MrHeater MHVFRD10NG Assembly instructions

1Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
Mr. Heater, Inc., 4560 W. 160TH ST., CLEVELAND, OHIO 44135 · 800-251-0001
INSTALLER: Leave this manual with the appliance.
CONSUMER: Retain this manual for future reference.
UNVENTED NATURAL GAS FIRED ROOM HEATER
Blue Flame Heaters
MHVFBF10NG
Plaque Heaters
MHVFRD10NG
OPERATING INSTRUCTIONS
AND OWNER’S MANUAL
Model #
MHVFRD10NG
MHVFBF10NG
READ INSTRUCTIONS CAREFULLY: YOUR SAFETY IS IMPORTANT TO YOU AND TO OTHERS 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.
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.
• Do not touch any electrical switch; do not use any phone in your building.
• Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
-Installation and service must be performed by a qualified installer, service agency or the gas supplier.
This is an unvented gas-fired 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.
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.

2Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
DANGER
HOT GLASS WILL CAUSE
BURNS.
DO NOT TOUCH GLASS
UNTIL COOLED.
NEVER ALLOW CHILDREN
TO TOUCH GLASS.
A barrier designed to reduce the risk of burns from the
hot viewing glass is provided with this appliance and shall
be installed for the protection of children and other at-risk
individuals.
WARNING: FIRE, EXPLOSION, AND ASPHYXIATION HAZARD
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 qualified installer, service agency, or gas supplier.
Read and follow instructions and precautions in User’s Information Manual provided with this
heater.
WARNING: THIS PRODUCT CAN EXPOSE YOU TO
CHEMICALS INCLUDING LEAD AND LEAD COMPOUNDS, WHICH ARE
KNOWN TO THE STATE OF CALIFORNIA TO CAUSE CANCER AND BIRTH
DEFECTS OR OTHER REPRODUCTIVE HARM. FOR MORE INFORMATION
VISIT WWW.P65WARNINGS.CA.GOV
Due to high temperatures, heater should be
kept out of traffic and away from furniture and
draperies.
Do not place clothing or other flammable material
on or near the appliance.
Children and adults should be alerted to the
hazard of high surface temperature and should
stay away to avoid burns or clothing ignition.
Young children should be carefully supervised
when they are in the same room with heater.
A barrier designed to reduce the risk of burns
from the hot viewing glass is provided with this
appliance and shall be installed for the protection
of children and other at-risk individuals.
If the barrier becomes damaged, the barrier shall
be replaced with the manufacturer’s barrier for
this appliance.
Any safety screen or guard removed for servicing
an appliance must be replaced prior to operating
the heater.
Installation and repair should be done by a
qualified service person. The appliance should
be inspected before use and at least annually
by a professional service person. More frequent
cleaning may be required due to excessive lint
from carpeting, bedding material, etc. It is
imperative that control compartments, burners,
and circulating air passageways of the appliance
be kept clean.
WARNING: This
appliance is equipped for Natural
gas. Field conversion is not
permitted.
WARNING: Do not use
a blower insert, heat exchanger
insert or other accessory not
approved for use with this heater.
SOCIAL MEDIA
In order to provide the best service possible Mr. Heater is now giving you more ways to get in touch with us:
WEBSITE: Mr. Heater’s full line of product are now at: www.mrheater.com
FACEBOOK: Find us on Facebook
TWITTER: Find us on twitter
YouTube: There are now informational videos on Youtube.

3Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
DANGER: Carbon monoxide poisoning may lead to
death.
Carbon Monoxide Poisoning:
Early signs of carbon monoxide poisoning resemble the flu,
with headaches, dizziness, or nausea. If you have these
signs, the heater may not be working properly. Get fresh
air at once! Have heater serviced. Some people are more
affected by carbon monoxide than others. These include
pregnant women, 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. The odor helps you detect a natural gas leak.
However, the odor added to the gas can fade. Gas may
be present even though no odor exists. Make certain you
read and understand all warnings. Keep this manual for
reference. It is your guide to safe and proper operation of
this heater.
Product Features
Figure 1
Control Knob
Grill
Front Panel
Burners
Heater
Cabinet
PRECAUTIONS:
1. Either of the 10,000 BTU (2931 W) units (the
MHVFRD10NG or the MHVFBF10NG) may be installed
in a bedroom, but shall not be installed in a 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,
page 4.
3. Keep all air openings in heater clear, free of debris
or any blockage. This will ensure 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 let cool before servicing. Only a qualified
service person should service and repair heater.
6. Do not run heater:
• Where flammable 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 qualified service technician to inspect
the room heater and to replace any part of the control
system and any gas control which has been underwater.
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
position. Never set control knob between locked
positions. Poor combustion and higher levels of carbon
monoxide may result if control knob is left between
locked positions.
**Operating heater above elevations of 4,500 feet could cause pilot/ODS to shutdown heater.**
SPECIFICATIONS
MODEL MHVFRD10NG / MHVFBF10NG
BTU (Available) 7,000(Low)-10,000 (High)
Type of Gas Natural Gas Only
Ignition Piezo
Manifold Pressure 4.5 Inches of Water
Inlet Gas Pressure (Maximum) 14 Inches of Water
Inlet Gas Pressure (Minimum) 7 Inches of Water
Thermostatic Control No
Clearances: inches (mm)
Top 36” (91.4 cm)
Sides 10” (25.4 cm)
Floor (min. to top of carpet) 3” (76.2 cm)
Fabric / flammable objects 36” (91.4 cm)
CONTENTS
WARNINGS...............................................2
SPECIFICATIONS........................................3
PRECAUTIONS...........................................3
DETERMINING THE TYPE
OF HEATER LOCATION SPACE ................4
INSTALLATION ..........................................5
FASTENING HEATER TO WALL ...................6
FLOOR MOUNTING AWAY FROM WALL ....8
CONNECTING TO GAS SUPPLY ..................8
OPERATING YOUR HEATER...................... 10
CLEANING AND MAINTENANCE............. 11
TROUBLESHOOTING ............................... 12
PARTS LIST AND DIAGRAM.................14-15
WARRANTY ........................................... 16

4Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
c. Caulking or sealants are applied to areas such as joints
around windows and door frames, between wall-
ceiling joints, between wall panels, at penetrations
for plumbing, electrical, and gas lines, and at other
openings.
If you home does not meet all of the three criteria above,
see Determining the Type of Heater Location Space, below.
Confined Space and Unconfined Space
The National Fuel Gas Code, NFPA 54/ ANSI 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 aggregate input rating of all appliances installed in
that space, and an unconfined space as a space whose
volume is not less than 50 cubic feet per 1,000 Btu per
hour (4.8 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 furnished with doors, are
considered a part of the unconfined space.
*Adjoining rooms are communication only if there are
doorless passageways or ventilation grills between
them.
DETERMINING THE TYPE OF HEATER LOCATION
SPACE:
Use this method to determine if you have a confined or
unconfined 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 determine
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: This heater shall not be installed in a
room or space unless the required volume of indoor
combustion air is provided by the method described
in the National Fuel Gas Code, ANSI Z223.1/NFPA
54, the International Fuel Gas Code, or applicable
local codes
SAFETY DEVICE
This heater has a pilot with an Oxygen Depletion Sensor
(ODS) safety shut off system. The ODS/pilot shuts off the
heater if there is not enough fresh air.
IGNITION SYSTEM
PIEZO: The heater is equipped with a piezo manual ignitor.
This system requires no matches, batteries, or other source
to light heater.
LOCAL CODES
Install and use heater with care.
Installation must conform to local codes or in the absences
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 confined
space or unusually tight construction unless provisions are
provided for adequate combustion and ventilation air. Read
the following instructions to insure proper fresh air for this
and other fuel-burning appliances in your home.
ESTABLISHING ADEQUATE VENTILATION
The following are excerpts from National Fuel Gas Code,
NFPA 54/ ANSI Z223.1, Section 5.3, Air for Combustion
and Ventilation. All spaces in homes fall into one of the
three following ventilation classifications:
1. Unusually Tight Construction
2. Unconfined Space
3. Confined Space
This heater must not be installed in a confined space
or unusually tight construction unless provisions are
provided for adequate combustion and ventilation air. The
information on pages 4 and 5 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 from
Outdoors, page 5.
Unusually tight construction is defined as construction
where:
a. Walls and ceilings exposed to the outside atmosphere
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 operable windows
and doors, and

5Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
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 fireplace 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 confined space
because the actual Btu/hr used is more than the
maximum Btu/hr the space can support.
You must provide additional fresh air. Your options
are as follows:
A. Rework worksheet, and the space of an adjoining room.
If the extra space provides an unconfined space, remove
door to adjoining room or add ventilation grills between
the rooms. See Ventilation From Inside Building (Fig. 2)
B. Vent room directly to the outdoors. See Ventilation
From Outdoors (Fig. 3).
C. Install a lower Btu/hr heater if lower Btu/hr size makes
room unconfined.
If 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.
VENTILATION AIR
Ventilation from Inside Building
This fresh air would come from an adjoining unconfined
space. When ventilation to an adjoining unconfined space,
you must provide two permanent openings: one within
12” of the ceiling and one within 12” of the floor on the
wall connecting the two spaces (see options 1 & 2 of figure
2). You can also remove door into adjoining room (see
option3, fig 2). Follow the National Fuel Gas Code NFPA
54/ ANSI Z223.1, Section 5.3, Air for Combustion and
Ventilation for required size of ventilation grills or ducts.
WARNING: Rework worksheet, adding the space of
the adjoining unconfined space. The combined space
must have enough fresh air to supply all appliance in
both spaces.
Ventilation from Outdoors
If necessary provide extra fresh air by using ventilation 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 Combustion and
Ventilation for required size of ventilation grills or ducts.
Ventilation
Gills into
Adjoining
Room -
Option 1
Ventilation Gills into
Adjoining Room - Option 2
(30.5 cm)12”
12” (30.5 cm)
Or remove
door into
Adjoining
Room -
Option 3
Figure 2
INLET
AIR
OUTLET
AIR
VENTILATION CRAWL SPACE
TO CRAWL
SPACE
TO ATTIC
VENTILATION AIR
VENTILATED
ATTIC
OUTLET AIR
Figure 3.
*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 beneficial, installing heater in rooms
without enough ventilation air may cause mildew to form
from too much moisture. See Fresh Air for Combustion
and Ventilation, pages 4 through 5.
INSTALLATION
WARNING: Any change to this heater or its controls
can be dangerous.
NOTICE: This heater is intended for the use as
supplemental heat. Use this heater along with your
primary heating system. Do not install this heater as your
primary 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 qualified service person must install
heater. Follow all local codes.

6Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
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
*A CSA/AGA certified equipment shutoff valve with 1/8” NPT
tap is an acceptable alternative to test gauge connection.
Purchase a CSA/AGA certified equipment shutoff valve from
your dealer.
LOCATING HEATER
This heater is designed to be mounted on the wall. The
heater can also be located on a non-combustible floor,
away from a wall by using the floor mounting stands
included with the heater. If installed on combustible
flooring such as carpeting, tile or other combustible
material other than wood flooring, the heater must be
placed on a metal or wood panel extending the full width
and depth of the appliance.
Left
Side Right
Side
36”(91.4cm)
min from ceiling
10”(25.4cm)
from sides
3” (7.62 cm) min. to top surface of carpet,
tile or other combustible material
Floor
Figure 4
For convenience and efficiency, install the heater:
• Where there is easy access for operation,
inspection, and service.
• In the coldest part of the room.
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.
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 fluids, oil or kerosene lamps, etc.) are present in
the air may discolor walls.
WARNING: Never install the heater:
• In a recreational vehicle.
• Where curtains, furniture, clothing, or other
flammable objects are less than 36 inches from the
front, top, or sides of the heater.
• As a fireplace insert
• In high-traffic areas
• In windy or drafty areas
WARNING: Heater must be mounted to maintain the
minimum clearances shown in Figure 4. If possible,
provide greater clearances from the floor, ceiling, and
joining walls.
FASTENING HEATER TO WALL
Mounting Bracket
The mounting bracket in located on the back panel of
heater (see figure 5). It has been taped there for shipping.
Remove mounting bracket from back panel.
Mounting
Bracket
Figure 5
Removing Front Panel of Heater
1. Remove (4) screws total there are (2) screws on
either side of the heater. (Figure 6)
2. Pull the front panel and back panel apart.
(2) Screws
(2) Screws
Figure 6

7Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
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 hollow
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
figure 7. If you can, provide greater clearances from the
floor and joining wall.
2. Mark screw locations on wall (see figure 7).
3. Remove tape and mount bracket from wall.
Adjoining Wall
18” Min.
See clearance
specs on Pg 3
16” (Lg)
12-9/64” (Sm)
Mark mounting hole locations
and drill holes where indicated.
Allow for minimum clearances
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 firmly
fastened to wall studs.
Attaching to Wall using Anchor:
For attaching mounting bracket to hollow walls (wall areas
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.
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 figure 8 below.
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.
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 firmly
fastened to wall.
Placing Heater on Mounting Bracket
1. Locate two horizontal slots on back pane of heater
(see figure 9).
2. Place heater onto mounting bracket. Slide
horizontal slots onto stand-out tabs on mounting
bracket.
Horizontal Slots
Mounting Bracket
mounted to wall
Figure 9
Installing Bottom Mounting Screws
1. Locate two bottom mounting holes. These holes
are near bottom on back panel of heater (see
figure 10).
Screw
hole
Screw
hole
Figure 10
2. Mark screws locations on wall.
3. Remove heater from mounting bracket.

8Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
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 firmly secured
to wall. Do not over tighten.
Note: Do not re-place front panel at this time.
Replace front panel after making gas connections and
checking for leaks.
FLOOR MOUNTING AWAY FROM WALL:
Installing Support Feet (See figure 11.)
1. Lay heater onto table on its back with bottom
edge overhanging table edge.
2. Securely attach feet to bottom of heater using 2 –
self-tapping screws each.
Figure 11
Note: Feet should have long end going out the front of
heater, and the edge coinciding with side of heater. If
feet overhang side of the heater, switch leg location.
3. Place heater on non-combustible surface (see
Locating Heater, page 6) before proceeding
with gas connection. If this will be a permanent
location, heater may be locked into position using
anchoring holes in mounting feet.
Note: Use of floor mounting feet will require you to
use a 3/8 NPT street elbow to make gas connection.
CONNECTING TO GAS SUPPLY
WARNING: A qualified service person must connect
heater to gas supply. Follow all local codes.
WARNING: This appliance requires a 3/8” NPT
(National Pipe Thread) inlet connection to the pressure
regulator. Use of floor mounting feet will require
you to use a 3/8 NPT street elbow to make gas
connection.
CAUTION: Never connect heater to private (non-
utility) gas well. This gas is commonly known as well-
head gas.
IMPORTANT: Check your gas line pressure before
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.
Internally-tinned copper tubing may be used in certain
areas. Check your local codes. Use pipe of large 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 figure 12).
*A CSA/AGA certified equipment shutoff valve with
1/8” NPT tap is an acceptable alternative to test gauge
connection. Purchase the CSA/AGA certified equipment
shutoff valve from your dealer.
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 figure 12.
Locate sediment trap where it is within reach for cleaning.
A sediment trap traps moisture and contaminants. 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 fittings.

9Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
Nipple
Tee Joint
Cap
Shutoff Valve
HEATER CABINET
Nipple
Nipple
Tee Joint
Ground Joint Union
3/8” NPT Pipe Nipple
Pressure
Regulator
Test Gauge
Connection
1/8” NPT Plug Tap
Reducer Bushing
to 1/8” NPT
Nipple
Sediment
Trap
3” minimum
Fuel line from
Gas Meter
(7”W.C to 14” WC Pressure)
Figure 12
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 flame 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
High Pressure
Test pressure in Excess of ½ psig (3.5kPa)
1.The appliance and its appliance main gas valve must be
disconnected from the gas supply piping system during
any pressure testing of that system at test pressures
in excess of ½ psi (3.5 kPa). The appliance must be
isolated from the gas supply piping system by closing its
equipment shutoff valve during any pressure testing of
the gas supply piping system at test pressures equal to
or less than ½ psi (3.5 kPa).
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 fittings must be checked for leaks in next
section.
Low Pressure
Test Pressure Equal To or Less Than ½ psig (3.5 kPa)
1. Close equipment shutoff valve (see figure 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 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.
5.Depressurize and relieve pressure from supply piping
system.
Pressure Testing Heater Gas Connections:
1.Make sure that the heater supply piping system 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 figure 13).
Equipment
Shutoff Valve
Open
Closed
Figure 13
4.Open natural gas supply valve.
5.Check all joints from equipment shutoff valve to control
valve (see figure 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, page page 10.
Control Valve
Equipment
Shutoff Valve
To gas meter
Figure 14
8. Turn off heater (see To Turn OFF Gas to Appliance,
page 10.
9. Replace lower front panel.

10 Installation Instructions and Owner’s Manual
Unvented Natural Gas Fired Room Heater
OPERATING YOUR HEATER
FOR YOUR SAFETY READ BEFORE LIGHTING
WARNING: If you do not follow these instructions
exactly, a fire or explosion may result causing property
damage, personal injury or loss of life.
A. This appliance has a pilot that must be lighted by hand.
When lighting the pilot, follow these instructions
exactly.
B. BEFORE LIGHTING smell all around the appliance area
for gas. Be sure to smell next to the floor because some
gas is heavier than air and will settle on the floor.
WHAT TO DO 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 can not reach your gas supplier, call the fire
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 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
underwater. Immediately call a qualified service
technician to inspect the appliance and to replace any
part of the control system which has been under water.
LIGHTING INSTRUCTIONS
1. STOP! Read the all safety information included with and
on the side of heater.
2. Check that gas supply to heater is on.
3.Push in gas control knob and slightly turn clockwise to
the OFF position (see figure 15).
Note: Knob cannot be turned from PILOT to OFF unless
knob is pushed in slightly. Do not force.
4. Wait five (5) minutes to clear out any gas. Then smell
for gas, including near the floor. If you smell gas, STOP!
Follow “B” in the safety information above. If you do not
smell gas, go to the next step.
5.Push in gas control know slightly and turn
counterclockwise to PILOT/IGN and depress for five
(5) seconds.
Note: The first 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.
6.Push in control knob and rotate control knob back to
OFF position then rotate counterclockwise to PILOT/
IGN position. This will light pilot. If needed gently keep
rotating control knob back and forth while depressed
until pilot lights.
7. Keep control knob depressed in for ten (10) seconds
after lighting pilot. If pilot goes out, repeat steps 4, 5, 6
and 7.
If pilot does not stay lit, refer to Troubleshooting, pages
12-13. Also, contact a qualified service person or gas
supplier for repairs.
If control knob does not pop up when released, contact
a qualified service person or gas supplier for repairs.
8. FOR MHVFRD10NG:
• Turn control knob to “HI” to light heater. Leave on “HI”
position until the tiles have turned bright orange.
• After the burner tiles have turned bright orange, adjust
heat output by turning Control Knob to desired position
(“LO” or “HI”).
FOR MHVFBF10NG:
• When the pilot is lit, turn the control knob to “HI”
position to light.
• After flame is established on “HI”, adjust heat output by
turning control knob to desired position (“LO” or “HI”).
Do not operate heater between locked positions.
Control Knob
Figure 15
CAUTION: Do not try to adjust heating level by using
equipment shutoff valve.
WARNING: When running heater, set control knob at
“LO” or “HI” locked positions. Poor combustion and
higher levels of carbon monoxide may result if heater
is operated with control knob positioned between
locked positions.
IMPORTANT: Release downward pressure while turning
control knob. Control knob must be locked at the desired
position.
TO TURN OFF GAS TO APPLIANCE
SHUTTING OFF HEATER:
1. Turn off equipment shutoff valve.
2. Turn control knob clockwise to the OFF
position.
SHUTTING OFF BURNER ONLY (PILOT STAYS LIT)
1. Turn control knob clockwise to the PILOT/IGN
position.