Desa Comfort Glow CGN20TA Quick start guide

1
104190
OWNER’S MANUAL
Save this manual for future reference.
BLUE FLAME VENT-FREE NATURAL GAS HEATER
OWNER’S OPERATION AND INSTALLATION MANUAL
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.
— Donotstoreorusegasolineorotherflammable
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.
• Ifyoucannotreachyourgassupplier,callthe
fire department.
— Installation and service must be performed by
a qualified installer, service agency, or the gas
supplier.
WARNING: This is an
unvented gas-fired heater. It
uses air (oxygen) from the
room in which it is installed.
Provisions for adequate
combustion must be pro-
vided.Refertopage4ofthis
manual
Heater Size: 20,000 Btu/Hr Thermostat
®
CGN20TA
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.
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
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
SAFETY
INFORMATION
WARNING ICON G 001
WARNINGS
IMPORTANT: Read this owner’s
manual carefully and completely
before trying to assemble, oper-
ate, or service this heater. Im-
proper use of this heater can
causeseriousinjuryordeathfrom
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 re-
semble the flu, with headaches, dizziness,
ornausea.Ifyouhavethesesigns,theheater
maynotbe workingproperly.Getfreshair
atonce!Haveheaterserviced.Somepeople
are more affected by carbon monoxide than
others. These include pregnant women,
peoplewithheartorlungdiseaseoranemia,
those under the influence of alcohol, and
those at high altitudes.
Natural Gas:Natural gas is odorless. An
odor-making agent is added to natural gas.
Theodorhelpsyoudetectanaturalgasleak.
However, the odor added to natural gas can
fade.Naturalgasmaybepresenteventhough
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:Anychangetothis
heateroritscontrols can be dan-
gerous.
1. This appliance is only for use with the
typeof gas indicated on therating plate.
Thisappliance isnot convertiblefor 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 build-
ing
• immediately call your gas supplier
from a neighbor’s phone. Follow the
gas supplier’s instructions
• ifyou cannot reach your gassupplier,
call the fire department
3. This heater shall not be installed in a
bedroom or bathroom.
4. Never install the heater
• in a recreational vehicle
• wherecurtains, furniture,clothing, or
otherflammable objects are lessthan
36inches from the front, top, or sides
of the heater
• as a fireplace insert
• in high traffic areas
• in windy or drafty areas
5. This heaterneeds fresh, outside air ven-
tilation to run properly. This heater has
an oxygen depletion sensor (ODS) pi-
lot light safety system. The ODS shuts
down the heater if not enough fresh air
is available. See Fresh Air for Combus-
tion and Ventilation, pages 4 through 6.
6. Keep air openings in front and bottom
of heater clear and free of debris. This
will ensure enough air for proper com-
bustion.
7. If heater shuts off, do not relight until
you provide fresh, outside air. If heater
keeps shutting off, have it serviced.
8. Do not run heater
• where flammable liquids or vapors
are used or stored
• under dusty conditions
9. Never place any objects on the heater.
10. Surface of heater becomes very hot
whenrunning heater. Keepchildren and
adults away from hot surface to avoid
burns or clothing ignition. Heater will
remain hot for a time after shut-down.
Allow surface to cool before touching.
11. Carefully supervise young children
when they are in the same room with
heater.
12. Make sure grill guard is in place be-
fore running heater.
13. Do not use heater if any part has been
under water. Immediately call a quali-
fied 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.
14. Turn off and unplug heater and let cool
before servicing. Only a qualified ser-
vice person should service and repair
heater.
15. Operating heater above elevations of
4,500 feet could cause pilot outage.

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104190
OWNER’S MANUAL
PRODUCT
IDENTIFICATION
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
GasCodeANSI Z223,alsoknown 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
Figure 1 - Vent-Free Natural Gas Heater
Ignitor Button Control Knob
Heater Cabinet
Front
Panel
Glass Panel
Grill Guard
UNPACKING
1. Remove heater from carton.
2. Remove all protective packaging ap-
plied to heater for shipment.
3. Check heater for any shipping damage.
If heater is damaged, promptly inform
dealer where you bought heater.
PRODUCT
FEATURES
Safety Device
This heater has a pilot with an Oxygen
Depletion Sensor Shutoff System (ODS).
TheODS/pilotisarequiredfeatureforvent-
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.
Thermostatic Heat Control
Thermostat models have a thermostat sens-
ing bulb and a control valve. This results in
the greatest heater comfort. This can also
result in lower gas bills.

4
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
FRESH AIR FOR
COMBUSTION AND
VENTILATION
Today’s homes are built more energy effi-
cient than ever. New materials, increased
insulation, and new construction methods
help reduce heat loss in homes. Home own-
ersweatherstripandcaulkaroundwindows
and doors to keep the cold air out and the
warm air in. During heating months, home
owners want their homes as airtight as pos-
sible.
While it is good to make your home energy
efficient,yourhomeneedstobreathe.Fresh
air must enter your home. All fuel-burning
appliances need fresh air for proper com-
bustion and ventilation.
Exhaustfans,fireplaces,clothesdryers,and
fuel burning appliances draw air from the
house to operate. You must provide ad-
equate fresh air for these appliances. This
will insure proper venting of vented fuel-
burning appliances.
PROVIDING ADEQUATE
VENTILATION
ThefollowingisexerptsfromNationalFuel
Gas Code. NFPA 54/ANSI Z223.1, Section
5.3, Air for Combustion and Ventilation.
Allspacesinhomesfallintooneofthethree
following ventilation classifications:
1. Unusually Tight Contruction
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 win-
dows 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 de-
fined as construction where:
a. walls and ceilings exposed to the
outside atmosphere have a con-
tinuouswater vapor retarder with
a rating of one perm (6x10-11 kg
per pa-sec-m2) or less with open-
ings gasketed or sealed and
b. weather stripping 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, be-
tween sole plates and floors, be-
tween wall-ceiling joints, be-
tween wall panels, at penetra-
tionsforplumbing, electrical, and
gas lines, and at other openings.
If your home meets all of the three
criteria above, you must provide ad-
ditional fresh air. See Ventilation Air
From Outdoors , page 6 .
If your home does not meet all of the
threecriteriaabove,proceedtopage5.
WARNING: This heater shall
not be installed in a confined
spaceunless provisions arepro-
vided for adequate combustion
and ventilation air. Read the fol-
lowing instructions to insure
properfreshairforthisandother
fuel-burning appliances in your
home.
Confined and Unconfined Space
TheNationalFuelGasCode(ANSIZ2123.1,
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 m3per kw) of the aggregate
inputratingofallappliancesinstalledinthat
space.Roomscommunicating directlywith
the space in which the appliances are in-
stalled*, through openings not furnished
with doors, are considered a part of the
unconfined space.
*Adjoiningroomsarecommunicatingonly
iftherearedoorlesspassagewaysorventila-
tion grills between them.
**Cubicfeetequalslength x widthxheight
of room.

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104190
OWNER’S MANUAL
FRESH AIR FOR
COMBUSTION AND
VENTILATION
Continued
DETERMINING FRESH-AIR
FLOW FOR HEATER
LOCATION
Determining if You Have a
Confined or Unconfined Space
Usethisworksheettodetermine if youhave
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: Space size 20 ft. (length) x
16 ft. (width) x 8 ft. (ceiling height) =
2560 cu. ft. (volume of space)
If additional ventilation to adjoining
room is supplied with grills or open-
ings, 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: 2560 cu. ft. (volume of
space) ÷ 50 cu. ft. = 51.2 or 51,200
(maximum Btu/Hr the space can sup-
port)
3. Add the Btu/Hr of all fuel burning ap-
pliances 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
Example:
Gas water heater 40,000 Btu/Hr
Vent-free heater + 20,000 Btu/Hr
Total = 60,000 Btu/Hr
* Do not include direct-vent gas appli-
ances. 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: 51,200 Btu/Hr (maximum
the space can support)60,000 Btu/Hr
(actual amount of Btu/Hr used)
The space in the above example is a con-
fined space because the actual Btu/Hr used
ismorethanthemaximumBtu/Hrthespace
can support. You must provide additional
fresh air. Your options are as follows:
A. Reworkworksheet, adding the space of
an adjoining room. If the extra space
provides an unconfined space, remove
door to adjoining room or add ventila-
tion grills between rooms. See Ventila-
tion 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
maximumBtu/Hrthespacecansupport,the
spaceisanunconfinedspace.Youwillneed
no additional fresh air ventilation.
Continued

6
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
Or
Remove
Door into
Adjoining
Room,
Option 3
Ventilation Grills
Into Adjoining Room,
Option 2
12"
12"
Ventilation
Grills
into Adjoining
Room,
Option 1
Figure 3 - Ventilation Air from Outdoors
FRESH AIR FOR
COMBUSTION AND
VENTILATION
Continued
WARNING:Iftheareainwhich
the heater may be operated is
smaller than that defined as an
unconfined space, provide ad-
equate combustion and ventila-
tion air by one of the methods
described in the
National Fuel
Gas Code, ANSI Z223.1, 1992,
Section 5.3
or applicable local
codes .
VENTILATION AIR
Ventilation Air From Inside
Building
Thisfreshairwouldcomefromanadjoining
unconfined space. When ventilating to an
adjoining unconfined space, you must pro-
vide two permanent openings: one within
12" of the ceiling and one within 12" of the
floor on the wall connecting the two spaces
(seeoptions1and2,Figure2).Youcanalso
remove door into adjoining room (see op-
tion 3, Figure 2). Follow the National Fuel
Gas Code NFPA 54/ANSI Z223.1, Section
5.3, Air for Combustion and Ventilation for
required size of ventilation grills or ducts.
Figure 2 - Ventilation Air from Inside Building
WARNING: Rework work-
sheet, adding the space of the
adjoiningunconfinedspace.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 per-
manent openings: one within 12" of the
ceiling and one within 12" of the floor.
Connecttheseitemsdirectlytotheoutdoors
orspacesopentotheoutdoors.Thesespaces
include attics and crawl spaces.
IMPORTANT: Donot provideopeningsfor
inlet or outlet air into attic if attic has a
thermostat-controlledpowervent.Heatedair
enteringtheatticwillactivatethepowervent.
Outlet
Air Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air Ventilated
Crawl Space
To
Crawl
Space
To Attic

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104190
OWNER’S MANUAL
INSTALLATION
NOTICE: A qualified service per-
son must install heater. Follow
all local codes.
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 ITEMS
Beforeinstallingheater,makesureyouhave
the items listed below.
• piping (check local codes)
• sealant (resistant to propane/LP gas)
• manual shutoff valve *
• ground joint union
• test gauge connection * (see Figure 13,
page 10)
• sediment trap
• tee joint
• pipe wrench
* AnA.G.A.design-certifiedmanualshutoff
valve with 1/8" NPT tap is an acceptable
alternative to test gauge connection. Pur-
chase the optional A.G.A. design-certified
manual shutoff valve from your dealer. See
Accessories, page 19.
LOCATING HEATER
This heater is designed to be mounted on a
wall.
WARNING:Maintainthemini-
mumclearancesshowninFigure
4.Ifyoucan,providegreaterclear-
ancesfromfloor,ceiling,andjoin-
ing wall.
Youcan locateheater onfloor, awayfrom a
wall. An optional floor mounting stand is
needed. Purchase the floor mounting stand
fromyourdealer. SeeAccessories,page19.
WARNING: Never install the
heater
•in a bedroom or a bathroom
•in a recreational vehicle
•where curtains, furniture,
clothing, or other flammable
objectsarelessthan36inches
from the front, top, or sides of
the heater
•as a fireplace insert
•in high traffic areas
•in windy or drafty areas
CAUTION: This heater cre-
ates warm air currents. These
currents move heat to wall sur-
faces next to heater. Installing
heater next to vinyl or cloth wall
coverings or operating heater
where impurities in the air (such
as tobacco smoke) exist, may
discolor walls.
IMPORTANT: Vent-free heaters add mois-
ture to the air. Although this is beneficial,
installing heater in rooms without enough
ventilationairmaycausemildewtoformfrom
too much moisture. See Fresh Air for Com-
bustion and Ventilation, pages 4 through 6.
Forconvenienceandefficiency,installheater
• where there is easy access for operation,
inspection, and service
• in coldest part of room
An optional fan kit is available from your
dealer. See Accessories, page 19. If plan-
ningtousefan,locateheaternearanelectri-
cal outlet.
Figure 4 - Mounting Clearances As Viewed From Front of Heater
CAUTION: If you install the
heater in a home garage
•heater pilot and burner must
be at least 18 inches above
floor
•locateheaterwheremovingve-
hicle will not hit it
Continued
Minimum
From
Sides Of
Heater
36"
3"
FLOOR
CEILING
Minimum
Minimum To Top Surface
Of Carpeting, Tile Or Other
Combustible Material
6"
Left
Side Right
Side

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104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
16"
18 3/4"
Min.
7 1/4"
Min.
Adjoining Wall
Only Insert Mounting
Screws Through Last
Hole On Each End
Floor
Marking Screw Locations
1. Tape mounting bracket to wall where
heater will be located. Make sure
mounting bracket is level.
Figure 8 - Mounting Bracket Clearances
WARNING:Maintainminimum
clearances shown in Figure 8. If
you can, provide greater clear-
ancesfromfloorandjoiningwall.
INSTALLING HEATER TO
WALL
Mounting Bracket
The mounting bracket is located on back
panel of heater. It has been taped there for
shipping. Remove mounting bracket from
back panel.
Figure 6 - Bracket Location
INSTALLATION
Continued
Figure7-RemovingFrontPanelOfHeater
Methods For Attaching
Mounting Bracket To Wall
Only use last hole on each end of mounting
bracket to attach bracket to wall. These two
holes are 16 inches apart from their centers.
Attach mounting bracket to wall in one of
two ways.
1. Attaching to wall stud
2. Attaching to wall anchor
Attaching to wall stud
This method provides the strongest hold.
Insert mounting screws through mounting
bracket and into wall studs.
Attaching to wall anchor
This method allows you to attach mounting
brackettohollowwalls(wall areas between
studs) or to solid walls (concrete or ma-
sonry).
Decidewhichmethodbettersuitsyourneeds.
Eithermethodwillprovideasecureholdfor
the mounting bracket.
Figure 5 - Attaching Thermostat Sensing
Bulb
Clamp
Thermostat
Sensing Bulb
Removing Front Panel Of Heater
1. Remove two screws near bottom cor-
ners of front panel.
2. Liftstraightupongrillguarduntilitstops.
Grill guard will slide up about 1/4".
3. Pull bottomof frontpanel forward,then
downward.
4. Remove cardboard packing from grill
and glass.
2. Mark screw locations on wall (see Fig-
ure 8).
Note: Only mark last hole on each end
of mounting bracket. Insert mounting
screws through these holes only.
3. Remove tape and mounting bracket
from wall.
THERMOSTAT SENSING
BULB
Thethermostatsensingbulbhasbeenplaced
inside the heater for protection during ship-
ping.
Locating Thermostat Sensing
Bulb
1. Remove front panel of heater (see Fig-
ure 7, page 8).
2. Locate thermostat sensing bulb just
under burner assembly.
IMPORTANT: Attach thermostat sensing
bulb to back of heater for proper operation.
Attaching Thermostat Sensing
Bulb
1. Remove thermostat sensing bulb from
holders inside heater. Route through
slot opening in bottom of heater.
2. Place clampon thermostat sensing bulb
as shown in Figure 5. Clamp is pro-
vided in hardware package.
3. Snap clamp into upper mounting hole
as shown in Figure 5. Mounting hole is
located on lower left edge on back of
heater. Make sure the thermostat sens-
ing bulb is pointing up.
Mounting
Bracket

9
104190
OWNER’S MANUAL
INSTALLATION
Continued
Figure 9 - Folding Anchor
3. Insert wall anchor (wings first) into
hole. Tap anchor flush to wall.
4. For thin walls (1/2" or less), insert red
key into wall anchor. Push red key to
“pop” open anchor wings.
IMPORTANT: Do not hammer key!
Forthick walls(over 1/2"thick) orsolid
walls, do not pop open wings.
Figure 10 - Popping Open Anchor Wings
For Thin Walls
Figure 11 - Mounting Heater Onto
Mounting Bracket
Stand-Out
Tab
Horizontal Slots
Mounting Bracket
(attached to wall)
5. Place mountingbracket onto wall.Line
up last hole on each end of bracket with
wall anchors.
6. Insert mountingscrews throughbracket
and into wall anchors.
7. Tighten screws until mounting bracket
is firmly fastened to wall.
Placing Heater On Mounting
Bracket
1. Locate two horizontal slots on back
panel of heater.
2. Place heater onto mounting bracket.
Slide horizontal slots onto stand-out
tabs on mounting bracket.
Figure 12 - Installing Bottom Mounting
Screws
Installing Bottom Mounting
Screws
1. Locate two bottom mounting holes.
These holes are near bottom on back
panel of heater (see Figure 12).
2. Mark screw locations on wall.
3. Remove heaterfrom mounting bracket.
4. If installing bottom mounting screws
into hollow or solid wall, install wall
anchors. Follow steps 1 through 4 un-
der Attaching To Wall Anchor Method,
column 1.
If installing bottom mounting screw
into wall stud, drill holes at marked lo-
cations using 9/64" drill bit.
5. Replace heater onto mounting bracket.
6. Place spacers between bottom mount-
ing holes and wall anchor or drilled
hole.
7. Hold spacer in place with one hand.
With otherhand, insert mounting screw
through bottom mounting hole and
spacer. Place tip of screw in opening
of wall anchor or drilled hole.
8. Tighten both screws until heater is
firmly secured to wall. Do not over
tighten.
Note: Do not replace front panel at this
time. Replace front panel after making
gas connections and checking for leaks
(see pages 10 and 11).
Attaching Mounting Bracket To
Wall
Note: Wall anchors, mounting screws, and
spacers are in hardware package. The hard-
ware package is provided with heater.
Attaching to wall stud method
Forattachingmountingbrackettowallstuds
1. Drill holes at marked locations using
9/64" drill bit.
2. Place mountingbracket onto wall.Line
up last hole on each end of bracket with
holes drilled in wall.
3. Insert mountingscrews throughbracket
and into wall studs.
4. Tighten screws until mounting bracket
is firmly fastened to wall studs.
Attaching to wall anchor method
For attaching mounting bracket to hollow
walls (wall areas between studs) or solid
walls (concrete or masonry)
1. Drill holes at marked locations using
5/16" drill bit. For solid walls (concrete
or masonry), drill at least 1" deep.
2. Fold wall anchor as shown in Figure 9.

10
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
IMPORTANT: Hold pressure regulator
with wrench when connecting it to gas pip-
ing and/or fittings.
Pressure
Regulator
Tee Joint
Reducer
Bushing to
1/8" NPT
1/8" NPT
Plug Tap
Test
Gauge
Connection*
Tee Joint
Pipe Nipple
Cap
3/8" NPT
Pipe Nipple
Figure 13 - Gas Connection
* An A.G.A. design-certified manual shutoff valve with 1/8" NPT tap is an acceptable
alternativetotest gaugeconnection.Purchase theoptionalA.G.A. design-certifiedmanual
shutoff valve from your dealer. See Accessories, page 19.
Heater
Cabinet
Sediment
Trap
Manual
Shutoff
Valve *
3" Minimum
Typical Inlet
Pipe from Gas
Meter (4" W.C.
to 10.5" W.C.
Pressure)
Ground Joint Union
CONNECTING TO
GAS SUPPLY
NOTICE: A qualified service per-
son must connect heater to gas
supply. Follow all local codes.
Typical Inlet Pipe Diameters
20,000 Btu/Hr 3/8" or greater
Installation must include a manual shutoff
valve, union, and plugged 1/8" NPT tap.
Locate NPT tap within reach for test gauge
hook up. NPT tap must be upstream from
heater (see Figure 13).
Installsedimenttrapinsupplylineasshown
in Figure 13. Locate sediment trap where it
is within reach for cleaning. Locate sedi-
menttrap where trapped matter is not likely
to freeze. A sediment trap traps moisture
and contaminants. This keeps them from
going into heater controls. If sediment trap
is not installed or is installed wrong, heater
may not run properly.
IMPORTANT :Checkgas linepressure be-
fore connecting heater to gas line. Gas line
pressure must be no greater than 14 inches
of water. If gas line pressure is higher,
heater regulator damage could occur.
CAUTION: Use only new,
black iron or steel pipe. Inter-
nally-tinned copper tubing may
be used in certain areas. Check
yourlocalcodes.Usepipeoflarge
enough diameter to allow proper
gas volume to heater. If pipe is
too small, undue loss of pres-
sure will occur.
CAUTION:Usepipejointseal-
ant that is resistant to liquid pe-
troleum (LP) gas.
WARNING: Never connect
heater to private (non-utility) gas
wells. This gas is commonly
known as well-head gas.
Apply pipe joint sealant lightly to male
threads. This will prevent excess sealant
fromgoing intopipe. Excess sealant in pipe
could result in clogged heater valves.

11
104190
OWNER’S MANUAL
WARNING: Test all gas pip-
ing and connections for leaks
after installation or servicing.
Correct all leaks at once.
WARNING:Neveruseanopen
flame to check for a leak. Apply a
mixture of liquid soap and water
to all joints. Bubbles forming
show a leak. Correct all leaks at
once.
PRESSURE TESTING GAS
SUPPLY PIPING SYSTEM
Test Pressures In Excess Of 1/2
PSIG
1. Disconnect heater and its individual
manual shutoff valve from gas supply
piping system. Pressures in excess of
1/2 psig will damage heater regulator.
2. Cap off open end of gas pipe where
manual shutoff valve was connected.
3. Pressurize supply piping system by ei-
ther using compressed air or
opening main gas valve located on or
near gas meter.
4. Check all joints of gas supply piping
system. Apply mixture of liquid soap
and water to gas joints. Bubbles form-
ing show a leak.
5. Correct all leaks at once.
CHECKING GAS
CONNECTIONS Test Pressures Equal To or
Less Than 1/2 PSIG
1. Close manual shutoff valve (see Fig-
ure 14).
2. Pressurize supply piping system by ei-
ther using compressed air or opening
main gas valve located on or near gas
meter.
3. Check all joints from gas meter to
manual shutoff valve (see Figure 15).
Apply mixture of liquid soap and wa-
ter to gas joints. Bubbles forming show
a leak.
4. Correct all leaks at once.
PRESSURE TESTING
HEATER GAS
CONNECTIONS
1. Open manual shutoff valve (see Fig-
ure 14).
2. Open main gas valve located on or near
gas meter.
3. Make sure control knob of heater is in
the OFF position.
4. Check all joints from manual shutoff
valve to thermostat gas valve (see Fig-
ure 15). Apply mixture of liquid soap
and water to gas joints. Bubbles form-
ing show a leak.
5. Correct all leaks at once.
6. Light heater (see Operating Heater,
pages 12 and 13). Check the rest of the
internal joints for leaks.
7. Turn off heater (see To Turn Off Gas to
Appliance, page 12).
8. Replace front panel.
ON
POSITION
OFF
POSITION
Figure 14 - Manual Shutoff Valve
Manual
Shutoff
Valve
Open
Closed
Thermostat Gas Valve
Gas Meter
Figure 15 - Checking Gas Joints
Manual
Shutoff
Valve

12
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
TO TURN OFF GAS
TO APPLIANCE
CAUTION:Donottrytoadjust
heating levels by using the
manual shutoff valve.
Thermocouple
Ignitor Electrode
Figure 17 - Pilot
Pilot Burner
OPERATING
HEATER
FOR YOUR SAFETY
READ BEFORE
LIGHTING
A. Thisappliance hasa pilotwhich must
belightedbyhand.Whenlightingthe
pilot, follow these instructions ex-
actly.
B. BEFORE LIGHTING smell all
aroundtheappliance areaforgas.Be
suretosmell nexttothe floorbecause
some gas is heavier than air and will
settle on the floor.
WHAT TO DO IF YOU SMELL
GAS
• Do not try to light any appliance.
• Do not touch any electric switch;
donot useany phonein yourbuild-
ing.
• Immediatelycall your gassupplier
from a neighbor’s phone. Follow
the gas supplier’s instructions.
• If you cannot reach your gas sup-
plier, call the fire department.
C. Useonly yourhandto pushin orturn
thegas controlknob.Neverusetools.
If the knob will not push in or turn
by hand, don’t try to repair it, call a
qualified service technician or gas
supplier. Force or attempted repair
may result in a fire or explosion.
D. Do not use this appliance if any part
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 which has been un-
der water.
WARNING: If you do not fol-
low these instructions exactly, a
fireorexplosionmayresultcaus-
ing property damage, personal
injury or loss of life.
PILOT
LO
OFF
HI
IGNITOR
Ignitor Button Control Knob
Figure 16 - Control Knob In The OFF
Position
LIGHTING
INSTRUCTIONS
1. STOP! Read the safety information
above.
2. Make sure manual shutoff valve is
fully open.
3. Turn control knob clockwise
Clockwise
to the OFF position.
4. Waitfive(5)minutesto clear outany
gas. Then smell for gas, including
near the floor. If you smell gas,
STOP! Follow “B” in the safety in-
formation in column 1. If you don’t
smell gas, go to the next step.
5. Turn control knob counterclockwise
C-clockwise
to the PILOT position.
Press in control knob for five (5) sec-
onds (see Figure 16).
Note: You may be running this
heater for the first time after hook-
ing up to gas supply. If so, the con-
trol knob may need to be pressed in
for 30 seconds. This will allow air to
bleed from the gas system.
• If control knob does not pop up
when released, contact a qualified
service person or gas supplier for
repairs.
6. With control knob pressed in, push
downandreleaseignitor button.This
will light pilot. The pilot is attached
to the front of burner. The pilot can
be seen through the glass panel. If
needed,keeppressingignitorbutton
until pilot lights.
Shutting Off Heater
1. Turn control knob clockwise
Clockwise
to the OFF position.
2. Turn off all electric power to the ap-
pliance if service is to be performed.
Shutting Off Burner Only (pilot
stays lit)
1. Turn control knob clockwise
Clockwise
to the PILOT position.
Note: If pilot does not stay lit, refer
to Troubleshooting, pages 14 through
16. Also contact a qualified service
person or gas supplier for repairs.
Untilrepairsaremade,lightpilotwith
match. To light pilot with match, see
Manual Lighting Procedure, page 13.
7. Keep control knob pressed in for 30
seconds after lighting pilot.After 30
seconds, release control knob.
Note: If pilot goes out, repeat steps
3 through 7.This heater has a safety
interlocksystem.Waitone (1)minute
before lighting pilot again.
8. Turn control knob counterclockwise
C-clockwise
to desiredheatinglevel.The
mainburnershouldlight.Set control
knob to any heat level between HI
and LO.

13
104190
OWNER’S MANUAL
OPERATING
HEATER
Continued
THERMOSTAT CONTROL
OPERATION
The thermostatic control used on these
models differs from standard thermo-
stats. Standard thermostats simply turn
on and off the burner. The thermostat
used on this heater senses the room tem-
perature. The thermostat adjusts the
amount of gas flow to the burner. This
increases or decreases the burner flame
height.Attimestheroommayexceed the
set temperature. If so, the burner will
shut off. The burner will cycle back on
whenroomtemperaturedrops belowthe
settemperature.Thecontrolknobcanbe
set to any heat level between HI and LO.
Note: The thermostat sensing bulb mea-
sures the temperature of air near the
heatercabinet.Thismaynotalwaysagree
with room temperature (depending on
housing construction, installation loca-
tion, room size, open air temperatures,
etc.). Frequent use of your heater will let
you determine your own comfort levels.
MANUAL LIGHTING
PROCEDURE
1. Remove front panel (see Figure 7,
page 8).
2. Followsteps1 through5under Light-
ing Instructions, page 12.
3. With control knob pressed in, strike
match. Hold match to pilot until pi-
lot lights.
4. Keep control knob pressed in for 30
seconds after lighting pilot.After 30
seconds, release control knob.
5. Replace front panel.
INSPECTING
BURNER
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure 18 shows a correct pilot flame pat-
tern. Figure 19 shows an incorrect pilot
flame pattern. The incorrect pilot flame is
not touching the thermocouple. This will
cause the thermocouple to cool. When the
thermocouple cools, the heater will shut
down.
Thermocouple
Pilot Burner
Figure 18 - Correct Pilot Flame Pattern
Pilot Burner
Thermocouple
Figure 19 - Incorrect Pilot Flame Pattern
If pilot flame pattern is incorrect, as shown
in Figure 19.
• turn heater off (see To Turn Off Gas to
Appliance, page 12).
• seeTroubleshooting, pages14 through16.
1/2
INCORRECT FLAME PATTERN
AT HIGH POSITION
NOTICE: Do not mistake orange
flames with yellow tipping. Dirt
or other fine particles enter the
heater and burn causing brief
patches of orange flame.
Figure 20 - Correct Burner Flame Pattern
Figure21-IncorrectBurnerFlamePattern
WARNING: If yellow tipping
occurs, your heater could pro-
duce increased levels of carbon
monoxide. If burner flame pat-
ternshowsyellowtipping,follow
instructions at bottom of this
page.
CORRECT FLAME PATTERN
AT HIGH POSITION
1/2
G
Yellow Tipping
BURNER FLAME PATTERN
Figure 20 shows a correct burner flame
pattern.Figure21showsanincorrectburner
flame pattern. The incorrect burner flame
patternshowsyellowtippingoftheflame.It
also shows the flame higher than 1/2 the
glass panel height.
Ifburnerflamepatternisincorrect,asshown
in Figure 21
• turn heater off (see To Turn Off Gas to
Appliance, page 12)
• seeTroubleshooting,pages 14through 16
1/2
Glass
Height
1/2
Glass
Height
Correct Flame Pattern
At High Position
Incorrect Flame Pattern
At High Position

14
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
TROUBLESHOOTING
Note: Alltroubleshootingitemsarelistedin
order of operation.
WARNING: Turn off and un-
plug heater and let cool before
servicing. Only a qualified ser-
vice person should service and
repair heater.
CAUTION: Never use a wire,
needle, or similar object to clean
ODS/pilot.ThiscandamageODS/
pilot unit.
POSSIBLE CAUSE
1. Ignitor electrode positioned wrong
2. Ignitor electrode broken
3. Ignitor electrode not connected to igni-
tor cable
4. Ignitor cable pinched or wet
5. Piezo ignitor nut is loose
6. Broken ignitor cable
7. Bad piezo ignitor
1. Gas supply turned off or manual shutoff
valve closed
2. Control knob not in PILOT position
3. Control knob not pressed in while in PI-
LOT position
4. Air in gas lines when installed
5. ODS/pilot is clogged
6. Gas regulator setting is not correct
1. Control knob not fully pressed in
2. Control knobnot pressed inlong enough
3. Safety interlock system has been trig-
gered (Thermostat models only)
4. Manual shutoff valve not fully open
5. Thermocouple connection loose at con-
trol valve
6. Pilot flame not touching thermocouple,
which allows thermocouple to cool,
causing pilot flame to go out. This prob-
lem could be caused by one or both of
the following:
A) Low gas pressure
B) Dirty or partially clogged ODS/
pilot
7. Thermocouple damaged
8. Control valve damaged
REMEDY
1. Replace ignitor
2. Replace ignitor
3. Reconnect ignitor cable
4. Free ignitor cable if pinched by any
metal or tubing. Keep ignitor cable dry
5. Tighten nut holding piezo ignitor to
heater cabinet. Nut is located inside
heater cabinet at top
6. Replace ignitor cable
7. Replace piezo ignitor
1. Turn on gas supply or open manual
shutoff valve
2. Turn control knob to PILOT position
3. Press in control knob while in PILOT
position
4. Continue holding down control knob.
Repeat igniting operation until air is re-
moved
5. Clean ODS/pilot (see Cleaning and
Maintenance, page17) or replace ODS/
pilot assembly
6. Replace gas regulator
1. Press in control knob fully
2. After ODS/pilot lights, keep control
knob pressed in 30 seconds
3. Wait one (1) minute for safety interlock
systemto reset. Repeatignition operation
4. Fully open manual shut-off valve
5. Hand tighten until snug, then tighten 1/4
turn more
6. A) Contact local natural gas company
B) Clean ODS/pilot (see Cleaning and
Maintenance, page 17) or replace ODS/
pilot assembly
7. Replace thermocouple
8. Replace control valve
OBSERVED PROBLEM
When ignitor button is pressed, there is no
spark at ODS/pilot
When ignitor button is pressed, there is
spark at ODS/pilot but no ignition
ODS/pilot lights but flame goes out when
control knob is released

15
104190
OWNER’S MANUAL
TROUBLESHOOTING
Continued
OBSERVED PROBLEM
Burner does not light after ODS/pilot is lit
Delayed ignition of burner
Burner backfiring during combustion
Yellow flame during burner combustion
Slight smoke or odor during initial opera-
tion
Heater produces a whistling noise when
burner is lit
REMEDY
1. Clean burner (see Cleaning and Mainte-
nance, page 17) or replace burner orifice
2. Replace burner orifice
3. Contact local natural gas company
1. Contact local natural gas company
2. Clean burner (see Cleaning and Mainte-
nance, page 17) or replace burner orifice
1. Clean burner (see Cleaning and Mainte-
nance, page 17) or replace burner orifice
2. Replace burner
3. Replace gas regulator
1. Check burner for dirt and debris. If
found, clean burner (see Cleaning and
Maintenance, page 17)
2. Replace gas regulator
1. Problem will stop after a few hours of
operation
1. Turn control knob to LO position and
let warm up for a minute
2. Operate burner until air is removed from
line. Have gas line checked by local
natural gas company
3. Observe minimum installation clear-
ances (see Figure 4, page 7)
4. Clean burner (see Cleaning and Mainte-
nance, page 17) or replace burner orifice
POSSIBLE CAUSE
1. Burner orifice is clogged
2. Burner orifice diameter is too small
3. Inlet gas pressure is too low
1. Manifold pressure is too low
2. Burner orifice is clogged
1. Burner orifice is clogged or damaged
2. Burner damaged
3. Gas regulator defective
1. Not enough air
2. Gas regulator defective
1. Residues from manufacturing processes
1. Turning control knob to HI position
when burner is cold
2. Air in gas line
3. Air passageways on heater blocked
4. Dirty or partially clogged burner orifice
Continued

16
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
TROUBLESHOOTING
Continued
WARNING: 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.
•Immediatelycallyourgassupplierfromaneighbor’sphone.Followthe
gas supplier’s instructions.
•If you cannot reach your gas supplier, call the fire department.
POSSIBLE CAUSE
1. Metal expanding while heating or con-
tracting while cooling
1. Heater burning vapors from paint, hair
spray, glues, etc. See IMPORTANT
statement above).
2. Gas leak. SeeWarning statement at
top of page
1. Not enough fresh air is available
2. Low line pressure
3. ODS/pilot is partially clogged
1. Gas leak. SeeWarning statement at
top of page
2. Control valve defective
1. Foreign matter between control valve
and burner
2. Gas leak. SeeWarning statement at
top of page
1. Not enough combustion/ventilation air.
OBSERVED PROBLEM
Heater produces a clicking/ticking noise
just after burner is lit or shut off
Heater produces unwanted odors
Heater shuts off in use (ODS operates)
Gas odor even when control knob is in OFF
position
Gas odor during combustion
Moisture/condensationnoticedonwindows
REMEDY
1. This is common with most heaters. If
noise is excessive, contact qualified ser-
vice person
1. Ventilate room. Stop using odor caus-
ing products while heater is running
2. Locate and correct all leaks (see Check-
ing Gas Csonnections, page 11)
1. Open windowand/or doorfor ventilation
2. Contact local propane/LP gas company
3. Clean ODS/pilot (see Cleaning and
Maintenance, page 17)
1. Locate and correct all leaks (see Check-
ing Gas Connections, page 11)
2. Replace control valve
1. Take apart gas tubing and remove for-
eign matter
2. Locate and correct all leaks (see Check-
ing Gas Connections, page 11)
1. Refer to Air for Combustion and Venti-
lation requirements (page 4)
IMPORTANT: Operating heater where impurities in air exist may create odors. Cleaning
supplies, paint, paint remover, cigarette smoke, cements and glues, new carpet or textiles,
etc., create fumes. These fumes may mix with combustion air and create odors.

17
104190
OWNER’S MANUAL
TECHNICAL
SERVICE
You may have further questions about in-
stallation, operation, or troubleshooting.
If so, contact DESA International’s
Technical Service Department at
1-800-323-5190.
CGN20TA
Btu (Variable) 10,000/20,000
Type Gas Natural Only
Ignition Piezo
Pressure Regulator Setting 3" W.C.
Inlet Gas Pressure (in. of water)
Maximum 10.5"
Minimum 4"
Dimensions, Inches (H x W x D)
Heater 23.5 x 18.5 x 8.0
Carton 25.8 x 21.3 x 10.1
Weight (pounds)
Heater 22
Shipping 27
SPECIFICATIONS
SERVICE HINTS
When gas pressure is too low
• pilot will not stay lit
• burner will have delayed ignition
• heater will not produce specified heat
When gas quality is bad
• pilot will not stay lit
• burner will produce flames and soot
• heater will backfire when lit
Youmayfeelyourgaspressureistoolowor
gas quality is bad. If so, contact your local
natural gas supplier.
SERVICE
PUBLICATIONS
Youcanpurchaseaservicemanualfromthe
address listed on the back page of this
manual. Send a check for $5.00 payable to
DESA International.
CLEANING
AND
MAINTENANCE
ODS/PILOT AND BURNER
• Use a vacuum cleaner, pressurized air,
or small, soft bristled brush to clean.
CABINET
Air Passageways
• Use a vacuum cleaner or pressurized air
to clean.
Exterior
• Use a soft cloth dampened with a mild
soap and water mixture. Wipe the cabi-
net to remove dust.
WARNING: Turn off heater
and let cool before cleaning.
CAUTION: You must keep
controlareas,burner,andcircu-
latingairpassagewaysofheater
clean. Inspect these areas of
heater before each use. Have
heater inspected yearly by a
qualifiedserviceperson.Heater
may need more frequent clean-
ing due to excessive lint from
carpeting,beddingmaterial,etc.
REPLACEMENT
PARTS
Note: Use only original replacement parts.
Thiswillprotectyourwarrantycoveragefor
parts replaced under warranty.
Parts Under Warranty
Contact authorized dealers of this product.
If they can’t supply original replacement
part(s), either contact your nearest Parts
Central (see below) or call DESA
International’s Technical Service Depart-
ment at 1-800-323-5190 for referral infor-
mation.
When calling DESA International, have
ready
• your name
• your address
• model number of your heater
• how heater was malfunctioning
• type of gas used (propane/LP or natural
gas)
• purchase date
Usually,wewillaskyoutoreturnthedefec-
tive part to the factory.
Parts Not Under Warranty
Contact authorized dealers of this product.
If they can’t supply original replacement
part(s), either contact your nearest Parts
Central (see below) or call DESA
International’s Parts Department at 1-800-
972-7879 for referral information.
When calling DESA International, have
ready
• model number of your heater
• the replacement part number

18
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
These Parts Centrals are privately owned businesses. They have agreed to support our
customer’s needs by providing original replacement parts and accessories.
Baltimore Electric
1348 Dixwell Avenue
Hamden, CT 06514
1-800-397-7553
203-248-7553
Parts Department
Portable Heater Parts
342 N. County Rd. 400 East
Valparaiso, IN 46383
All States
219-462-7441
1-800-362-6951
FBD
P.O. Box 1096
1720 Kummer Road
Franklin, KY 42134
502-586-1922
1-800-654-8534
Four Flags Power Products
1115 Stateline Road
Niles, MI 49120
616-684-2697
1-800-268-4983
Master Service Center
1184 Wilson NW
Walker, MI 49504
616-791-4760
1-800-446-1446
Washer Equipment Co.
1715 Main Street
Kansas City, MO 64108
KS, MO, AR
816-842-3911
East Coast Energy
Products
833 Broadway
W. Long Branch, NJ 07764
908-870-8809
1-800-755-8809
Tarantin Tank Co.
P.O. Box 6129
Freehold, NJ 07728
908-780-9340
1-800-922-0724
Albany Ladder
1586-90 Central Avenue
Albany, NY 12205
NY, MA, VT
518-869-5335
1-800-354-7368
Dayton Hardware
P.O. Box 275
North Dayton Station
Dayton, OH 45404
All States
513-258-3721
OH 1-800-762-3426
Halco Enterprises
208 Carter Drive, Unit 21
West Chester, PA 19382
215-696-2670
1-800-368-0803
LA Porte's Parts & Service
2444 N. 5th Street
Hartsville, SC 29550
803-332-0191
Parts Department
Cans Unlimited, Inc.
P.O. Box 645
Taylor, SC 29687
All States
803-879-3009
1-800-845-5301
PARTS CENTRALS

19
104190
OWNER’S MANUAL
ACCESSORIES
Purchasetheseheateraccessoriesfromyour
local dealer. If they can not supply these
accessories,eithercontactyournearestParts
Central (see page 18) or call DESA
International’s Parts Department at 1-800-
972-7879 for referral information. You can
also write to the address listed on the back
page of this manual.
MANUAL SHUTOFF
VALVE - GA5010
Forallmodels.Manualshutoffvalvewith1/8"
NPT tap.
FLOOR MOUNTING STAND
- GA4500 - Champagne
For locating heater on the floor, away from
a wall. Complete installation instructions
included.
FAN KITS - GA3100A AND
GA3200TA
For all models. Provides better heat distri-
bution. Makes heater more efficient. Com-
plete installation and operating instructions
included.
Manually controlled - GA3100A. Includes
ON/OFF switch.
Thermostatically controlled - GA3200TA.
Includes three settings: ON/OFF/AUTO.

20
104190
Blue Flame Vent-Free Natural Gas Heater
CGN20TA
ILLUSTRATED
PARTS
BREAKDOWN
CGN20TA
12 ODS/Pilot Assembly
12-1
12-2
1
2
3
4
5
6
7
8
9
10
10
11
12
13
14
15
17
19
20
21
22
23
24
26
25
18
16