Desa NTH50, NTH35, NTH70, NTH150, NTH100 User Manual
PORTABLE
FORCED
AIR HEATERS
OWNER’S MANUAL
Heater Sizes: 35,000 50,000 70,000
100,000 150,000 Btu/Hr
Models: NTH35, NTH50, NTH70, NTH100, and NTH150
IMPORTANT: Read and understand this manual before assembling, starting or servicing heater. Improper use of heater can cause serious injury.
Keep this manual for future reference.
PORTABLE FORCED AIR HEATERS
SAFETY
INFORMATION
WARNINGS
IMPORTANT: Read this Owner’s
Manual carefully and completely
before trying to assemble, operate, or service this heater. Improper use of this heater can
cause serious injury or death from
burns, fire, explosion, electrical
shock, and carbon monoxide
poisoning.
DANGER: Carbon monoxide
poisoning may lead to death!
Carbon Monoxide Poisoning: Early signs
of carbon monoxide poisoning resemble the
flu, with headaches, dizziness, and/or nausea. If you have these signs, the heater may
not be working properly. Get fresh air at
once! Have heater serviced. Some people
are more affected by carbon monoxide than
others. These include pregnant women, persons with heart or lung disease or anemia,
those under the influence of alcohol, and
those at high altitudes.
Make certain you read and understand all
Warnings. Keep this manual for reference.
It is your guide to safe and proper operation
of this heater.
• Use only kerosene or No. 1 fuel oil to
avoid risk of fire or explosion. Never use
gasoline, naphtha, paint thinners, alcohol,
or other highly flammable fuels.
• Fueling
a) Personnel involved with fueling shall
be qualified and thoroughly familiar
with the manufacturer's instructions
and applicable regulations regarding
the safe fueling of heating units.
b) Only the type of fuel specified on the
heater's data plate shall be used.
c) All flame, including the pilot light, if
any, shall be extinguished and the
heater allowed to cool, prior to
fueling.
d) During fueling, all fuel lines and fuel-
line connections shall be inspected for
leaks. Any leaks shall be repaired
prior to returning the heater to service.
e) At no time shall more than one day's
supply of heater fuel be stored inside
a building in the vicinity of the heater.
Bulk fuel storage shall be outside the
structure.
f) All fuel storage shall be located a
minimum of 762cm (25 feet) from
heaters, torches, welding equipment,
and similar sources of ignition
(exception: the fuel reservoir integral
with the heater unit).
g) Whenever possible, fuel storage shall
be confined to areas where floor
penetrations do not permit fuel to drip
onto or be ignited by a fire at lower
elevation.
h) Fuel storage shall be in accordance
with the authority having jurisdiction.
• Never use heater where gasoline, paint
thinner, or other highly flammable vapors
are present.
• Follow all local ordinances and codes
when using heater.
• Heaters used in the vicinity of tarpaulins,
canvas, or similar enclosure materials
shall be located a safe distance from such
materials. The recommended minimum
safe distance is 304.8cm (10 feet). It is
further recommended that these enclosure materials be of a fire retardant nature. These enclosure materials shall be
securely fastened to prevent them from
igniting or from upsetting the heater due
to wind action.
• Use only in well-vented areas. Before using heater, provide at least a 2800 square
cm (three-square-foot) opening of fresh,
outside air for each 100,000 Btu/Hr of
rating.
• Use only in places free of flammable vapors or high dust content.
• Use only the electrical voltage and frequency specified on model plate.
• Use only a three-prong, grounded extension cord.
• Minimum heater clearances from combustibles:
Outlet: 250 cm (8 Ft.)
Sides, Top, and Rear: 125 cm (4 Ft.)
• Locate heater on a stable and level surface if heater is hot or running or a fire
may occur.
• When moving or storing heater, keep
heater in a level position or fuel spillage
may occur.
• Keep children and animals away from
heater.
• Unplug heater when not in use.
• When used with thermostat, heater may
start anytime.
• Never use heater in living or sleeping
areas.
• Never block air inlet (rear) or air outlet
(front) of heater.
• Never move, handle, refuel, or service a
hot, operating, or plugged-in heater.
• Never attach duct work to front or rear
of heater.
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OWNER’S MANUAL
PRODUCT
IDENTIFICATION
Hot Air Outlet
Upper Shell
Lower Shell
Fuel Tank
Side Cover
ON/OFF Switch
Flame-Out Control
Reset Button
Figure 1 - 35/50/70,000 Btu/Hr Models
Power
Cord
Handle
Fan Guard
Air Filter
End Cover
Fuel Cap
UNPACKING
1. Remove all packing items applied to
heater for shipment.
2. Remove all items from carton.
3. Check items for any shipping damage.
If heater is damaged, promptly inform
dealer where you bought heater.
FUELS
WARNING: Use only kerosene
or No. 1 fuel oil to avoid risk of fire
or explosion. Never use gasoline,
naphtha, paint thinners, alcohol
or other highly flammable fuels.
Do not use heavy fuels such as No. 2 fuel oil
or No. 2 Diesel. Using heavy fuels will
result in:
• clogged fuel filter and nozzle
• carbon build up on spark plug
• use of non-toxic anti-icer in fuel during
very cold weather
Hot Air Outlet
Lower
Shell
Fuel Cap
Side Cover
Figure 2 - 100/150,000 Btu/Hr Models
Upper Shell
ON/OFF Switch
Fan Guard
Fuel Tank
Flame-Out
Control Reset
Button
Power Cord
IMPORTANT:
Use a KEROSENE ONLY
container. Be sure storage container is clean.
Foreign matter such as rust, dirt, or water
will cause the flame-out control to shut
down heater. Foreign matter may also require you to clean fuel system often.
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3
PORTABLE FORCED AIR HEATERS
ASSEMBLY
(FOR 100,000 AND 150,000
BTU/HR MODELS ONLY)
These models are furnished with wheels and
handles. Wheels, handles, and the mounting
hardware are found in the shipping carton.
Tools Needed
• Medium Phillips Screwdriver
• 3/8" Open or Adjustable Wrench
• Hammer
1. Slide axle through wheel support
frame. Install wheels on axle.
IMPORTANT:
point extended hub of wheels toward
wheel support frame (see Figure 3).
When installing wheels,
2. Place cap nuts on axle ends. Gently tap
with hammer to secure.
3. Place heater on wheel support frame.
Make sure air inlet end (rear) of heater
is over wheels. Line up holes on fuel
tank flange with holes on wheel support frame.
4. Place front handle and rear handle on
top of fuel tank flange. Insert screws
through handles, fuel tank flange, and
wheel support frame. Attach nut finger
tight after each screw is inserted.
5. After all screws are inserted, tighten
nuts firmly.
Front Handle
VENTILATION
WARNING: Follow the minimum fresh, outside air ventilation
requirements. If proper fresh, outside air ventilation is not provided,
carbon monoxide poisoning can
occur. Provide proper fresh, outside air ventilation before running
heater.
Provide a fresh air opening of at least 2800
square cm (three square feet) for each
100,000 Btu/Hr rating. Provide extra fresh
air if more heaters are being used.
Example:
one of the following:
• a two-car garage door (16 feet wide open-
• a single-car garage door (9 feet wide
• two, 76 cm (30 inch) windows raised 31
A 150,000 Btu/Hr heater requires
ing) raised 9 cm (3 1/2 inches)
opening) raised 15.25 cm (6 inches)
cm (12 inches)
Screw
Hot Air
Outlet
Fuel Tank
Flange
Wheel
Support
Frame
Wheel
Cap Nut
Figure 3 - Wheel and Handle Assembly, 100/150,000 Btu/Hr Models Only
Nut
Axle
Extended
Hub
Rear
Handle
Air
Inlet
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OWNER’S MANUAL
THEORY OF
OPERATION
The Fuel System: The air pump forces
air through the air line. The air is then
pushed through the burner head nozzle. This
air causes fuel to lift from the tank. A fine
mist of fuel is sprayed into the combustion
chamber.
The Air System: The motor turns the fan.
The fan pushes air into and around the
combustion chamber. This air is heated and
provides a stream of clean, hot air.
The Ignition System: The electronic
ignitor sends voltage to the spark plug. The
spark plug ignites the fuel and air mixture.
The Flame-Out Control System: This
system causes the heater to shut down if the
flame goes out.
OPERATION
WARNING: Review and understand the warnings in the
Safety Information Section. They
are needed to safely operate this
heater. Follow all local codes
when using this heater.
TO START HEATER
1. Follow all ventilation and safety information.
2. Fill fuel tank with kerosene or No. 1
fuel oil.
3. Attach fuel cap.
4. Plug power cord of heater into standard
230 volt/50 hertz, grounded (earthed)
outlet. Use an extension cord if needed.
Use only a three-prong, grounded
(earthed) extension cord.
EXTENSION CORD WIRE
SIZE REQUIREMENTS
Up to 30.5 meters (100 feet) long, use 1.0
mm2 (16 AWG) conductor
30.6 to 61 meters (101 to 200 feet) long, use
1.5 mm2 (14 AWG) conductor
Push ON/OFF switch to ON and heater
should start. If heater does not start, press
flame-out control reset button (see Figures 5
and 6).
TO STOP HEATER
1. Push ON/OFF switch to OFF.
TO RESTART HEATER
1. Wait 2 minutes after stopping heater.
2. Repeat steps under To Start Heater.
Flame-Out Control
Reset Button
ON/OFF Switch
Combustion
Chamber
Clean
Heated
Air Out
Fuel
Tank
Figure 4 - Cross Section Operational View
Nozzle
Air For Fuel
System
Spark
Plug
Fuel
Filter
Burner
Head
Air Line
To Burner
Air For
Combustion
And Heating
Motor
Fan
Air Pump
Intake Air
Filter
Electronic
Ignitor
Fuel
Cool
Air In
Output
Air Filter
Figure 5 - Flame-Out Control Reset
Button, 35/50/70,000 Btu/Hr
Flame-Out Control
Reset Button
ON/OFF
Switch
Figure 6 - Flame-Out Control Reset
Button, 100/150,000 Btu/Hr
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5
PORTABLE FORCED AIR HEATERS
STORING,
TRANSPORTING,
OR SHIPPING
Note:
If shipping, transport companies re-
quire fuel tanks to be empty.
1. Drain fuel tank.
Note:
Some models have drain plug on
underside of fuel tank. If so, remove
drain plug to drain all fuel. If heater
does not have drain plug, drain fuel
through fuel cap opening. Be sure all
fuel is removed.
2. Replace drain plug if provided.
3. If any debris is noted in old fuel, add 1
or 2 quarts of clean kerosene to tank,
stir, and drain again. This will prevent
excess debris from clogging filters during future use.
4. Replace fuel cap or drain plug. Properly dispose of old and dirty fuel. Check
with local automotive service stations
that recycle oil.
5. If storing, store heater in dry place.
Make sure storage place is free of dust
and corrosive fumes.
IMPORTANT:
summer months for use during next heating
season. Using old fuel could damage heater.
Do not store kerosene over
PREVENT A TIVE
MAINTENANCE
SCHEDULE
Item
Fuel tank
Air output and
lint filters
Air intake filter
Fuel filter
Spark plug
Fan blades
Motor
How Often
Flush every 150-200 hours of
operation or as needed.
Replace every 500 hours of
operation or once a year.
Wash and dry with soap and
water every 500 hours of operation or as needed.
Clean twice a heating season
or as needed.
Clean and regap every 600
hours operation or replace as
needed.
Clean every season or as
needed.
Not required/permanently lubricated
WARNING: Never service heater
while it is plugged in, operating, or hot.
Severe burns and electrical shock can
occur.
How To
See Storing, Transporting, or Shipping.
See Air Output, Air Intake, and Lint
Filters, page 10.
See Air Output, Air Intake, and Lint
Filters, page 10.
See Fuel Filter, page 8.
See Spark Plug, page 9.
See Fan, page 13.
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104976
OWNER’S MANUAL
TROUBLESHOOTING
OBSERVED FAULT
Heater ignites, but flame-out control shuts
off heater after a short period of time.
Heater will not ignite, but motor runs for a
short period of time.
WARNING: Never service heater while it is plugged in, operating, or
hot. Severe burns and electrical shock can occur.
POSSIBLE CAUSE
1. Wrong pump pressure
2. Dirty air output, air intake, and lint filters
3. Dirty fuel filter
4. Dirt in nozzle
5. Dirty photocell lens
6. Bad flame-out control
1. Wrong pump pressure
2. Carbon deposits on spark plug and/or
improper gap
3. Dirty fuel filter
4. Dirt in nozzle
5. Water in fuel tank
WARNING: High voltage!
REMEDY
1. See Pump Pressur e Adjustment, page 10.
2. See Air Output, Air Intake and Lint
Filters, page 10.
3. See Fuel Filter, page 8.
4. See Nozzle, page 11.
5. Clean photocell lens.
6. Replace flame-out control.
1. See Pump Pressur e Adjustment, page 10.
2. See Spark Plug, page 9.
3. See Fuel Filter, page 8.
4. See Nozzle, page 11.
5. Drain and flush fuel tank with clean
kerosene. See Storing, Transporting, or
Shipping, page 6.
Motor does not start when heater is plugged
in, fan rotates slowly or does not turn.
6. Electronic ignitor not grounded (earthed)
7. Bad electronic ignitor
1. Flame-out control not reset
2. Binding pump rotor
6. Make sure electronic ignitor mounting
is tight.
7. Replace electronic
ignitor.
1. Reset flame-out control button, see
Figures 5 and 6, page 5.
2. If fan is hard to turn, see Pump Rotor,
page 12.
104976
7
PORTABLE FORCED AIR HEATERS
SERVICE
PROCEDURES
WARNING: Never service
heater while it is plugged in, operating, or hot. Severe burns and
electrical shock can occur.
Upper Shell Removal
1. Remove screws and lock washers along
each side of heater using 5/16" nutdriver. These screws attach upper and
lower shells together.
2. Lift upper shell off.
3. Remove fan guard.
Fuel Filter
(35/50/70,000 Btu/Hr Models)
1. Remove side cover screws using 5/16"
nut-driver.
2. Remove side cover.
3. Pull rubber fuel line off fuel filter neck.
4. Carefully pry bushing and fuel filter out
of fuel tank.
5. W ash fuel filter with clean fuel and replace in tank.
6. Attach rubber fuel line to fuel filter
neck.
7. Replace side cover.
Fuel Filter
(100/150,000 Btu/Hr Models)
1. Remove side cover screws using 5/16"
nut-driver.
2. Remove side cover.
3. Pull upper fuel line off fuel filter neck.
4. Carefully pry bushing, lower fuel line,
and fuel filter out of fuel tank.
5. W ash fuel filter with clean fuel and replace in tank.
6. Attach upper fuel line to fuel filter neck.
7. Replace side cover.
Upper Shell
Fan
Guard
Figure 7 - Upper Shell Removal, 35/50/
70,000 Btu/Hr Models
Fuel Filter
Side Cover
Figure 9 - Fuel Filter Removal, 35/50/70,000 Btu/Hr Models
Fuel Filter, Bushing,
and Lower Fuel Line
Upper
Shell
Figure 8 - Upper Shell Removal, 100/
150,000 Btu/Hr Models
Fuel Line
Fan
Guard
Upper Fuel
Line
Side Cover
Figure 10 - Fuel Filter Removal, 100/150,000 Btu/Hr Models
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