MrHeater MHVFG30TB NG Assembly instructions

MR. HEATER, INC., 4560 W. 160TH ST., CLEVELAND, OHIO 44135 · 800-251-0001
WARNING: If the information in this manual is not followed exactly, a re or explosion may result causing
property damage, personal injury, or loss of life.
- Do not store or use gasoline or other ammable vapors and liquids in the vicinity of this or any other appliance.
- WHAT TO DO IF YOU SMELL GAS
• Shut off gas supply
• Do not try to light any appliance
• Do not touch an 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 re department.
- Installation and service must be performed by a qualied installer, service agency, or the gas supplier.
WARNING: This is an unvented gas-red heater. It uses air (oxygen) from the room in which it is installed.
Provisions for adequate combustion and ventilation air must be provided. Refer to Fresh Air for Combustion and
Ventilation section on page 4 of this manual.
WARNING: Improper installation, adjustment, alteration, service or maintenance can cause injury or property
damage. Refer to this manual for correct installation and operational procedures. For assistance or additional
information consult a qualied installer, service agency, or gas supplier.
01/15 70599 2015 JM
Installer: Leave this manual with the appliance. Consumer: Retain this manual for future reference.
OPERATING INSTRUCTIONS
AND OWNER’S MANUAL
READ INSTRUCTIONS CAREFULLY: Read and follow all instructions. Place instructions in a safe
place for future reference. Do not allow anyone who has not read these instructions to assemble,
light, adjust or operate the heater.
UNVENTED NATURAL GAS FIRED GARAGE HEATER
CAUTION: If you install the heater in a home garage: Heater pilot and burner must be at least 18 inches above
oor . Locate heater where moving vehicle will not hit it.
Blue Flame Garage
Heaters
MHVFG30TB NG

2Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
This appliance may be installed in an aftermarket* permanently manufactured (mobile) home, where not prohibited
by local codes. This appliance is only for use with the type of gas indicated on the rating plate. This appliance is not
convertible for use with any other gas.
*Aftermarket completion of sale, not for the purpose of resale, from the manufacturer.
WARNINGS
IMPORTANT: Read this owner’s manual carefully
and completely before trying to assemble, operate,
or service this heater. Improper use of this heater
can cause serious injury or death from burns, re,
explosion, electrical shock, and carbon monoxide
poisoning.
WARNING: This appliance is equipped for (natural
or propane) gas. Field conversion is not permitted.
WARNING: Do not use any accessory not ap-
proved for use with this heater.
WARNING: Any change to this heater or its con-
trols can be dangerous.
• Do not place clothing or other ammable
material on or near the appliance. Never place
any objects on the heater.
• Due to high temperatures, heater should be
kept out of trafc and away from furniture and
draperies.
• Surface of heater becomes very hot when
running. Keep children and adults away from
hot surfaces to avoid burns or clothing igni-
tion. Heater will remain hot for a time after
shutdown. Allow heater surfaces to cool before
handling.
• Young children should be carefully supervised
when they are in the same room with heater.
• Make sure grille guard is in place before run-
ning heater. If screen or grille guard is removed
for servicing it must be replaced prior to operat-
ing the heater.
• Keep the appliance area clear and free from
combustible materials, gasoline, and other
ammable vapors and liquids.
CONTENTS
WARNINGS........................................................................2
SPECIFICATIONS.................................................................3
PRECAUTIONS....................................................................3
IGNITION SYSTEM BATTERY INSTALLATION .......................4
BLOWER FAN CONTROL SWITCH OPERATION ....................4
DETERMINING THE TYPE OF HEATER LOCATION SPACE .....5
INSTALLATION ...................................................................6
FASTENING HEATER TO WALL............................................7
FLOOR MOUNTING AWAY FROM WALL .............................8
CONNECTING TO GAS SUPPLY ...........................................8
OPERATING YOUR HEATER............................................... 10
CLEANING AND MAINTENANCE.......................................11
TROUBLESHOOTING ........................................................ 14
EXPLODED-VIEW PARTS DRAWING................................... 16
PARTS LIST....................................................................... 17
WARRANTY .................................................................... 20

3Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
9. Operating heater above elevations of 4,500 feet
could cause pilot/ODS to shutdown heater.
10. Always run heater with control knob in a locked po-
sition. Never set control knob between locked posi-
tions. Poor combustion and higher levels of carbon
monoxide may result if control knob is left between
locked positions.
DANGER: Carbon monoxide poisoning may lead to
death.
Carbon Monoxide Poisoning:
Early signs of carbon monoxide poisoning resemble the
u, 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 oth-
ers. These include pregnant women, persons with heart
or lung disease or anemia, those under the inuence of
alcohol, and those at high altitudes.
Natural Gas:
Raw natural gas is odorless. An odor making agent is
added to natural gas, which helps you detect a natural
gas leak. However the odor added to natural gas can
fade. So natural gas may be present even though no
odor is detected. Make certain you read and under-
stand all warnings. Keep this manual for reference. It is
your guide to safe and proper operation of this heater.
PRECAUTIONS:
1. MHVFG30NG may not be installed in a bedroom or
bathroom, or any place where a strong wind would
shut down the appliance.
2. This heater needs outside ventilation air to run
properly. The Oxygen Depletion Sensor (ODS)
safety shutoff system shuts down the heater if not
enough fresh air is available. See Fresh Air for
Combustion and Ventilation, pages 4 through 6.
3. Keep all air openings in heater clear, free of debris
or any blockage. This will insure that enough air for
proper combustion enters the heater.
4. If heater shuts off, do not relight until you provide
fresh, outside air. If heater keeps shutting off, it
requires servicing.
5. Turn off and unplug heater and let cool before
servicing. Only a qualied service person should
service and repair heater.
6. Do not run heater:
• Where ammable liquids or vapors are used or
stored
• During dusty conditions.
7. Before using furniture polish, wax, carpet cleaner
or similar products, turn heater off. If heated the
vapors from these products may create a white
powder residue within burner box or on adjacent
walls or furniture.
8. Do not use heater if any part has been underwater.
Immediately call a qualied service technician to
inspect the room heater and to replace any part of
the control system and any gas control which has
been underwater.
SPECIFICATIONS
MHVFG30NG
BTU (Available) 30,000
Type of Gas Natural Gas Only
Ignition Battery igniter (1-AA)
Pressure Regulator Setting 4.5 Inches of Water
Inlet Gas Pressure (Maximum) 14 Inches of Water
Inlet Gas Pressure (Minimum) 9 Inches of Water
Electrical Rating /Blower 120V, 60Hz , 1
Burners / Orice nozzles 1
Thermostatic Control Yes
Clearances: inches (mm)
Top 36” (915cm)
Sides 10” (254cm)
Floor (min to top of carpet) 3” (76cm)
Fabric / ammable objects 36” (915cm)

4Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
Product Features
Figure 1
SAFETY DEVICE
This heater has a pilot with an Oxygen Depletion Sen-
sor (ODS) safety shut off system. The ODS/pilot shuts
off the heater if there is not enough fresh air.
IGNITION SYSTEM / BATTERY INSTALLATION
– The heater is equipped with an electronic manual ig-
niter. This system requires no matches, or other source
to light heater, but does require one AA battery to oper-
ate igniter. (AA Battery included).
To install or replace battery unscrew the ignitor cap
(red button), insert battery positive (+) terminal up
and replace cap.
(AA Battery included)
THERMOSTATIC CONTROL
These heaters have a control valve with a thermostat
sensing bulb. This results in the greatest heater comfort
and may result in lower bills.
BLOWER FAN CONTROL SWITCH OPERATION
These heaters also include an electrical blower. The
blower switch has three positions: MANUAL, OFF and
AUTO. In AUTO, the blower will cycleon and off as the
thermal switch requires. On MANUAL, the blower will run
continuously. To turn blower off, use the OFF position.
LOCAL CODES
Install and use heater with care.
Installation must conform to local codes or in the ab-
sences of local codes, use the latest edition of National
Fuel Gas Code ANSI Z223.1/NFPA 54.
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.
FRESH AIR FOR COMBUSTION AND
VENTILATION
WARNING: This heater shall not be installed in a
conned space or unusually tight construction un-
less provisions are provided for adequate combus-
tion and ventilation air. Read the following instruc-
tions to insure proper fresh air for this and other
fuel-burning appliances in your home.
ESTABLISHING ADEQUATE VENTILATION
The following are excerpts from National Fuel Gas
Code, NFPA 54/ ANSI Z223.1, Section 5.3, Air for Com-
bustion and Ventilation. All spaces in homes fall into
one of the three following ventilation classications:
1. Unusually Tight Construction
2. Unconned Space
3. Conned Space
This heater must not be installed in a conned space or
unusually tight construction unless provisions are pro-
vided for adequate combustion and ventilation air. The
information on pages 4 through 6 will help you classify
your space and provide adequate ventilation.
Unusually Tight Construction
If your home meets all of the three following criteria you
must provide additional fresh air. See Ventilation Air
from Outdoors, page 6.
Unusually tight construction is dened as construction
where:
a. Walls and ceilings exposed to the outside atmo-
sphere have a continuous water vapor retarder with
a rating of one perm (6 x 10-11 kg per pa-sec-m2) or
less with openings gasketed or sealed and
b. Weather stripping has been added on openable win-
dows and doors, and
c. Caulking or sealants are applied to areas such as
joints around windows and door frames, between
wall-ceiling joints, between wall panels, at penetra-
tions for plumbing, electrical, and gas lines, and at
other openings.
If your home does not meet all of the three criteria
above, see Determining the Type of Heater Location
Space, page 5.
Conned Space and Unconned Space
The National Fuel Gas Code, NFPA 54/ ANSI Z223.1
denes a conned space as a space whose volume is
less than 50 cubic feet per 1,000 Btu per hour (4.8 m3
per kW) of the aggregate input rating of all appliances
installed in that space, and an unconned space as a
space whose volume is not less than 50 cubic feet per
1,000 Btu per hour (4.8 m3 per kW) of the aggregate
input rating of all appliances installed in that space.
Rooms communicating directly with the space in which
the appliances are installed*, through openings not fur-
nished with doors, are considered a part of the uncon-
ned space.
Ignitor Button
Control Knob
Grill
Front Panel
Burners
Heater
Cabinet
Fan Blower
Switch
(located on back of
heater)

5Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
*Adjoining rooms are communication only if there
are odorless passageways or ventilation grills be-
tween them.
DETERMINING THE TYPE OF HEATER
LOCATION SPACE:
Use this method to determine if you have a conned or
unconned space.
Note: the space includes the room in which you
install heater plus any adjoining rooms with doorless
passageways or ventilation grills between the rooms.
1. Find the volume of the space by multiplying room
length x width x height.
Example: Space size 18ft (length) x 18ft. (width) x 8ft.
(height) = 2592
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 deter-
mine the maximum Btu/hr the space can support.
Example: 2592 cu.ft. (volume of space) / 50 cu.ft. =
51.8 or 51,800 (maximum Btu/hr the space
can support)
WARNING: If the area in which the heater may be
operated is smaller than dened as an unconned
space or if the building is of unusually tight con-
struction, provide adequate combustion and ventila-
tion air by the methods described in the National
Fuel Gas Code, NFPA 54/ ANSI Z223.1, Section
5.3 or applicable local codes.
3. Add the Btu/hr of all the fuel-burning appliances
in the space such as, Vent–free heater, Gas water
heater, Gas furnace, Vented gas heater, Gas re-
place logs, and Other gas appliances*
*Do not include direct-vent gas appliances. Direct-
vent draws combustion air from the outdoors and
vents to the outdoors.
Example: Gas water heater 40,000 Btu/hr
Vent Free Heater + 20,000 Btu/hr
Total =60,000 Btu/hr
4. Compare the maximum Btu/hr the space can support
with the actual amount of Btu/hr used.
Example: 51,800 Btu/hr (maximum Btu/hr the
space can support)
60,000 Btu/hr (Actual amount of Btu/hr
used)
The space in the above example is a conned
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, and the space of an adjoining
room. If the extra space provides an unconned
space, remove door to adjoining room or add venti-
lation grills between the rooms. See Ventilation Air
From Inside Building (Figure 2).
B. Vent room directly to the outdoors. See Ventilation
Air From Outdoors (Figure 3).
C. Install a lower Btu/hr heater if lower Btu/hr size
makes room unconned.
If actual Btu/hr used is less than the maximum Btu/
hr the space can support, the space is an uncon-
ned space. You will need no additional fresh air
ventilation.
VENTILATION AIR
Ventilation from Inside Building
This fresh air would come from an adjoining unconned
space. When ventilation to an adjoining unconned
space, you must provide two permanent openings: one
within 12” of the ceiling and one within 12” of the oor
on the wall connecting the two spaces (see options 1
& 2 of g. 2). You can also remove door into adjoin-
ing room (see option3, g 2). Follow the National Fuel
Gas Code NFPA 54/ ANSI Z223.1, Section 5.3, Air for
Combustion and Ventilation for required size of ventila-
tion grills or ducts.
Figure 2.
Figure 3.
Ventilation
Gills into
Adjoining
Room -
Option 1
Ventilation Gills into
Adjoining Room - Option 2
12”
12”
Or remove
door into
Adjoining
Room -
Option 3
INLET
AIR
OUTLET
AIR
VENTILATION CRAWL SPACE
TO CRAWL
SPACE
TO ATTIC
VENTILATION AIR
VENTILATED
ATTIC
OUTLET AIR

6Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
*A CSA/AGA certied equipment shutoff valve with
1/8” NPT tap is an acceptable alternative to test gauge
connection. Purchase a CSA/AGA certied equipment
shutoff valve from your dealer.
LOCATING HEATER
This heater is designed to be mounted on the wall.
For convenience and efciency, install the heater:
• Where there is easy access for operation,
inspection, and service
• In the coldest part of the room.
• If planning to use fan, locate heater near an
electrical outlet.
CAUTION: If you install the heater in a home garage:
Heater pilot and burner must be at least 18 inches
above oor . Locate heater where moving vehicle will
not hit it.
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
covering or operating heater where impurities (such
as tobacco smoke, aromatic candles, cleaning uids,
oil or kerosene lamps, etc.) are present in the air may
discolor walls.
WARNING: Never install the heater:
• In a bedroom (IR20NGT, IR30NGT, BF20NGT
or BF30NGT)
• In a recreational vehicle ·.
• Where curtains, furniture, clothing, or other
ammable objects are less than 36 inches from
the front, top, or sides of the heater.
• As a replace insert
• In high-trafc areas
• In windy or drafty areas
WARNING: Heater must be mounted to maintain
the minimum clearances shown in Figure 4. If pos-
sible, provide greater clearances from the oor, ceil-
ing, and joining walls.
WARNING: Rework worksheet, adding the space
of the adjoining unconned space. The combined
space must have enough fresh air to supply all ap-
pliance in both spaces.
Ventilation from Outdoors
If necessary provide extra fresh air by using ventila-
tion grills or ducts. Connect these items directly to the
outdoors or spaces open to the outdoors. These include
attics* and crawl spaces. Follow the National Fuel Gas
Code NFPA 54/ ANSI Z223.1, Section 5.3, Air for Com-
bustion and Ventilation for required size of ventilation
grills or ducts.
*IMPORTANT: Do not provide openings for inlet or
outlet into attic. If attic has a thermostat-controlled
power vent, heated air entering the attic will activate
the power vent.
IMPORTANT: Vent-free heaters add moisture to
the air. Although this is benecial, installing heater
in rooms without enough ventilation air may cause
mildew to form from too much moisture. See Fresh
Air for Combustion and Ventilation, pages 4 through
6.
INSTALLATION
NOTICE: This heater is intended for the use as supple-
mental heat. Use this heater along with your primary
heating system. Do not install this heater as your pri-
mary heat source. If you have a central heating system,
you may run system’s circulating blower while using
heater. This will help circulate the heat throughout the
house. In the event of a power outage, you can use this
heater as your primary heat source for the duration of
the outage.
WARNING: A qualied service person must install
heater. Follow all local codes.
CHECK GAS TYPE
Use only natural gas. If your gas supply is not natural
gas, do not install heater. Call dealer where you bought
heater for proper type heater.
THIS INSTALLATION REQUIRES:
Before installing heater, make sure you have the items
listed below:
• Piping (check local codes)
• Sealant (resistant to natural gas)
• Equipment shutoff valve*
• Ground joint union
• Test gauge connection*
• Sediment trap
• Tee joint
• Pipe wrench

7Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
Figure 4
FASTENING HEATER TO WALL
Mounting Bracket
The mounting bracket in located on the back panel of
heater (see gure 5). It has been taped there for ship-
ping. Remove mounting bracket from back panel.
Figure 5
Removing Front Panel of Heater
1. Remove three screws on bottom front of front
panel.
2. Pull bottom of front panel forward, then down
(see gure 6)
Figure 6
Attaching Mounting Bracket to Wall
Use holes on each end of mounting bracket to attach
bracket to wall. These holes are 16 inches apart. Attach
mounting bracket to wall in one of two following ways.
1. Attach to wall studs
2. Attach to wall anchor
Attaching to Wall Stud:
This way is the best providing the strongest mounting in
wood frame houses.
Attaching to Wall Anchor:
This way allows you to attach mounting bracket to hol-
low walls (wall areas between studs) or to solid walls
(concrete or masonry).
Decide which way best suits your needs. Either method
will provide a secure hold for the mounting bracket.
1. Tape mounting bracket to wall where heater
will be located. Make sure mounting bracket is
level. For wall stud mounting locate one end of
the mounting bracket over a wall stud.
WARNING: Maintain minimum clearances shown in
gure 7. If you can, provide greater clearances from
the oor and joining wall.
2. Mark screw locations on wall (see gure 7).
3. Remove tape and mount bracket from wall.
Figure 7
Attaching to Wall Stud:
For attaching mounting bracket to wall studs
1. Drill holes at marked locations using 9/64” drill
bit.
2. Place mounting bracket onto wall. Line up
holes on each end of bracket with hole drilled in
wall.
3. Insert mounting screws through bracket and
into wall studs.
4. Tighten screws until mounting bracket is rmly
fastened to wall studs.
Attaching to Wall using Anchor:
For attaching mounting bracket to hollow walls (wall ar-
eas between studs) or solid walls (concrete or masonry)
Note: Wall anchors, mounting screws, and spacer
are in hardware package. The hardware package is
provided with heater.
Adjoining Wall
18” Min.
SEE CLEARANCE
SPECIFICATIONS ON PG. 3
16” (Lg)
12-9/64” (Sm)
Mark mounting hole locations
and drill holes where indicated.
Allow for minimum clearances
Left
Side Right
Side
36” min. from
ceiling
SEE
CLEARANCE
SPECIFICATIONS
ON PG. 3
3” min. to top surface of carpet, tile
or other combustible material
Floor
Mounting
Bracket

8Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
1. Drill holes at marked locations using 5/16” drill
bit. For solid walls (concrete or masonry), drill
at least 1” deep.
2. Fold wall anchor as shown in gure 8 below.
Figure 8.
3. Insert wall anchor (wings rst) into hole. Tap
anchor ush to wall.
4. For thin walls (1/2” or less) insert red key into
wall anchor.
5. Place mounting bracket onto wall. Line up
holes on each end of bracket with wall anchors.
6. Insert mounting screws through bracket and
into wall anchors.
7. Tighten screws until mounting bracket is rmly
fastened to wall.
Placing Heater on Mounting Bracket
1. Locate two horizontal slots on back pane of
heater (see gure 9).
2. Place heater onto mounting bracket. Slide hori-
zontal slots onto stand-out tabs on mounting
bracket.
Figure 9.
Installing Bottom Mounting Screws
1. Locate two bottom mounting holes. These
holes are near bottom on back panel of heater
(see gure 10).
Figure 10
2. Mark screws locations on wall.
3. Remove heater from mounting bracket.
Horizontal Slots
Mounting Bracket
mounted to wall
4. If installing bottom mounting screw into hollow
or solid wall, install wall anchors. Follow steps 1
through 4 under Attaching to Wall using Anchor.
If installing bottom mounting screw into wall
stud, drill holes at marked locations using 9/64”
drill bit.
5. Re-place heater onto mounting bracket.
6. Place spacers between bottom mounting holes
and wall anchor or drilled hole.
7. Hold spacer in place with one hand. With the
other hand, insert mounting screw through
bottom mounting hole and spacer. Place tip of
screw in opening of wall anchor or drilled hole.
8. Tighten both screws until heater is rmly se-
cured to wall. Do not over tighten.
Note: Do not re-place front panel at this time. Re-
place front panel after making gas connections and
checking for leaks.
CONNECTING TO GAS SUPPLY
WARNING: A qualied service person must con-
nect heater to gas supply. Follow all local codes.
Screw
hole
Screw
hole

9Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
WARNING: This appliance requires a 3/8” NPT
(National Pipe Thread) inlet connection to the
pressure regulator. Use of oor mounting feet will
require you to use a 3/8 NPT street elbow to make
gas connection.
CAUTION: Never connect heater to private (non-utili-
ty) gas well. This gas is commonly known as well-head
gas.
IMPORTANT: Check your gas line pressure before con-
necting 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.
Internally-tinned copper tubing may be used in cer-
tain areas. Check your local codes. Use pipe of larger
enough diameter to allow proper gas volume to heater.
If pipe is too small, undue loss of pressure will occur.
Installation must include an equipment shutoff valve,
union and plugged 1/8” NPT tap. Locate NPT tap within
reach of test gauge hookup. NPT tap must be upstream
from heater (see gure 12).
Figure 12
*A CSA/AGA certied equipment shutoff valve with
1/8” NPT tap is an acceptable alternative to test gauge
connection. Purchase the CSA/AGA certied equipment
shutoff valve from your dealer. See Accessories, page
17.
IMPORTANT: Install an equipment shutoff valve in an
accessible location. The equipment 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 from going into pipe. Excess
sealant in pipe could result in clogged heater fuel train.
CAUTION: Use pipe joint sealant that is resistant to
natural gas.
Install sediment trap in supply line as shown in gure
12. Locate sediment trap where it is within reach for
cleaning. A sediment trap traps moisture and con-
Pressure
Regulator
Heater
Cabinet
Ground Joint Union
Equipment
Shutoff Valve
From Gas Meter
(4” W.C. to 10.5”
W.C. Pressure)
Tee Joint
1/8” NPT Plug Tap
Cap
Pipe Nipple
Tee Joint
3/8” NPT Pipe Nipple
Sediment
Trap
Test Gauge
Connection
Reducer Bushing
to 1/8” NPT
3” Minimum
taminants. This keeps them from going into heater. If
sediment trap is not installed or is installed improperly,
heater may not run correctly.
IMPORTANT: Hold pressure regulator with wrench
when connecting it to gas piping and/or ttings.
CHECKING GAS CONNECTIONS
WARNING: Test all gas piping and connections for
leaks after installing or servicing. Correct all leaks
at once.
WARNING: Never use an open ame to check for
a gas leak. Apply a mixture of liquid soap and water
to all joints. Bubbles forming show a leak. Correct
all leaks at once.
PRESSURE TESTING GAS SUPPLY PIPING
SYSTEM
Test pressure in Excess of ½ psig (3.5kPa)
1. Disconnect appliance with its appliance main
gas valve (control valve) and equipment shutoff
valve from gas supply piping system. Pressures
in excess of ½ psig will damage heater regula-
tor.
2. Cap off open end of gas pipe where equipment
shutoff valve was connected.
3. Pressurize supply piping system by either using
compressed air or opening main gas valve on
or near gas meter.
4. Check all connections and joints in gas supply
piping system. Apply mixture of liquid soap and
water to gas joints. Bubbles forming show a
leak.
5. Correct all leaks at once.
6. Depressurize and relieve pressure in supply
piping system.
7. Reconnect heater and equipment shutoff valve
to gas supply.
8. Reconnected ttings must be checked for leaks
in next section.
Test Pressure Equal To or Less Than ½ psig (3.5 kPa)
1. Close equipment shutoff valve (see gure 13).
2. Pressurize supply piping system by either using
compressed air or opening main gas valve on
or near gas meter.
3. Check all joints from the gas meter to equip-
ment shutoff valve (see gure 14). Apply
mixture of liquid soap and water to gas joints.
Bubbles forming show a leak.
4. Correct all leaks at once.
5. Depressurize and relieve pressure from supply
piping system.

10 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
Equipment
Shutoff Valve
Open
Closed
Figure 15
WARNING: Electrical Grounding Instructions: This
heater is equipped with a three-prong (grounding)
plug for your protection against shock hazard and
should be plugged into a properly grounded three-
prong receptacle.
OPERATING YOUR HEATER
FOR YOUR SAFETY READ BEFORE LIGHTING
WARNING: If you do not follow these instructions
exactly, a re or explosion may result causing prop-
erty damage, personal injury or loss of life.
A. This appliance has a pilot which must be lighted
by pushing the ignitor button. When lighting the
pilot, follow these instructions exactly.
B. BEFORE LIGHTING smell all around the appli-
ance area for gas. Be sure to smell next to the
oor because some gas is heavier than air and
will settle on the oor.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use
any phone in your building.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you can not reach your gas supplier, call the
re department.
C. Use only your hand to push in or turn the gas
control knob. Never use tools. If knob will not
push in or turn by hand, don’t try to repair it call
a qualied service technician or gas supplier.
Force or attempted repair may result in a re or
explosion.
D. Do not use this appliance if any part has been
underwater. Immediately call a qualied service
Pressure Testing Heater Gas Connections:
1. Make sure that the heater supply piping sys-
tem is connected and has been leak tested as
described above.
2. Make sure control knob of heater is in OFF
position.
3. Open equipment shutoff valve (see gure 13).
4. Open main gas valve on or near gas meter.
5. Check all joints from equipment shutoff valve
to control valve (see gure 14). Apply mixture
of liquid soap and water to gas joints. Bubbles
forming show a leak.
6. Correct all leaks at once.
7. Light heater (see Operating Your Heater, pages
10 and 11. Check the rest of the internal joints
for leaks.
8. Turn off heater (see To Turn OFF Gas to Appli-
ance, page 11.
9. Replace lower front panel.
Figure 13
Figure 14
ELECTRICAL WIRING DIAGRAM:
If any original wiring as supplied with the heater must
be replaced, it must be replaced with type AWG 105oC
wire or its equivalent except as indicated.
Control Valve
Equipment
Shutoff Valve
To gas meter

11 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
THERMOSTAT CONTROL OPERATION
FOR MHVFG30NG: The thermostatic control used
modulates the ame size as the temperature gets
closer to set point, then it turns off the burner upon
reaching temperature.
The burner will cycle back on when room temperature
drops below the set temperature. The control knob can
be set to any heat level between 1 and 5. Selecting the
HI setting will cause the burner to remain on.
TO TURN OFF GAS TO APPLIANCE
SHUTTING OFF HEATER
1. Turn control knob clockwise to the OFF posi-
tion.
2. Turn off all electrical power to the appliance if
servicing is to be preformed.
3. Turn off equipment shutoff valve.
SHUTTING OFF BURNER ONLY (PILOT STAYS LIT)
1. Turn control knob clockwise to the PILOT/IGN
position.
INSPECTING BURNER
Check pilot ame pattern and burner ame pattern
often.
PILOT FLAME PATTERN
Figure 21 shows a correct pilot ame pattern. Figure
22 shows an incorrect pilot ame pattern. The incorrect
pilot ame pattern is not touching thermocouple. This
will cause the thermocouple to cool. When the thermo-
couple cools, the heater will shut down. If pilot ame
pattern is incorrect, as shown in Figure 22:
• Turn heater off (see To Turn OFF Gas to Appli-
ance, above.
• See Troubleshooting, pages 14-15.
CLEANING AND MAINTENANCE
WARNING: Turn off heater and let cool before
servicing.
CAUTION: You must keep control areas, burner
and circulation air passageways of heater clean.
Inspect these areas of heater before use. Have
the heater inspected yearly by a qualied service
person. Heater may need more frequent cleaning
due to excess lent from carpeting, bedding material,
pet hair, etc.
Make sure grille guard is in place before running
heater. If screen or grille guard is removed for
servicing it must be replaced prior to operating the
heater.
technician to inspect the appliance and to re-
place any part of the control system which has
been underwater.
LIGHTING INSTRUCTIONS
1. STOP! Read the all safety information included
with and on the side of heater.
2. Make sure the equipment shutoff valve is fully
open.
3. Push in gas control knob and slightly turn clock-
wise to the OFF position (see gure 19).
4. Wait ve (5) minutes. Then smell for gas includ-
ing near the oor. If you smell gas, STOP! Fol-
low “B” in the safety information above. If you
do not smell gas, go to the next step.
5. Push in and turn control knob counterclockwise
to PILOT. Press in control knob for ve (5) sec-
onds.
Note: The rst time that the heater is operated after
connecting the gas supply, the control knob should
be depressed for about 30 seconds. This will allow
air to bleed from the gas system. This may take
longer in some installations
Figure 19.
6. With control knob pressed in, push down and
release the ignition button. This will light pilot. If
needed keep pressing igniter button until pilot
lights.
7. Keep control knob pressed in for (30) seconds
after lighting pilot. After 30 seconds, release
control knob.
• If pilot does not stay lit, refer to Troubleshoot-
ing, pages 14 & 15. Also, contact a qualied
service person of gas supplier for repairs.
• If control knob does not pop up when released,
contact a qualied service person or gas sup-
plier for repairs.
8. When the pilot is lit, turn control knob coun-
terclockwise to heating level. The main burner
should light.
9. To select the desired heat level, turn the
temperature setting knob counterclockwise to
between 1 & 5.
Ignitor Button Control Knob

12 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
A yellow tip on the pilot ame indicates dust and dirt in
the pilot assembly. To clean the pilot assembly nd the
small pilot air inlet hole about two inches from where
the pilot ame comes out of the pilot assembly (see
gure 25). With the unit off, lightly blow air through the
air inlet hole. You may blow through a drinking straw if
compressed air is not available.
Figure 25
CLEANING HEATER 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 cabinet to remove
dust.
WARNING: Failure to keep the primary air
opening(s) of the burner(s) clean may result in soot-
ing and property damage.
CLEANING ODS/PILOT AND BURNER
• Use as vacuum cleaner, pressurized air or
small soft bristled brush to clean.
CLEANING BURNER PILOT AIR HOLE INLET
We recommend that you clean the unit ever 2,500
hours of operation or every three months. We also
recommend that you keep the burner tube and pilot
assembly clean and free of dust and dirt. To clean these
parts we recommend using compressed air no greater
than 30 psig.
This can be done by using a vacuum cleaner in the
blow position, using compressed air in a can, please
follow the directions on the can. If you don’t follow
directions on the can you could damage the burner or
pilot assembly. In addition, the directions that follow
should also be followed.
1. Shut off the unit, including the pilot. Allow the
unit to cool for at least thirty minutes.
2. Inspect burner and pilot for dust and dirt.
3. Blow air through the port/slots and holes in the
burner.
Figure 17
Note: Your heater may have either pilot assembly.
Figure 21
Correct pilot position.
Figure 22
Incorrect pilot position.
Pilot Air Inlet Hole
Pilot Assembly

13 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
OBSERVED SYMPTOM POSSIBLE CAUSE REMEDY
When ignitor button is pressed in, there is
no spark at pilot
1. Ignitor electrode positioned wrong.
2. Ignitor electrode is broken.
3. Ignitor electrode not connected to
ignitor.
4. Ignitor cable pinched or wet.
5. Broken ignitor cable.
6. Bad Piezo ignitor.
7. Low Battery.
1. Reposition electrode
2. Replace electrode
3. Reconnect ignitor cable
4. Free ignitor cable if pinched by any
metal or tubing. Keep ignitor cable dry.
5. Replace ignitor cable
6. Replace control valve
7. Replace battery
ODS/pilot lights but ame goes out when
control knob is released
1. Gas supply turned off or equipment
shutoff valve closed.
2. Control knob not fully pressed in while
pressing ignition button.
3. Air in gas line when installed.
4. ODS/pilot is clogged.
5. Gas regulator setting is not correct
6. Control knob not in pilot position
7. Thermocouple connection loose at
control valve
8. Pilot ame not touching thermocouple,
which allows thermocouple to cool,
causing pilot ame 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
1. Turn on gas supply turn off or open
equipment shutoff valve closed
2. Fully press in control knob while press-
ing ignition button
3. Continue holding down control knob.
Repeat ignition operation until air is
removed.
4. Clean ODS/pilot (see Cleaning and
Maintenance pages 11 and 12).
5. Replace gas regulator
6. Turn Control knob to pilot position
When ignitor button is pressed in, there is
a spark at the ODS/pilot but no ignition
1. Control knob not fully pressed in.
2. Control knob not pressed in long
enough
3. Equipment shutoff valve not fully open
4. Thermocouple damaged
5. Control valve damaged
1. Press in control knob fully
2. After ODS/pilot lights, keep control
knob pressed in for 30 seconds
3. Fully open equipment shutoff valve
4. Hand tighten thermocouple nut until
snug, and then tighten 1/4 turn more.
5. -
a. Contact local gas company
b. Clean ODS/pilot (see Cleaning and
Maintenance, pages 11 and 12).
6. Replace thermocouple
7. Replace Control valve.
TROUBLESHOOTING
NOTE: All troubleshooting items are listed in order of operation and likely occurrence.
WARNING: Only a qualied service person should service and repair heater.
CAUTION: Never use a wire needle, or similar object to clean ODS/pilot. This can damage ODS/pilot unit.
Make sure grille guard is in place before running heater. If screen or grille guard is removed for servicing it must be
replaced prior to operating the heater.
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
• Immediately call you gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the re department.
IMPORTANT: Operating heater where impurities in air exist may create odors. Cleaning supplies, paint, paint remov-
er, cigarette smoke, cements and glues, new carpet or textiles, etc., create fumes. These fumes may mix with com-
bustion air and create odors and possible discoloration of walls and ceilings.

14 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
Burner does not light after ODS/pilot is lit 1. Burner orice is clogged
2. Burner orice diameter to small
3. Inlet gas pressure is too low
1. Clean burner orice (see Cleaning and
Maintenance on pages 11 and 12), or
replace burner orice
2. Replace burner orice
3. Contact local gas company
Delayed ignition of burner 1. Manifold pressure is too low
2. Burner orice is clogged
1. Contact local gas company
2. Clean burner orice (see Cleaning and
Maintenance on pages 11 and 12), or
replace burner orice
Burner backring during operation 1. Burner orice is clogged or damaged
2. Burner damaged
3. Gas regulator defective
1. Clean burner orice (see Cleaning and
Maintenance on pages 11 and 12), or
replace burner orice
2. Replace burner
3. Replace gas regulator
Burner plaque(s) does not glow [Infrared
Only]
1. Plaque damaged
2. Control knob set between locked posi-
tions.
3. Inlet gas pressure is too low
1. Replace burner
2. Turn control knob until it locks at de-
sired setting.
3. Replace gas regulator
Slight smoke or odor during initial opera-
tion
1. Residues from manufacturing process 1. Problem will stop after a few hours of
operation
Heater produces a whistling noise when
burner is lit
1. Turning control knob to HI position
when burner is cold
2. Air in gas line
3. Air passageways on heater blocked
4. Dirty or partially clogged burner orice.
1. Turn control knob to LO position and
let warm up for a minute.
2. Operate burner until air is removed
from line have gas line checked by lo-
cal gas company.
3. Observe minimum installation clear-
ances (see Figure 4 page 7)
4. Clean burner orice (see Cleaning and
Maintenance on pages 11 and 12), or
replace burner orice.
White powder residue forming within
burner box or on adjacent walls or furni-
ture
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 cleaner or similar
products.
Heater produces unwanted odors. 1. Heater burning vapors from paint, hair
spray, glues, etc. See IMPORTANT
statement at top of page 14.
2. Gas leak. See WARNING statement at
top of page 14.
1. Ventilate room. Stop using odor-caus-
ing products while heater is running.
2. Locate and correct all leaks (see
Checking Gas Connections, page 10)
Heater shuts off in use (ODS operates) 1. Not enough fresh air is available
2. Low line pressure
3. ODS/pilot is partially clogged
1. Open window and/or door for
ventilation
2. Contact local gas company
3. Clean ODS/pilot (see Cleaning and
Maintenance, pages 11 and 12)
Gas odor even when control knob is in
OFF position
1. Gas leak. See WARNING statement at
top of page 14.
2. Control valve is defective
1. Locate and correct all leaks (see
Checking Gas Connections, page 10)
2. Replace control valve
Gas odor during combustion 1. Foreign matter between control valve
and burner
2. Gas leak. See WARNING statement at
top of page 14.
1. Take apart gas tubing and remove
foreign matter
2. Locate and correct all leaks (see
Checking Gas Connections, page 10)
Heater produces a clicking/ticking noise
just after burner is lit or shut off
1. Metal expanding while heating or con-
tracting while cooling
1. This is common with most heaters. If
noise is excessive, contact qualied
service person
Moisture/condensation noticed on win-
dows
1. Not enough combustion/ventilation air 1. Refer to Fresh Air for Combustion and
Ventilation page 3 through 5.

15 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
70828

16 Installation Instructions and Owner’s Manual
Unvented Natural Gas Vent Free Heaters
Mr. Heater, Inc. reserves the right to make changes at any time, without notice or
obligation, in colors, specifications, accessories, materials and models.
WARNING:
USE ONLY MANUFACTURER’S REPLACEMENT PARTS. USE OF ANY OTHER PARTS
COULD CAUSE INJURY OR DEATH. REPLACEMENT PARTS ARE ONLY AVAILABLE
DIRECT FROM THE FACTORY AND MUST BE INSTALLED BY A QUALIFIED SERVICE
AGENCY.
REPLACEMENT PARTS ORDERING INFORMATION:
PURCHASING: Accessories may be purchased at any Mr. Heater local dealer or
direct from the factory
FOR INFORMATION REGARDING SERVICE
Please call Toll-Free 800-251-0001
www.mrheater.com
Our office hours are 8:30 AM – 5:00 PM, EST, Monday through Friday.
Please include the model number, date of purchase, and description of problem in
all communication.
LIMITED WARRANTY
Mr. Heater, Inc. warrants its heaters and accessories to be free from defects in
material and workmanship for a period of 1 year from date of purchase. Mr. Heater,
Inc. will repair or replace this product free of charge if it has been proven to be
defective within the 1-year period, and is returned at customer expense with proof
of purchase to Mr. Heater, Inc. within the warranty period.
Mr. Heater, Inc., 4560 W. 160TH ST., CLEVELAND, OHIO 44135 • 800-251-0001
Mr. Heater is a registered trademarks of Mr. Heater, Inc.
© 2015, Mr. Heater. All rights reserved
ANSI Z21.11.2b - 2010
OPERATING INSTRUCTIONS
AND OWNER’S MANUAL
READ INSTRUCTIONS CAREFULLY: Read and follow all instructions. Place instructions in a safe
place for future reference. Do not allow anyone who has not read these instructions to assemble,
light, adjust or operate the heater.
PRODUCT REGISTRATION: Thank you for your purchase.
Please log in to http://www.egiregistration.com to register your product.