Desa Comfort Glow CGN20T Quick start guide

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BLUE FLAME VENT-FREE NATURALGAS 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.
— 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.
• Donottouchanyelectricalswitch;donotuse
any phone in your building.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• Ifyou cannot reach yourgas supplier, call the
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 provided. Refer to
page 5 of this manual
This appliance may be in-
stalled 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 appli-
ance is not convertible for
use with other gases.
Heater Sizes: 20,000 Btu/Hr Thermostat and
30,000 Btu/Hr Thermostat Model Heaters
®
CGN20T
CGN20TL
CGN30T
CGN30TL

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103873
CONTENTS SECTION PAGE
SAFETY
INFORMATION
WARNING ICON G 001
WARNINGS
IMPORTANT: Read this owner’s manual carefully and completely be-
foretryingtoassemble, operate,or servicethis heater.Improper useof
thisheatercancauseseriousinjuryordeathfromburns,fire,explosion,
electrical shock, and carbon monoxide poisoning.
WARNING ICON G 001
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 natural
gas. The odor helps you detect a natural gas leak. However, the odor added to
natural gas can fade. Natural gas may be present even though no odor exists.
Make certain you read and understand all Warnings. Keep this manual for refer-
ence. It is your guide to safe and proper operation of this heater.
Safety Information.......................................................................................2
Product Identification ..................................................................................4
Local Codes .................................................................................................4
Unpacking....................................................................................................4
Product Features ..........................................................................................4
Fresh Air For Combustion And Ventilation ................................................5
Installing To Wall........................................................................................9
Connecting To Gas Supply..........................................................................14
Checking Gas Connections..........................................................................15
Operating Heater .........................................................................................17
Inspecting Burner ........................................................................................20
Cleaning And Maintenance .........................................................................22
Troubleshooting...........................................................................................22
Technical Service ........................................................................................26
Specifications ..............................................................................................26
Service Hints ...............................................................................................26
Service Publications ....................................................................................26
Replacement Parts .......................................................................................27
Parts Centrals...............................................................................................27
Illustrated Parts List.....................................................................................28-29
Accessories ..................................................................................................30
Warranty Information ..................................................................................Back Cover
Safety Information continues on next page

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103873
SAFETY
INFORMATION
Continued
WARNING ICON G 001
WARNINGS Continued
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.
4. Never install the heater
• in a recreational vehicle
• where curtains, furniture, clothing, or other flammable objects are less than
36 inches from the front, top, or sides of the heater
• as a fireplace insert
• in high traffic areas
• in windy or drafty areas
5. 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 Fresh Air for Combus-
tion and Ventilation, pages 5 through 8.
6. Keep air openings in front and bottom of heater clear and free of debris. This will
ensure enough air for proper combustion.
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 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 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 before running heater.
13.Do not use heater if any part has been under water. Immediately call a qualified
service technician to inspect the room heater and to replace any part of the
control system and any gas control which has been under water.
14.Turn off and unplug heater and let cool before servicing. Only a qualified
service person should service and repair heater.
15.Operating heater above elevations of 4,500 feet could cause pilot outage.

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103873
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 Gas Code ANSI 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
Figure 1 - Vent-Free Natural Gas Heater (30,000 Btu/Hr Model Shown)
Ignitor Button Control Knob
Heater
Cabinet
Front
Panel
Glass
Panel
Grill
Guard
UNPACKING 1. Remove heater from carton.
2. Remove all protective packaging applied 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). 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.
Thermostatic Heat Control
Thermostat models have a thermostat sensing bulb and a control valve. This results in
the greatest heater comfort. This can also result in lower gas bills.

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103873
FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
WARNING ICON G 001
WARNING
This heater shall not be installed in a confined space unless provi-
sions 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 fuel-burning appliances.
Continued
Confined and Unconfined Space
The National Fuel Gas Code (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 m3per kw) of the aggregate input rating of all appliances installed in that
space and an unconfined space as a space whose volume is not less than 50 cubic
feet per 1,000 Btu per hour (4.8 m3per kw) of the aggregate input rating of all
appliances installed in that space. Rooms communicating directly with the space in
which the appliances are installed*, through openings not furnished with doors, are
considered a part of the unconfined space.
* Adjoining rooms are communicating only if there are doorless passageways or
ventilation grills between them.
** Cubic feet equals length x width x height of room.
PROVIDING ADEQUATE VENTILATION
The following is exerpts from National Fuel Gas Code. NFPA 54/ANSI 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 Contruction; 2. Unconfined Space; 3. Confined Space.
The information on pages 5 through 7 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 continu-
ous water vapor retarder with a rating of one perm (6x10-11 per pa-sec-
m2) or less with openings gasketed or sealed and
b. weather stripping has been added on openable windows and doors and
c. caulkingorsealantsareappliedtoareassuchasjointsaroundwindowand
door frames, between sole plates and floors, between wall-ceiling joints,
betweenwallpanels,atpenetrationsforplumbing,electrical,andgaslines,
and at other openings.
If your home meets all of the three criteria above, you must provide additional
fresh air. See Ventilation Air From Outdoors , page 8 .
If your home does not meet all of the three criteria above, proceed to page 6.

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FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
Continued
DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
Determining if You Have a Confined or Unconfined Space
Use this worksheet 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: 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 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: 2560 cu. ft. (volume of space) ÷50 cu. ft. = 51.2 or 51,200 (maximum
Btu/Hr the space can support)
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
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 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: 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 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 adjoining room or add ventilation
grills between rooms. See Ventilation Air From Inside Building, page 7.
B. Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 8.
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.

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103873
FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
Continued
WARNING ICON G 001
WARNING
If the area in which the heater may be operated is smaller than that
defined as an unconfined space, provide adequate combustion and
ventilation 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
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/ANSI
Z223.1, Section 5.3, Air for Combustion and Ventilation for required size of ventila-
tion grills or ducts.
WARNING ICON G 001
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.
Figure 2 - Ventilation Air from Inside Building
Continued
Or
Remove
Door into
Adjoining
Room,
Option 3
Ventilation Grills
Into Adjoining Room,
Option 2
12"
12"
Ventilation
Grills
into Adjoining
Room,
Option 1

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103873
FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
Continued
Figure 3 - Ventilation Air from Outdoors
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: Do not provide openings 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.
Outlet
Air Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air Ventilated
Crawl Space
To
Crawl
Space
To Attic

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103873
INSTALLINGTO
WALL NOTICE
A qualified service person 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
Before installing heater, make sure you have 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 12, page 15)
• sediment trap
• tee joint
• pipe wrench
* An A.G.A. design-certified manual shutoff valve with 1/8" NPT tap is an acceptable
alternative to test gauge connection. Purchase the optional A.G.A. design-certified
manual shutoff valve from your dealer. See Accessories, page 30.
LOCATING HEATER
This heater is designed to be mounted on a wall.
WARNING ICON G 001
WARNING
Maintain the minimum clearances shown in Figure 4 (page 10). If you
can, provide greater clearances from floor, ceiling, and joining wall.
You can locate heater on floor, away from a wall. An optional floor mounting stand is
needed. Purchase the floor mounting stand from your dealer. See Accessories, page 30.
WARNING ICON G 001
WARNING
Never install the heater
• in a bedroom or a bathroom
• in a recreational vehicle
• where curtains, furniture, clothing, or other flammable objects are
less than 36 inches from the front, top, or sides of the heater
• as a fireplace insert
• in high traffic areas
• in windy or drafty areas
WARNING ICON G 001
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 in the air (such
as tobacco smoke) exist, may discolor walls.
Continued
IMPORTANT: Vent-free heaters add moisture 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 Fresh Air for Combustion and Ventilation, pages 5
through 8.

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103873
For convenience and efficiency, install heater
• 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 30. If plan-
ning to use fan, locate heater near an electrical outlet.
Figure 4 - Mounting Clearances As Viewed From Front of Heater
INSTALLINGTO
WALL
Continued
WARNING ICON G 001
CAUTION
If you install the heater in a home garage
• heater pilot and burner must be at least 18 inches above floor
• locate heater where moving vehicle will not hit it
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
Figure 5 - Attaching Thermostat Sensing Bulb
Clamp
Thermostat
Sensing Bulb
THERMOSTAT SENSING BULB
The thermostat sensing bulb has been placed inside the heater for protection during
shipping.
Locating Thermostat Sensing Bulb
1. Remove front panel of heater (see Figure 7, page 11).
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 clamp on thermostat sensing bulb as shown in Figure 5. Clamp is provided 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 sensing
bulb is pointing up.