Desa 20 User manual

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
OWNER’S MANUAL
Heater Sizes: 8,8 (30,000) 20,5 (70,000)
26,4 (90,000) 44 kW (150,000 Btu/Hr)

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099623
CONTENTS SECTION PAGE
Safety Information.................................................................................. 3
Product Identification ............................................................................. 4
Unpacking............................................................................................... 5
Assembly ................................................................................................ 5
Theory of Operation ............................................................................... 6
Fuels ....................................................................................................... 6
Ventilation .............................................................................................. 7
Operation ................................................................................................ 7
Storing, Transporting, or Shipping ......................................................... 8
Preventative Maintenance Schedule....................................................... 8
Troubleshooting...................................................................................... 9
Service Procedures ................................................................................ 10
Upper Shell Removal ...................................................................... 10
Fuel Filter (8,8/20,5 kW [30/70,000 Btu/Hr] Models) ................... 10
Fuel Filter (26,4 kW [90,000 Btu/Hr] Model) ................................ 11
Fuel Filter (44 kW [150,000 Btu/Hr] Model) ................................. 11
Spark Plug (8,8 kW [30,000 Btu/Hr] Model) ................................. 12
Spark Plug (20,5/26,4/44 kW [70/90/150,000 Btu/Hr] Models) .... 13
Air Output, Air Intake, and Lint Filters .......................................... 14
Pump Pressure Adjustment ............................................................. 14
Nozzle (8,8 kW [30,000 Btu/Hr] Model)........................................ 15
Nozzle (20,5/26,4 kW [70/90,000 Btu/Hr] Models)....................... 16
Nozzle (44 kW [150,000 Btu/Hr] Model)....................................... 17
Pump Rotor ..................................................................................... 18
Fan................................................................................................... 19
Specifications......................................................................................... 19
Wiring Diagrams ................................................................................... 20
Illustrated Parts Breakdown and Parts List............................................ 21
Wheels and Handles (26,4/44 kW [90/150,000 Btu/Hr] Models) .. 21
8,8 kW (30,000 Btu/Hr) Model....................................................... 22
20,5 kW (70,000 Btu/Hr) Model..................................................... 24
26,4 kW (90,000 Btu/Hr) Model..................................................... 26
44 kW (150,000 Btu/Hr) Model...................................................... 28
Accessories ............................................................................................ 30
Warranty and Repair Service................................................... Back Cover

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SAFETY
INFORMATION
WARNING ICON G 001
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.
WARNING ICON G 001
DANGER
Carbon monoxide poisoning may lead to death!
Carbon Monoxide Poisoning: Early signs of carbon monoxide poisoning
resemblethe flu,with headaches,dizziness, ornausea. Ifyou have these signs, the
heater may not be working properly. Getfreshair atonce!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.
• Never use heater where gasoline, paint thinner, or other highly flammable
vapors are present.
• Follow all local ordinances and codes when using heater.
• Use only in well-vented areas. Provide at least a three-square foot (2800
square cm) opening of fresh, outside air for each 29,3 kW (100,000 Btu/Hr)
of rating.
• Use only in places free of flammable vapors or high dust content.
• Use only with the electrical voltage and frequency specified on model plate.
• Use only a grounded (earthed) extension cord.
• Minimum heater clearances from combustibles:
Outlet: 250 cm (8 Ft.) Sides, Top, and Rear: 125 cm (8 Ft.)
• Locate heater on a stable and level surface while 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. Using duct work could
reduce the necessary air flow of heater. Heater would produce excessive
carbon monoxide.

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Fuel Cap
Lower
Shell
Power Cord
Upper Shell
Figure 3 - 44 kW (150,000 Btu/Hr) Model
Handle
Fuel Cap
Lower Shell
Side Cover
Fuel Tank
Figure 1 - 8,8/20,5 kW (30/70,000 Btu/Hr) Models
PRODUCT
IDENTIFICATION Upper Shell
Hot Air Outlet
Hot Air
Outlet
Air Filter
End Cover
Fan Guard
Power Cord
Flame-Out
Control Reset
Button
Figure 2 - 26,4 kW (90,000 Btu/Hr) Model
Fan Guard
Air Filter
End Cover
Flame-Out Control
Reset Button
Side Cover
Fuel Tank
Lower
Shell
Fuel Cap
Fan Guard
Power Cord
Upper Shell
Flame-Out
Control Reset Button
Hot Air
Outlet
Fuel
Tank

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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.
ASSEMBLY
(For 26,4 and 44 kW [90,000
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: When installing wheels, point extended hub of wheels toward
wheel support frame (see Figure 4).
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.
Figure 4 - Wheel and Handle Assembly, 26,4/44 kW
(90/150,000 Btu/Hr Models) Only
Wheel
Air
Inlet
Front
Handle
Hot Air
Outlet
Fuel
Tank
Flange
Rear
Handle
Screw
Wheel
Support
Frame
Nut
Cap Nut Extended
Hub
Axle

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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.
Fan
Fuel
Filter
Air For Fuel
System Air For Combustion And Heating Fuel
Spark
Plug
Combustion
Chamber Intake
Air
Filter
Motor Air Pump
Air line
To Burner Electronic Ignitor
Clean
Heated
Air Out
Cool
Air
In
Output
Air
Filter
Nozzle
Fuel
Tank
Figure 5 - Cross Section Operational View
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
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.
WARNING ICON G 001
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.
Burner
Head

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VENTILATION
OPERATION
Continued
Figure 6 - Flame-Out Control Reset
Button, 8,8/20,5 kW (30/70,000 Btu/Hr)
Models
Figure 7 - Flame-Out Control Reset
Button, 26,4 kW (90,000 Btu/Hr)
Model
WARNING ICON G 001
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
29,3 kW (100,000 Btu/Hr) rating. Provide extra fresh air if more heaters are being
used.
Example: A 44 kW (150,000 Btu/Hr) heater requires one of the following:
• a 4,88 m (16 foot) wide two-car garage door raised 8,59 cm (3.38 inches)
• a 2,75 m (9 foot) wide single-car garage door raised 15,24 cm (6 inches)
• two, 76,20 cm (thirty-inch) wide windows raised 28 cm (11 inches)
Flame-Out
Control
Reset
Button
WARNING ICON G 001
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 grounded (earthed) exten-
sion cord.
Extension Cord Wire Size Requirements
Up to 100 feet (30.5 meters) long, use 16 AWG (1.0 mm2) conductor
101 to 200 feet (30.6 to 61 meters) long, use 14 AWG (1.5 mm2) conductor
Heater will start when power cord is plugged into outlet. If not, push in flame-
out control reset button (see Figures 6 thru 8).
Flame-Out
Control
Reset
Button

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OPERATION
Continued
Figure 8 - Flame-Out Control Reset Button, 44 kW (150,000 Btu/Hr) Model
Continued
PREVENTATIVE
MAINTENANCE
SCHEDULE
Item How Often How To
Fuel tank Flush every 150-200 hours See Storing, Transporting, or
of operation or as needed. Shipping, above.
Air output and Replace every 500 hours of See Air Output, Air Intake,
lint filters operation or once a year. and Lint Filters, page 14.
Air intake Wash and dry with soap and See Air Output, Air Intake,
filter water every 500 hours of and Lint Filters, page 14.
operation or as needed.
Fuel filter Clean twice a heating season See Fuel Filter, pages 10
or as needed. and 11.
To Stop Heater
1. Unplug power cord from outlet.
To Restart Heater
1. Wait 2 minutes after stopping heater.
2. Repeat steps under To Start Heater, page 7.
WARNING ICON G001
WARNING
Never service heater while it is plugged in, operating, or
hot. Severe burns and electrical shock can occur.
Flame-Out
Control
Reset Button
(Fan Guard
Removed)
STORING,
TRANSPORTING ,
OR SHIPPING
Note: If shipping, transport companies require 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: Do not store kerosene over summer months for use during next
heating season. Using old fuel could damage heater.

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Continued
Item How Often How To
Spark plug Clean and regap every 600 See Spark Plug, pages 12 and 13.
hours operation or replace
as needed.
Fan blades Clean every season or as needed. See Fan, page 19.
Motor Not required/permanently lubricated
TROUBLE-
SHOOTING
WARNING ICON G 001
WARNING
Never service heater while it is plugged in, operating, or hot.
Severe burns and electrical shock can occur.
Wrong pump pressure
Dirty air output, air intake,
and lint filters
Dirty fuel filter
Dirt in nozzle
Dirty photocell lens
Bad flame-out control
Heater ignites, but
flame-out control
shuts off heater after
a short period of
time.
See Pump Pressure
Adjustment, page 14.
See Air Output, Air Intake
and Lint Filters, page 14.
See Fuel Filter, pages 10
and 11.
SeeNozzle,pages15thru17.
Clean photocell lens.
Replace flame-out control.
Heater will not
ignite, but motor runs
for a short period of
time.
OBSERVED FAULT POSSIBLE CAUSE REMEDY
See Pump Pressure
Adjustment, page 14.
See Spark Plug, pages 12
and 13.
See Fuel Filter, pages 10
and 11.
See Nozzle, pages 15 thru
17.
Drain and flush fuel tank
with clean kerosene. See
Storing, Transporting, or
Shipping, page 8.
Make sure electronic
ignitor mounting is tight.
Replace electronic ignitor.
Wrong pump pressure
Carbon deposits on spark
plug and/or improper gap
Dirty fuel filter
Dirt in nozzle
Water in fuel tank
Electronic ignitor not
grounded (earthed)
Bad electronic ignitor
WARNING ICON G001
WARNING: High voltage!
Motor does not start
when heater is
plugged in, fan
rotates slowly or
does not turn.
Flame-out control not reset
Binding pump rotor
Reset flame-out control
button, see Figures 6 thru
8, pages 7 and 8.
If fan is hard to turn, see
Pump Rotor, page 18.

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Upper
Shell
Fan
Guard
Figure 12 - Fuel Filter Removal, 8,8/20,5 kW (30/70,000 Btu/Hr) Models
Figure 11 - Upper Shell Removal, 44 kW (150,000 Btu/Hr) Model
Upper
Shell
Fuel Filter
(8,8/20,5 kW [30/70,000 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. Wash fuel filter with clean
fuel and replace in tank.
6. Attach rubber fuel line to
fuel filter neck.
7. Replace side cover.
Fan Guard
Upper
Shell
SERVICE
PROCEDURES
Upper Shell Removal
1. Remove screws along each
side of heater using 5/16"
nut-driver. These screws
attach upper and lower
shells together.
2. Lift upper shell off.
3. Remove fan guard.
WARNING ICON G 001
WARNING
Never service heater while it is plugged in, operating, or
hot. Severe burns and electrical shock can occur.
Fan
Guard
Fuel Filter
Side Cover Fuel Line
Figure 10 - Upper Shell Removal,
25,4 kW (90,000 Btu/Hr) Model
Figure 9 - Upper Shell Removal,
8,8/20,5 kW (30/70,000 Btu/Hr)
Models