Desa Comfort Glow CGN12A Quick start guide

OWNER’S OPERATION AND INSTALLATION MANUAL
VENT-FREE NATURAL GAS HEATER
Model: CGN12A
Save this manual for future reference.
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;donotuseanyphoneinyourbuilding.
• Immediately call your gas supplier from a neighbor’s phone. Follow the
gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
— Installation and service must be performed by a qualified installer, service
agency, or the gas supplier.
®

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100847
CONTENTS SECTION PAGE
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............................................................13
Checking Gas Connections............................................................14
Operating Heater ........................................................................... 16
Inspecting Burner ..........................................................................19
Cleaning And Maintenance ...........................................................21
Troubleshooting.............................................................................21
Technical Service ..........................................................................24
Specifications ................................................................................ 25
Service Hints ................................................................................. 25
Replacement Parts .........................................................................25
Parts Centrals.................................................................................26
Service Publications ......................................................................26
Accessory ......................................................................................26
Parts List ........................................................................................ 27
Illustrated Parts Breakdown .......................................................... 27
Warranty Information .................................................................... Back Cover
WARNINGICON G 001
WARNINGS
IMPORTANT: Read this owner’s manual carefully and completely before
trying to assemble, operate, or service this heater. Improper use of this
heatercancauseseriousinjuryordeathfromburns,fire,explosion,and
carbon monoxide poisoning.
WARNINGICON 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.
NaturalGas:Natural gasisodorless.Anodor-makingagentisaddedtonaturalgas.
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 reference.
It is your guide to safe and proper operation of this heater.
Safety Information continues on next page
SAFETY
INFORMATION

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SAFETY
INFORMATION
Continued
WARNINGICON G 001
WARNINGS Continued
WARNING: Any change to this heater or its controls can be dangerous.
1. Use only natural gas. Do not convert heater to use different fuel type.
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. Always run heater with control knob at LOW or HIGH locked positions.
Never set control knob between locked positions. Poor combustion and higher
levels of carbon monoxide may result.
6. 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.
7. Never run heater in small, closed room. Open door into next room to help
ventilate.
8. Keep all air openings in front and bottom of heater clear and free of debris.
This will insure enough air for proper combustion.
9. If heater shuts off, do not relight until you provide fresh, outside air. If heater
keeps shutting off, have it serviced.
10.Do not run heater
• where flammable liquids or vapors are used or stored
• under dusty conditions
11.Never place any objects on the heater.
12.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.
13.Carefully supervise young children when they are in same room with heater.
14.Make sure grill guard is in place before running heater.
15. 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.
16.Turn off heater and let cool before servicing. Only a qualified service person
should service and repair heater.
17.Operating heater above elevations of 4,500 feet may cause pilot outage.

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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 Z223.1, 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
Heater
Cabinet
Grill
Guard
Burners
Front
Panel
Figure 1 - Vent-Free Natural Gas Heater
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.
Piezo Ignitor Button
Control Knob

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100847
FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
WARNING ICON G 001
WARNING
This heater must have fresh air for proper operation. If not, poor
fuel combustion could result. 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.
PRODUCING ADEQUATE 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 8 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 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, 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 addi-
tional fresh air. See Ventilation Air From Outdoors , page 8 .
If your home does not meet all of the three criteria above, continue reading.
Unconfined Space
An unconfined space has a minimum air volume of 50 cubic feet for each 1000
BTU/Hr input rating of all appliances in the space (cubic feet equals length x
width x height of space). Include adjoining rooms only if there are doorless
passageways or ventilation grills between the rooms.
Confined Space
A confined space has an air volume of less than 50 cubic feet for each 1000
BTU/Hr input rating of all appliances in the space (cubic feet equals length x
width x height of space). Include adjoining rooms only if there are doorless
passageways or ventilation grills between the rooms. Continued

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FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
Continued
WARNING ICON G 001
WARNING
You must provide additional ventilation air in a confined space.
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 18 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) =
2304 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: 2304 cu. ft. (volume of space) ÷50 cu. ft. = 46.1 or 46,100 (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 +10,000 BTU/Hr
Total =50,000 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: 46,100 BTU/Hr (maximum the space can support)
50,000 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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100847
FRESH 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
adjoiningunconfinedspace,you must provide two permanent openings: one within 12" of the
ceilingandonewithin12"of theflooronthewallconnectingthetwospaces(seeoptions 1and
2, Figure 2). You can also remove door into adjoining room (see option 3, Figure 2).
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
Or
Remove
Door into
Adjoining
Room,
Option 3
Ventilation Grills
Into Adjoining Room,
Option 2
12"
12"
Ventilation
Grills
into Adjoining
Room,
Option 1
Continued

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100847
FRESH AIR
FOR
COMBUSTION
AND
VENTILATION
Continued
VENTILATION AIR (Continued)
Ventilation Air From Outdoors
Provide extra fresh air by using ventilation grills or ducts. You must provide two perma-
nent 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/ANSI Z223.1, Section 5.3,
Air for Combustion and Ventilation for required size of ventilation grills or ducts.
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.
Figure 3 - Ventilation Air from Outdoors
Outlet
Air Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air Ventilated
Crawl Space
To
Crawl
Space
To Attic

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INSTALLING
TO WALL
Continued
NOTICE
Aqualifiedservicepersonmustinstallheater.Followalllocalcodes.
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 ITEMS
Before installing heater, make sure you have the items listed below.
• piping (check local codes)
• sealant (resistant to propane gas)
• manual shutoff valve *
• ground joint union
• test gauge connection * (see
Figure 12, page 14)
• sediment trap
• tee joint
• pipe wrench
*An A.G.A. design-certifiedmanual shutoff valvewith 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 Accessory, page 26.
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.
WARNING ICON G 001
WARNING
Never install the heater
• in a bedroom or bathroom
• in a recreational vehicle
• wherecurtains,furniture,clothing,orotherflammableobjectsare
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.
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
IMPORTANT: Vent-free heaters add moisture to the air. Although this is beneficial, in-
stalling 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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100847
2. Mark two mounting screw locations on wall (see Figure 5).
INSTALLING HEATER TO WALL
Marking Screw Locations
1. Determine where you will locate heater.
Figure 5 - Mounting Screw Locations
Mounting
Screw
Locations
10 7/8"
Minimum To
Maintain 6"
Clearance
From Wall
7 3/4"
20 1/4"
Minimum To
Maintain 3"
Clearance
From Floor
FLOOR
JOINING WALL
INSTALLING
TO WALL
Continued
WARNINGICON G 001
WARNING
Maintain minimum clearances shown in Figure 5. If you can,
provide greater clearances from floor and joining wall.
For convenience and efficiency, install heater
• where there is easy access for operation, inspection, and service
• in coldest part of room
36"
3"
FLOOR
CEILING
Minimum
Minimum To Top Surface
Of Carpeting, Tile Or Other
Combustible Material
8"
Minimum
From
Sides Of
Heater
Right
Side
Left
Side
Figure 4 - Mounting Clearances As Viewed From Front of Heater