Desa CFS24NVC, VS30N User Manual
DESA INTERNATIONAL
UNVENTED (VENT-FREE)
NATURAL GAS LOG HEATER
Variable Manually-Controlled Models Also Design-Certified As Vented
Decorative Appliances
OWNER’S OPERATION AND INSTALLATION MANUAL
18", 24", and 30"
(“C” Models) Variable
Manually-Controlled,
and (“B” Models)
Thermostatically-
Controlled
LO
PILOT
OFF
HI
®
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.
WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause injury or property
damage. Refer to this manual for correct installation and operational proce-
— Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
dures. For assistance or additional information consult a qualified installer,
service agency, or the gas supplier.
— 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 per-
formed by 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
Air for Combustion and Ventilation
section on page 4 of this manual.
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
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 air
at 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. Follow 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 Installing
Damper Clamp Accessory for Vented
Operation, page 10 (V ariable Manually-
Controlled models only).
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 fireplace 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
person.
slight smoking may occur due to log
curing and heater burning manufacturing residues.
9. T o prevent the creation of soot, follow
the instructions in Cleaning and Main-
tenance, page 18.
Note:
During initial operation,
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 cleaners, 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 Combustion
and 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. Keep 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.
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. T urn heater of f and let cool before servicing. Only a qualified service person
should service and repair heater.
22. Operating heater above elevations of
4,500 feet may cause pilot outage.
2
104414
OWNER’S MANUAL
PRODUCT
IDENTIFICATION
Front
Branch
Piezo
Ignitor
Front
Burner
Control Knob
Figure 1 - Split Oak Design Model
LOCAL CODES
Crossover Log
Base Assembly
UNPACKING
Rear Log
Rear
Burner
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
both realistic flames and glowing coals.
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 ventfree heaters. This heater may also be operated as a vented decorative (ANS Z21.60)
product by opening the flue damper (nonthermostat models only).
SAFETY DEVICE
This heater has a pilot with an Oxygen
Detection Safety Pilot System (ODS). The
ODS/pilot is a required feature for vent-free
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.
Install and use heater with care. Follow all
local codes. In the absence of local codes, use
the latest edition of The National Fuel Gas
Code ANS Z223.1, 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 models are not
permitted.
104414
CAUTION: Do not remove
the metal data plates from the
grate assembly. The data plates
contain important product 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
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 through 6 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 (6 x 10
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, proceed to
mining Fresh-Air Flow For Heater
Location
and
Ventilation Air
, page 6 .
, page 5.
-11
and
Deter-
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
104414
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 adjo ining
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 heater 40,000 Btu/Hr
Vent-free heater + 33,000 Btu/Hr
Total = 73,000 Btu/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
or if the building is of unusually tight construction, provide adequate combustion and ventilation air by one of
the methods described in the
104414
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
Grills
Into Adjoining
Room,
Option 1
Figure 2 - Ventilation Air from Inside Building
Or
Remove
Door into
Adjoining
Room,
Option
3
12"
Outlet
Air
Ventilation Grills
Into Adjoining Room,
Ventilated
Attic
12"
Option 2
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. 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.
IMPORTANT:
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 for
Outlet
Air
Inlet
Air
Inlet Air
Figure 3 - Ventilation Air from Outdoors
To Attic
To
Crawl
Space
Ventilated
Crawl Space
6
104414
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.
WARNING: 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: 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.
WARNING: Never install the
heater
• in a bedroom or bathroom unless installed as a vented appliance, see page 10 (Variable
Manually-Controlled models
only)
• 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, 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 18", 24", 30"
Side Wall 16"
Ceiling 42"
Floor 5"
LOG SIZING REQUIREMENTS
Minimum Firebox Size
Log Front Rear*
Size Height Depth Width Width
18" 17" 14" 20" 14"
24" 17" 14" 26" 18"
30" 17" 14" 32" 22"
*Measured at 14" depth
Carefully follow the instructions below. This
will ensure safe installation into a masonry,
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.
104414
Left and
Right Sides
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
Clamp Accessory for Vented
Operation
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 on this page.
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 (24" and 30" models only). See
Figure 5 for minimum clearances.
IMPORTANT:
minimum clearances, you must operate
heater with chimney flue damper open. Go
to Installing Damper Clamp Accessory for
Vented Operation, page 10.
Installing Damper
, 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 (for all
models). If noncombustible material is less
than 12", you must install the fireplace hood
accessory (24" and 30" models only). 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.
Noncombustible Requirements for
Material Distance (A) Safe Installation
12" or more Noncombustible material OK.
Between 8" and 12" 24" or 30" Models: Install fireplace hood accessory
(GA6050, GA6052, or GA6053, see
page 28).
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
(A)
IMPORTANT: If you cannot meet these
minimum clearances, you must operate
heater with chimney flue damper open. Go
to Installing Damper Clamp Accessory for
Vented Operation, page 10.
Accessories
Between 8" and 12"
, above. If you
,
Figure 5 - Heat Resistant Material (Slate, Marble, Tile, etc.) Above Fireplace
8
104414
OWNER’S MANUAL
INSTALLATION
Continued
MANTEL CLEARANCES
In addition to meeting noncombustible material clearances, you must also meet required
clearances between fireplace opening and
mantel shelf. If you do not meet the clearances losted below, you will need a hood.
Determining Minimum Mantel
Clearance
If you meet minimum clearance between
mantel shelf and top of fireplace opening, a
hood is not required (see Figure 6).
Determining Minimum Mantel
Clearance When Using a Hood
If minimum clearances in Figure 6 are not
met, you must have a hood. When using a
hood there are still certain minimum mantel
clearances required. Follow minimum clearances shown in Figure 7 when using hood.
NOTICE: If your installation does
not meet the minimum clearances
shown, you must do one of the
following:
• operate the logs only with the
flue damper open
• raise the mantel to an acceptable height
• remove the mantel
FLOOR CLEARANCES
A. If installing appliance on the floor level,
you must maintain the minimum distance of 14" to combustibles (see Figure 8).
B. If combustible materials are less than
14" to the fireplace, you must install
appliance at least 5" above the combustible flooring (see Figure 9).
Mantel Shelf
Minimum NonCombustible
Material
10"
8"
6"
1
2
"
/2
(A)
12"
8"
Minimum NonCombustible
Material Height
18"
14"
20"
22"
3
16
18
/
"
4
Distances to
Underside of
Mantel
1
/
2
24"
20"
"
Underside of
Mantel Shelf
All minimum
distances are
in inches
Log Set
24"/30" Models
18" Model
Top of Fireplace
Opening
Figure 6 - Minimum Mantel Clearances Without Using Hood
"
Mantel Shelf
8"
Min.
12" 15" 18"
Distances to
Underside of
Mantel
Underside of
Mantel Shelf
20"
Top of Fireplace
Opening
Minimum NonCombustible
Material
12"
10"
8"
6"
1
/2
2
Hood
Hood
(GA6050, GA6052)
(GA6050, GA6052,
or GA6053)
Figure 7 - Minimum Mantel Clearances When Using Hood
All minimum
distances are
in inches
Log Sets
18", 24",
& 30" Models
104414
Combustible
14"
Min.
Material
Noncombustible
Non-Combustible
Material
Material
Figure 8 - Minimum Fireplace Clearances
If Installed at Floor Level
9
Hearth
5"
Min.
Combustible
Material
Figure 9 - Minimum Fireplace Clearances
Above Combustible Flooring
Continued
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