Vanguard VMH3000TNA Quick start guide

Save this manual for future reference.
OWNER’S OPERATION AND INSTALLATION MANUAL
VENT-FREE NATURAL GAS
MINI-HEARTH®HEATER
VMH3000TNA
15,000 to 30,000 Btu/Hr
with Thermostat
WARNING:Iftheinformationinthismanualisnot
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’sphone.Followthegassupplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
— Installation and service must be performed
byaqualifiedinstaller,serviceagency,orthe
gas supplier.
WARNING:Improperinstalla-
tion, adjustment, alteration,
service, or maintenance can
causeinjuryorpropertydam-
age. Refer to this manual for
correct installation and op-
erational procedures. For as-
sistance or additional infor-
mation consult a qualified in-
staller,serviceagency,orthe
gas supplier.
WARNING:Thisisanunvented
gas-fired heater. It uses air
(oxygen) from the room in
whichitisinstalled.Provisions
for adequate combustion and
ventilation air must be pro-
vided. Refer to Air For Com-
bustion and Ventilation sec-
tion on page 5 of this manual.
®
Shown with Optional
Mantel Which Features
a Built-In Base
This appliance may be installed in an aftermarket*, permanently located, manufactured
(mobile) home, where not prohibited by local codes.
Thisapplianceisonlyforusewiththetypeofgasindicatedontheratingplate.Thisappliance
is not convertible for use with other gases.
*Aftermarket: Completion of sale, not for purpose of resale, from the manufacturer

2
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
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,ANSZ223.1,alsoknownasNFPA54*.
*Available from:
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
SAFETY
INFORMATION
WARNINGS
IMPORTANT: Read this owner’s
manual carefully and completely
before trying to assemble, oper-
ate, or service this heater. Im-
properuseofthisheatercancause
seriousinjuryordeathfromburns,
fire, explosion, electrical shock,
and carbon monoxide poisoning.
DANGER: Carbon monoxide
poisoning may lead to death!
WARNING: Any change to
this heater or its controls can be
dangerous.
CarbonMonoxidePoisoning:Earlysignsof
carbon monoxide poisoning resemble the flu,
with headaches, dizziness, or nausea. If you
have these signs, the heater may not be work-
ing properly. Get fresh air at once! Have
heater serviced. Some people are more af-
fectedbycarbonmonoxidethanothers.These
includepregnantwomen,peoplewithheartor
lung disease or anemia, those under the influ-
ence of alcohol, and those at high altitudes.
Natural Gas: Natural gas is odorless. An
odor-making agent is added to natural gas.
Theodorhelpsyoudetectanaturalgasleak.
However, the odor added to natural gas can
fade.Naturalgasmaybepresenteventhough
no odor exists.
Make certain you read and understand all
warnings.Keepthismanualforreference.It
isyourguidetosafeandproperoperationof
this heater.
1. This appliance is only for use with the
typeof gas indicatedon the ratingplate.
Thisappliance is notconvertible for use
with other gases.
2. If you smell gas
• shut off gas supply
• do not try to light any appliance
• do not touch any electrical switch; do
not use any phone in your building.
• immediately call your gas supplier
from a neighbor’s phone. Follow the
gas supplier’s instructions
• ifyou cannot reachyour gas supplier,
call the fire department
WARNING: Do not use a
blower insert, heat exchanger
insert, or other accessory not
approvedforusewiththisheater.
3. This heater shall not be installed in a
bedroom or bathroom.
4. This heater needsfresh, outside air ven-
tilation to run properly.This heater has
an Oxygen Depletion Sensing (ODS)
safety shutoff system. The ODS shuts
down the heater if not enough fresh air
is available. See Air For Combustion
and Ventilation, pages 5 through 7.
5. Before using furniture polish, wax, car-
pet cleaner, or similar products, turn
heater off. If heated, the vapors from
theseproducts maycreate awhite pow-
der residue within burner box or on
adjacent walls or furniture.
6. If heater shuts off, do not relight until
you provide fresh, outside air. If heater
keeps shutting off, have it serviced.
7. Do not run heater
• where flammable liquids or vapors
are used or stored.
• under dusty conditions.
8. Do not use heater if any part has been
under water. Immediately call a quali-
fied service technician to inspect the
room heater and to replace any part of
the control system and any gas control
which has been under water.
9. To prevent the creation of soot, follow
the instructions in Cleaning and Main-
tenance, page 19.
10. Turn off and unplug heater and let cool
beforeservicing.Only aqualifiedservice
person should service and repair heater.
11. Operating heater above elevations of
4,500 feet could cause pilot outage.
WARNING: Do not allow fans
to blow directly into the heater.
Avoidanydraftsthatalterburner
flame patterns. Ceiling fans can
create drafts that alter burner
flame patterns. Altered burner
patterns can cause sooting.
Do not place clothing or other
flammable material on or near
the appliance. Never place any
objects on the heater.
Carefully supervise young chil-
drenwhentheyareinsameroom
with heater.
Keeptheapplianceareaclearand
free from combustible materials,
gasoline, and other flammable
vapors and liquids.
Due to high temperatures, the
appliance should be located out
oftraffic and away from furniture
and draperies.
Surface of heater becomes very
hot when running heater. Keep
children and adults away from
hot surfaces to avoid burns or
clothing ignition. Fireplace will
remain hot for a time after shut-
down. Allow surfaces to cool be-
fore touching.
Make sure screen is in place be-
fore running heater.

3
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
PRODUCT
FEATURES
SAFETY DEVICE
This heater has a pilot with an Oxygen
Depletion Sensing (ODS) safety shutoff
system. The ODS/pilot is a required feature
for vent-free room heaters. The ODS/pilot
shuts off the heater if there is not enough
fresh air.
PIEZO IGNITION SYSTEM
This heater has a piezo ignitor. This system
requires no matches, batteries, or other
sources to light heater.
THERMOSTATIC HEAT
CONTROL
This heater has a thermostat sensing bulb
andacontrolvalve.Thisresultsinthegreat-
est heater comfort. This can also result in
lower gas bills.
PRODUCT
IDENTIFICATION
Figure 1 - Vent-Free Gas Log Propane/LP Gas Space Heater
1. Remove heater from carton.
2. Remove all protective packaging ap-
plied to heater for shipment.
3. Make sure your heater includes two
hardware packets.
4. Check heater for any shipping damage.
If heater is damaged, promptly inform
dealer where you bought heater.
ASSEMBLY
ASSEMBLING HEATER
Tools Required:
• Phillips screwdriver
• 5/16" hex wrench
• slotted screwdriver
Removing Front Panel Of Heater
1. Remove two screws near bottom cor-
ners of front panel with Phillips screw-
driver.
2. Pull bottom offront panel forward,then
down (see Figure 2) .
Figure2-RemovingFrontPanelofHeater
Continued
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'ASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
SDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'ASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'ASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
SDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'ASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
ASDFKIGLFJIalskdidkoemkgo dkirlnfgpd'fASDFKIGLFJI alskdidkoemkgo dkirlnfgpd'f
Ignitor Button
Screen
Front
Panel
Heater
Cabinet
Log
Lighting and
Warning Plates
Control Knob
Installing Hood
1. Remove hood from protective tray.
2. Locate 4 black sheet metal screws in-
side hardware pack.
3. Place hood on deflector and line up
holes (see Figure 3, page 4).
4. Secure hood to deflector with 4 black
sheet metal screws.
Note: Sideofhood should beontheoutside
flange of deflector.
Installing Log
Note: For easier installation, lay heater on
its back.
1. With Phillips screwdriver, remove two
screwsholdingscreen in place. Remove
screen.
2. Remove log from inside of deflector.
Discard protective packaging.
3. Gently slide log between log retaining
brackets on deflector assembly (see Fig-
ure 3, page 4). The log should fit firmly
against bottom of log retaining brackets.
4. Reattach screen using two screws re-
moved in step 1.
Note: Do not remove
Lighting and Warning
Plates from heater
UNPACKING
CAUTION: Do notremovethe
metal data plates attached to the
heater base assembly. The data
platescontainimportantwarranty
information.

4
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
Truss-Head
Screw
Nut
Front Panel
Figure 4 - Attaching Brass Front Trim to
Front Panel
Brass Front
Trim
Figure 3 - Assembling Heater
Side Brass
Trim
Top Brass
Trim
Slot
Mitered Edge
Slot
Set
Screws
Adjusting
Plate
Screws
Assembled
Brass Trim
Shim
Assembling and Attaching
Brass Trim
1. Remove packaging from remaining
three pieces of brass trim.
2. Locate four brass screws, two adjust-
ing plates with set screws, and two
shims in the hardware packet.
3. Align shim under adjusting plate as
shown in Figure 4.
4. Slide one end of adjusting plate/shim
inslot onmitered edge of top brasstrim
(see Figure 5).
5. Slide other end of adjusting plate/shim
in slot on mitered edge of side brass
trim (see Figure 5).
6. While firmly holding edges of brass
trim together, tighten both set screws
on the adjusting plate with slotted
screwdriver.
7. Repeat steps 1 through 6 for other side.
8. Place the assembled trim on front of
heater cabinet.Attach on top and sides
withfour brass screws includedin hard-
ware package (see Figure 6).
9. Reattach front panel to heater if youare
going to mount the heater to the base.
Do not reattach front panel at this time
ifyou are goingto mount heaterto wall.
Figure 5 - Assembling Brass Trim
Figure6 -Attaching Brass Trim to Heater
Attaching Brass Front Trim to
Front Panel
1. Locate brass front trim in brass trim
package.
2. Slide the head of two truss-head screws
from hardware packet into each end of
brass front trim (see Figure 4).
3. Line up screwswith holes infrontpanel
(see Figure 3). Insert screws in holes.
Attach nuts from inside of front panel.
Tighten with wrench.
ASSEMBLY
Continued
WARNING: Always have
burnershieldandscreeninplace
beforeoperatingheater.Thispre-
ventsexcessivetemperatureson
heater surfaces.
Failure to position the parts in
accordance with these diagrams
or failure to use only parts spe-
cificallyapprovedwiththisheater
mayresultinpropertydamageor
personal injury.
Log
Retaining
Brackets
Burner Shield
Screen
Front Panel
Deflector
Log
Truss-
Head
Screw
Brass Front Trim
Screw
Screw
Heater
Cabinet
Nut
Hood
Sheet Metal
Screw

5
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
Today’s homes are built more energy effi-
cient than ever. New materials, increased
insulation, and new construction methods
helpreduceheatlossinhomes.Homeowners
weatherstripandcaulkaroundwindowsand
doorstokeepthecoldairoutandthewarmair
in. During heating months, home owners
want their homes as airtight as possible.
While it is good to make your home energy
efficient,yourhomeneedstobreathe.Fresh
air must enter your home. All fuel-burning
appliances need fresh air for proper com-
bustion and ventilation.
Exhaustfans,fireplaces,clothesdryers,and
fuel burning appliances draw air from the
house to operate. You must provide ad-
equate fresh air for these appliances. This
will insure proper venting of vented fuel-
burning appliances.
PROVIDING ADEQUATE
VENTILATION
The following are excerpts from National
Fuel Gas Code, NFPA 54/ANS Z223.1, Sec-
tion5.3,AirforCombustionandVentilation.
Allspacesinhomesfallintooneofthethree
following ventilation classifications:
1. Unusually Tight Construction
2. Unconfined Space
3. Confined Space
The information on pages 5 through 7 will
help you classify your space and provide
adequate ventilation.
Unusually Tight Construction
The air that leaks around doors and win-
dows may provide enough fresh air for
combustion and ventilation. However, in
buildings of unusually tight construction,
you must provide additional fresh air.
Unusually tight construction is de-
fined as construction where:
a. walls and ceilings exposed to the
outside atmosphere have a con-
tinuous water vapor retarder with
a rating of one perm (6x10-11 kg
per pa-sec-m2) or less with open-
ings gasketed or sealed and
b. weather stripping has been
added on openable windows and
doors and
c. caulking or sealants are applied
to areas such as joints around
window and door frames, be-
tween sole plates and floors,be-
tween wall-ceiling joints, be-
tween wall panels, at penetra-
tionsforplumbing,electrical,and
gas lines, and at other openings.
If your home meets all of the three
criteria above, you must provide ad-
ditional fresh air. See Ventilation Air
From Outdoors , page 7 .
If your home does not meet all of the
threecriteriaabove,proceedto Deter-
mining Fresh-Air Flow For Heater Lo-
cation , page 6.
Confined and Unconfined Space
The National Fuel Gas Code, ANS Z223.1
defines a confined space as a space whose
volume is less than 50 cubic feet per 1,000
Btu per hour (4.8 m3per kw) of the aggre-
gate input rating of all appliances installed
in that space and an unconfined space as a
space whose volume is not less than 50
cubicfeetper1,000Btuperhour(4.8m3per
kw) of the aggregate input rating of all
appliances installed in that space. Rooms
communicating directly with the space in
whichtheappliancesareinstalled*,through
openings not furnished with doors, are con-
sidered a part of the unconfined space.
This heater shall not be installed in a con-
fined space or unusually tight construction
unlessprovisions are provided foradequate
combustion and ventilation air.
*Adjoiningroomsarecommunicatingonly
iftherearedoorlesspassagewaysorventila-
tion grills between them.
AIR FOR
COMBUSTION AND
VENTILATION
WARNING: This heater shall
notbeinstalledinaconfinedspace
or unusually tight construction
unless provisions are provided
foradequatecombustionandven-
tilation air. Read the following in-
structions to insure proper fresh
air for this and other fuel-burning
appliances in your home.
Continued

6
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
Determining if You Have a Confined or Unconfined Space
Use this worksheet to determine if you have a confined or unconfined space.
Space:Includestheroominwhichyouwillinstallheaterplusanyadjoiningroomswithdoorlesspassagewaysorventilationgrillsbetween
the rooms.
1. Determine the volume of the space (length x width x height).
Length x Width x Height = _________________cu. ft. (volume of space)
Example: Space size 20 ft. (length) x 16 ft. (width) x 8 ft. (ceiling height) = 2560 cu. ft. (volume of space)
If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms to the total volume of
the space.
2. Divide the space volume by 50 cubic feet to determine the maximum Btu/Hr the space can support.
_____________________(volume of space) ÷50 cu. ft. = (Maximum Btu/Hr the space can support)
Example: 2560 cu. ft. (volume of space) ÷50 cu. ft. = 51.2 or 51,200 (maximum Btu/Hr the space can support)
3. Add the Btu/Hr of all fuel burning appliances in the space.
Vent-free heater ___________________Btu/Hr
Gas water heater* ___________________Btu/Hr
Gas furnace ___________________Btu/Hr
Vented gas heater ___________________Btu/Hr
Gas fireplace logs ___________________Btu/Hr
Other gas appliances*+ ___________________Btu/Hr
Total = ___________________Btu/Hr
* Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors.
4. Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used.
_________________ Btu/Hr (maximum the space can support)
_________________ Btu/Hr (actual amount of Btu/Hr used)
Example: 51,200 Btu/Hr (maximum the space can support)
60,000 Btu/Hr (actual amount of Btu/Hr used)
ThespaceintheaboveexampleisaconfinedspacebecausetheactualBtu/HrusedismorethanthemaximumBtu/Hrthespacecansupport.
You must provide additional fresh air. Your options are as follows:
A. Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined space, remove door to adjoin-
ing room or add ventilation grills between rooms. See Ventilation Air From Inside Building, page 7.
B. Vent room directly to the outdoors. See Ventilation Air From Outdoors, page 7.
C. Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.
If the actual Btu/Hr used is less than the maximum Btu/Hr the space can support, the space is an unconfined space. You will need no
additional fresh air ventilation.
AIR FOR
COMBUSTION AND
VENTILATION
Continued
Example:
Gas water heater 30,000 Btu/Hr
Vent-free heater + 30,000 Btu/Hr
Total = 60,000 Btu/Hr
WARNING:Iftheareainwhichtheheatermaybeoperatedissmallerthanthatdefinedasanunconfinedspace
or if the building is of unusually tight construction, provide adequate combustion and ventilation air by one of
the methods described in the National Fuel Gas Code, ANS Z223.1, Section 5.3 or applicable local codes.

7
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
VENTILATION AIR
Ventilation Air From Inside
Building
Thisfreshairwouldcomefromanadjoining
unconfined space. When ventilating to an
adjoining unconfined space, you must pro-
vide two permanent openings: one within
12" of the ceiling and one within 12" of the
floor on the wall connecting the two spaces
(seeoptions1and2,Figure7).Youcanalso
remove door into adjoining room (see op-
tion 3, Figure 7). Follow the National Fuel
Gas Code, NFPA 54/ANS Z223.1, Section
5.3, Air for Combustion and Ventilation for
required size of ventilation grills or ducts.
Or
Remove
Door into
Adjoining
Room,
Option 3
Ventilation Grills
Into Adjoining Room,
Option 2
12"
12"
Ventilation
Grills
into Adjoining
Room,
Option 1
Figure 7 - Ventilation Air from Inside Building
Outlet
Air Ventilated
Attic
Outlet
Air
Inlet
Air
Inlet Air Ventilated
Crawl Space
To
Crawl
Space
To Attic
Figure 8 - Ventilation Air from Outdoors
AIR FOR
COMBUSTION AND
VENTILATION
Continued
WARNING: Rework work-
sheet, adding the space of the
adjoiningunconfinedspace.The
combined spaces must have
enough fresh air to supply all
appliances in both spaces.
Ventilation Air From Outdoors
Provide extra fresh air by using ventilation
grills or ducts. You must provide two per-
manent openings: one within 12" of the
ceiling and one within 12" of the floor.
Connecttheseitemsdirectlytotheoutdoors
orspacesopentotheoutdoors.Thesespaces
include attics and crawl spaces. Follow the
National Fuel Gas Code, NFPA 54/ANS
Z223.1,Section5.3,AirforCombustionand
Ventilation for required size of ventilation
grills or ducts.
IMPORTANT: Do not provide openings for
inlet or outlet air into attic if attic has a
thermostat-controlledpowervent.Heatedair
enteringtheatticwillactivatethepowervent.

8
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
3"
FLOOR
CEILING
36"
Minimum
6"
Minimum
From
Sides Of
Heater
Left
Side Right Side
Figure9-MountingClearancesAsViewed
From Front of Heater
CAUTION: If you install the
heater in a home garage
• heaterpilotandburnermustbe
at least 18 inches above floor.
• locateheaterwheremovingve-
hicle will not hit it.
WARNING: Never install the
heater
• in a bedroom or bathroom
• in a recreational vehicle
• where curtains, furniture,
clothing, or other flammable
objectsarelessthan42inches
from the front, top, or sides of
the heater
• as a fireplace insert
• in high traffic areas
• in windy or drafty areas
CAUTION: This heater cre-
ates warm air currents. These
currents move heat to wall sur-
faces next to heater. Installing
heater next to vinyl or cloth wall
coverings or operating heater
where impurities (such as to-
bacco smoke, aromatic candles,
cleaning fluids, oil or kerosene
lamps, etc.) in the air exist, may
discolor walls.
INSTALLATION
NOTICE: This heater is intended
foruseassupplementalheat.Use
this heater along with your pri-
mary heating system. Do not in-
stall this heater as your primary
heatsource. Ifyouhave acentral
heating system, you may run
system’scirculatingblowerwhile
usingheater.Thiswillhelpcircu-
late the heat throughout the
house. In the event of a power
outage, you can use this heater
as your primary heat source.
CHECK GAS TYPE
Use only natural gas. If your gas supply is
not natural gas, do not install heater. Call
dealer where you bought heater for proper
type heater.
INSTALLATION ITEMS
Beforeinstallingheater,makesureyouhave
the items listed below.
• piping (check local codes)
• sealant (resistant to propane/LP gas)
• equipment shutoff valve *
• ground joint union
• test gauge connection *
• sediment trap
• tee joint
• pipe wrench
* ACSAdesign-certifiedequipmentshutoff
valve with 1/8" NPT tap is an acceptable
alternative to test gauge connection. Pur-
chase the optional CSA design-certified
equipment shutoff valve from your dealer.
See Accessories, page 23.
WARNING:Maintainthemini-
mumclearancesshowninFigure
9.Ifyoucan,providegreaterclear-
ancesfromfloor,ceiling,andjoin-
ing wall.
You can locate heater on floor. The op-
tional hearth base is needed. You can also
install optional decorative mantels on the
heater (some mantels require the hearth
base). IMPORTANT: Only use optional
mantels and hearth base specified in this
manual. Purchase the optional mantel and
hearthbasefromyourdealer.SeeAccesso-
ries, page 23.
The heater may also be mounted on a wall.
Youcannotuseoptionalmantelifmounting
heater on a wall.
LOCATING HEATER
WARNING: A qualified ser-
vice person must install heater.
Follow all local codes.
IMPORTANT: Vent-freeheatersaddmois-
ture to the air. Although this is beneficial,
installing heater in rooms without enough
ventilation air may cause mildew to form
from too much moisture. See Air for Com-
bustion and Ventilation, pages 5 through 7.
Forconvenienceandefficiency,installheater
• where there is easy access for operation,
inspection, and service.
• in coldest part of room.
An optional fan kit is available from your
dealer. See Accessories, page 23. If plan-
ningtousefan,locateheaternearan electri-
cal outlet.
Minimum to
Top Surface
of Carpeting,
Tile, or Other
Combustible
Material

9
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
Thermostat
Sensing Bulb
Clamp
THERMOSTAT SENSING
BULB
The thermostat sensing bulb has been placed
insidetheheaterforprotectionduringshipping.
Locating Thermostat Sensing
Bulb
1. Remove front panel of heater (see Fig-
ure 2, page 3).
2. Locate thermostat sensing bulb just
under burner assembly.
IMPORTANT: Attach thermostat sensing
bulb to back of heater for proper operation.
Attaching Thermostat Sensing
Bulb
1. Remove thermostat sensing bulb from
holders inside heater. Route through
slot opening in bottom of heater.
2. Place clamp onthermostat sensing bulb
as shown in Figure 10. Clamp is pro-
vided in hardware package.
3. Snap clamp into upper mounting hole
as shown in Figure 10. Mounting hole
is located on lower left edge on back
of heater. Make sure the thermostat
sensing bulb is pointing up.
Figure 10 - Attaching Thermostat Sens-
ing Bulb
INSTALLATION OPTIONS
There are three options for mounting this
heater.
A. Mounting heater to wall
B. Mounting heater tooptional hearth base
C. Mounting heater to optional mantel
(some mantels require the hearth base)
A. MOUNTING HEATER TO
WALL
Mounting Bracket
Themountingbracketislocatedinthepack-
age tray. Remove mounting bracket from
tray.
Methods For Attaching
Mounting Bracket To Wall
Only use last hole on each end of mounting
bracket to attach bracket to wall. These two
holes are 16 inches apart from their centers.
Attach mounting bracket to wall in one of
two ways.
1. Attaching to wall stud
2. Attaching to wall anchor
Attaching To Wall Stud: This method pro-
vides the strongest hold. Insert mounting
screws through mounting bracket and into
wall studs.
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).
Decidewhichmethodbettersuitsyourneeds.
Eithermethodwillprovideasecureholdfor
the mounting bracket.
Marking Screw Locations
1. Tape mounting bracket to wall where
heater will be located. Make sure
mounting bracket is level.
18
3
/ 4 "
Min.
11"
Min. 16"
Adjoining Wall
Only Insert Mounting
Screws Through Last
Hole On Each End
Floor
Figure11-Mounting Bracket Clearances
Attaching Mounting Bracket To
Wall
Note: Wall anchors, mounting screws, and
spacers are in hardware package. The hard-
ware package is provided with heater.
Attaching To Wall Stud Method
Forattachingmountingbrackettowallstuds.
1. Drill holes at marked locations using
9/64" drill bit.
2. Place mounting bracket onto wall. Line
uplast holeon eachend of bracket with
holes drilled in wall.
3. Insert mounting screwsthrough bracket
and into wall studs.
4. Tighten screws until mounting bracket
is firmly fastened to wall studs.
Continued
INSTALLATION
Continued
WARNING:Maintainminimum
clearancesshown in Figure 11.If
you can, provide greater clear-
ancesfromfloorandjoiningwall.
2. Mark screw locations on wall (see Fig-
ure 11).
Note: Only mark last hole on each end
of mounting bracket. Insert mounting
screws through these holes only.
3. Remove tape and mounting bracket
from wall.

10
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
INSTALLATION
Continued
Figure 12 - Folding Anchor
Figure 13 - Popping Open Anchor Wings
For Thin Walls
Figure14 - MountingHeater Onto Mount-
ing Bracket
Horizontal Slots
Mounting Bracket
(attached to wall)
Stand-Out
Tab
Installing Bottom Mounting
Screws
1. Locate two bottom mounting holes.
These holes are near bottom on back
panel of heater (see Figure 15).
2. Mark screw locations on wall.
3. Remove heater frommounting bracket.
4. If installing bottom mounting screws
into hollow or solid wall, install wall
anchors. Follow steps 1 through 4 un-
der Attaching To Wall Anchor Method.
If installing bottom mounting screw
into wall stud, drill holes at marked lo-
cations using 9/64" drill bit.
5. Replace heater onto mounting bracket.
6. Place spacers between bottom mount-
ingholesandwallanchorordrilledhole.
7. Hold spacer in place with one hand.
With other hand, insert mountingscrew
through bottom mounting hole and
spacer. Place tip of screw in opening
of wall anchor or drilled hole.
8. Tighten both screws until heater is
firmly secured to wall. Do not over
tighten.
Note: Do not replace front panel at this
time. Replace front panel after making
gas connections and checking for leaks
(see pages 12 and 13).
Figure 15 - Installing Bottom Mounting
Screws
Attaching To Wall Anchor Method
For attaching mounting bracket to hollow
walls (wall areas between studs) or solid
walls (concrete or masonry).
1. Drill holes at marked locations using
5/16"drill bit.For solidwalls (concrete
or masonry), drill at least 1" deep.
2. Fold wall anchorasshown in Figure12.
3. Insert wall anchor (wings first) into
hole. Tap anchor flush to wall.
4. For thin walls (1/2" or less), insert red
key into wall anchor. Push red key to
“pop” open anchor wings.
IMPORTANT: Do not hammer key!
Forthick walls (over 1/2"thick) or solid
walls, do not pop open wings.
5. Place mounting bracket onto wall. Line
uplast holeon eachend of bracket with
wall anchors.
6. Insert mounting screwsthrough 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
panel of heater.
2. Place heater onto mounting bracket.
Slide horizontal slots onto stand-out
tabs on mounting bracket.

11
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
INSTALLATION
Continued
Continued
Figure 16 - Attaching Heater to Hearth
Base
Figure17-PlacingHearthInsertonHeater
Base and Attaching Brass Base Trim
Mounting Heater to Optional
Hearth Base
1. Lay heater on its back on a table with
the bottom of heater overhanging the
edge of the table.
2. Remove 2 shipping screws in bottom
of heater. Discard shipping screws.
3. Line up mountingholeson top of hearth
basewith holesin bottom of heater (see
Figure 16).
4. Using a Phillips screwdriver, secure
hearth base to heater with four sheet
metal screws (see Figure 16).
5. Stand heater up on base.
6. Place hearth insert in hearth base as
shown in Figure 17.
7. Assemble brass trim (see steps 1
through 7 under Assembling and At-
taching Brass Trim, page 4).
8. Slide base trim on heater base. Attach
brasstrim to basewith two brass screws
included as shown in Figure 17.
Securing Hearth Base to Floor
1. Position hearth basein desired location.
Markholes fordrilling (See Figure 16).
Remove hearth base.
2. For carpeted floor, make a small cut
with a sharp knife at marked locations
before drilling.
If securing to a wood floor, drill a 3/4"
deep hole using a 1/8" diameter drill
bit. Do not use anchors in wood floors.
If securing to a concrete floor, drill a 1
3/8" deep hole using a 1/4" diameter
concretedrill bit.Completely insertan-
chors into each hole.
3. Mount heater to hearth base following
steps under Mounting Heater to Op-
tional Hearth Base. After mounting
heater, position heater and hearth base
over drilled holes. With slotted screw-
driver, secure hearth base to floor with
four wood screws.
B. MOUNTING HEATER ON
OPTIONAL HEARTH BASE
Tools needed:
• #2 Phillips screwdriver
• slotted screwdriver
• electric drill (if securing base to floor)
The optional hearth base kit includes the
following:
• Hearth Base
• 4 Wood Screws
• 4 Sheet Metal Screws
• Brass Base Trim
• Hearth Insert
• 4 Anchors
• 2 Brass Screws
Note: It is an option to secure “A” model
hearthbasetofloor.Youmustsecurethe“B”
and “C” model hearth bases to floor. To
secure hearth base to floor, follow instruc-
tionsunderSecuringHearthBasetoFloor.If
not securing hearth base to floor, proceed to
Mounting Heater to Optional Hearth Base.
Brass Base
Trim
Hearth
Insert
Screw
Base
Holes for Securing
Heater to Floor
Shipping Screw Bottom of Heater
Sheet Metal
Screw
Mounting
Holes

12
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
INSTALLATION
Continued
C. MOUNTING HEATER TO
OPTIONAL MANTEL
See Instructions Included
With Mantel Kit.
Assembling Mantel
IMPORTANT: Only use the optional man-
tels specified in this manual. See Accesso-
ries, page 23 for proper mantel kits. This
heateris onlyapproved for use with models
GMF800/GMU801 series, GM900F/
GM901Useries,GM902F/GM903Useries,
GM700F/GM701U series, and GM702F/
GM703Useriesmantelkits.Usinganyother
mantel will void the CSA approval for this
heater.OnlyusemodelsGMF800/GMU801
series,GM900F/GM901Useries,GM902F/
GM903Useries,GM700F/GM701Useries,
andGM702F/GM703Useries mantelswith
this heater. Do not use these mantels with
any other product.
* A CSA design-certified equipment shutoff valve with 1/8" NPT tap is an acceptable
alternativetotestgaugeconnection.PurchasetheoptionalCSAdesign-certifiedequipment
shutoff valve from your dealer. See Accessories, page 23.
Figure 18 - Gas Connection
CONNECTING TO GAS
SUPPLY
WARNING:A qualifiedservice
personmustconnectheatertogas
supply. Follow all local codes.
WARNING: Never connect
heater to private (non-utility) gas
wells. This gas is commonly
known as wellhead gas.
IMPORTANT: Check gas line pressurebe-
fore connecting heater to gas line. Gas line
pressure must be no greater than 14 inches
of water. If gas line pressure is higher,
heater regulator damage could occur.
CAUTION: Use only new,
black iron or steel pipe. Inter-
nally-tinned copper tubing may
be used in certain areas. Check
yourlocalcodes.Usepipeof1/2"
or greater diameter to allow
proper gas volume to heater. If
pipe is too small, undue loss of
pressure will occur.
Installation must include an equipment
shutoffvalve,union,andplugged1/8"NPT
tap. Locate NPT tap within reach for test
gauge hook up. NPT tap must be upstream
from heater (see Figure 18).
IMPORTANT: Installanequipmentshutoff
valve in an accessible location. The equip-
ment shutoff valve is for turning on or
shutting off the gas to the appliance.
Apply pipe joint sealant lightly to male
threads. This will prevent excess sealant
fromgoing into pipe.Excess sealant in pipe
could result in clogged heater valves.
CAUTION:Usepipejointseal-
ant that is resistant to liquid pe-
troleum (LP) gas.
We recommend that you install a sediment
trap in supply line as shown in Figure 18.
Locate sediment trap where it is within
reach for cleaning. Install in piping system
betweenfuelsupplyandheater.Locatesedi-
menttrap wheretrapped 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.
IMPORTANT: Holdpressureregulatorwith
wrench when connecting it to gas piping
and/or fittings.
Tee Joint
Reducer
Bushing to
1/8" NPT
1/8" NPT
Plug Tap
Test Gauge
Connection *
Tee Joint
Pipe
Nipple
Cap
Sediment
Trap
Pressure
Regulator
3/8" NPT
Pipe Nipple
Ground
Union
Joint Heater Cabinet
3" Minimum
Note: Burner bracket not
shown for clarity
Equipment Shutoff
Valve *
From Gas Meter
(5" W.C. to 10.5"
W.C. Pressure)
WARNING:Thisappliancere-
quires a 3/8" NPT (National Pipe
Thread) inlet connection to the
pressure regulator.

13
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
Pressure Testing Gas Supply
Piping System
Test Pressures In Excess Of 1/2 PSIG
(3.5 kPa)
1. Disconnect appliance with its appliance
maingas valve(controlvalve)andequip-
ment shutoff valve from gas supply pip-
ingsystem.Pressuresinexcessof1/2psig
will damage heater regulator.
2. Cap off open end of gas pipe where
equipmentshutoffvalve wasconnected.
3. Pressurize supply piping system by
either using compressed air or open-
ing main gas valve located on or near
gas meter.
4. Check all joints of gas supply piping
system. Apply mixture of liquid soap
and water to gas joints. Bubbles form-
ing show a leak.
5. Correct all leaks at once.
6. Reconnect heater and equipment
shutoff valve to gas supply. Check re-
connected fittings for leaks.
ON
POSITION
OFF
POSITION
Open
Closed
Equipment
Shutoff
Valve
Equipment
Shutoff
Valve
Thermostat Gas
Valve Location
Figure 19 - Equipment Shutoff Valve
Gas Meter
Figure 20 - Checking Gas Joints
Test Pressures Equal To or Less Than
1/2 PSIG (3.5 kPa)
1. Close equipment shutoffvalve (seeFig-
ure 19).
2. Pressurize supply piping system by
either using compressed air or open-
ing main gas valve located on or near
gas meter.
3. Check all joints from gas meter to
equipment shutoff valve (see Figure
20). Apply mixture of liquid soap and
water to gas joints. Bubbles forming
show a leak.
4. Correct all leaks at once.
Pressure Testing Heater Gas
Connections
1. Open equipment shutoffvalve (seeFig-
ure 19).
2. Open main gas valve located on or near
gas meter.
3. Make sure control knob of heater is in
the OFF position.
4. Check all jointsfromequipment shutoff
valve to thermostat gas valve (see Fig-
ure 20). Apply mixture of liquid soap
and water to gas joints. Bubbles form-
ing show a leak.
5. Correct all leaks at once.
6. Light heater (see Operating Heater,
pages 14 and 15). Check all other in-
ternal joints for leaks.
7. Turn off heater (see To Turn Off Gas to
Appliance, page 14).
8. Replace front panel.
INSTALLATION
Continued
CHECKING GAS
CONNECTIONS
WARNING: Test all gas pip-
ing and connections for leaks
after installing or servicing. Cor-
rect all leaks at once.
WARNING:Neveruseanopen
flame to check for a leak. Apply a
mixture of liquid soap and water
toalljoints.Bubblesformingshow
a leak. Correct all leaks at once.

14
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
OPERATING
HEATER
TO TURN OFF GAS
TO APPLIANCE
Pilot Burner
Thermocouple
Figure 22 - Pilot
7. Keep control knob pressed in for 30
seconds after lighting pilot.After 30
seconds, release control knob.
• If control knob does not pop up
when released, contact a qualified
service person or gas supplier for
repairs.
Note: If pilot goes out, repeat steps
3 through 7.This heater has a safety
interlocksystem.Waitone(1) minute
before lighting pilot again.
8. Turn control knob counterclockwise
to desiredheatinglevel.The
mainburnershould light.Set control
knob to any heat level between HI
and LO.
LIGHTING
INSTRUCTIONS
Figure 21 - Control Knob In The OFF
Position
PILOT
LO
OFF
HI
IGNITOR
Control Knob
Ignitor Button
1. STOP! Read the safety information
in column 1.
2. Make sure equipment shutoff valve
is fully open.
3. Turn control knob clockwise
to the OFF position.
4. Wait five(5) minutesto clearout any
gas. Then smell for gas, including
near the floor. If you smell gas,
STOP! Follow “B” in the safety in-
formation, column 1. If you don’t
smell gas, go to the next step.
5. Turn control knob counterclockwise
to PILOT position. Press in
control knob for five (5) seconds (see
Figure 21).
Note: You may be running this
heater for the first time after hook-
ing up to gas supply. If so, the con-
trol knob may need to be pressed in
for 30 seconds. This will allow air to
bleed from the gas system.
6. With control knob pressed in, push
down and release ignitor button.
This will light pilot. The pilot is at-
tached to the front of burner. If
needed, keep pressing ignitor but-
ton until pilot lights.
Note: If pilot does not stay lit, refer
to Troubleshooting, pages 16 through
18. Also contact a qualified service
person or gas supplier for repairs.
Untilrepairsaremade, lightpilotwith
match. To light pilot with match, see
Manual Lighting Procedure, page 15.
Ignitor Electrode
FOR YOUR SAFETY
READ BEFORE
LIGHTING
Shutting Off Heater
1. Turn controlknobclockwise
to the OFF position.
2. Turn off all electric power to the ap-
pliance if service is to be performed.
Shutting Off Burner Only (pilot
stays lit)
Turn control knob clockwise to
the PILOT position.
A. Thisappliance has apilotwhichmust
belightedbyhand.Whenlightingthe
pilot,followtheseinstructionsexactly.
B. BEFORE LIGHTING smell all
aroundtheapplianceareaforgas.Be
sureto smellnexttothefloor because
some gas is heavier than air and will
settle on the floor.
WHAT TO DO IF YOU SMELL
GAS
• Do not try to light any appliance.
• Donottouchanyelectricswitch; do
notuse anyphone inyourbuilding.
• Immediatelycallyourgas supplier
from a neighbor’s phone. Follow
the gas supplier’s instructions.
• If you cannot reach your gas sup-
plier, call the fire department.
C. Useonly yourhand topushin orturn
thegas controlknob.Neveruse tools.
If the knob will not push in or turn
by hand, don’t try to repair it, call a
qualified service technician or gas
supplier. Force or attempted repair
may result in a fire or explosion.
D. Do not use this appliance if any part
has been under water. Immediately
call a qualified service technician to
inspect the appliance and to replace
any part of the control system and
any gas control which has been un-
der water.
WARNING: If you do not fol-
low these instructions exactly, a
fireorexplosionmayresultcaus-
ing property damage, personal
injury or loss of life.
CAUTION:Donottrytoadjust
heatinglevelsbyusingtheequip-
ment shutoff valve.

15
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
OPERATING
HEATER
Continued
THERMOSTAT
CONTROL OPERATION
The thermostatic control used on this
heaterdiffersfromstandardthermostats.
Standardthermostats simply turn on and
off the burner. The thermostat used on
this heater senses the room temperature.
The thermostat adjusts the amount of gas
flow to the burner. This increases or de-
creases the burner flame height. At times
theroommayexceedthesettemperature.
If so, the burner will shut off. The burner
willcyclebackonwhenroomtemperature
drops below the set temperature.
The control knob can be set to any heat
level between HI and LO.
Note: The thermostat sensing bulb mea-
sures the temperature of air near the
heatercabinet.Thismaynotalwaysagree
with room temperature (depending on
housing construction, installation loca-
tion, room size, open air temperatures,
etc.). Frequent use of your heater will let
you determine your own comfort levels.
MANUAL LIGHTING
PROCEDURE
1. Remove front panel (see Figure 2,
page 3).
2. Follow steps1through5under Light-
ing Instructions, page 14.
3. With control knob pressed in, strike
match. Hold match to pilot until pi-
lot lights.
4. Keep control knob pressed in for 30
seconds after lighting pilot.After 30
seconds, release control knob. Now
follow step 8 under Lighting Instruc-
tions, page 14.
5. Replace front panel.
Figure 23 - Correct Pilot Flame Pattern
Thermocouple
Thermocouple
INSPECTING
BURNER
Figure 24 - Incorrect Pilot Flame Pattern
Pilot Burner
Pilot Burner
Check pilot flame pattern and burner flame
pattern often.
PILOT FLAME PATTERN
Figure23showsacorrectpilotflamepattern.
Figure 24 shows an incorrect pilot flame
pattern.Theincorrectpilotflameisnottouch-
ing the thermocouple. This will cause the
thermocouple to cool. When the thermo-
couple cools, the heater will shut down.
If pilot flame pattern is incorrect, as shown
in Figure 24
• turn heater off (see To Turn Off Gas to
Appliance, page 14)
• seeTroubleshooting,pages16through 18
BURNER FLAME PATTERN
Figure 25 shows a correct burner flame
pattern.Figure26showsanincorrectburner
flame pattern. The incorrect burner flame
pattern shows yellow tipping of the flame.
It also shows the flame higher than one
inch above the log.
Note: When using the heater the first time,
the flame will be yellow for approximately
one hour until the log cures.
NOTICE: Do not mistake orange
flames with yellow tipping. Dirt
or other fine particles enter the
heater and burn causing brief
patches of orange flame.
WARNING: If yellow tipping
occurs, your heater could pro-
duce increased levels of carbon
monoxide. If burner flame pat-
ternshowsyellowtipping,follow
instructions,bottomofthispage.
Top of Flame Even
With Top of Log
Yellow Tipping
Ifburnerflamepatternisincorrect,asshown
in Figure 26
• turn heater off (see To Turn Off Gas to
Appliance, page 14)
• seeTroubleshooting, pages16 through 18
Figure26-IncorrectBurnerFlamePattern
Figure 25 - Correct Burner Flame Pattern

16
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
TROUBLESHOOTING WARNING: Turn off and un-
plug heater and let cool before
servicing. Only a qualified ser-
vice person should service and
repair heater.
REMEDY
1. Replace ignitor
2. Replace ignitor
3. Reconnect ignitor cable
4. Free ignitor cable if pinched by any
metal or tubing. Keep ignitor cable dry
5. Tighten nut holding piezo ignitor to
heater cabinet. Nut is located inside
heater cabinet at top
6. Replace ignitor cable
7. Replace piezo ignitor
1. Turn on gas supply or open equipment
shutoff valve
2. Turn control knob to PILOT position
3. Press in control knob while in PILOT
position
4. Continue holding down control knob.
Repeat igniting operation until air is re-
moved
5. Clean ODS/pilot (see Cleaning and
Maintenance,page 19) or replace ODS/
pilot assembly
6. Replace gas regulator
1. Press in control knob fully
2. After ODS/pilot lights, keep control
knob pressed in 30 seconds
3. Waitone minute for safety interlock sys-
tem to reset. Repeat ignition operation
4. Fully open equipment shutoff valve
5. Hand tighten until snug, then tighten 1/4
turn more
6. A) Contact local natural gas company
B) Clean ODS/pilot (see Cleaning and
Maintenance, page 19) or replace ODS/
pilot assembly
7. Replace thermocouple
8. Replace control valve
POSSIBLE CAUSE
1. Ignitor electrode positioned wrong
2. Ignitor electrode broken
3. Ignitor electrode not connected to igni-
tor cable
4. Ignitor cable pinched or wet
5. Piezo ignitor nut is loose
6. Broken ignitor cable
7. Bad piezo ignitor
1. Gas supply turned off or equipment
shutoff valve closed
2. Control knob not in PILOT position
3. Control knob not pressed in while in
PILOT position
4. Air in gas lines when installed
5. ODS/pilot is clogged
6. Gas regulator setting is not correct
1. Control knob not fully pressed in
2. Control knob notpressed in long enough
3. Safety interlock systemhasbeentriggered
4. Equipment shutoff valve not fully open
5. Thermocouple connection loose at con-
trol valve
6. Pilot flame not touching thermocouple,
which allows thermocouple to cool,
causing pilot flame to go out. This prob-
lem could be caused by one or both of
the following:
A) Low gas pressure
B) Dirty or partially clogged ODS/pilot
7. Thermocouple damaged
8. Control valve damaged
OBSERVED PROBLEM
When ignitor button is pressed, there is no
spark at ODS/pilot
When ignitor button is pressed, there is
spark at ODS/pilot but no ignition
ODS/pilot lights but flame goes out when
control knob is released
CAUTION: Never use a wire,
needle, or similar object to clean
ODS/pilot.ThiscandamageODS/
pilot unit.
Note: For additional help, visit DESA
International’stechnicalservicewebsite
at www.desatech.com.
Note: Alltroubleshootingitemsarelistedin
order of operation.
www.desatech.com

17
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
REMEDY
1. Clean burner (see Cleaning and Mainte-
nance, page 19) or replace burner orifice
2. Replace burner orifice
3. Contact local natural gas company
1. Contact local natural gas company
2. Clean burner (see Cleaning and Mainte-
nance, page 19) or replace burner orifice
1. Clean burner (see Cleaning and Mainte-
nance, page 19) or replace burner orifice
2. Replace burner
3. Replace gas regulator
1. Check burner for dirt and debris. If
found, clean burner (see Cleaning and
Maintenance, page 19)
2. Replace gas regulator
1. Problem will stop after a few hours of
operation
1. Turn control knob to LO position and
let warm up for a minute
2. Operateburner untilair isremoved from
line. Have gas line checked by local
natural gas company
3. Observe minimum installation clear-
ances (see Figure 9, page 8)
4. Clean burner (see Cleaning and Mainte-
nance, page 19) or replace burner orifice
1. Turn heater off when using furniture
polish, wax, carpet cleaners, or similar
products
TROUBLESHOOTING
Continued
OBSERVED PROBLEM
Burner does not light after ODS/pilot is lit
Delayed ignition of burner
Burner backfiring during combustion
Yellow flame during burner combustion
Slightsmokeorodor during initial operation
Heater produces a whistling noise when
burner is lit
Whitepowderresidueformingwithinburner
box or on adjacent walls or furniture
POSSIBLE CAUSE
1. Burner orifice is clogged
2. Burner orifice diameter is too small
3. Inlet gas pressure is too low
1. Manifold pressure is too low
2. Burner orifice is clogged
1. Burner orifice is clogged or damaged
2. Burner damaged
3. Gas regulator defective
1. Not enough air
2. Gas regulator defective
1. Residues from manufacturing processes
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 orifice
1. When heated, vapors from furniture pol-
ish, wax, carpet cleaners, etc. turn into
white powder residue
Continued
www.desatech.com

18
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
TROUBLESHOOTING
Continued
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.
• Immediatelycallyourgassupplierfromaneighbor’sphone.Followthe
gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
IMPORTANT: Operating heater where impurities in air exist may create odors. Cleaning
supplies, paint, paint remover, cigarette smoke, cements and glues, new carpet or textiles,
etc., create fumes. These fumes may mix with combustion air and create odors.
OBSERVED PROBLEM
Heater produces a clicking/ticking noise
just after burner is lit or shut off
Heater produces unwanted odors
Heater shuts off in use (ODS operates)
Gas odor even when control knob is in OFF
position
Gas odor during combustion
POSSIBLE CAUSE
1. Metal expanding while heating or con-
tracting while cooling
1. Heater burning vapors from paint, hair
spray, glues, etc. (see IMPORTANT
statement above)
2. Gas leak. SeeWarning statement at
top of page
1. Not enough fresh air is available
2. Low line pressure
3. ODS/pilot is partially clogged
1. Gas leak. SeeWarning statement at
top of page
2. Control valve defective
1. Foreign matter between control valve
and burner
2. Gas leak. SeeWarning statement at
top of page
REMEDY
1. This is common with most heaters. If
noise is excessive, contact qualified ser-
vice person
1. Ventilate room. Stop using odor caus-
ing products while heater is running
2. Locate and correct all leaks (see Check-
ing Gas Connections, page 13)
1. Open window and/ordoorfor ventilation
2. Contact local natural gas company
3. Clean ODS/pilot (see Cleaning and
Maintenance, page 19)
1. Locate and correct all leaks (see Check-
ing Gas Connections, page 13)
2. Replace control valve
1. Take apart gas tubing and remove for-
eign matter
2. Locate and correct all leaks (see Check-
ing Gas Connections, page 13)
www.desatech.com

19
107097
OWNER’S MANUAL
For more information, visit www.desatech.com
CLEANING AND
MAINTENANCE
CABINET
Air Passageways
• Use a vacuum cleaner or pressurized air
to clean.
Exterior
• Use a soft cloth dampened with a mild
soap and water mixture. Wipe the cabi-
net to remove dust.
CAUTION: You must keep
control areas, burner, and circu-
lating air passageways of heater
clean. Inspect these areas of
heater before each use. Have
heaterinspectedyearlybyaquali-
fied service person. Heater may
needmorefrequentcleaningdue
to excessive lint from carpeting,
pet hair, bedding material, etc.
WARNING: Turn off heater
and let cool before cleaning.
REPLACEMENT
PARTS
Note: Use only original replacement parts.
Thiswillprotectyourwarrantycoveragefor
parts replaced under warranty.
PARTS UNDER WARRANTY
Contact authorized dealers of this product.
If they can’t supply original replacement
part(s), call DESA International’s Techni-
cal Service Department at 1-800-323-5190
for referral information.
WhencallingDESAInternational,haveready
• your name
• your address
• model and serial numbers of your heater
• how heater was malfunctioning
• typeofgasused(propane/LPornaturalgas)
• purchase date
Usually,wewillaskyoutoreturnthedefec-
tive part to the factory.
PARTS NOT UNDER
WARRANTY
Contact authorized dealers of this product.
If they can’t supply original replacement
part(s), call DESA International’s Parts
Department at 1-800-972-7879 for referral
information.
WhencallingDESAInternational,haveready
• model number of your heater
• the replacement part number
SERVICE HINTS
When Gas Pressure Is Too Low
• pilot will not stay lit
• burner(s) will have delayed ignition
• heater will not produce specified heat
When Gas Quality Is Bad
• pilot will not stay lit
• burner(s) will produce flames and soot
• heater will backfire when lit
Youmayfeelyourgaspressureistoolowor
gas quality is bad. If so, contact your local
natural gas supplier.
CLEANING BURNER
INJECTOR HOLDER AND
PILOT AIR INLET HOLE
The primary air inlet holes allow the proper
amount of air to mix with the gas. This
provides a clean burning flame. Keep these
holes clear of dust, dirt, lint, and pet hair.
Clean these air inlet holes prior to each
heating season. Blocked air holes will cre-
ate soot. We recommend that you clean the
unit every three months during operation
andhaveheater inspected yearly byaquali-
fied service person.
Wealsorecommendthatyoukeeptheburner
tube and pilot assembly clean and free of
dustanddirt.Tocleanthesepartswerecom-
mend using compressed air no greater than
30 PSI. Your local computer store, hard-
ware store, or home center may carry com-
pressed air in a can. You can use a vacuum
cleaner in the blow position. If using com-
pressed air in a can, please follow the direc-
tions on the can. If you don't follow direc-
tionsonthecan, youcoulddamagethepilot
assembly.
1. Shut off the unit, including the pilot.
Allow the unit to cool for at least thirty
minutes.
2. Inspect burner, pilot, and primary air
inlet holes on injector holder for dust
and dirt (see Figure 27).
3. Blow air through the ports/slots and
holes in the burner.
Figure 27 - Injector Holder On Outlet
Burner Tube
4. Check the injector holder located at the
end of the burner tube again. Remove
any large particles of dust, dirt, lint, or
pet hairs with a soft cloth or vacuum
cleaner nozzle.
5. Blow air into the primary air holes on
the injector holder.
6. In case any large clumps of dust have
now been pushed into the burner repeat
steps 3 and 4.
Clean the pilot assembly also. A yellow tip
on the pilot flame indicates dust and dirt in
the pilot assembly. There is a small pilot air
inlet hole about two inches from where the
pilot flame comes out of the pilot assembly
(see Figure 28). With the unit off, lightly
blowair through the airinlet hole. Youmay
blowthroughadrinkingstrawifcompressed
air is not available.
Burner
Tube
Injector
Holder
Primary Air
Inlet Hole
Figure 28 - Pilot Inlet Air Hole
Pilot
Assembly
Pilot Air Inlet Hole
Ports/Slots

20
107097
NATURAL GAS RESIDENTIAL HEATERS
®
For more information, visit www.desatech.com
ILLUSTRATED
PARTS
BREAKDOWN
VMH3000TNA
1
2
9
10
10
12 13
14
15
17
19
20
23
24
25
6
26
6
7
1
1
31
28
5
16 18
4
22
1 1
1
21
11
8
27