Variable Manually-Controlled Models Also Design-Certified As
Vented Decorative Appliances
OWNER’S OPERATION AND INSTALLATION MANUAL
CFS18NR, VS18NR,
VS24NR VS30NR
18", 24", and 30"
Remote-Ready Models
LO
O
L
T
I
P
O
N
F
F
O
HI
REMOTE
OFF
ON
®
WARNING: 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.
WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause injury or property
damage. Refer to this manual for correct installation and operational procedures. For assistance or additional information consult a qualified installer,
service agency, or the gas supplier.
WARNING: This appliance is for installation only in a solid-fuel burning
masonry or UL127 factory-built fireplace, or in an approved ventless firebox. It is design-certified for these
installations in accordance with ANS
Z21.11.2. Exception: Do not install
this appliance in a factory-built fireplace that includes instructions stating it has not been tested or should
not be used with unvented gas logs.
WARNING: 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
This appliance may be installed in an aftermarket* manufactured (mobile) home, where not prohibited by
state or local codes.
* Aftermarket: Completion of sale, not for purpose of resale, from the manufacturer
Air for Combustion and Ventilation
section on page 4 of this manual.
Save this manual for future reference
DESA INTERNATIONAL
UNVENTED NATURAL GAS LOG HEATER
SAFETY
INFORMATION
WARNINGS
IMPORTANT: Read this owner’s
manual carefully and completely
before trying to assemble, operate, or service this heater. Improper use of this heater can cause
serious injury or death from burns,
fire, explosion, electrical shock,
and carbon monoxide poisoning.
DANGER: Carbon monoxide
poisoning may lead to death!
Carbon Monoxide Poisoning: Early
signs of carbon monoxide poisoning resemble the flu, with headaches, dizziness,
or nausea. If you have these signs, the heater
may not be working properly. Get fresh airat once! Have heater serviced. Some people
are more affected by carbon monoxide than
others. These include pregnant women,
people with heart or lung disease or anemia,
those under the influence of alcohol, and
those at high altitudes.
Natural Gas: Natural gas is odorless. An
odor-making agent is added to the gas. The
odor helps you detect a gas leak. However,
the odor added to the gas can fade. Gas may
be present even though no odor exists.
Make certain you read and understand all
Warnings. Keep this manual for reference.
It is your guide to safe and proper operation
of this heater.
WARNING: Any change to
this heater or its controls can be
dangerous.
1.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.
2.If you smell gas
• shut off gas supply
• 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. F ollow the
gas supplier’s instructions
• if you cannot reach your gas supplier ,
call the fire department
3.This heater shall not be installed in a
bedroom or bathroom unless installed
as a vented appliance (see InstallingDamper Clamp Accessory, page 10).
4.Never install the heater
• in a recreational vehicle
• where curtains, furniture, clothing, or
other flammable objects are less than
42 inches from the front, top, or sides
of the heater
• in high traffic areas
• in windy or drafty areas
5.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. Creosote will ignite
if highly heated. Inspect chimney flue
for damage. If damaged, operate heater
with flue damper closed.
6.If fireplace has glass doors, never operate this heater with glass doors closed.
If you operate heater with doors closed,
heat buildup inside fireplace will cause
glass to burst. Also if fireplace opening has vents at the bottom, you must
open the vents before operating heater .
7.Y ou must operate this heater with a fir eplace screen in place. Make sure fireplace
screen is closed before running heater.
8.This log heater is designed to be smokeless. If logs ever appear to smoke, turn
off heater and call a qualified service per son.
Note:
During initial operation, slight
smoking may occur due to log curing and
heater burning manufacturing residues.
9.To prevent the creation of soot, follow
the instructions in Cleaning and Main-tenance, page 18.
10. Do not allow fans to blow directly into
the fireplace. Avoid any drafts that alter burner flame patterns. Ceiling fans
may create drafts that alter burner flame
patterns. Altered burner patterns can
cause sooting.
11. Before using furniture polish, wax, carpet cleaner, or similar products, turn
heater off. If heated, the vapors from
these products may create a white powder residue within burner box or on
adjacent walls or furniture.
12. Do not use a blower insert, heat exchanger insert or other accessory not
approved for use with this heater.
13. This heater needs fresh, outside air ventilation to run properly. This heater has
an oxygen depletion sensor (ODS) pilot light safety system. The ODS shuts
down the heater if not enough fresh air
is available. See Air for Combustionand Ventilation, pages 4 through 6. If
heater keeps shutting off, see Trouble-shooting, pages 19 through 21.
14. Do not run heater
• where flammable liquids or vapors
are used or stored
• under dusty conditions
15. Do not use this heater to cook food or
burn paper or other objects.
16. Never place any objects on the heater.
17. Heater base assembly becomes very hot
when running heater. K eep children and
adults away from hot surface to avoid
burns or clothing ignition. Heater will
remain hot for a time after shutdown.
Allow surface to cool before touching.
18. Carefully supervise young children when
they are in the room with heater. When
using the hand-held remote accessory,
keep selector switch in the OFF position
to prevent children from turning on burners with hand-held remote control unit.
19. Do not use heater if any part has been
exposed to or 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 .
20. Do not operate heater if any log is broken. Do not operate heater if a log is
chipped (dime-sized or larger).
21. Turn heater off and let cool before servicing, installing, or repairing. When using the hand-held remote accessory, mak e
sure the selector switch is in the OFF
position. Only a qualified service person
should install, service, or repair heater.
22. When using the hand-held remote accessory, make sure the selector switch is in
the OFF position when you are away
from home for long periods of time.
23. This heater must not be connected to
any external electrical source.
24. Operating heater above elevations of
4,500 feet may cause pilot outage.
2
103449
OWNER’S MANUAL
PRODUCT
IDENTIFICATION
Top Middle
Log
Left
Front
Branch
Front
Burner
Piezo
Ignitor
Remote
Control
(Optional)
Figure 1 - VS24NR Shown
HI
TEMP
MAN
AUTO
ONLO
OFF
STATUS
Right Front
Branch
Control Knob
Flame
Adjustment
Knob
Selector
Switch
(Optional)
Crossover Log
Rear Log
Base
Assembly
Rear
Burner
Bottom
Middle
Log
PRODUCT
FEATURES
OPERATION
This heater is clean burning. It requires no
outside venting. There is no heat loss out a
vent or up a chimney. Heat is generated by
realistic, dancing yellow flames. This heater
is designed for vent-free operation with flue
damper closed. It has been tested and approved to ANS Z21.11.2 standard for
unvented heaters. State and local codes in
some areas prohibit the use of vent-free
heaters. This heater may also be operated as
a vented decorative (ANS Z21.60) product
by opening the flue damper (non-thermostat
operation only).
SAFETY PILOT
This heater has a pilot with an Oxygen
Depletion Sensor Shutoff System (ODS).
The ODS/pilot is a required feature for ventfree room heaters. The ODS/pilot shuts off
the heater if there is not enough fresh air.
PIEZO IGNITION SYSTEM
This heater has a piezo ignitor. This system
requires no matches, batteries, or other
sources to light heater.
LOCAL CODES
Install and use heater with care. Follow all
local codes. In the absence of local codes, use
the latest edition of The National Fuel GasCode ANS Z223, also known as NFPA 54*.
*Available from:
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
Note:
Where listed vented decorative logs
are required, thermostat operation is not
permitted.
103449
UNPACKING
CAUTION: Do not remove the
warning and instruction labels
attached to the heater base assembly. These markings contain
important warranty information.
1.Remove logs and heater base assembly from carton.
heater base assembly by burners. This
could damage heater. Always handle
base assembly by grate.
2.Remove all protective packaging applied to logs and heater for shipment.
3.Check all items for any shipping damage. If damaged, promptly inform
dealer where you bought heater.
Note:
Do not pick up
3
REMOTE CONTROL
ACCESSORIES
There are four optional remote controls that
can be purchased separately for this log
heater:
• wall switch
• wall thermostat
• hand-held ON/OFF remote
• hand-held thermostat remote
See Accessories, page 23.
The wall thermostat or hand-held thermo-
stat may not be used where vented decorative listing is required.
DESA INTERNATIONAL
UNVENTED NATURAL GAS LOG HEATER
AIR FOR
COMBUSTION AND
VENTILATION
WARNING: This heater shall
not be installed in a confined space
or unusually tight construction
unless provisions are provided
for adequate combustion and ventilation air. Read the following instructions to insure proper fresh
air for this and other fuel-burning
appliances in your home.
Today’s homes are built more energy efficient than ever. New materials, increased
insulation, and new construction methods
help reduce heat loss in homes. Home owners
weather strip and caulk around windows and
doors to keep the cold air out and the warm air
in. During heating months, home owners
want their homes as airtight as possible.
While it is good to make your home energy
efficient, your home needs to breathe. Fresh
air must enter your home. All fuel-burning
appliances need fresh air for proper combustion and ventilation.
Exhaust fans, fireplaces, clothes dryers, and
fuel burning appliances draw air from the
house to operate. You must provide adequate fresh air for these appliances. This
will insure proper venting of vented fuelburning appliances.
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from National
Fuel Gas Code. NFPA 54/ANS Z223.1, Section 5.3, Air for Combustion and Ventilation.
All spaces in homes fall into one of the three
following ventilation classifications:
1.Unusually Tight Construction
2.Unconfined Space
3.Confined Space
The information on pages 4 and 5 will help
you classify your space and provide adequate ventilation.
Unusually Tight Construction
The air that leaks around doors and windows may provide enough fresh air for
combustion and ventilation. However, in
buildings of unusually tight construction,
you must provide additional fresh air.
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 one perm (6x10
per pa-sec-m2) or less with openings gasketed or sealed
b. weather stripping has been
added on openable windows and
doors
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.
If your home meets all of the three
criteria above, you must provide additional fresh air. See
From Outdoors
If your home does not meet all of the
three criteria above, See
Fresh-Air Flow For Heater Location
page 5.
and
, page 5
Ventilation Air
.
Determining
and
-11
kg
Confined and Unconfined Space
The National Fuel Gas Code (ANS Z223.1,
1992 Section 5.3) defines a confined space
as a space whose volume is 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 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 the
unconfined space.
This heater shall not be installed in a confined space or unusually tight construction
unless provisions are provided for adequate
combustion and ventilation air.
* Adjoining rooms are communicating only
if there are doorless passageways or ventilation grills between them.
,
4
103449
OWNER’S MANUAL
AIR FOR
COMBUSTION AND
VENTILATION
Continued
DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
Determining if You Have a Confined or Unconfined Space
Use this work sheet to determine if you have a confined or unconfined space.
Space: Includes the room in which you will install heater plus any adjoining rooms with doorless passageways or ventilation grills between
the rooms.
1.Determine the volume of the space (length x width x height).
Length x Width x Height = ___________________ cu. ft. (volume of space)
Example:
If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms to the total volume of
the space.
2.Divide the space volume by 50 cubic feet to determine the maximum Btu/Hr the space can support.
_________________ (volume of space) ÷ 50 cu. ft. = (Maximum Btu/Hr the space can support)
Example:
3.Add the Btu/Hr of all fuel burning appliances in the space.
Vent-free heater_______________________Btu/Hr
Gas water heater*_______________________Btu/Hr
Gas furnace_______________________Btu/Hr
Vented gas heater_______________________Btu/Hr
Gas fireplace logs_______________________Btu/Hr
Other gas appliances* + _______________________Btu/Hr
Total = _______________________Btu/Hr
* Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors.
4.Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used.
_________________ Btu/Hr (maximum the space can support)
_________________ Btu/Hr (actual amount of Btu/Hr used)
Example:
The space in the above example is a confined space because the actual Btu/Hr used is more than the maximum Btu/Hr the space can support.
You must provide additional fresh air. Your options are as follows:
A. Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoin-
ing room or add ventilation grills between rooms. See Ventilation Air From Inside Building, page 6.
B. Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 6.
C. Install a lower Btu/Hr heater, if lower Btu /Hr size makes room unconfined.
If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an unconfined space. You will need no
additional fresh air ventilation.
Space size 20 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) = 2560 cu. ft. (volume of space)
2560 cu. ft. (volume of space) ÷ 50 cu. ft. = 51.2 or 51,200 (maximum Btu/Hr the space can support)
Example:
Gas water heater40,000Btu/Hr
Vent-free heater +33,000Btu/Hr
Total=73,000Btu/Hr
51,200 Btu/Hr (maximum the space can support)
73,000 Btu/Hr (actual amount of Btu/Hr used)
WARNING: If the area in which the heater may be operated is smaller than that defined as an unconfined space
orif the building is of unusually tight construction, provide adequate combustion and ventilation air by one of the
methods described in the
103449
National Fuel Gas Code, ANS Z223.1, 1992, Section 5.3
5
or applicable local codes
Continued
.
DESA INTERNATIONAL
UNVENTED NATURAL GAS LOG HEATER
AIR FOR
COMBUSTION AND
VENTILATION
Continued
VENTILATION AIR
Ventilation Air From Inside
Building
This fresh air would come from an adjoining
unconfined space. When ventilating to an
adjoining unconfined space, you must provide two permanent openings: one within
12" of the ceiling and one within 12" of the
floor on the wall connecting the two spaces
(see options 1 and 2, Figure 2). You can also
remove door into adjoining room (see option 3, Figure 2). Follow the National Fuel
Gas Code NFPA 54/ANS Z223.1, Section
5.3, Air for Combustion and Ventilation for
required size of ventilation grills or ducts.
WARNING: Rework worksheet, adding the space of the
adjoining unconfined space. The
combined spaces must have
enough fresh air to supply all
appliances in both spaces.
Ventilation Air From Outdoors
Provide extra fresh air by using ventilation
grills or ducts. You must provide two permanent openings: one within 12" of the
ceiling and one within 12" of the floor.
Connect these items directly to the outdoors
or spaces open to the outdoors. These spaces
include attics and crawl spaces.
IMPORTANT:
for inlet or outlet air into attic if attic has
a thermostat-controlled power vent.
Heated air entering the attic will activate
the power vent.
Do not provide openings
Ventilation
Grills
Into Adjoining
Room,
Option 1
Or
Remove
Door into
Into Adjoining Room,
Adjoining
Room,
Option
3
12"
Figure 2 - Ventilation Air from Inside Building
Outlet
Air
Outlet
Air
Inlet
Air
Inlet Air
Figure 3 - Ventilation Air from Outdoors
Ventilated
Attic
Ventilated
Crawl Space
12"
Ventilation Grills
Option 2
To Attic
To
Crawl
Space
6
103449
OWNER’S MANUAL
42"
16"
INSTALLATION
NOTICE: This heater is intended
for use as supplemental heat. Use
this heater along with your primary heating system. Do not install this heater as your primary
heat source. If you have a central
heating system, you may run
system’s circulating blower while
using heater. This will help circulate the heat throughout the
house. In the event of a power
outage, you can use this heater
as your primary heat source.
NOTICE: A qualified service person must install heater. Follow
all local codes.
NOTICE: State or local codes may
only allow operation of this appliance in a vented configuration.
Check your state or local codes.
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. Creosote
will ignite if highly heated. A dirty
chimney flue may create and distribute soot within the house. Inspect chimney flue for damage. If
damaged, operate heater with flue
damper closed.
WARNING: Never install the
heater
• in a bedroom or bathroom unless install as a vented appliance, see page 10
• in a recreational vehicle
• where curtains, furniture,
clothing, or other flammable
objects are less than 42 inches
from the front, top, or sides of
the heater
• in high traffic areas
• in windy or drafty areas
CAUTION: This heater creates warm air currents. These
currents move heat to wall surfaces next to heater. Installing
heater next to vinyl or cloth wall
coverings or operating heater
where impurities (such as tobacco smoke, aromatic candles,
cleaning fluids, oil or kerosene
lamps, etc.) in the air exist, may
discolor walls.
IMPORTANT:
ture to the air. Although this is beneficial,
installing heater in rooms without enough
ventilation air may cause mildew to form
from too much moisture. See Air for Com-bustion and Ventilation, pages 4 through 6.
Vent-free heaters add mois-
CHECK GAS TYPE
Use only natural gas. If your gas supply is
not natural gas, do not install heater. Call
dealer where you bought heater for proper
type heater.
INSTALLATION AND
CLEARANCES
(Vent-Free Operation Only)
WARNING: Maintain the minimum clearances. If you can, provide greater clearances from
floor, ceiling, and adjoining wall.
MINIMUM FIREPLACE
CLEARANCE TO
COMBUSTIBLE MATERIALS
Log Size Side Wall Ceiling Floor
18" 24" 30"16"42"5"
LOG SIZING REQUIREMENTS
Minimum Firebox Size
LogFront
Size HeightDepthWidth
18"17"14"20"
24"17"14"26"
30"17"14"32"
Carefully follow the instructions below. This
will ensure safe installation into a masonry
or UL127-listed manufactured fireplace, or
listed vent-free firebox.
Minimum Wall and Ceiling
Clearances (see Figure 4)
A. Clearances from the side of the fire-
place opening to any combustible wall
should not be less than 16 inches.
B. Clearances from the top of the fireplace
opening to the ceiling should not be less
than 42 inches.
WARNING: 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. Do not seal
chimney flue damper.
103449
Figure 4 - Minimum Clearance to Wall and
Ceiling
Continued
7
DESA INTERNATIONAL
UNVENTED NATURAL GAS LOG HEATER
INSTALLATION
Continued
NOTICE: Manual control heaters
may be used as a vented product.
If so, you must always run heater
with chimney flue damper open.
If running heater with damper
open, noncombustible material
above fireplace opening is not
needed. Go to Installing Damper
Clamp Accessory for Vented
Operation, page 10
Minimum Noncombustible
Material Clearances
If Not Using Mantel
Note:
If using a mantel, proceed to If Using
Mantel. If not using a mantel, follow the
information below.
You must have noncombustible material(s)
above the fireplace opening. Noncombustible materials (such as slate, marble, tile,
etc.) must be at least 1/2 inch thick. With
sheet metal, you must have noncombustible
material behind it. Noncombustible material
must extend at least 8" up (for all models). If
noncombustible material is less than 12", you
must install the fireplace hood accessory. See
Figure 5 for minimum clearances.
IMPORTANT:
minimum clearances, you must operate
heater with chimney flue damper open. Go
to Installing Damper Clamp Accessory forVented Operation, page 10.
If you cannot meet these
If Using Mantel
You must have noncombustible material(s)
above the fireplace opening. Noncombustible materials (such as slate, marble, tile,
etc.) must be at least 1/2 inch thick. With
sheet metal, you must have noncombustible
material behind it. Noncombustible material must extend at least 8 inches up. If
noncombustible material is less than 12",
you must install the fireplace hood acces-
Noncombustible
Material Distance (A)Requirements for Safe Installation
12" or moreNoncombustible material OK.
Between 8" and 12"Install fireplace hood accessory (GA6050, GA6052
or GA6053 see
18" Model: Noncombustible material OK.
Less than 8"Noncombustible material must be extended to at
least 8". See
cannot extend material, you must operate heater
with flue damper open.
Heat Resistant
Material
sory. Even if noncombustible material is
more than 12", you may need the hood
accessory to deflect heat away from your
mantel shelf. See Figure 5 and Figures 6 and
7, page 9 for minimum clearances.
IMPORTANT:
minimum clearances, you must operate
heater with chimney flue damper open. Go
to Installing Damper Clamp Accessory forVented Operation, page 10.