the space in which the appliances are installed, through openings not furnished with doors, are considered a
part of the unconfined 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;
b) weather striping has been added on openable 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 at other openings.
Do not install the heater:
• Where curtains, furniture, clothing, or other flammable objects are less than 42"
from the front of the heater.
• In high traffic areas.
• In windy or drafty areas.
WARNING