Procom MD300HGA User manual

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CAUTION - FOR YOUR SAFETY
Vent-Free Gas Wall Heater
Blue Flame
PC-ML062-03D-0904
Model # MD300HGA
MD300TGA
WARNING:This appliance is
equipped for (Natural and Propane)
gas. Field conversion is not permitted
other than between natural or
propane gases.
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 ammable vapors and liquids in 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 re department.
-- Installation and service must be performed by a qualied installer, service
agency or the gas supplier.
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 Air For Combustion and Ventilation section on page 6 of this manual.
INSTALLER: DO NOT DISCARD THIS MANUAL – LEAVE FOR HOMEOWNER’S
FUTURE REFERENCE.
This appliance may be installed in an aftermarket, permanently located manufactured
(mobile) home, where not prohibited by local codes. This appliance is for use with
the type of gas indicated on the rating plate only. This appliance is not convertible for
use with other gases.
Questions about installation, operation, or troubleshooting? Before returning to your retailer,
call customer service department toll-free at [phone].

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TABLE OF CONTENTS
Important Safety Information ..............................................................................................................................3
Product Features................................................................................................................................................4
Preparing for Installation.....................................................................................................................................5
Air for Combustion & Ventilation.........................................................................................................................6
Installation ........................................................................................................................................................9
Operation .........................................................................................................................................................15
Care and Maintenance .................................................................................................................................19
Troubleshooting .................................................................................................................................20
Replacement Parts.............................................................................................................................22
WARNING: READ THE INSTALLATION & OPERATION INSTRUCTIONS BEFORE USING THIS APPLIANCE.
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, and carbon
monoxide poisoning.
PRODUCT SPECIFICATIONS
TABLE OF CONTENTS
MODEL MD300HGA MD300TGA
Gas Type Natural Only Propane/LP Only Natural Only Propane/LP Only
Input rating (BTU/Hr)
MAX. 30,000 28,000 30,000 28,000
MIN. 15,000 14,000 15,000 14,000
Ignition Electric Piezo Electric Piezo Electric Piezo Electric Piezo
Pressure
Regulator
Setting
4 in. W.C. 9 in. W.C. 4 in. W.C. 9 in. W.C.
Inlet Gas Pressure* (inches of water) *For purpose of input adjustment
Maximum 10.5 in. 14 in. 10.5 in. 14 in.
Minimum 5 in. 11 in. 5 in. 11 in.
Dimensions, Inches (H x W x D)
Heater 23 1/2 x 26 5/8 x 8 23 1/2 x 26 5/8 x 8 23 1/2 x 26 5/8 x 8 23 1/2 x 26 5/8 x 8
Carton 26 1/2 x 28 1/2 x 9 1/4 26 1/2 x 28 1/2 x 9 1/4 26 1/2 x 28 1/2 x 9 1/4 26 1/2 x 28 1/2 x 9 1/4
Weight (Pounds)
Heater 27.6 27.6 29.6 29.6
Shipping 32.6 32.6 34.6 34.6

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IMPORTANT SAFETY INFORMATION
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.
Only a qualied installer, service agent, or local gas supplier may install and service this product.
WARNING: Do not store or use gasoline or other ammable vapors and liquids in the vicinity of this or any
other appliance.
CARBON MONOXIDE POISONING: Early signs of carbon monoxide poisoning resemble the u with headache,
dizziness and/or nausea. If you have these signs, heater may not be working properly. Get fresh air at once!
Have heater serviced. Some people - pregnant women, persons with heart or lung disease, anemia, those
under the inuence of alcohol, those at high altitude - are more affected by carbon monoxide than others.
NATURAL AND PROPANE/LP GAS: Natural and Propane/LP gas are odorless. An odor-producing agent is
added to the gas. The odor helps you detect a gas leak. However, the odor added to the gas can fade. Gas may
be present even though no odor exists.
WARNING: Any change to this heater or its controls can be dangerous.
WARNING: Do not use any accessories not approved for use with this heater.
WARNING: Carefully supervise young children when they are in the room with the heater.
WARNING: Make sure grill guard is in place before running heater.
WARNING: Keep the appliance area clear and free from combustible materials, gasoline, and other am
mable vapors and liquids.
WARNING: Due to high temperatures, the appliance should be located out of trafc and away from furniture
and draperies.
WARNING: Heater becomes very hot when running . Keep children and adults away from hot surfaces to
avoid burns or clothing ignition. Heater will remain hot for a time after shutoff. Allow surfaces to cool before
touching.
WARNING: Do not place clothing or other ammable material on or near the appliance. Never place any
objects in the heater.
1. This appliance is for use with only the type of gas indicated on the rating plate. This appliance is not
convertible for use with other gases.
2. Do not place Propane/LP supply tank(s) inside any structure. Propane/LP supply tank(s) must be Placed
outdoors.
3. This heater shall not be installed in a bedroom or bathroom, or the place which the strong wind would shut down
the appliance.
4. This heater needs fresh air ventilation to run properly. This heater has an Oxygen Depletion Sensing (ODS)
safety shutoff system. The ODS shuts down the heater if not enough fresh air is available. See Air for
Combustion and Ventilation, pages 6 through 8. If heater keeps shutting off, see Troubleshooting, pages 20
through 22.
5. Keep all air openings in front and bottom of heater clear and free of debris. This will ensure enough air for
proper combustion.
IMPORTANT SAFETY INFORMATION

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6. If heater shuts off, do not relight until you have provided fresh, outside air. If heater keeps shutting off, have it
serviced.
7. Do not run heater:
Where ammable liquids or vapors are used or stored.
Under dusty conditions.
8. 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.
9. Always run heater with control knob at PILOT/IGN, LOW or HIGH locked positions. Never set control knob be
tween locked positions. Poor combustion and higher levels of carbon monoxide may result.
10. Do not use heater if any part has been under water. 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 under water.
11.Turn off and unplug heater and let cool before servicing. Only a qualied service person should service and repair
heater.
12. Operating heater above elevations of 4,500 feet could cause pilot outage.
13. To prevent performance problems, do not use propane/LP fuel tank of less than 100 lbs. capacity.
QUALIFIED INSTALLING AGENCY
Only a qualied agency should install and replace gas piping, gas utilization equipment or accessories, and repair and
equipment servicing.The term “qualied agency” means any individual, rm, corporation, or company that either in
person or through a representative is engaged in and is responsible for:
a) Installing, testing, or replacing gas piping or
b) Connecting, installing, testing, repairing, or servicing equipment; that is experienced in such work; that is familiar
with all precautions required; and that has complied with all the requirement of the authority having jurisdiction.
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PRODUCT FEATURES
SAFETY PILOT
This heater has a pilot with an Oxygen Depletion Sensing (ODS) safety shutoff system. The ODS/pilot shuts off the
heater if there is not enough fresh air.
PIEZO IGNITION SYSTEM
Heater is equipped with an electronic piezo control system. This system requires AAA batteries (provided).
2 GAS OPTIONS CAPABLE
Your heater is equipped to operate on either Propane or Natural gas. The heater is shipped from the factory ready for
connecting to Propane. The heater can easily be changed to Natural gas by having your qualied installer follow the
instructions on page 13 and the markings on the heater.
LOCAL CODES
Install and use heater with care. Follow all local codes. In the absence of local codes, use the latest edition of The
National Fuel Gas Code, ANSI Z223.1/ NFPA 54.
*Available from:
American National Standards Institute, lnc.
1430 Broadway
New York, NY 10018
National Fire Protection Association, lnc.
1 Batterymarch Park
Quincy, MA 02269-9101

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State of Massachusetts: The installation must be made by a licensed plumber or gas tter in the Commonwealth
of Massachusetts. Sellers of unvented propane or natural gas-red supplemental room heaters shall provide to
each purchaser a copy of 527 CMR 30 upon sale of the unit.
In the State of Massachusetts, unvented propane or natural gas-red space heaters shall be prohibited in
bedrooms and bathrooms.
In the State of Massachusetts the gas cock must be a T-handle type. The State of Massachusetts requires that
a exible appliance connector cannot exceed three feet in length.
PREPARING FOR INSTALLATION
Before beginning assembly or operation of the product, make sure all parts are present. Compare parts with package
contents list and diagram above. If any part is missing or damaged, do not attempt to assemble, install or operate the
product. Contact customer service for replacement parts.
Before installing heater, make sure you have the items listed below:
piping (check local codes)
sealant (resistant to natural gas and propane/LP gas)
equipment shutoff valve*
test gauge connection*
sediment trap
tee joint
pipe wrench
exible gas hose (check local codes)
* A CSA design-certied equipment shutoff valve with 1/8-inch NPT tap is an acceptable
alternative to test gauge connection. Purchase the optional CSA design-certied
equipment shutoff valve from your dealer.
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WATER VAPOR: A BY-PRODUCT OF UNVENTED ROOM HEATERS
Water vapor is a by-product of gas combustion. An unvented room heater produces approximately one (1) ounce
(30 mL) of water for every 1,000 BTUs (.3 KWs) of gas input per hour. Unvented room heaters are recommended
as supplemental heat (a room) rather than a primary heat source (an entire house). In most supplemental heat
applications, the water vapor does not create a problem. In most applications, the water vapor enhances the low
humidity atmosphere experienced during cold weather.
The following steps will help ensure that water vapor does not become a problem.
1. Be sure the heater is sized properly for the application, including ample combustion air and circulation air.
2. If high humidity is experienced, a dehumidier may be used to help lower the water vapor content of the air.
3. Do not use an unvented room heater as the primary heat source.
UNPACKING
1. Remove heater from carton.
2. Remove all protective packaging applied to heater for shipping
3. Check heater for any shipping damage. If heater is damaged, promptly inform dealer where you bought heater.

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AIR FOR COMBUSTION AND VENTILATION
WARNING: This heater shall not be installed in a conned space or unusually tight construction unless provi
sions are provided for adequate combustion and ventilation air. Read the following instructions to ensure proper
fresh air for this and other fuel-burning appliances in your home.
Providing Adequate Ventilation
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.
The following are excerpts from National Fuel Gas Code, ANSI Z223.1/ NFPA 54. Air for Combustion 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
The information on pages 6 through 8 will help you classify your space and provide adequate ventilation.
Conned and Unconned Space
The National Fuel Gas Code, ANSI Z223.1/NFPA 54 denes a conned space as a space whose volume is less than
50 cu. ft. per 1,000 BTU/hr (4.8 m^3 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/hr (4.8 m^3 per kw) of the
aggregate input rating of all appliances installed in that space. Rooms connecting directly with the space in which the
appliances are installed*, through openings not furnished with doors, are considered a part of the unconned space.
This heater shall not be installed in a conned space or unusually tight construction unless provisions are provided for
adequate combustion and ventilation air.
* Adjoining rooms are connecting only if there are doorless passageways or ventilation grills between them.
Unusually Tight Construction
The air that leaks around doors and windows may provide enough fresh air for combustion and ventilation. However,
in buildings of unusually tight construction, you must provide additional fresh air.
Unusually tight construction is dened as construction where:
Walls and ceilings exposed to the outside atmosphere have a continuous water vapor retarder with a rating of
one perm (6×10-11kg per pa-sec-m2) or less with openings gasketed or sealed and
Weather stripping has been added on openable windows and on doors and
Caulking or sealants are applied to areas such as joints around window and door frames, between sole plates
and oors, between wall ceiling joints, between wall panels, at penetrations for plumbing, electrical, and gas
lines, and at other openings.
If your home meets all of the three criteria above, you must provide additional fresh air. See “Ventilation Air From
Outdoors”. If your home does not meet all of the three criteria above, proceed to “Determining Fresh-Air Flow For
Heater Location”.
a)
b)
c)

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DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
Determining if You Have a Conned or Unconned Space
Use this worksheet to determine if you have a conned or unconned 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 × Width × Height = cu. ft. (volume of space)
Example: Space size 20 ft. (length) × 16 ft. (width)×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)
3. Add the BTU/hr of all fuel burning appliances in the space.
*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)
56,000 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:
Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space,
remove door to adjoining room or add ventilation grills between rooms. See “ Ventilation Air From Inside Building ”
on next page.
Vent room directly to the outdoors. See “ Ventilation Air From Outdoors ” on next page.
c) Install a lower BTU/hr heater if lower BTU/hr size makes room unconned. If the 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.
a)
b)
Example:
Gas water heater 30,000 BTU/hr
Vent-free heater + 26,000 BTU/hr
Total = 56,000 BTU/hr
BTU/hr
BTU/hr
BTU/hr
BTU/hr
BTU/hr
BTU/hr
BTU/hr
Vent-free heater
Gas water heater*
Gas furnace
Vented gas heater
Gas heater logs
Other gas appliances* +
Total =

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Figure 2 - Ventilation Air from Outdoors
Figure 1 - Ventilation Air from Inside Building
NOTE: Base not included. Not for use in
bedrooms or bathrooms.
WARNING: If the area in which the heater
may be operated is smaller than that dened as an
unconned space 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, ANSI Z223.1/NFPA 54. Air for
Combustion and Ventilation, or applicable local codes.
WARNING: If the area in which the heater may be
operated does not meet the required volume for indoor
combustion air, combustion and ventilation air shall
be provided by one of the methods described in the
NATIONAL FUEL GAS CODE, ANSI Z223.1/
NFPA 54, the INTERNATIONAL FUEL GAS CODE, or
applicable local codes.
Ventilation Air From lnside Building
This fresh air would come from an adjoining unconned
space. When ventilating to an adjoining unconned
space, you must provide two permanent openings: one
within 12 inches of the ceiling and one within 12 inches
of the oor on the wall connecting the two spaces
(see options 1 and 2, Figure 1). You can also remove
the door into adjoining room (see option 3, Figure 1).
Follow the National Fuel Gas Code. ANSI Z223.1/
NFPA 54, Air for Combustion and Ventilation for
required size of entilation grills or ducts.
Ventilation Air From Outdoors
Provide extra fresh air by using ventilation grills or
ducts. You must provide two permanent openings: one
within 12 inches of the ceiling and one within 12 inches
of the oor. Connect these items directly to the outdoors
or spaces open to the outdoors. These spaces include
attics and crawl spaces. Follow the National Fuel Gas
Code, ANSI Z223.1/ NFPA 54, Air for Combustion and
Ventilation for required size of ventilation grills or ducts.
IMPORTANT: Do not provide openings for inlet or
outlet air into attic if attic has a thermostat-controlled
power vent. Heated air entering the attic will activate
the power vent. Rework worksheet, adding the space of
the adjoining unconned space. The combined spaces
must have enough fresh air to supply all appliances in
both spaces.

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Figure 3 - Mouting clearances as viewed from
front of heater (inches)
NOTICE: This heater is intended for 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.
CAUTION: If you install the heater in a home garage:
Heater pilot and burner must be at least 18 inches above the oor.
Place heater where moving vehicle will not hit it.
WARNING: A qualied service person must install heater. Follow all local codes.
WARNING: Never install the heater
in a bedroom or bathroom
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
in high trafc areas
in windy or drafty areas
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INSTALLATION
CAUTION: This heater creates warm air currents. These currents move heat to wall surfaces next to heater.
Installing heater next to vinyl or cloth wall coverings or operating heater where impurities (such as tobacco
smoke, aromatic candles, cleaning uids, oil or kerosene lamps, etc.) in the air exist, may cause walls to discolor.
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 too much moisture. See Air for Combustion and
Ventilation, pages 6 through 8.
Check Gas Type
Be sure your gas supply is right for your heater.
Otherwise, call dealer where you bought the
heater for proper type heater.
Clearances To Combustibles
Carefully follow the instructions below. This
heater is a freestanding unit designed to be
mounted on a wall or set directly on the oor.
WARNING: Maintain the minimum clearances
shown in Figure 3. If you can, provide greater
clearances from oor, ceiling, and joining wall.

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Figure 4 - Mounting Bracket Location
LOCATING HEATER
This heater is designed to be mounted on a wall. For convenience and
efciency, install heater:
1) where there is easy access for operation, inspection, and service.
2) In the coldest part of room.
FASTENING HEATER TO WALL
Mounting Bracket
The mounting bracket is located on back panel of heater (see Figure 4).
It has been taped there for shipping. Remove mounting bracket from
back panel.
Removing Front Panel of Heater
1. Remove two screws near bottom corners of lower front panel .
2. Pull bottom of lower front panel forward, then down (see Figure 5).
Methods For Attaching Mounting Bracket To Wall
Use only the last hole on each end of mounting bracket to attach bracket
to wall. Attach mounting bracket to a wall only in one of two ways:
1. Attaching to wall stud: This method provides the strongest hold.
Insert mounting screws through mounting bracket and into wall studs.
2. Attaching to wall anchor: This method allows you to attach mounting
bracket to hollow walls (wall areas between studs) or to solid walls
(concrete or masonry).
3. Decide which method better suits your needs. Either method will provide
a secure hold for the mounting bracket.
Marking Screw Locations
1. Tape mounting bracket to wall where heater will be located. Make sure mounting bracket is level.
WARNING: Maintain minimum clearances shown in Figure 3. If you can, provide greater clearances from oor
and joining wall.
2. Mark screw locations on wall (see Figure 6).
Note: Mark only last hole on each end of mounting bracket. Insert mounting screws through these holes only.
3. Remove tape and mounting bracket from wall.
Attaching Mounting Bracket To Wall
Note: Wall anchors, mounting screws, and spacers are in hardware package. The hardware package is provided with
heater.
Attaching to Wall Stud Method
For attaching mounting bracket to wall studs:
1. Drill holes at marked locations using 9/64-inch drill bit.
2. Place mounting bracket onto wall. Line up last hole on
each end of bracket with holes 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. Figure 6 - Mounting Bracket
Clearances (inches)
Figure 5 - Mounting Bracket
Clearances (inches)

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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-inch drill bit. For solid
walls (concrete or masonry), drill at least 1 inch deep.
2. Fold wall anchor as shown in Figure 7.
3. Insert wall anchor (wings rst) into hole. Tap anchor ush to
wall.
4. For thin walls (1/2 inch or less), insert red key into wall anchor.
Push red key to “pop” open anchor wings (see Figure 8).
IMPORTANT: Do not hammer anchor key! For thick walls (over
1/2 inch thick) or solid walls, do not pop open wings.
5. Place mounting bracket onto wall. Line up last hole 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 panel of heater (see Figure
9).
2. Place heater onto mounting bracket. Slide horizontal slots onto
stand-out tabs on mounting bracket.
Installing Bottom Mounting Bracket
1. Install bottom bracket to heater bottom with two screws. It may
be more convenient to remove heater from wall bracket to
attach.
2. Place heater on wall mounting bracket.
3. Mark screw locations on wall.
4. Remove heater from mounting bracket.
5. If installing bottom mounting screws into hollow or solid wall,
install wall anchors. Follow steps 1 through 4 under “Attaching
To Wall Anchor Method”. If installing bottom mounting screw into
wall stud, drill holes at marked locations using 9/64-inch drill bit.
6. Replace heater onto mounting bracket.
7. Tighten both screws until heater is rmly secured to wall. Do not
over-tighten.
Figure 7 - Folding Anchor
Figure 8 - Popping Open
Anchor Wing For Thin Walls
Figure 9 - Mounting Heater
Onto Mounting Bracket
Figure 10 - Installing Bottom
Mounting Bracket

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WARNING: A qualied service technician must connect heater to gas supply. Follow all local codes.
WARNING: This appliance requires a 3/8-inch NPT (National Pipe Thread) inlet connection to the pressure
regulator.
WARNING: Never connect heater to private (non-utility) gas wells. This gas is commonly known as wellhead gas.
WARNING: Do not over-tighten gas connections.
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 1/2-in. diameter or greater to allow proper gas volume to heater. If pipe is
too small, undue loss of pressure will occur.
NATURAL GAS MODELS:
CAUTION: Check your gas line pressure before connecting heater to gas line. Gas line pressure must be no
greater than 10.5 inches of water. If gas line pressure is higher, heater regulator damage could occur.
PROPANE MODELS:
CAUTION: Never connect heater directly to the gas supply. This heater requires an external regulator (not
supplied). Install the external regulator between the heater and gas supply.
CAUTION: Avoid damage to regulator. Hold gas regulator with wrench when connecting into gas piping and/or
ttings.
CAUTION: Use pipe joint sealant that is resistant to gas (Propane or Natural Gas).
CONNECTING TO GAS SUPPLY
Figure 11 - Gas Connection (inches)
* Purchase the optional CSA design-certied equipment shutoff valve from your dealer.
Typical Inlet Pipe Diameters Use 3/8-inch black iron pipe or greater. Installation must include
an equipment shutoff valve, union, and plugged 1/8-inch NPT tap. Locate NPT tap within reach for test gauge
hook up. NPT tap must be upstream from heater (see Figure 11).
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.

1313
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 valves.
The installer must supply an external regulator. The external regulator will reduce
incoming gas pressure. You must reduce incoming gas pressure to between 11 and
14 inches of water. If you do not reduce incoming gas pressure, heater regulator
damage could occur. Install external regulator with the vent pointing down as shown
in Figure 12. Pointing the vent down protects it from freezing rain or sleet.
Install sediment trap in supply line as shown in Figure 11. Place sediment trap
where it is within reach for cleaning. Place sediment trap where trapped matter 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.
Figure 12 - External Regulator with
Vent Pointing Down
Continued
INSTALLATION
CAUTION: Two gas line installation at the same time is forbidden. Do not the open cover while the heater is
running.
Heater is pre-set at factory for propane gas; no changes are required for connecting to propane. Only a qualied installer
or service technician can perform gas selection and connecting to gas supply.
CAUTION: To avoid gas leakage at the inlet of regulator, a qualied installer or service technician must use
steel or metal hex plug with sealant.
For changing from propane to natural gas supply:
1. Remove top screw from cover plate, See Figure 13, and rotate to expose gas selection valve.
2. For NATURAL GAS, press knob using a at screwdriver with a blade with thickness of a quarter and turn knob
counterclockwise until the knob locks into the NG position (see Figure 14). Selection valve must be locked in
the NG position. Do not operate heater between locked positions!
3. Rotate and close cover over gas selection valve and reinstall screw.
4. Remove steel or metal hex plug (with wrench provided) from natural gas inlet of regulator and install into LP inlet of
regulator; use thread sealant to ensure that there are no leaks.
For changing from natural gas supply to propane supply:
1. Remove top screw from cover plate, See Figure 13, and rotate to expose gas selection valve.
2. For propane gas, press in knob using a flat screwdriver with a blade the thickness of a quarter and turn knob
clockwise until the knob locks into the LP position, see Figure 15. Selection valve must be locked in the LP
position. Do not operate heater between locked positions.
3. Rotate and close cover over gas selection valve and reinstall screw.
4. Remove steel or metal hex plug from liquid propane inlet of regulator and install into NG inlet of regulator; use
thread sealant to assure there are no leaks.

1414
CHECKING GAS CONNECTIONS
Figure 16 - Equipment Shutoff Valve
Figure 17 - Fuel Supply
Figure 13 Figure 14 Figure 15
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 leak. Apply a mixture of liquid soap and water to all joints. If
bubbles form, there is a leak. Correct all leaks at once.
PRESSURE TESTING GAS SUPPLY PIPING SYSTEM
Test Pressures In Excess Of 1/2 PSIG (3.5kPa)
1. Disconnect heater with its appliance main gas valve (control valve) and equipment 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 equipment shutoff valve was connected.
3. Pressurize supply piping system by either using compressed air or opening
gas supply valve.
4. Check all joints of gas supply piping system. Apply mixture of liquid soap
and water to gas joints. If bubbles form, there may be a leak.
5. Correct all leaks at once.
6. Reconnect heater and equipment shutoff valve to gas suply. Check
reconnected ttings for leaks.
Test Pressures Equal To or Less Than 1/2 PSIG (3.5 kPa)
1. Close equipment shutoff valve (see Figure 16).
2. Pressurize supply piping system by either using compressed air or
opening natural supply tank valve.
3. Check all joints from gas meter to equipment shutoff valve
(see Figure 17).
Apply mixture of liquid soap and water to gas joints. If bubbles
form, there is a leak.
4. Correct all leaks at once.

1515
Pressure Testing Heater Gas Connections
1. Open equipment shutoff valve (see Figure 16).
2. Open gas supply tank valve.
3. Make sure control knob of heater is in the OFF position.
4. Remove front panel.
5. Check all joints from equipment shutoff valve to control valve (see Figure 17). Apply mixture of liquid soap and
water to gas joints. If bubbles form, there may be a leak.
6. Correct all leaks at once.
7. Light heater (see Lighting Instructions on page 16). Check all other internal joints for leaks.
8. Turn off heater (see “To Turn Off Gas Appliance” on page 16).
9. Replace lower front panel.
OPERATION
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.
When lighting the pilot, follow these instructions exactly.
BEFORE LIGHTING, smell all around the appliance area for gas. Be sure to smell next to the oor because
some gas is heavier than air and will settle on the oor.
Use only your hand to push in or turn the gas control knob. Never use tools. If the knob will not push in or turn
by hand, don’t try to repair it, call a qualied service technician or gas supplier. Forced or attempted repair may
result in a re or explosion.
Do not use this appliance if any part has been under water. Immediately call a qualied service technician to
inspect the appliance and to replace any part of the control system and any gas control which has been under
water.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance.
Do not touch any electric switch, do not use any phone in your building.
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.
A.
B.
C.
D.
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1616
LIGHTING INSTRUCTIONS
FOR MD300HGA
1. STOP! Read the safety information on other side of this plate and on front and back of on Warning plate.
2. Make sure manual shutoff valve is fully open.
3. Turn control knob clockwise to the OFF position.
4. Wait ve(5) minutes to clear out any gas. Then smell for gas around heater and near oor. If you smell gas,
STOP! Follow "B" in the safety information on Warnings plate. If you don't smell gas, go to the next step.
5. Turn control knob counterclockwise to the PILOT position. Keep control knob for ve (5) seconds (see
Figure 19).
Note: You may be running this heater for the rst time after hooking up to gas supply. If so, the control knob
may need to be pressed in for 30 seconds. This will allow air to escape from the gas system.
If control knob does not pop up when released, contact a qualied service person or gas supplier for repairs.
6. With control knob pressed in, push and hold in ignitor button. This will light pilot. The pilot is attached to the
front of the front burner (see gure 18). If needed, keep holding in ignitor button until pilot lights.
Note: If pilot does not stay lit, contact a qualied service person or gas supplier for repairs. Until repairs are
made, light pilot with match.
7. Keep control knob pressed in for 30 seconds after lighting pilot. After 30 seconds, release control knob.
Note: If pilot goes out, repeat steps 4 through 8. This heater has a safety interlock system. Wait one (1) minute
before lighting pilot again.
8. Turn control knob counterclockwise to the desired heating level. The main burner should light. Set control
knob to any heat level between HI and LO.
TO TURN OFF GAS TO APPLIANCE
Shutting Off Heater
Turn control knob clockwise to the OFF position.
Shutting Off Burner Only (pilot stays lit )
Turn control knob clockwise to the PILOT position.
Figure 18 Control knob in the OFF position
Figure 19 pilot
MANUAL LIGHTING
PROCEDURE
1. Remove lower front panel (gure 6 page 10).
2. Follow steps 1 through 5 under Lighting Instructions.
3. With control knob pressed in, strike mach. Hold
match to pilot until pilot lights.
4. Keep control knob pressed in for 30 sectonds after
lighting pilot. After 30 seconds, release control knob.
Follow step 8 under Lighting Instructions.
5. Replace Lower front panel.

1717
LIGHTING INSTRUCTIONS
FOR MD300TGA
Unscrew ignitor cap and install a AAA battery with the + pointing out. Replace cap.
1. STOP! Read the safety information on the side of the heater.
2. Make sure equipment shutoff valve is fully open.
3. Turn control knob clockwise to the OFF position.
4. Wait ve (5) minutes to clear out any gas. Then smell for gas, including near the oor. If you smell gas, STOP! Do
not try to light any appliance. Do not touch electrical switch or use any phone in the building. Immediately contact
gas supplier from a neighbor’s phone. Follow gas supplier’s instructions. If you can’t reach the gas supplier, call the
re dept. If you don’t smell gas, go to the next step.
5. Turn control knob counterclockwise to the PILOT position.Press in control knob for ve (5) seconds (see Figure
19).
Note: The rst time that the heater is operated after connecting the gas supply,the control knob should be depressed
for about thirty (30) seconds.This will allow air to bleed from the gas sysystem. If pilot does not stay lit, refer to
Troubleshooting, pages 20 through 22. Also contact a qualied service technician or gas supplier for repairs. Until
repairs are made, light pilot with match.
• If control knob does not pop up when released, contact a qualied service technician or gas supplier for repairs.
6. With control knob pressed in, push down and release ignitor button. This will light pilot. The pilot is attached to
the front of burner. The pilot can be seen through the gill. If needed, keep pressing ignitor button until pilot lights.
Note: If pilot does not stay lit, refer to Troubleshooting, pages 20 through 22. Also contact a qualified service
technician or gas supplier for repairs. Until repairs are made, light pilot with match. To light pilot with match, see “Manual
Lighting Procedure”.
7. Keep control knob pressed in for 30 seconds after lighting pilot. After 30 seconds, release control knob.
If control knob does not pop up when released, contact a qualied service technician or gas supplier for repairs.
Note: If pilot goes out, repeat steps 3 through 7. This heater has a safety interlock system. Wait one (1) minute
before lighting pilot again.
8. Turn control knob counterclockwise to desired heating level. The main burner should light. Set control knob to
any heat level between 1 and 5.
CAUTION: Do not try to adjust heating levels by using the equipment shutoff valve.
THERMOSTAT CONTROL OPERATION
The thermostatic control used on this model differs from standard thermostats.
Standard thermostats simply turn the burner on and off. The thermostat
used on this heater senses the room temperature. At times the room may
exceed the set temperature. If so, the burner will shut off. The burner will
cycle back on when room temperature drops below the set temperature.
The control knob can be set to any comfort level between 1 and 5.
TO TURN OFF GAS TO APPLIANCE
Shutting Off Heater
Turn control knob clockwise to the OFF position.
Shutting Off Burner Only (pilot stays lit )
Turn control knob clockwise to the PILOT position.
Figure 20 - Control Knob in the
OFF Position

1818
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 a incorrect pilot ame pattern. The incorrect pilot
ame is not touching the thermocouple. This will cause the thermocouple to cool, which shuts the heater off. If
pilot ame pattern is incorrect:
turn heater off (see “To Turn Off Gas to Appliance” on page 16)
see Troubleshooting pages 20 through 22.
WARNING: If yellow tipping occurs, your heater could produce increased levels of carbon monoxide. If
burner ame pattern shows yellow tipping, follow instructions at bottom of this page.
Notice: Do not mistake orange ames with yellow tipping. Dirt or other ne particles enter the heater and burn
causing brief patches of orange ame.
BURNER FLAME PATTERN
Figure 23 shows a correct burner ame pattern. Figure 24 shows an incorrect burner ame pattern. If burner
ame pattern is incorrect then:
turn heater off (see “To Turn Off Gas to Appliance” on page 16).
see Troubleshooting, pages 20 through 22.
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Figure 21 - Correct Pilot Flame Pattern Figure 22 - Incorrect Pilot Flame Pattern
Figure 23 - Correct Burner Flame Pattern Figure 24 - Incorrect Burner Flame Pattern

1919
CARE AND MAINTENANCE
WARNING: Turn off heater and let cool before servicing
CAUTION: You must keep control areas, burner, and circulating air passageways of heater clean. Inspect
these areas of heater before each use. Have heater inspected yearly by a qualied service technician. Heater
may need more frequent cleaning due to excessive lint from carpeting, bedding material, pet hair, etc.
ODS/PILOT AND BURNER
Use a vacuum cleaner, pressurized air, or a small, soft bristled brush to clean.
CLEANING BURNER PILOT AIR INLET HOLE
We recommend that you clean the unit every 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 PSl. Your local computer store, hardware store, or home center may carry
compressed air in a can. You can use a vacuum cleaner in the blow position. If 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 pilot assembly.
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 ports/slots and holes in the burner. Also clean the pilot assembly. A yellow tip on the pilot
ame indicates dust and dirt in the pilot assembly. There is a small pilot air inlet hole about two inches from
where the pilot ame comes out of the pilot assembly (see Figure 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.
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.
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Figure 25 - Pilot Inlet Air Hole

2020
PROBLEM
When ignitor button is
pressed in there is no spark
at ODS/pilot.
When ignitor button is
pressed in there is a spark
at ODS/pilot but no ignition.
ODS/pilot lights but ame
goes out when control
knob is released.
POSSIBLE CAUSE
1. Ignitor electrode is positioned wrong or
broken.
2. Ignitor electrode is not connected to
ignitor cable.
3. Ignitor cable is pinched or wet.
4. Broken ignitor cable.
5. Bad piezo ignitor.
1. Gas supply is turned off or equipment
shutoff valve is closed.
2. Control knob not fully pressed in while
pressing ignitor button.
3. Air in gas lines when installed.
4. ODS/pilot is clogged.
5. Gas regulator setting is not correct.
6. Control knob not in PILOT position.
7. Depleted gas supply (propane).
1. Control knob is not fully pressed in.
2. Control knob is not pressed in long
enough.
3. Equipment shutoff valve is not
fully open.
4. Thermocouple connection is loose
at control valve.
5. Thermocouple damaged.
6. Control valve damaged.
REMEDY
1. Replace ignitor.
2. Reconnect ignitor cable.
3. Free ignitor cable if pinched by any metal
or tubing. Keep ignitor cable dry.
4. Replace ignitor cable.
5. Replace piezo ignitor.
1. Turn on gas supply or open equipment
shutoff valve.
2. Fully press in control knob while pressing
ignitor button.
3. Continue holding down control knob.
Repeat igniting operation until air is
removed.
4. Clean ODS/pilot (see Care and
Maintenance, page 19) or replace ODS/
pilot assembly.
5. Replace gas regulator.
6. Turn control knob to PILOT position.
7. Contact local propane/LP gas company.
1. Press in control knob fully.
2. After ODS/pilot lights, keep control knob
pressed in 30 seconds.
3. Fully open equipment shutoff valve
4. Hand tighten until snug, and then tighten
1/4 turn more.
5. Replace thermocouple.
6. Contact customer service.
TROUBLESHOOTING
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 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.
IMPORTANT: Operating heater where impurities in air exist may create odors. Cleaning supplies, paint, paint re-
mover, cigarette smoke, cements and glues, new carpet or textiles, etc., create fumes. These fumes may mix with
combustion air and create odors.
WARNING: Only a qualied service technician should service and repair heater.
CAUTION: Never use a wire, needle, or similar object to clean ODS/pilot. This can damage ODS/ pilot unit.
Note: All troubleshooting items are listed in order of operation.
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