Medallion MBN20LB Quick start guide

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
causingpropertydamage,personalinjury,orloss
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.
• Do not touch any electrical switch; do not
use any phone in your building.
• Immediately call your gas supplier from a
neighbor’sphone.Followthegassupplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
— Installation and service must be performed by
aqualifiedinstaller,serviceagency,orthegas
supplier.
MBN20LB
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. (I.E. Installation of this
product is permitted after the manufactured (mobile) home is sited)
WARNING: Improper installa-
tion,adjustment,alteration,ser-
vice,ormaintenancecancause
injury or property damage. Re-
fer to this manual for correct
installationandoperationalpro-
cedures. For assistance or ad-
ditional information consult a
qualified installer, service
agency, or the gas supplier.
WARNING: This is an unvented
gas-firedheater.Itusesair(oxy-
gen)from theroomin whichitis
installed. Provisions for ad-
equate combustion and ventila-
tion air must be provided. Refer
to Air for Combustion and Ven-
tilation sectiononpage4 of this
manual.
Save this manual for future reference.
™

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105735
VENT-FREE NATURAL GAS HEATERS
BLUE-FLAME MBN20LB
™
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.Theseincludepregnantwomen,per-
sons 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. Keep this manual for reference.
It is your guide to safe and proper operation
of this heater.
SAFETY
INFORMATION
1. This appliance is only for use with the
typeof gasindicated onthe rating 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 building
• 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 areless than
36inches from thefront, top, or sides
of the heater
• as a fireplace insert
• in high traffic areas
• in windy or drafty areas
5. This heaterneeds fresh,outside airven-
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 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. 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 shutdown.
Allow surface to cool before touching.
WARNING ICON G001
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!
WARNING: Any change to
this heater or its controls can be
dangerous.
11. Carefully supervise young children
when they are in 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 heater and let cool before ser-
vicing. Only a qualified service person
should service and repair heater.
15. Operating heater above elevations of
4,500 feet could cause pilot outage.
16. Before using furniturepolish, wax,car-
pet cleaner, or similar products, turn
heater off. If heated, the vapors from
theseproducts may createa white pow-
der residue within burner box or on
adjacent walls or furniture.

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105735
OWNER’S MANUAL
PRODUCT
IDENTIFICATION
Figure 1 - Vent-Free Natural Gas Heater
Grill
Guard
Ignitor Button Control Knob
Front
Panel
Glass Panel
Heater
Cabinet
LOCAL CODES
Install and use heater with care. Follow all
localcodes.Intheabsenceof local codes,use
the latest edition of National Fuel Gas Code
ANS Z223.1, also known as NFPA 54*.
*Available from:
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
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 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.

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105735
VENT-FREE NATURAL GAS HEATERS
BLUE-FLAME MBN20LB
™
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
weatherstrip andcaulk aroundwindows 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.
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from National
Fuel Gas Code. NFPA 54/ANS Z223.1,
Section 5.3, Air for Combustion and
Ventilation.
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 (6 x 10-11 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
DeterminingFresh-AirFlowforHeater
Location on page 5.
WARNING: This heater shall
notbeinstalledinaconfinedspace
or unusually tight construction
unless provisions are provided
foradequatecombustionandven-
tilation air. Read the following in-
structions to insure proper fresh
air for this and other fuel-burning
appliances in your home.
Confined and Unconfined Space
The National Fuel Gas Code (ANS Z223.1,
1992 Section 5.3) defines a confined space
as a space whose volume is less than 50
cubicfeetper1,000Btuperhour(4.8m3per
kw) of the aggregate input rating of all
appliances installed in that space and an
unconfiningspaceasaspacewhosevolume
is not less than 50 cubic feet per 1,000 Btu
per hour (4.8 m3per kw) of the aggregate
inputratingofallappliancesinstalledinthat
space.Rooms communicatingdirectlywith
the space in which the appliances are in-
stalled*, through openings not furnished
with doors, are considered a part of the
unconfined space.
This heater shall not be installed in a con-
fined space or unusually tight construction
unlessprovisions areprovided foradequate
combustion and ventilation air.
*Adjoiningroomsarecommunicatingonly
iftherearedoorlesspassagewaysorventila-
tion grills between them.

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105735
OWNER’S MANUAL
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, 1992, Section 5.3 or applicable local codes.
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
* 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)
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.
Example:
Gas water heater 40,000 Btu/Hr
Vent-free heater +20,000 Btu/Hr
Total =60,000 Btu/Hr
Continued

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105735
VENT-FREE NATURAL GAS HEATERS
BLUE-FLAME MBN20LB
™
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
AIR FOR
COMBUSTION
AND VENTILATION
Continued
Outlet
Air Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air Ventilated
Crawl Space
To
Crawl
Space
To Attic
Figure 3 - Ventilation Air from Outdoors
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.
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/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.

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105735
OWNER’S MANUAL
INSTALLATION
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 *
• sediment trap
• tee joint
• pipe wrench
WARNING: A qualified ser-
vice person must install heater.
Follow all local codes.
*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 17.
WARNING:Maintainthemini-
mumclearancesshowninFigure
4.Ifyoucan,providegreaterclear-
ancesfromfloor,ceiling,andjoin-
ing wall.
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 bedroom or 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
You can locate model MBN20LB on the
floor, away from a wall. An optional floor
mountingstandisneeded.Purchasethefloor
mounting stand from your dealer. See Ac-
cessories, page 17.
LOCATING HEATER
This heater is designed to be mounted on a
wall.
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
Forconvenienceandefficiency,installheater
• where there is easy access for operation,
inspection, and service
• where strong wind gusts from an open
dooror garage doorcan not blow directly
into heater.
An optional fan kit is available from your
dealer. See Accessories, page 17. If plan-
ningtousefan,locateheater nearan electri-
cal outlet.
Figure 4 - Mounting Clearances As Viewed From Front of Heater
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.If you haveacentral
heating system, you may run
sytem’s circulating blower while
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.
36"
*
FLOOR
CEILING
Minimum
Minimum To Floor
6"
Minimum
From
Sides Of
Heater
Left
Side Right Side
Continued
3"
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.
Mounting
Bracket
Figure 5 - Mounting Bracket Location

8
105735
VENT-FREE NATURAL GAS HEATERS
BLUE-FLAME MBN20LB
™
Figure 9 - Popping Open Anchor Wings
For Thin Walls
Figure 8 - Folding Anchor
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
uplast hole oneach end ofbracket 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.
Figure 10 - Mounting Heater Onto
Mounting Bracket
Mounting
Bracket
(attached
to wall)
Horizontal
Slots
Stand-Out
Tab
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. Forsolid walls (concrete
or masonry), drill at least 1" deep.
2. Fold wall anchor as shown in Figure 8.
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.
5. Place mountingbracket onto wall.Line
uplast hole oneach end ofbracket 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.
INSTALLATION
Continued
Figure6-RemovingFrontPanelOfHeater
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 guard will slide up about
1/4".
3. Pull bottomof frontpanel forward,then
down.
4. Remove cardboard packing from grill
and glass.
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
providesthestrongesthold.Insertmounting
screws through mounting bracket and into
wall studs.
AttachingtoWallAnchor: Thismethod
allows you to attach mounting bracket to
hollow walls (wall areas between studs) or
to solid walls (concrete or masonry).
Decidewhichmethodbettersuitsyourneeds.
Eithermethodwillprovideasecureholdfor
the mounting bracket.
Marking Screw Locations
1. Tape mounting bracket to wall where
heater will be located. Make sure
mounting bracket is level.
2. Mark screw locations on wall (see Fig-
ure 7).
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.
16"
18 3/4"
Min.
7 1/4"
Min.
Adjoining Wall
Only Insert Mounting
Screws Through Last
Hole On Each End
Floor
Figure 7 - Mounting Bracket Clearances
WARNING:Maintainminimum
clearances shown in Figure 7. If
you can, provide greater clear-
ancesfromfloorandjoiningwall.

9
105735
OWNER’S MANUAL
INSTALLATION
Continued
Figure 11 - Installing Bottom Mounting
Screws
Continued
CONNECTING TO GAS
SUPPLY
WARNING: A qualified ser-
vicepersonmust connectheater
to gas supply. Follow all local
codes.
WARNING: Never connect
heater to private (non-utility) gas
wells. This gas is commonly
known as wellhead gas.
IMPORTANT: Check gasline pressurebe-
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.Usepipeof1/2"
diameter or greater to allow
proper gas volume to heater. If
pipe is too small, undue loss of
pressure will occur.
Installsedimenttrapinsupplylineasshown
in Figure 12. Locate sediment trap where it
is within reach for cleaning. Locate sedi-
menttrap where trappedmatter 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: Holdpressureregulatorwith
wrench when connecting it to gas piping
and/or fittings.
CAUTION:Usepipejointseal-
ant that is resistant to liquid pe-
troleum (LP) gas.
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 12).
Apply pipe joint sealant lightly to male
threads. This will prevent excess sealant
from going into pipe. Excess sealant in the
pipe could result in clogged heater valves.
Typical Inlet Pipe Diameters
20,000 Btu/Hr models 3/8" or greater
30,000 Btu/Hr models 1/2" or greater
Installing Bottom Mounting
Screws
1. Locate two bottom mounting holes.
These holes are near bottom on back
panel of heater (see Figure 11).
2. Mark screw locations on wall.
3. Remove heaterfrom mountingbracket.
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,
page 8.
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-
ingholesand wallanchoror drilledhole.
7. Hold spacer in place with one hand.
With other hand,insert mountingscrew
through bottom mounting hole and
spacer. Place tip of screw in opening
of wall anchor or drilled hole.
8. Tightenboth screws untilheateris 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 page 10).
Figure 12 - Gas Connection
* An A.G.A. design certified manual shutoff valve with 1/8" NPT tap is an acceptable
alternativetotestgaugeconnection.PurchasetheoptionalA.G.A.design-certifiedmanual
shutoff valve from your dealer. See Accessories, page 17.
Tee Joint
Reducer
Bushing to
1/8" NPT
1/8" NPT
Plug Tap
Pressure
Regulator
Test
Gauge
Connection *
Sediment
Trap
Tee Joint
Pipe Nipple
Cap
Heater
Cabinet
3/8" NPT
Pipe Nipple
Note: Burner
bracket not shown
for clarity
Manual Shutoff
Valve *
Typical Inlet Pipe
From Gas Meter
(5" W.C. to 10.5"
W.C. Pressure)
Ground Joint Union
3" Minimum

10
105735
VENT-FREE NATURAL GAS HEATERS
BLUE-FLAME MBN20LB
™
WARNING: Test all gas pip-
ing and connections for leaks
after installing or servicing. Cor-
rect all leaks at once.
CHECKING GAS
CONNECTIONS
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
TestPressuresInExcessOf1/2PSIG
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.
6. Reconnect heater and manual shutoff
valve to gas supply. Check reconnected
fittings for leaks.
TestPressuresEqualToorLessThan
1/2 PSIG
1. Close manual shutoff valve (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.
3. Check all joints from gas meter to
manual shutoff valve (see Figure 14).
Apply mixture of liquid soap and wa-
ter to gas joints. Bubbles forming show
a leak.
4. Correct all leaks at once.
Figure 13 - Manual Shutoff Valve
Figure 14 - Checking Gas Joints
ON
POSITION
OFF
POSITION
Manual
Shutoff
Valve
Closed
Open
Manual
Shutoff
Valve
Gas Meter
Control Valve Location
Pressure Testing Heater Gas
Connection
1. Open manual shutoff valve (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 all joints from manual shutoff
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,
page 11). Check the rest of the internal
joints for leaks.
7. Turn off heater (see To Turn Off Gas to
Appliance, page 11).
8. Replace front panel.
INSTALLATION
Continued