DeWalt D55273 User manual

D55273
Contractor’s Gas Wheeled Portable Air Compressor
Compresseur d’air portatif à essence, sur roues, de classe entrepreneur
Compresor de aire portátil a gasolina con ruedas para contratistas
INSTRUCTION MANUAL
GUIDE D'UTILISATION
MANUAL DE INSTRUCCIONES
INSTRUCTIVO DE OPERACIÓN, CENTROS DE SERVICIO Y PÓLIZA
DE GARANTÍA.ADVERTENCIA: LÉASE ESTE INSTRUCTIVO ANTES
DE USAR EL PRODUCTO.
If you have questions or comments, contact us.
Pour toute question ou tout commentaire, nous contacter.
Si tiene dudas o comentarios, contáctenos.
1-800-4-DEWALT • www.dewalt.com

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200
180
160
140
120
100
80
60
40
20
A. Pump Air Intake Filter
B. Engine Air Filter
C. Engine On/Off Switch
D. Air Tank Pressure Gauge
E. Regulated Pressure Gauge
F. Pressure Regulator
G. Air Outlet
H. Unloader Valve
I. Safety Valve
J. Air Tank Drain Valve
Pump Specifications
Inline, vertical twin cylinder, aluminum head
Single stage
Oil lubricated
Cast iron crankcase, cylinder and head
Bore: 2.756" (70 mm)
Stroke: 2.26" (57.5 mm)
Weight: 46 lbs. (20.86 kg)
Oil Capacity: 24.7 oz. (730 mL)
D55273 Air Compressor
K. Throttle Control
L. Pump Oil Dipstick
M. Pump Oil Drain Plug
N. Belt Tensioning Bolt
O. Low Oil Shut Down
P. Handle
Q. Handle Bracket
Engine Specifications
Honda GX160
Internal Combustion
4-stroke
3450 RPM
I
B
A
E
C
K
O
M
L
G
FD
HQ
P
FIG. 1
NOT A
STEP
N
J

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Specifications
MODEL WEIGHT HEIGHT WIDTH LENGTH AIR TANK CAPACITY
(GALLONS)
APPROX.
UNLOADER
RESET
PRESSURE
APPROX.
BLOW OFF
PRESSURE
TYPICAL
VALUES
@ 100 PSI CFM
D55273 185 lbs.
(83.9 kg) 22.3" (566.4 mm) 24.2" (614.68 mm) 50" (1270 mm) 10.5 39.7 liters 120 PSI (827.4 kPa) 150 PSI
(1034.2 kPa)
10.3
PUMP CYLNDER
AND HEAD
GASOLINE
ENGINE
Hot Surfaces
AFTERCOOLER
FIG. 2 ENGINE
MUFFLER
CROSSOVER BAR
Definitions: Safety Guidelines
The definitions below describe the level of severity
for each signal word. Please read the manual and
pay attention to these symbols.
DANGER: Indicates an imminently hazardous
situation which, if not avoided, will result in death
or serious injury.
WARNING: Indicates a potentially hazardous
situation which, if not avoided, could result in death
or serious injury.
CAUTION: Indicates a potentially hazardous
situation which, if not avoided, may result in minor
or moderate injury.
CAUTION: Used without the safety alert symbol
indicates a potentially hazardous situation which, if
not avoided, may result in property damage.
IF YOU HAVE ANY QUESTIONS OR COMMENTS ABOUT
THIS OR ANY D
E WALT TOOL, CALL US TOLL FREE AT:
1-800-4-DEWALT (1-800-433-9258)

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DANGER: RISK OF EXPLOSION OR FIRE
WHAT CAN HAPPEN HOW TO PREVENT IT
• Spilled gasoline and it’s
vapors can become ignited
from cigarette sparks, electri-
cal arcing, exhaust gases
and hot engine components
such as the muffler.
• Shut off engine and allow it to
cool before adding fuel to the
tank.
• Use care in filling tank to avoid
spilling fuel. Move unit away
from fueling area before start-
ing engine.
• Heat will expand fuel in the
tank which could result in
spillage and possible fire
explosion.
• Keep maximum fuel level
1/2" (12.7 mm) below bottom
of filler neck to allow for
expansion.
• Combustible materials
which come into contact
with hot engine parts can
become ignited.
• Add fuel outdoors in a well
ventilated area. Make sure
there are no sources of igni-
tion, such as cigarettes near
refueling location.
• Operate compressor in a
clean, dry, well ventilated
area a minimum of forty-
eight inches from any build-
ing, object or wall. Do not
operate unit indoors or in
any confined area.
• Operate compressor in an
open area away from dry
brush, weeds or other com-
bustible materials
.
Important Safety Instructions
Important Safety Instructions
WARNING: Do not operate this unit until you read and understand
this instruction manual and the engine instruction manual for safety,
operation and maintenance instructions.
WARNING: This product is not equipped with a spark arresting
muffler. If the product is not equipped and will be used around
flammable materials or on land covered with materials such as
agricultural crops, forest, brush, grass or other similar items, then
an approved spark arrester must be installed and is legally required
in the state of California. It is a violation of California statutes
section 130050 and/or sections 4442 and 4443 of the California
Public Resources Code, unless the engine is equipped with a spark
arrester, as defined in section 4442, and maintained in effective
working order. Spark arresters are also required on some U.S. Forest
Service land and may also be legally required under other statutes
and ordinances. Contact the engine manufacturer for information on
purchasing a spark arresting muffler.
WARNING: This product contains chemicals, including lead,
known to the State of California to cause cancer, and birth defects
or other reproductive harm.Wash hands after handling.
SAVE THESE INSTRUCTIONS

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• Improperly stored fuel could
lead to accidental ignition.
Fuel improperly secured
could get into the hands of
children or other unqualified
persons.
• Store fuel in an OSHA-
approved container, in a
secure location away from
work area.
• Unattended operation
of this product could
result in personal injury
or property damage. To
reduce the risk of fire, do
not allow the compressor
to operate unattended.
• Always remain in attendance
with the product when it is
operating.
DANGER: RISK OF INJURY OR PROPERTY DAMAGE WHEN
TRANSPORTING OR STORING
WHAT CAN HAPPEN HOW TO PREVENT IT
• Oil can leak or spill and could
result in fire or breathing
hazard; serious injury or
death can result. Oil leaks will
damage carpet, paint or other
surfaces in vehicles or trailers.
• Always place compressor
on a protective mat when
transporting to protect against
damage to vehicle from leaks.
Remove compressor from
vehicle immediately upon
arrival at your destination.
Always keep compressor level
and never lie on its side.
WARNING: RISK OF BURSTING
Air Tank: The air tank on your Air Compressor is designed and may
be UM coded (for units with air tanks greater than 6 inch diameter)
according to ASME Section VIII, Div. 1 rules. All pressure vessels
should be inspected once every two years. To find your state pressure
vessels inspector, look under the Division of Labor and Industries in
the government section of a phone book or call 1-800-4-
DEWALT for
assistance.
The following conditions could lead to a weakening of the air tank, and
result in a violent air tank explosion:
WHAT CAN HAPPEN HOW TO PREVENT IT
• Failure to properly drain
condensed water from
air tank, causing rust and
thinning of the steel air tank.
• Drain air tank daily or after each
use. If air tank develops a leak,
replace it immediately with a
new air tank or replace the
entire compressor.
• Modifications or attempted
repairs to the air tank. • Never drill into, weld, or make any modifications to the air
tank or its attachments. Never
attempt to repair a damaged or
leaking air tank. Replace with a
new air tank.
• Unauthorized modifications
to the unloader valve,
safety valve, or any other
components which control air
tank pressure.
• The air tank is designed
to withstand specific
operating pressures. Never
make adjustments or parts
substitutions to alter the factory
set operating pressures.

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• Excessive vibration can
weaken the air tank and
cause rupture or explosion.
Excessive vibration will
occur if the compressor is
not properly mounted or
if engine operates above
recommended RPM.
• Do not remove the stiffener bar
connecting the compressor
pump to the engine, except
to adjust belt tension, Then
securely tighten the stiffener
bar bolts.This bar controls unit
vibration.
Attachments & accessories:
• Exceeding the pressure rating
of air tools, spray guns, air
operated accessories, tires,
and other inflatables can
cause them to explode or
fly apart, and could result in
serious injury.
• Follow the equipment
manufacturers recommendation
and never exceed the maximum
allowable pressure rating
of attachments. Never use
compressor to inflate small
low pressure objects such
as children’s toys, footballs,
basketballs, etc.
Tires:
• Over inflation of tires could
result in serious injury and
property damage.
• Use a tire pressure gauge to
check the tires pressure before
each use and while inflating
tires; see the tire sidewall for
the correct tire pressure.
NOTE: Air tanks, compressors and
similar equipment used to inflate
tires can fill small tires similar to
these very rapidly. Adjust pressure
regulator on air supply to no more
than the rating of the tire pressure.
Add air in small increments and
frequently use the tire gauge to
prevent over inflation.
WARNING: RISK FROM FLYING OBJECTS
WHAT CAN HAPPEN HOW TO PREVENT IT
• The compressed air stream
can cause soft tissue damage
to exposed skin and can
propel dirt, chips, loose
particles, and small objects
at high speed, resulting in
property damage or personal
injury.
• Always wear certified safety
equipment: ANSI Z87.1 eye
protection (CAN/CSA Z94.3)
with side shields when using
the compressor.
• Never point any nozzle or
sprayer toward any part of
the body or at other people or
animals.
• Always turn the compressor off
and bleed pressure from the
air hose and air tank before
attempting maintenance,
attaching tools or accessories.

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DANGER: RISK TO BREATHING (ASPHYXIATION)
WHAT CAN HAPPEN HOW TO PREVENT IT
• Breathing exhaust fumes
will cause serious injury
or death! Engine exhaust
contains carbon monoxide,
an odorless and deadly gas.
• Always operate air compressor
outside in a clean, well
ventilated area. Avoid enclosed
areas such as garages,
basements, storage sheds,
which lack a steady exchange
or air. Keep children, pets
and others away from area of
operation.
• The compressed air directly
from your compressor is not
safe for breathing.The air
stream may contain carbon
monoxide, toxic vapors,
or solid particles from the
air tank. Breathing these
contaminant's can cause
serious injury or death.
• Air obtained directly from the
compressor should never be
used to supply air for human
consumption. In order to use air
produced by this compressor
for breathing, suitable filters and
in-line safety equipment must
be properly installed. In-line
filters and safety equipment
used in conjunction with the
compressor must be capable
of treating air to all applicable
local and federal codes prior to
human consumption.
• Sprayed materials such as
paint, paint solvents, paint
remover, insecticides, weed
killers, may contain harmful
vapors and poisons.
• Work in an area with good
cross ventilation. Read and
follow the safety instructions
provided on the label or safety
data sheets for the materials
you are spraying. Always use
certified safety equipment:
NIOSH/OSHA respiratory
protection designed for use with
your specific application.
WARNING: RISK OF HOT SURFACES
WHAT CAN HAPPEN HOW TO PREVENT IT
• Touching exposed metal such
as the compressor head,
engine head, engine exhaust
or outlet tubes, can result in
serious burns.
• Never touch any exposed
metal parts on compressor
during or immediately after
operation. Compressor will
remain hot for several minutes
after operation
• Do not reach around
protective shrouds or attempt
maintenance until unit has
been allowed to cool.

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WARNING: RISK FROM MOVING PARTS
WHAT CAN HAPPEN HOW TO PREVENT IT
• The engine can start
accidentally if the flywheel is
turned by hand or moved by
pulling on the starter rope.
• Always disconnect the spark
plug and bleed pressure from
the air tank before performing
maintenance.
• Moving parts such as the
pulley, flywheel, and belt can
cause serious injury if they
come into contact with you or
your clothing.
• Never operate the compressor
with guards or covers which are
damaged or removed.
• Keep your hair, clothing, and
gloves away from moving parts.
Loose clothes, jewelry, or long
hair can be caught in moving
parts.
• Air vents may cover moving
parts and should be avoided as
well.
• Attempting to operate
compressor with damaged or
missing parts or attempting
to repair compressor with
protective shrouds removed
can expose you to moving
parts and can result in serious
injury.
• Any repairs required on this
product should be performed
by a
DEWALT factory
service center or a DEWALT
authorized service center
WARNING: RISK OF UNSAFE OPERATION
WHAT CAN HAPPEN HOW TO PREVENT IT
• Unsafe operation of your air
compressor could lead to seri-
ous injury or death to you or
others.
• Review and understand all
instructions and warnings in
this manual.
• Become familiar with the oper-
ation and controls of the air
compressor.
• Keep operating area clear of all
persons, pets, and obstacles.
• Keep children away from the
air compressor at all times.
• Do not operate the product
when fatigued or under the
influence of alcohol or drugs.
Stay alert at all times.
• Never defeat the safety fea-
tures of this product.
• Equip area of operation with a
fire extinguisher.
• Do not operate machine with
missing, broken, or unautho-
rized parts.
• Never stand on the
compressor.

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WARNING: RISK OF INJURY FROM LIFTING
WHAT CAN HAPPEN HOW TO PREVENT IT
• Serious injury can result
from attempting to lift too
heavy an object.
• The compressor is too heavy
to be lifted by one person.
Obtain assistance from others
before lifting.
CAUTION: RISK FROM NOISE
WHAT CAN HAPPEN HOW TO PREVENT IT
• Under some conditions and
duration of use, noise from
this product may contribute
to hearing loss.
• Always wear certified safety
equipment: ANSI S12.6
(S3.19) hearing protection.
SAVE THESE INSTRUCTIONS
FOR FUTURE USE
FEATURES
UNLOADER VALVE
When the maximum air tank pressure is obtained, the unloader
valve (H) will blow-off. This will cause the compressor to exhaust
the air to the atmosphere and not the tank.
Manual Lock: The manual lock allows you to manually unload the
compressor with air pressure in the air tank. To operate the manual
lock:
Rotate the manual lock unloader
OPEN CLOSED
HH
lever to the open position to
prevent air tank pressure buildup.
Rotate manual lock unloader
lever to the closed position after
starting the engine to allow air
tank pressure to build. NOTE: Air
will not build in tank when manual lock unloader lever in the open
position.
SAFETY VALVE
This valve (I) is designed to prevent system failures
I
by relieving pressure from the system when the
compressed air reaches a predetermined level. The
valve is preset by the manufacturer and must not be
removed or modified in any way.
AIR INTAKE FILTER
The filter (A) is designed to clean air entering the pump. A
To ensure the pump continually receives a clean,
cool, and dry air supply the filter must always be clean
and the filter intake must be free from obstructions.
AIR TANK DRAIN VALVE
The drain valve (J) is used to remove J
moisture from the air tank after the air
compressor is shut off.
AIR TANK PRESSURE GAUGE
The air tank pressure gauge (D) indicates
air pressure in the air tank.

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REGULATED PRESSURE GAUGE
The regulated pressure gauge (E) indicates
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180
160
140
120
100
80
60
40
20
EF
D
the air pressure available at the outlet side
of the regulator. This pressure is controlled
by the regulator and is always less or equal
to the air tank pressure.
REGULATOR
The regulator knob (F) controls the air pressure coming from the air
tank.
Adjusting Regulator
1. Pull regulator knob (F) out.
2. Turn knob clockwise to increase regulated pressure and
counterclockwise to decrease regulated pressure.
3. When desired pressure is shown on the regulated pressure
gauge push knob in to lock.
THROTTLE CONTROL
When maximum air tank pressure is reached and
K
the unloader valve vents air, it activates the throttle
control (K) on the engine. This gas saving feature
holds the engine at a factory-set idling speed until
air pressure in the air tank drops to reset pressure.
The unloader valve then reactivates the throttle
control and accelerates the engine to full throttle.
LOW OIL SHUT DOWN SENSORS
The air compressor engine and pump are equipped
O
with low oil shutdown sensors (O). These are
safety devices designed to protect your engine and
pump from damage in the event the oil level in the
crankcase is below minimum.
If the oil in the pump or engine gets low while the air compressor is
running it will automatically shut down the engine and will not restart
until oil is added to the engine or pump. If the oil is low before start-
up, the engine will not start until oil is added.
NOTE: The low oil shutdown sensors are very sensitive. You must
fill the engine and pump to the full mark on the dipstick to inactivate
this safety device.
INSTALLATION
Assembly (Fig. 1)
HANDLE
Assembly handle (P) to handle bracket (Q) using hardware supplied.
The nuts supplied will not spin onto bolts, after two turns a wrench,
ratchet, or air tool needs to be used to tighten securely.
INSTALLING HOSES
WARNING: Risk of unsafe operation. Firmly grasp hose in hand
when installing or disconnecting to prevent hose whip.
1. Ensure regulated pressure gauge reads 0 PSI (0 kPa).
2. Apply sealant tape to hose threads.
3. Assemble hose(s) to air outlet(s) (G). IMPORTANT: Do not
assemble splitters directly to the air outlet(s) (G).
NOTE: Assembling quick connect bodies to air outlets (G) and quick
connect plugs to hose ends make connecting and disconnecting
hoses simple and easy. Quick connect bodies and plugs are
available for purchase from your local dealer or authorized service
center.
DISCONNECTING HOSES
WARNING: Risk of unsafe operation. Firmly grasp hose in hand
when installing or disconnecting to prevent hose whip.
1. Ensure regulated pressure gauge reads 0 PSI (0 kPa).

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2. Remove hose(s) from air outlet(s) (G).
Lubrication and Oil
ENGINE
1. The engine was filled WITH oil at the manufacturer. Check engine
oil level before operating unit. If necessary, fill engine to the
appropriate level with recommended oil, see engine's instruction
manual supplied by engine manufacturer for correct procedure.
2. Add fuel to engine. See engine's instruction manual supplied by
engine manufacturer for correct procedure.
WARNING: Risk of explosion or fire. Gasoline vapor is highly
flammable. Refuel outdoors preferably, or only in well-ventilated
areas. Do not refuel or check gasoline level while the engine is
running. Do not store, spill, or use gasoline near an open flame,
a source of sparks (such as welding), or near operating electrical
equipment.
AIR COMPRESSOR
The air compressor pump was filled WITH oil at the manufacturer.
Check air compressor pump oil level before operating unit. See
Compressor Pump Oil under Maintenance.
Compatibility
Air tools and accessories that are run off the compressor must be
compatible with petroleum based products. If you suspect that a
material is not compatible with petroleum products, an air line filter
for removal of moisture and oil vapor in compressed air is required.
NOTE: Always use an air line filter to remove moisture and oil vapor
when spraying paint.
Location
WARNING: Risk of breathing. Exhaust from the gasoline engine
contains deadly carbon monoxide, which is odorless and toxic.
Operate engine only in well ventilated areas.
CAUTION: Risk of property damage. In order to avoid damaging
the air compressor, do not allow the unit to be tilted more than 10º
when operating.
Place air compressor at least 4 feet (1.2 m) away from obstacles that
may prevent proper ventilation. Keep unit away from areas that have
dirt, vapor and volatile fumes in the atmosphere which may clog and
gum up the intake filter and valves, causing inefficient operation.
HUMID AREAS
In frequently humid areas, moisture may form in the pump and
produce sludge in the oil, causing running parts to wear out
prematurely. Excessive moisture is especially likely to occur if the unit
is located in an unheated area that is subject to large temperature
changes.Two signs of excessive humidity are external condensation
on the pump when it cools down and a “milky” appearance in
compressor oil.You may be able to prevent moisture from forming in
the pump by increasing ventilation or operating for longer intervals.
NOISE CONSIDERATIONS
Consult local officials for information regarding acceptable noise
levels in your area. To reduce excessive noise, use vibration mounts
or silencers, relocate the unit or construct total enclosures or baffle
walls. Contact a D
E WALT service center or call 1-800-4-D E WALT for
assistance.
TRANSPORTING
WARNING: Risk injury from lifting. Unit weighs more than 160 lbs.
(72.6 kg) Do not move or lift without assistance.
CAUTION: Risk of property damage. The wheels and handle do
not provide adequate clearance, stability or support for pulling the
unit up and down stairs or steps. The unit must be lifted, or pushed
up a ramp.

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When transporting the com-
SR,S
P
R,S
R
pressor in a vehicle, trailer,
etc. ensure that the air tank
is drained and the unit is
secured and placed on a flat
horizontal surface. Do not
transport in a standing
position. NOTE: Use
recommended tie down
points (R) when transporting. Use care when driving so to avoid
tipping the unit over in the vehicle. Damage can occur to the unit or
surrounding items if unit is tipped. Use a ramp if loading or unloading
the unit from a height of more than 12" (304.8 mm).
LIFTING
Always use two people when lifting and lift from the recommended
lift points (S).
WARNING: Risk injury from lifting. Unit weighs more than 160 lbs.
(72.6 kg) Do not move or lift without assistance.
MOVING
1. Grasp handle (P) of compressor, and lift compressor high
enough so unit can be rolled on the front tires.
WARNING: Risk of unsafe operation. Ensure proper footing and
use caution when rolling compressor so that unit does not tip or
cause loss of balance.
2. When location is reached slowly lower rear of compressor to
ground. Always store compressor in a horizontal position. NOTE:
Do not store in a standing position.
NOTE: Should the unit tip over, hard starting and smoking will occur
due to oil spillage.
General Requirements
The piping, fittings, receiver tank, etc. must be certified safe for at
least the maximum working pressure of the unit. Use hard welded or
threaded steel or copper pipes, cast iron fittings and hoses that are
certified safe for the units discharge pressure and temperature. Use
pipe thread sealant on all threads, and tighten joints thoroughly to
prevent air leaks. DO NOT USE PVC PLASTIC.
WARNING: Risk of bursting. Plastic or PVC pipe is not designed
for use with compressed air. Regardless of its indicated pressure
rating, plastic pipe can burst from air pressure. Use only metal pipe
for air distribution.
CONDENSATE DISCHARGE PIPING
If installing a condensate discharge line, the piping must be at least
one size larger than the connection, as short and direct as possible,
secured tightly and routed to a suitable drain point. Condensate must
be disposed of in accordance with local, state and federal laws and
regulations.
NOTE: All compressed air systems generate condensate that
accumulates in any drain point (e.g., tank, filter, aftercoolers, dryers).
This condensate contains oil and/or substances which may be
regulated and must be disposed of in accordance with local, state,
and federal laws and regulations.
PREPARATION FOR USE
Pre-Start Checklist
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Ensure air tank is drained, see Draining Air Tank under
Maintenance.
3. Ensure the drain valve (J) is closed.
4. Ensure safety valve (I) is functioning properly, see Checking
Safety Valve under Maintenance.

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5. Check pump oil level, see Compressor Pump Oil under
Maintenance.
CAUTION: Do not operate without oil or with inadequate oil.
DEWALT is not responsible for compressor failure caused by
inadequate oil.
6. Check engine's oil and fuel level, see engine's instruction manual
for correct procedures.
7. Visually inspect drive belt. Replace belt if frayed, cracked, or worn.
NOTE: Outer belt cover must be removed to inspect drive belt.
8. Ensure all guards, covers, and labels are in place, legible (for
labels) and securely mounted. Do not use compressor until all
items have been verified.
Initial Set-up
Read safety instructions before setting-up air compressor.
BREAK-IN PROCEDURE
WARNING: Risk of property damage. Serious damage may result
if the following break-in instructions are not closely followed.
This procedure is required:
• Before the air compressor is used for the first time.
• When the unloader valve has been replaced.
• When the compressor pump has been replaced.
The procedure:
1. Follow Pre-Start Checklist under Preparation for Use.
2. Rotate the unloader's manual lock to the open position to
prevent air tank pressure buildup.
3. Open the pressure regulator. Pull regulator knob (F) out and
rotate clockwise until it stops.
WARNING: Do not operate this unit until you read and understand
the engine instruction's manual for safety, operation and maintenance
instructions.
4. Prepare engine for first time use, see engine's instruction manual
for correct procedure.
5. Turn the engine ON/OFF switch (C) to the ON Position.
6. Start engine, see engine's instruction manual for correct
procedure.
7. Run the air compressor for 30 minutes to seat the rings and
lubricate all the internal surfaces. Ensure there is no pressure
build up in the air tank by observing the reading on the air tank
pressure gauge.
8. Rotate the manual lock on the unloader valve into the closed
position so the air tank pressure can build.
9. Close the pressure regulator. Rotate the regulator knob (F)
counterclockwise to its built-in stop and push knob in to lock in
place. This will allow air to build pressure in the air tank.
10. Compressed air will be available from the hose air outlet until it
is used up or bled off.
OPERATING PROCEDURES
Start-up (Fig. 1)
1. Follow Pre-Start Checklist under Preparation for Use.
2. Pull out and turn regulator knob (F) counterclockwise until fully
closed. Push in to lock. Regulated pressure gauge should read
0 PSI (0 kPa).
3. Rotate the manual lock unloader lever to the open position to
assist with start up.
4. Turn the engine ON/OFF switch (C) to the ON Position.
5. Start engine, see engine's instruction manual for correct
procedure.
6. Rotate manual lock unloader lever to the closed position to allow
air tank pressure to build. NOTE: Pump will not operate with the
manual lock unloader lever in the open position.

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7. Allow compressor to pump up to blow off pressure.
NOTE: If any unusual noise or vibration is noticed, stop the compressor
and refer to the troubleshooting section.
NOTE: The air compressor pump is capable of running continuously.
To prolong the air compressor's life, it is recommended to run at high
throttle 50-75% of the run time and idle for 25% of the run time
8. Attach hose and accessory.
WARNING: Risk of unsafe operation. Firmly grasp hose in hand
when installing or disconnecting to prevent hose whip.
CAUTION: Risk of unsafe operation. Compressed air from the unit
may contain water condensation and oil mist. Do not spray unfiltered
air at an item that could be damaged by moisture. Some air operated
tools or devices may require filtered air. Read the instructions for the
air tool or device.
9. Adjust regulator (F) to desired setting. See Regulator under
Features.
Shut-down
1. Stop engine, see engine's instruction manual for correct
procedure.
NOTE: If finished using compressor, follow Steps 2–6.
2. Turn regulator knob (F) counterclockwise until fully closed. Ensure
regulated pressure gauge reads 0 PSI (0 kPa).
3. Remove hose and accessory.
4. Drain the air tank. Ensure air tank pressure gauge reads 0 PSI
(0 kPa).
WARNING: Risk of bursting.Drain air tank daily.Water will condense
in air tank. If not drained, water will corrode and weaken the air tank
causing a risk of air tank rupture.
5. Allow the compressor to cool down.
6. Wipe air compressor clean and store in a safe, non freezing area.
MAINTENANCE
The following procedures must be followed when maintenance or
service is performed on the air compressor.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Disconnect spark plug wire.
3. Drain air tank.
4. Allow air compressor to cool down before starting service
NOTE: All compressed air systems contain maintenance parts (e.g.
oil, filters, separators) that are periodically replaced. These used parts
may contain substances that are regulated and must be disposed of in
accordance with local, state, and federal laws and regulations.
NOTE: Take note of the positions and locations of parts during
disassembly to make reassembly easier.
NOTE: Any service operations not included in this section should
be performed by a DEWALT factory service center or a DEWALT
authorized service center.
Maintenance Chart
Procedure Daily Weekly Monthly 1 year or
200 Hours
Check safety valve X
Inspect air filter + X
Drain air tank X
Check pump oil level X
Change pump oil**+
X
Oil leak inspection X
Inspect drive belt X
Check drive belt tension
X

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Procedure Daily Weekly Monthly 1 year or
200 Hours
Check pulley/flywheel
alignment
X
Check for unusual noise/
vibration
X
Check for air leaks* X
Clean compressor exterior X
Engine See engine instruction manual.
* To check for air leaks apply a solution of soapy water around joints.
While compressor is pumping to pressure and after pressure cuts out,
look for air bubbles to form.
** The pump oil must be changed after the first 20 hours or operation.
Thereafter, when using
DEWALT synthetic compressor oil, change oil
every 200 hours of operation or once a year, whichever comes first.
+ Perform more frequent in dusty or humid conditions.
Checking Safety Valve (Fig. 1)
WARNING: Hot surfaces. Risk of burn. Aftercooler, pump head,
and surrounding parts are very hot, do not touch (see the Hot
Surfaces identified in Fig. 2). Allow compressor to cool prior to
servicing.
WARNING: Risk of bursting. If the safety valve does not work
properly, over-pressurization may occur, causing air tank rupture or
an explosion.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Ensure air tank pressure gauge reads 0 PSI (0 kPa). Drain air
tank if necessary.
3. Grasp wire ring on safety valve (I).
4. Pull and release ring a few times to ensure plunger moves in and
out.
Checking Air Filter Element (Fig. 1)
WARNING: Hot surfaces. Risk of burn. Aftercooler, pump head,
and surrounding parts are very hot, do not touch (see the Hot
Surfaces identified in Fig. 2). Allow compressor to cool prior to
servicing.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Allow unit to cool.
3. Unscrew filter (A) top from filter base by turning counterclock-
wise about 5 degrees.
4. Separate filter top from base.
5. Remove element from filter base.
6. If element needs cleaning, blow out with air. Replace if needed.
Purchase replacement parts from your local dealer or authorized
service center. Always use identical replacement parts.
7. Place element back in filter base.
8. Reconnect filter top to filter base. While pushing in, rotate clock-
wise 5 degrees.
CAUTION: Risk of unsafe operation. Do not operate without air
inlet filter.
Draining Air Tank (Fig. 1)
WARNING: Risk of unsafe operation. Risk from noise. Air tanks
contain high pressure air. Keep face and other body parts away from
outlet of drain. Use safety glasses when draining as debris can be
kicked up into face. Use ear protection (
ANSI S12.6 (S3.19) hearing
protection)
as air flow noise is loud when draining.
NOTE: All compressed air systems generate condensate that
accumulates in any drain point (e.g., tanks, filter, aftercoolers,
dryers). This condensate contains lubricating oil and/or substances
which may be regulated and must be disposed of in accordance with
local, state, and federal laws and regulations.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.

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2. Move compressor into an inclined position so drain valve (J) is
at the lowest point (this will assist in removing moisture, dirt, etc.
from air tanks)
3. Place a suitable container under the drain valve to catch
discharge.
4. Grasp black lever on drain valve.
5. Slowly rotate lever to gradually bleed air from air tank.
CAUTION: Risk of Property Damage. Drain water from air tank
may contain oil and rust which can cause stains.
6. When air tank pressure gauge reads 10 PSI (68.9 kPa), rotate
valve to the fully open position.
7. Close drain valve when finished.
Compressor Pump Oil (Fig. 1)
CHECKING OIL
WARNING: Hot surfaces. Risk of burn. Aftercooler, pump head,
and surrounding parts are very hot, do not touch (see the Hot
Surfaces identified in Fig. 2). Allow compressor to cool prior to
servicing.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Place unit on a flat level surface.
3. Remove dipstick (L) and wipe clean.
4. Insert and remove dipstick without
MAX.
OIL
MIN.
threading dipstick into crankcase as
shown in figure.
5. Check the oil level on dipstick.
If oil level is at or below “Add”,
oil needs to be added. Add DEWALT
synthetic oil to the proper maximum
level as shown in figure.
NOTE: When filling the crankcase, the oil flows very slowly
into the pump. If the oil is added too quickly, it will overflow and
appear to be full.
CAUTION: Risk of Unsafe Operation. Overfilling with oil will cause
premature compressor failure. Do not overfill.
6. Replace dipstick and tighten securely.
CHANGING OIL
NOTE: Pump oil contains substances that are regulated and must
be disposed of in accordance with local, state and federal laws and
regulations.
WARNING: Hot surfaces. Risk of burn. Aftercooler, pump head,
and surrounding parts are very hot, do not touch (see the Hot
Surfaces identified in Fig. 2). Allow compressor to cool prior to
servicing.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Allow the unit to cool.
3. Disconnect spark plug wire.
4. Drain air tank.
5. Locate a suitable container under pump drain plug (J).
6. Remove the dipstick (L) from crankcase.
7. Remove the oil drain plug (M).
8. Allow ample time for all oil to drain out. (Tilting the compressor
towards the drain plug will assist in draining.)
9. Install the oil drain plug.
10. Fill pump with DEWALT synthetic compressor oil. Oil should not
exceed top raised line on side of crackcase. (Oil will be even with
bottom of threads in crankcase fill port.)
11. Install dipstick.
12. Reconnect spark plug wire.

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Checking Belt Tension (Fig. 1)
WARNING: Hot surfaces. Risk of burn. Aftercooler, pump head,
and surrounding parts are very hot, do not touch (see the Hot
Surfaces identified in Fig. 2). Allow compressor to cool prior to
servicing.
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Allow the unit to cool.
3. Disconnect spark plug wire.
4. Drain air tank.
5. Remove eight belt guard screws.
6. Remove outer belt cover.
7. Measure belt tension. Proper tension is achieved when a three
(3) pound weight or equivalent finger pressure applied midway
between the motor pulley and compressor flywheel causes a
1/4" (6.35 mm) deflection of the belt., if adjustment is needed
see Adjusting Belt Tension under Maintenance.
8. Replace belt guard.
9. Reconnect spark plug wire.
Adjusting Belt Tension
WARNING: Hot surfaces. Risk of burn. Aftercooler, pump head,
and surrounding parts are very hot, do not touch (see the Hot
Surfaces identified in Fig. 2). Allow compressor to cool prior to
servicing.
1. Ensure engine ON/OFF switch (C) is in the OFF position.
2. Allow the unit to cool.
3. Disconnect spark plug wire.
4. Drain air tank
5. Loosen but do not remove four pump mounting bolts.
6. Remove eight belt cover screws.
7. Remove outer belt cover.
8. Loosen but do not remove pump stiffener T
bracket bolt (T).
9. Turn belt tensioning (S) bolt
clockwise to increase belt tension or
counterclockwise to loosen belt tension.
10. Check the belt tension again. See Step
7 in Checking Belt Tension under
Maintenance.
11. When tension is correct, retighten four S
pump mounting bolts (torque to
18–22 ft.-lbs./24.4–29.8 Nm), stiffener
bracket bolt (torque to 18–22 ft.-lbs./
24.4–29.8 Nm), and replace belt cover.
12. Reconnect spark plug wire.
Pulley and Flywheel
Alignment
The air compressor flywheel and engine pulley must be in-line (in
the same plane) within 1/16" (1.6 mm) to ensure belt retention within
flywheel belt grooves. To check alignment:
1. Ensure engine ON/OFF switch (C) is in the OFF Position.
2. Allow the unit to cool.
3. Disconnect spark plug wire.
4. Drain air tank.
5. Remove outer belt cover.
6. Place a straightedge
X
U
WA1
A1
A2
A2 B1 B2
B1 B2
V
(U) against the outside
of the flywheel (W) and
the engine drive pulley
(X).

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7. Measure the distance between the edge of the belt (V) and
the straightedge at points A1 and A2 in Figure. The difference
between measurements should be no more than 1/16" (1.6
mm).
8. If the difference is greater than 1/16" (1.6 mm), loosen the
setscrew holding the engine drive pulley to the shaft and adjust
the pulley's position on the shaft until the A1 and A2 measure-
ments are within 1/16" (1.6 mm) of each other.
9. Tighten the engine drive pulley setscrew to 140–150 in.-lbs.
(15.42–16.95 Nm).
10. Visually inspect the engine drive pulley to verify that it is
perpendicular to the drive motor shaft. Points B1 and B2 of Figure
should appear to be equal. If they are not, loosen the setscrew of
the engine drive pulley and equalize B1 and B2, using care not to
disturb the belt alignment performed in Step 8.
11. Retighten the engine drive pulley setscrew to 140–150 in.-lbs.
(15.42–16.95 Nm).
12. Reinstall belt guard.
13. Reconnect spark plug wire.
ACCESSORIES
Recommended accessories for use with your tool are available
for purchase from your local dealer or authorized service center.
If you need assistance in locating any accessory for your tool,
please contact D
E WALT Industrial Tool Co., 701 East Joppa Road,
Baltimore, MD 21286, call 1-800-4-DEWALT (1-800-433-9258) or
visit our website www.dewalt.com.
CAUTION: The use of any other accessory not recommended for
use with this tool could be hazardous. Use only accessories rated
equal to or higher than the rating of the air compressor.
SERVICE INFORMATION
Please have the following information available for all service calls:
Model Number ____________ Serial Number ___________
Date and Place of Purchase ____________________________
Repairs
To assure product SAFETY and RELIABILITY, repairs, maintenance
and adjustment should be performed by a D
E WALT factory service
center, a D
E WALT authorized service center or other qualified
service personnel. Always use identical replacement parts.
Full One Year Warranty
DEWALT heavy duty industrial tools are warranted for one year from
date of purchase. We will repair, without charge, any defects due
to faulty materials or workmanship. For warranty repair information,
call 1-800-4-D
E WALT. This warranty does not apply to accessories
or damage caused where repairs have been made or attempted by
others. This warranty gives you specific legal rights and you may
have other rights which vary in certain states or provinces.
LATIN AMERICA: This warranty does not apply to products sold
in Latin America. For products sold in Latin America, see country
specific warranty information contained either in the packaging, call
the local company or see website for warranty information.

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FREE WARNING LABEL REPLACEMENT: If your warning labels
become illegible or are missing, call 1-800-4-D
E WALT for a free
replacement.
A20550
DO NOT STORE OR OPERATE
IN UPRIGHT POSITION.
NO LO GUARDE NI OPERE
EN POSICIÓN VERTICAL.
NE PAS RANGER NI UTILISERL'APPAREIL
EN POSITION VERTICALE.
GLOSSARY
CFM: Cubic feet per minute.
SCFM: Standard cubic feet per minute; a unit of measure of air
delivery.
PSIG: Pounds per square inch gauge; a unit of measure of
pressure.
Code Certification: Products that bear one or more of the
following marks: UL, CUL, ETL, CETL, have been
evaluated by OSHA certified independent safety
laboratories and meet the applicable Underwriters
Laboratories Standards for Safety.
California Code: Unit may comply with California Code 462 (l)
(2)/(M) (2). Specification/model label is on the side of the
air tank on units that comply with California Code.
Unloader Blow-Off Pressure: All models are continuous
running units controlled by air tank pressure. When the
maximum air tank pressure is obtained, the unloader
valve will blow-off. This will cause the compressor to
exhaust the air to the atmosphere and not the tank. This
decreases the load on the engine and allows it to run at
a near no-load condition.
Unloader Reset Pressure: When the air tank pressure drops
to a predetermined point, the unloader valve closes. The
air tank pressure will now increase until it reaches the
unloader blow-off pressure.

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Troubleshooting Guide
This section provides a list of the more frequently encountered malfunctions, their causes and corrective actions.The operator or maintenance
personnel can perform some corrective actions, and others may require the assistance of a qualified DEWALT technician or your dealer.
Problem Code
Excessive air tank pressure-safety valve pops off ......................................................................1
Air leaks ....................................................................................................................................2
Continuous air leak at unloader valve........................................................................................3
Air leaks in air tank or at air tank welds ....................................................................................4
Air leaks between head and valve plate....................................................................................5
Air leaks from safety valve.........................................................................................................6
Compressor is not supplying enough air to operate accessories..............................................2,7,8,9,10,12,13
Restricted air intake...................................................................................................................12
Excessive vibration ....................................................................................................................14,15
Knocking Noise..........................................................................................................................6,13,14,15,16,17,18,19
Excessive belt wear ...................................................................................................................13,16,19,20
Squealing sound........................................................................................................................13
Engine will not run .....................................................................................................................21,22,23,34
Pressure reading on the regulated pressure gauge drops when an accessory is used...........24
Regulator knob has continuous air leak ....................................................................................25
Regulator will not shut off air outlet ...........................................................................................25
Moisture in pump crankcase......................................................................................................2,5,11,26,27,28,29,30,31
Pump will not run.......................................................................................................................32
Air tank pressure will not build...................................................................................................32,33