Desa Medallion MR10NT Quick start guide

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MR10NT
INFRARED 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.
— 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.
• Ifyoucannotreachyourgassupplier,callthe
fire department.
— Installation and service must be performed by
a qualified installer, service agency, or the gas
supplier.
WARNING: Improper instal-
lation,adjustment,alteration,
service, or maintenance can
causeinjuryorpropertydam-
age. Refer to this manual for
correct installation and op-
erationalprocedures.Foras-
sistance or additional infor-
mationconsultaqualifiedin-
staller,serviceagency,orthe
gas supplier.
WARNING: This is an
unvented gas-fired heater.
It uses air (oxygen) from
the room in which it is in-
stalled. Provisions for ad-
equate combustion and
ventilationair mustbe pro-
vided.Referto AirForCom-
bustion and Ventilation on
page 4 of this manual.
Thisappliancemaybeinstalledin an aftermarket*,permanentlylocated,manufac-
tured (mobile) home, where not prohibited by local codes.
Thisapplianceisonlyforusewiththetypeofgasindicatedontheratingplate.This
appliance is not convertible for use with other gases.
*Aftermarket: Completion of sale, not for purpose of resale, from the manufacturer

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VENT-FREE NATURAL GAS HEATER
MR10NT
™
Carbon Monoxide Poisoning: Early signs
ofcarbonmonoxidepoisoningresemblethe
flu, with headaches, dizziness, or nausea. If
you have these signs, the heater may not be
working properly. Get fresh air at once!
Haveheaterserviced.Somepeoplearemore
affected by carbon monoxide than others.
These include pregnant women, persons
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.
Theodorhelpsyoudetectanaturalgasleak.
However, the odor added to natural gas can
fade.Naturalgasmaybepresenteventhough
no odor exists.
Make certain you read and understand all
warnings.Keepthismanualforreference.It
isyourguidetosafeandproperoperationof
this heater.
SAFETY
INFORMATION
1. This appliance is only for use with the
typeofgas indicated ontherating plate.
Thisapplianceis not 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;
donotuse anyphonein yourbuilding
• immediately call your gas supplier
from a neighbor’s phone. Follow the
gas supplier’s instructions
• ifyoucannot reach yourgassupplier,
call the fire department
3. Heater shall not be installed in a bath-
room.
4. Before usingfurniturepolish,wax, car-
pet cleaner, or similar products, turn
heater off. If heated, the vapors from
theseproductsmaycreate a white pow-
der residue within burner box or on
adjacent walls or furniture.
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, and car-
bon monoxide poisoning.
DANGER: Carbon monoxide
poisoning may lead to death!
5. This heater needsfresh, outside air ven-
tilation to run properly.This heater has
an Oxygen Depletion Sensing (ODS)
safety shutoff system. The ODS shuts
down the heater if not enough fresh air
is available. See Air for Combustion
and Ventilation, pages 4 through 6.
6. Keep all air openings in front and bot-
tom of heater clear and free of debris.
This will insure 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. 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.
10. Turn off heater and let cool before ser-
vicing. Only a qualified service person
should service and repair heater.
11. Operating heater above elevations of
4,500 feet could cause pilot outage.
WARNING: Any change to
this heater or its controls can be
dangerous.
Due to high temperatures, the
appliance should be located out
oftrafficandawayfromfurniture
and draperies.
Do not place clothing or other
flammable material on or near
the appliance. Never place any
objects on the heater.
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 re-
main hot for a time after shut-
down. Allow surface to cool be-
fore touching.
Carefully supervise young chil-
dren when they are in the same
room with heater.
Make sure grill guard is in place
before running heater.
Keeptheapplianceareaclearand
free from combustible materials,
gasoline and other flammable
vapors and liquids.
WARNING: Do not use any
accessory not approved for use
with this heater.

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OWNER’S MANUAL
LOCAL CODES
Install and use heater with care. Follow all
localcodes.Intheabsenceoflocalcodes,use
thelatest editionofNationalFuelGas 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
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 PILOT
This heater has a pilot with an Oxygen
Depletion Sensing (ODS) safety shutoff
system. 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.
PRODUCT
IDENTIFICATION
Figure 1 - Model MR10NT Vent-Free Natural Gas Heater
Heater Cabinet
Grill Guard
Burners
Front Panel
Control Knob
Piezo Ignitor Button

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VENT-FREE NATURAL GAS HEATER
MR10NT
™
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from National
Fuel Gas Code, NFPA 54/ANS Z223.1, Sec-
tion5.3,AirforCombustionandVentilation.
Allspacesinhomesfallintooneofthethree
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 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-
tinuous water 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
three criteria above, proceed to De-
termining Fresh-Air Flow For Heater
Location , page 5.
Confined and Unconfined Space
The National Fuel Gas Code, ANS Z223.1
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 aggre-
gate input rating of all appliances installed
in that space and an unconfined space as a
space whose volume is not less than 50
cubicfeetper1,000Btuperhour(4.8m3per
kw) of the aggregate input rating of all
appliances installed in that space. Rooms
communicating directly with the space in
whichtheappliancesareinstalled*,through
openings not furnished with doors, are con-
sidered a part of the unconfined space.
This heater shall not be installed in a con-
fined space or unusually tight construction
unlessprovisionsare providedforadequate
combustion and ventilation air.
*Adjoiningroomsarecommunicatingonly
iftherearedoorlesspassagewaysorventila-
tion grills between them.
AIR FOR
COMBUSTION AND
VENTILATION
Today’s homes are built more energy effi-
cient than ever. New materials, increased
insulation, and new construction methods
helpreduceheatlossinhomes.Homeowners
weatherstripand caulkaroundwindows and
doorstokeepthecoldairoutandthewarmair
in. During heating months, home owners
want their homes as airtight as possible.
While it is good to make your home energy
efficient,yourhomeneedsto breathe.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.
WARNING:This heater shall
not be installed in a confined
space or unusually tight con-
struction unless provisions are
provided for adequate combus-
tion and ventilation air. Read
the following instructions to in-
sure proper fresh air for this
and other fuel-burning appli-
ances in your home.

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OWNER’S MANUAL
Example:
Gas water heater 40,000 Btu/Hr
Vent-free heater +10,000 Btu/Hr
Total = 50,000 Btu/Hr
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:Includestheroominwhichyouwillinstallheaterplusanyadjoiningroomswithdoorlesspassagewaysorventilationgrillsbetween
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
* 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)
ThespaceintheaboveexampleisaconfinedspacebecausetheactualBtu/HrusedismorethanthemaximumBtu/Hrthespacecansupport.
You must provide additional fresh air. Your options are as follows:
A. Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoin-
ing room or add ventilation grills between rooms. See Ventilation Air From Inside Building, page 6.
B. Vent room directly to the outdoors. See Ventilation Air From Outdoors,page 6.
C. Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.
If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an unconfined space. You will need no
additional fresh air ventilation.
AIR FOR
COMBUSTION AND
VENTILATION
Continued
WARNING:Iftheareainwhichtheheatermaybeoperatedissmallerthanthatdefinedasanunconfinedspace
or if the building is of unusually tight construction, provide adequate combustion and ventilation air by one of
the methods described in the National Fuel Gas Code, ANS Z223.1, Section 5.3 or applicable local codes.
Continued

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VENT-FREE NATURAL GAS HEATER
MR10NT
™
Or
Remove
Door into
Adjoining
Room,
Option 3
Ventilation Grills
Into Adjoining Room,
Option 2
12"
12"
Ventilation
Grills
into Adjoining
Room,
Option 1
VENTILATION AIR
Ventilation Air From Inside
Building
This fresh air would come from an adjoin-
ing unconfined space. When ventilating to
an adjoining unconfined space, you must
providetwopermanentopenings:onewithin
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/ANS Z223.1, Section
5.3, Air for Combustion and Ventilation for
required size of ventilation grills or ducts.
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. Follow the
National Fuel Gas Code, NFPA 54/ANS
Z223.1,Section5.3,AirforCombustionand
Ventilation for required size of ventilation
grills or ducts.
IMPORTANT: Do notprovideopenings for
inlet or outlet air into attic if attic has a
thermostat-controlledpowervent.Heatedair
enteringtheatticwillactivatethepowervent.
AIR FOR
COMBUSTION AND
VENTILATION
Continued
Figure 2 - Ventilation Air from Inside Building
Figure 3 - Ventilation Air from Outdoors
Outlet
Air Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air Ventilated
Crawl Space
To
Crawl
Space
To Attic

7
105935
OWNER’S MANUAL
2. Mark two mounting screw locations on
wall (see Figure 5).
INSTALLING HEATER TO
WALL
Marking Screw Locations
1. Determine whereyouwill locateheater.
Figure 5 - Mounting Screw Locations
Mounting
Screw
Locations
10 7/8"
Minimum To
Maintain 8"
Clearance
From Wall
7 3/4"
20 1/4"
Minimum To
Maintain 3"
Clearance
From Floor
FLOOR
JOINING WALL
WARNING:Maintainminimum
clearances shown in Figure 5. If
you can, provide greater clear-
ancesfromfloorandjoiningwall.
Forconvenienceandefficiency,installheater
• where there is easy access for operation,
inspection, and service
• in coldest part of room
INSTALLATION
CHECK GAS TYPE
Use only natural gas. If your gas supply is
notnatural, donotinstall 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)
• equipment shutoff valve *
• ground joint union
• test gauge connection *
• sediment trap
• tee joint
• pipe wrench
WARNING: A qualified ser-
vice person must install heater.
Follow all local codes.
*AnCSA/AGAdesign-certifiedequipment
shutoff valve with 1/8" NPT tap is an ac-
ceptable alternative to test gauge connec-
tion. Purchase the optional CSA/AGA de-
sign-certifiedequipmentshutoffvalvefrom
your dealer. See Accessory, page 18.
LOCATING HEATER
This heater is designed to be mounted on
a wall.
WARNING:Maintainthemini-
mumclearancesshowninFigure
4.Ifyoucan,providegreaterclear-
ancesfromfloor,ceiling,andjoin-
ing wall.
CAUTION: If you install the
heater in a home garage
• heaterpilotandburnermustbe
at least 18 inches above floor
• locate heater where moving
vehicle will not hit it
IMPORTANT: Vent-freeheatersaddmois-
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.
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 (such as to-
bacco smoke, aromatic candles,
cleaning fluids, oil or kerosene
lamps, etc.) in the air exist, may
discolor walls.
WARNING: Never install the
heater
• in 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
Continued
Figure4-MountingClearancesAsViewed
From Front of Heater
36"
3"
FLOOR
CEILING
Minimum
Minimum T
Of Carpeti
Combustib
8"
Minimum
From
Sides Of
Heater
Right
Side
Left
Side
Minimum To
Top Surface Of
Carpeting, Tile
Or Other
Combustible
Material
NOTICE: This heater is intended
foruseassupplementalheat.Use
this heater along with your pri-
mary heating system. Do not in-
stall this heater as your primary
heatsource.Ifyouhaveacentral
heating system, you may run
system’scirculatingblowerwhile
usingheater.Thiswillhelpcircu-
late the heat throughout the
house. In the event of a power
outage, you can use this heater
as your primary heat source.

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VENT-FREE NATURAL GAS HEATER
MR10NT
™
Figure 9 - Location Of Keyhole Slots On
Back Panel Of Heater
Removing Front Panel Of Heater
1. Remove two screws near bottom cor-
ners of front panel.
2. Lift straight up on grill guard until it
stops.Grill guardwillslideupabout 1/4".
3. Pull bottomoffront panelforward,then
down.
Installing Bottom Mounting
Screw
1. Locate bottom mounting hole. This
hole is near bottom on back panel of
heater (see Figure 11).
2. Mark screw location on wall.
3. Remove heater from wall.
4. If installing bottom mounting screw
into hollow or solid wall, install wall
anchor. Follow steps 1 through 5 un-
der Attaching To Wall Anchor Method.
If installing bottom mounting screw
into wall stud, drill hole at marked lo-
cation using 9/64" drill bit.
5. Replace heater on wall.
6. Insert bottom anchor screw through
backpanelinto bottomanchoror drilled
hole (see Figure 11).
7. Tighten screw until heater is firmly se-
cured 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 9 and 10).
Installing Two Mounting Screws
Note: Wall anchors and mounting screws
are in hardware package. The hardware
package is provided with heater.
Attaching To Wall Stud Method
For attaching mounting screw to wall stud
1. Drill hole at marked location using
9/64" drill bit.
2. Insert mounting screw into wall stud.
3. Tighten screw until 1/16" space (thick-
ness of penny) is between screwhead
and wall.
Attaching To Wall Anchor Method
Follow instructions below to attach mount-
ing screws to hollow walls (wall areas be-
tween studs) or solid walls (concrete or
masonry).
1. Drill holes at marked locations using
5/16"drillbit. For solid walls(concrete
or masonry), drill at least 1 1/4" deep.
2. Fold wall anchor (see Figure 6).
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 anchorwings (seeFigure7).
IMPORTANT: Do not hammer key!
For thick walls (over 1/2" thick) or
solid walls, do not pop open wings.
5. Tighten two screws until 1/16" space
(thickness of penny) is between
screwheads and wall (see Figure 8).
INSTALLATION
Continued
Figure 7 - Popping Open Anchor Wings
For Thin Walls
Thin Walls
(1/4" to 1/2"
thick)
Figure 6 - Folding Anchor
Figure 10 - Removing Front Panel Of
Heater
Placing Heater On Mounting
Screws
1. Locate two keyhole slots on back panel
of heater (see Figure 9).
2. Place large openings of slots over
screwheads. Slide heater down until
screws are in small portion of slots.
Keyhole Slots
ANCHOR
Thin or
Thick Wall
(thick wall
shown)
Solid
Wall
1/16"
Space
Figure 8 - Tightening Anchors
Figure 11 - Installing Bottom Mounting
Screw

9
105935
OWNER’S MANUAL
Figure 12 - Gas Connection
* An CSA/AGA design-certified equipment shutoff valve with 1/8" NPT tap is an
acceptable alternative to test gauge connection. Purchase the optional CSA/AGA design-
certified equipment shutoff valve from your dealer. See Accessory, page 18.
Tee Joint
Reducer
Bushing to
1/8" NPT
1/8" NPT
Plug Tap
Test
Gauge
Connection *
Pressure
Regulator
Tee
Joint
Pipe
Nipple
Cap
Equipment
Shutoff
Valve *
Ground Joint
Union
Heater
Cabinet
Sediment
Trap
3" Minimum
3/8" NPT
Pipe Nipple
From
Gas Meter
(4" W.C. to
10.5" W.C.
Pressure)
Installation must include an equipment
shutoff valve, ground joint union, and
plugged1/8"NPTtap.LocateNPTtapwithin
reach for test gauge hook up. NPT tap must
be upstream from heater (see Figure 12).
IMPORTANT: Installanequipmentshutoff
valve in an accessible location. The equip-
ment shutoff valve is for turning on or
shutting off the gas to the appliance.
Apply pipe joint sealant lightly to male
threads. This will prevent excess sealant
fromgoinginto pipe. Excesssealant in pipe
could result in clogged heater valves.
Installsedimenttrapinsupplylineasshown
in Figure 12. Locate sediment trap where it
is within reach for cleaning. Locate sedi-
menttrapwhere trapped matter is notlikely
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: Hold pressure regulator
with wrench when connecting it to gas pip-
ing and/or fittings.
IMPORTANT: Check gas line pressure
before connecting heater to gas line. Gas
line pressure must be no greater than 14
inchesofwater.Ifgaslinepressureishigher,
heater regulator damage could occur.
WARNING:Aqualifiedservice
person must connect heater to
gassupply.Followalllocalcodes.
WARNING: Never connect
heater to private (non-utility) gas
wells. This gas is commonly
known as wellhead gas.
CAUTION: Use only new,
black iron or steel pipe. Inter-
nally-tinned copper tubing may
be used in certain areas. Check
your local codes. Use pipe 3/8"
diameter or greater to allow
proper gas volume to heater. If
pipe is too small, undue loss of
pressure will occur
CAUTION:Usepipejointseal-
ant that is resistant to liquid pe-
troleum (LP) gas.
INSTALLATION
Continued
Continued
CONNECTING TO GAS
SUPPLY
WARNING:Thisappliancere-
quires a 3/8" NPT (National Pipe
Thread) inlet connection to the
pressure regulator.

10
105935
VENT-FREE NATURAL GAS HEATER
MR10NT
™
3. Check all joints from gas meter to
equipment shutoff valve (see Figure
14). Apply mixture of liquid soap and
water to gas joints. Bubbles forming
show a leak.
4. Correct all leaks at once.
Pressure Testing Heater Gas
Connections
1. Open equipmentshutoffvalve(see Fig-
ure 13).
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 alljointsfrom equipmentshutoff
valve to control valve (see Figure 14).
Apply mixture of liquid soap and wa-
ter to gas joints. Bubbles forming show
a leak.
5. Correct all leaks at once.
6. Light heater (see Operating Heater,
pages 10 and 11). Check all other in-
ternal joints for leaks.
7. Turn off heater (see To Turn Off Gas to
Appliance, page 11).
8. Replace front panel.
ON
POSITION
OFF
POSITION
Figure 13 - Equipment Shutoff Valve
Equipment
Shutoff
Valve
Open
Closed
Control Valve
Location
Gas Meter
Figure 14 - Checking Gas Joints
Pressure Testing Gas Supply
Piping System
Test Pressures In Excess Of 1/2 PSIG
(3.5 kPa)
1. Disconnect appliance with its appliance
maingasvalve (controlvalve)and equip-
ment shutoff valve from gas supply pip-
ing system. Pressures in excess of 1/2
PSIG will damage heater regulator.
2. Cap off open end of gas pipe where
equipment shutoff valve was con-
nected.
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.
6. Reconnect heater and equipment
shutoff valve to gas supply. Check re-
connected fittings for leaks.
Test Pressures Equal To or Less Than
1/2 PSIG (3.5 kPa)
1. Close equipmentshutoffvalve(see Fig-
ure 13).
2. Pressurize supply piping system by ei-
ther using compressed air or opening
main gas valve located on or near gas
meter.
CHECKING GAS
CONNECTIONS
WARNING: Test all gas pip-
ing and connections for leaks
after installing or servicing. Cor-
rect all leaks at once.
WARNING: Never use an
open 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.
Equipment
Shutoff
Valve
OPERATING
HEATER
FOR YOUR SAFETY
READ BEFORE
LIGHTING
WARNING: If you do not fol-
low these instructions exactly, a
fireorexplosionmayresultcaus-
ing property damage, personal
injury or loss of life.
A. This appliance has a pilot which
mustbelighted by hand.Whenlight-
ingthepilot, followtheseinstructions
exactly.
B. BEFORE LIGHTING smell all
aroundthe applianceareafor gas.Be
suretosmellnextto thefloorbecause
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;
do not use any phone in your
building.
• Immediatelycallyour gas supplier
from a neighbor’s phone. Follow
the gas supplier’s instructions.
• If you cannot reach your gas
supplier, call the fire department.
C. Useonlyyourhandto pushinorturn
thegascontrolknob. 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.
INSTALLATION
Continued

11
105935
OWNER’S MANUAL
1. Remove front panel (see Figure 10,
page 8).
2. Followsteps1through5 under Light-
ing Instructions.
3. With control knob pressed in, strike
match. Hold match to pilot until pi-
lot lights.
4. Keep control knob pressed in for 10
secondsafterpilot is lit.After 10 sec-
onds, release control knob. Now fol-
low step8underLightingInstructions.
5. Replace front panel.
4. Wait five (5) minutes to clear out any
gas.Thensmellforgas,includingnear
thefloor.Ifyousmellgas,STOP!Fol-
low “B” in the safety information on
page 10, column 3. If you don’t smell
gas, go to the next step.
5. Pressin controlknob, andturncoun-
terclockwise C-clockwise topilotposition.
Keep control knob pressed for five
seconds.
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.
6. With control knob pressed in, push
downandreleaseignitorbutton.This
will light pilot. The pilot is attached
tothebottom ofburner.Thepilotcan
be seen below the left hand plaque.
If needed, keep pressing ignitor but-
ton until pilot lights.
• If pilot does not stay lit, contact a
qualified service person or gas
supplier for repairs.
THERMOSTAT
CONTROL
OPERATION
The control knob can be set to any heat
levelbetweenHIandLO.Whentheroom
temperatureexceedsthesettemperature,
the burner will cycle to pilot. The burner
will cycle back on when room tempera-
ture drops below the set temperature.
Selecting a higher setting will cause the
heater to run longer, producing greater
heat output. At lower settings, the heater
will run less.
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.
TO TURN OFF GAS
TO APPLIANCE
Shutting Off Heater
1. Turncontrolknobclockwise Clockwise
to the OFF position.
Shutting Off Burner Only (pilot
stays lit)
1. Turncontrolknobclockwise Clockwise
to the PILOT position.
MANUAL LIGHTING
PROCEDURE
7. Keep control knob pressed in for 30
seconds after lighting pilot.After 30
seconds, release control knob.
• If control knob does not pop up
when released, contact a qualified
service person or gas supplier for
repairs.
Note: If pilotdoes not light, repeat
steps 3 through 7. This heater has
a safetyinterlocksystem.Waitone
(1) minute before lighting pilot
again.
8. Turn control knob counterclockwise
C-clockwise todesiredheatinglevel. Both
plaques should light. Set control
knob to any heat level between HI
and LO.
Ignitor Electrode
Pilot Burner
Thermocouple
Figure 16 - Pilot
CAUTION:Donottrytoadjust
heatinglevelsbyusingtheequip-
ment shutoff valve.
OPERATING
HEATER
Continued
IGNITOR
PILOT
LO
OFF
HI
LIGHTING
INSTRUCTIONS
1. STOP! Read the safety information
on page 10, column 3.
2. Make sure equipment shutoff valve
is fully open.
3. Turncontrolknobclockwise
Clockwise
to the OFF position.
Figure 15 - Control Knob In The OFF
Position
Ignitor Button Control Knob

12
105935
VENT-FREE NATURAL GAS HEATER
MR10NT
™
ware store, or home center may carry com-
pressed air in a can. You can use a vacuum
cleaner in the blow position. If using com-
pressed air in a can, please follow the direc-
tions on the can. If you don't follow direc-
tionsonthecan, youcoulddamagethepilot
assembly.
1. Shut off the unit, including the pilot.
Allow the unit to cool for at least thirty
minutes.
2. Inspect burner, pilot for dust and dirt.
3. Blow air through the ports/slots and
holes in the burner.
Clean the pilot assembly also. A yellow tip
on the pilot flame indicates dust and dirt in
the pilot assembly. There is a small pilot air
inlet hole about two inches from where the
pilot flame comes out of the pilot assembly
(see Figure 21). With the unit off, lightly
blowairthrough theairinlet hole.Youmay
blowthroughadrinkingstrawifcompressed
air is not available.
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.
BURNER FLAME PATTERN
Figure 19 shows a correct burner flame
pattern.Figure20showsanincorrectburner
flame pattern.
Figure 19 - Correct Burner Flame Pattern
Ifburnerflamepatternisincorrect,asshown
in Figure 20
• turn heater off (see To Turn Off Gas to
Appliance, page 11)
• seeTroubleshooting,pages 13through15
CLEANING AND
MAINTENANCE
ODS/PILOT AND BURNER
ORIFICE
• Use a vacuum cleaner, pressurized air,
or small, soft bristled brush to clean.
CLEANING BURNER
PILOT AIR INLET HOLE
We recommend that you clean the unit ev-
ery 2,500 hours of operation or every three
months.
Wealsorecommendthatyoukeeptheburner
tube and pilot assembly clean and free of
dustanddirt.Tocleanthesepartswerecom-
mend using compressed air no greater than
30 PSI. Your local computer store, hard-
WARNING: Turn off heater
and let cool before cleaning.
CAUTION: You must keep
control areas, burner, and circu-
lating air passageways of heater
clean. Inspect these areas of
heater before each use. Have
heaterinspectedyearlybyaquali-
fied service person. Heater may
needmorefrequentcleaningdue
to excessive lint from carpeting,
bedding material, pet hair, etc.
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure17showsacorrectpilotflamepattern.
Figure 18 shows an incorrect pilot flame
pattern.Theincorrectpilotflameisnottouch-
ing the thermocouple. This will cause the
thermocouple to cool. When the thermo-
couple cools, the heater will shut down.
INSPECTING
BURNER
If pilot flame pattern is incorrect, as shown
in Figure 18
• turn heater off (see To Turn Off Gas to
Appliance, page 11)
• seeTroubleshooting,pages 13through15
Figure 21 - Pilot Inlet Air Hole
Pilot Assembly
Pilot Air Inlet
Hole
GRH/OV 009GOOD PILOT
GRH/OV 010BAD PILOT
Pilot Burner
Thermocouple
Thermocouple
Pilot Burner
Figure 18 - Incorrect Pilot Flame Pattern
Figure 17 - Correct Pilot Flame Pattern
Figure20-IncorrectBurnerFlamePattern

13
105935
OWNER’S MANUAL
TROUBLESHOOTING
POSSIBLE CAUSE
1. Ignitor cable pinched or wet
2. Ignitor electrodenotconnected to ignitor
cable
3. Piezo ignitor nut is loose
4. Broken ignitor cable
5. Ignitor electrode broken
6. Bad piezo ignitor
7. Ignitor electrode positioned wrong
1. Gas supply turned off or equipment
shutoff valve closed
2. Control knob not in PILOT position
3. Control knob not pressed in while in
PILOT 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 knobnotpressed in long enough
3. Equipment shutoff valve not fully open
4. Thermocouple connection loose at
control valve
5. Pilot flame not touching thermocouple,
which allows thermocouple to cool,
causing pilot flame to go out. This
problem could be caused by one or both
of the following:
A) Low gas pressure
B) Dirty or partially clogged ODS/pilot
6. Thermocouple damaged
7. Control valve damaged
REMEDY
1. Free ignitor cable if pinched by any
metal or tubing. Keep ignitor cable dry
2. Reconnect ignitor cable
3. Tightennut holding piezoignitorto base
panel of log set. Nut is located behind
base panel.
4. Replace ignitor cable
5. Replace ignitor
6. Replace piezo ignitor
7. Replace ignitor
1. Turn on gas supply or open equipment
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
removed
5. Clean ODS/pilot (see Cleaning and
Maintenance, page 12) 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 10 seconds
3. Fully open equipment shutoff valve
4. Hand tighten until snug, then tighten 1/4
turn more
5. A) Contact local natural gas company
B) Clean ODS/pilot (see Cleaning and
Maintenance, page 12) or replace ODS/
pilot assembly
6. Replace thermocouple
7. Replace control valve
OBSERVED PROBLEM
Whenignitorbuttonispressedinthere isno
spark at ODS/pilot
When ignitor button is pressed and control
knob is pressed in and turned to the PILOT
position, there is spark at ODS/pilot but no
ignition
ODS/pilot lights but flame goes out when
control knob is released
Note: All troubleshooting items are listed
in order of operation.
WARNING: Turn off heater
andletcoolbeforeservicing.Only
aqualifiedservicepersonshould
service and repair heater.
CAUTION: Never use a wire,
needle, or similar object to clean
ODS/pilot.ThiscandamageODS/
pilot unit.
Continued

14
105935
VENT-FREE NATURAL GAS HEATER
MR10NT
™
OBSERVED PROBLEM
Burner plaques do not light after ODS/pilot
is lit
Delayed ignition of burner plaques
Burner backfiring during combustion
POSSIBLE CAUSE
1. Burner orifice(s) is clogged
2. Burner orifice(s) diameter is too small
3. Inlet gas pressure is too low
1. Manifold pressure is too low
2. Burner orifice(s) is clogged
1. Burner orifice(s) is clogged or damaged
2. Inlet gas pressure is too low
3. Burner damaged
4. Gas regulator defective
REMEDY
1. Clean burner orifice(s) (see Cleaning
and Maintenance, page 12) or replace
burner orifice(s)
2. Replace burner orifice(s)
3. Contact local natural gas company
1. Contact local natural gas company
2. Clean burner orifice(s) (see Cleaning
and Maintenance, page 12) or replace
burner orifice(s)
1. Clean burner orifice(s) (see Cleaning
and Maintenance, page 12) or replace
burner orifice(s)
2. Contact local natural gas company
3. Replace burner
4. Replace gas regulator
1. Plaque damaged
2. Inlet gas pressure is too low
3. Control knob set too low
1. Residues from manufacturing processes
1. Metal expanding while heating or
contracting while cooling
Burner plaques do not glow
Slightsmoke orodorduring initialoperation
Heater produces a clicking/ticking noise
just after burner is lit or shut off
TROUBLESHOOTING
Continued
1. Replace burner
2. Contact local natural gas company
3. Turn control knob to higher setting
1. Problem will stop after a few hours of
operation
1. This is common with most heaters. If
noise is excessive, contact qualified
service person
Whitepowderresidueformingwithinburner
box or on adjacent walls or furiture 1. When heated, vapors from furniture polish, wax, carpet cleaners, etc, turn
into white powder residue
1. Turn heater off when using furniture
polish, wax, carpet cleaners, or similar
products

15
105935
OWNER’S MANUAL
OBSERVED PROBLEM
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
POSSIBLE CAUSE
1. Heater burning vapors from paint, hair
spray, glues, etc. See IMPORTANT
statement above
2. Gas leak. See Warning 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. See Warning statement at
top of page
2. Control valve defective
1. Foreign matter between control valve
and burner
2. Gas leak. See Warning statement at
top of page
1. Not enough combustion/ventilation air
REMEDY
1. Ventilate room. Stop using odor-causing
products while heater is running
2. Locate and correct all leaks (see
Checking Gas Connections, page 10)
1. Open windowand/or door forventilation
2. Contact local natural gas company
3. Clean ODS/pilot (see Cleaning and
Maintenance, page 12)
1. Locate and correct all leaks (see
Checking Gas Connections, page 10)
2. Replace control valve
1. Take apart gas tubing and remove
foreign matter
2. Locate and correct all leaks (see
Checking Gas Connections, page 10)
1. Refer to Air for Combustion and
Ventilation requirements (page 4)
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.
• Immediatelycall your gassupplier from a neighbor’s phone. Follow the
gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
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.
TROUBLESHOOTING
Continued

16
105935
VENT-FREE NATURAL GAS HEATER
MR10NT
™
12
A
B
16
7
8
4
6
5
3
2
1
11
14
13
19
18
6
17 15
16
10
9
7-1
ODS/PILOT
7-2
ILLUSTRATED
PARTS LIST
MR10NT

17
105935
OWNER’S MANUAL
PARTS LIST
MR10NT
Thislistcontainsreplaceablepartsusedinyourheater.Whenorderingparts,followtheinstructionslisted
under Replacement Parts on page 18 of this manual.
KEY PART
NO. NUMBER DESCRIPTION QTY.
1 098304-01 Screw, #10 x 3/8" 2
2 099467-06 Front Panel Assy., Ivory 1
3 099318-04 Grill Guard 1
4 101108-01 Removable Speed Clip 2
5 099275-01 Reflector 1
6 M15823-37 Screw Hex #8 x 1/4" 10
7 503329 ODS/Pilot Assembly 1
7-1 098514-01 Thermocouple 1
7-2 098594-01 Ignitor Electrode 1
8 099884-03 Burner Assembly 1
9 099056-24 Injector 1
10 104087-01 Tubing - Burner 1
11 099387-11 Pilot Tubing - Valve to pilot 1
12 M11084-26 Screw, #10 x 3/8" 2
13 104084-01 Tubing - Inlet 1
14 098522-16 Control Valve 1
15 097159-04 Piezo Ignitor 1
16 098271-03 Ignitor Cable 1
17 102462-06 Cabinet Assembly, Ivory 1
18 099415-12 Gas Regulator 1
19 098303-02 Screw, #6 x 5/16" 2
PARTS AVAILABLE - NOT SHOWN
102471-01 Control Position Label 1
100642-02 Assembly, Hardware 1

18
105935
VENT-FREE NATURAL GAS HEATER
MR10NT
™
ACCESSORY
Purchase this heater accessory from your
local dealer. If they cannot supply this ac-
cessory,callCansUnlimited,Incorporated’s
Parts Department at 1-800-922-7407 for
referral information. You can also write to
the address listed on the back page of this
manual.
EQUIPMENT SHUTOFF
VALVE - GA5010
Equipmentshutoffvalvewith1/8"NPTtap.
When Gas Pressure Is Too Low
• pilot will not stay lit
• burner(s) will have delayed ignition
• heater will not produce specified heat
When Gas Quality Is Bad
• pilot will not stay lit
• burner(s) will produce flames and soot
• heater will backfire when lit
Youmayfeelyourgaspressureistoolowor
gas quality is bad. If so, contact your local
natural gas supplier.
SERVICE HINTS
Note: Use only original replacement parts.
Thiswillprotectyourwarrantycoveragefor
parts replaced under warranty.
PARTS UNDER WARRANTY
Contact authorized dealer from whom you
purchased this product. If they cannot sup-
ply original replacement part(s), call Cans
Unlimited, Incorporated’s Technical Ser-
vice Department at 1-800-922-7407 for in-
formation.
When contacting your dealer or Cans Un-
limited, Incorporated, have ready:
• your name
• your address
• model and serial numbers of your heater
• how heater was malfunctioning
• typeofgasused(propane/LPornaturalgas)
• purchase date
Usually,wewillaskyoutoreturnthedefec-
tive part to the factory.
PARTS NOT UNDER
WARRANTY
Contact authorized dealers of this product.
If they cannot supply original replacement
part(s),callCansUnlimited,Incorporated’s
Parts Department at 1-800-922-7407 for
referral information.
WhencallingCansUnlimited,Incorporated,
have ready:
• model number of your heater
• the replacement part number
REPLACEMENT
PARTS
You may have further questions about in-
stallation, operation, or troubleshooting.
Ifso,contactCansUnlimited,Incorporated’s
Technical Service Department at
1-800-922-7407.
TECHNICAL
SERVICE
SPECIFICATIONS
MR10NT
Btu 10,000
Type Gas Natural Only
Ignition Piezo
Pressure Regulator Setting 3.5" W.C.
Inlet Gas Pressure (inches of water)
Maximum 10.5"
Minimum 5"
Dimensions, Inches (H x W x D)
Heater 21 1/2x 13 1/2x 7
Carton 24 3/4x 16 3/4x 7 1/2
Weight (pounds)
Heater 14
Shipping 18

19
105935
OWNER’S MANUAL
NOTES
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KEEP THIS WARRANTY
Model
Serial No.
Date Purchased
Always specify model and serial numbers when communicating with the factory.
We reserve the right to amend these specifications at any time without notice. The only warranty applicable is our
standard written warranty. We make no other warranty, expressed or implied.
WARRANTY INFORMATION
LIMITED WARRANTY
MEDALLION VENT-FREE HEATERS
Cans Unlimited, Incorporated warrants this product to be free from defects in materials and components for two
(2) years from the date of first purchase, provided that the product has been properly installed, operated and
maintained in accordance with all applicable instructions. To make a claim under this warranty the Bill of Sale or
cancelled check must be presented.
Thiswarrantyisextendedonlytotheoriginalretailpurchaser.Thiswarrantycoversonlythecostofpart(s)required
torestore thisheaterto properoperating conditionandan allowancefor laborwhen providedbya CansUnlimited,
Incorporated Authorized Service Center. Warranty part(s) MUST be obtained through authorized dealers of this
product and/or Cans Unlimited, Incorporated who will provide original factory replacement parts. Failure to use
original factory replacement parts voids this warranty. The heater MUST be installed by a qualified installer in
accordance with all local codes and instructions furnished with the unit.
This warranty does not apply to parts that are not in original condition because of normal wear and tear, or parts
that fail or become damaged as a result of misuse, accidents, lack of proper maintenance or defects caused by
improper installation. Travel, diagnostic cost, labor, transportation and any and all such other costs related to
repairing a defective heater will be the responsibility of the owner.
TOTHEFULL EXTENT ALLOWEDBYTHE LAW OF THEJURISDICTION THAT GOVERNS THESALE
OF THE PRODUCT; THIS EXPRESS WARRANTY EXCLUDES ANY AND ALL OTHER EXPRESSED
WARRANTIES AND LIMITS THE DURATION OF ANY AND ALL IMPLIED WARRANTIES, INCLUD-
ING WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE TO TWO
(2)YEARS ONALL COMPONENTS FROMTHE DATEOF FIRSTPURCHASE: ANDCANSUNLIMITED,
INCORPORATED’S LIABILITY IS HEREBY LIMITED TO THE PURCHASE PRICE OF THE PRODUCT
AND CANS UNLIMITED, INCORPORATED SHALL NOT BE LIABLE FOR ANY OTHER DAMAGES
WHATSOEVER INCLUDING INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES.
Some states do not allow a limitation on how long an implied warranty lasts or an exclusion or limitation of
incidental or consequential damages, so the above limitation on implied warranties, or exclusion or limitation on
damages may not apply to you.
This warranty gives you specific legal rights, and you may also have other rights that vary from state to state.
For information about this warranty write:
105935-01
REV. B
03/00
105935 01
NOT A UPC
Distributed by: C.U.I.
Cans Unlimited, Incorporated
1700 Poplar Drive
Greer, SC 29651
GAS PRODUCTS
™