DeWalt DCST920 User manual

RECONDITIONED DCST920 20V Max* Lithium String Trimmer
Taille-bordure DCST920 au lithium-ion de 20 V max.*
Podadora de cuerda con batería de iones de litio de 20 V Máx* DCST920
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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Denitions: 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.
NOTICE: Indicates a practice not related to personal injury
which, if not avoided, may result in property damage.
KEY INFORMATION YOU SHOULD KNOW
•
WARNING: Do not remove guard. The guard
must be attached when trimming. Operating this trimmer without
the guard will violate the product warranty.
•
CAUTION: When replacing the line, use only
.080 inches (2.032 mm) diameter line (MODEL NO. DWO1DT801
OR DWO1DT802 are recommended). Other sizes may degrade
performance or cause damage to the trimmer.
• For use only with DeWALT 20V batteries.
IF YOU HAVE ANY QUESTIONS OR COMMENTS ABOUT THIS OR
ANYDeWALTAPPLIANCE,CALLUSTOLLFREEAT: 1-800-4-DeWALT
(1-800-433-9258).
Important Safety Warnings
WARNING:When using electric gardening appliances,
basic safety precautions should always be followed to reduce risk of
fire, electric shock, and personal injury, including the following.
READ ALL INSTRUCTIONS
• ALWAYS WEAR EYE PROTECTION – Wear safety spectacles
or goggles at all times when battery is installed. These items are
available for purchase.
• DRESS PROPERLY – Do not wear loose clothing or jewelry. They
can be caught in moving parts. Gloves and substantial rubber
soled footwear are recommended when working outdoors. Don’t
operate the appliance when barefoot or wearing open sandals.
Wear heavy long pants to protect your legs. Wear protective hair
covering to contain long hair.
• NYLON LINE – Keep face, hands and feet clear of rotating nylon
line at all times.
• THE ROTATING LINE PERFORMS A CUTTING FUNCTION –
Use care when trimming around screens and desirable plantings.
• DO NOT USE materials not recommended, such as metal wire,
rope, and the like.
• KEEP ALL BYSTANDERS AWAY – at a safe distance from work
area, especially children.
• MAKE SURE that other persons and pets are at least 100 feet
(30m) away.
• TO REDUCE THE RISK of rebound (ricochet) injury, work going
away from any nearby solid object such as wall, steps, large stone,
tree, etc. Use great care when working close to solid objects and
where necessary, do trimming by hand.
• AVOID ACCIDENTALLY STARTING – Don’t carry with finger on
trigger when battery is installed.
• USE THE RIGHT APPLIANCE – Do not use this appliance for any
job except that for which it is intended.
• DON’T OVERREACH – Keep proper footing and balance at all times.
•
DON’T FORCE APPLIANCE – It will do the job better and with less
likelihood of a risk of injury at the rate for which it was designed
• DAMAGE TO UNIT – If you strike or become entangled with a
foreign object, stop appliance immediately, remove battery, check

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WARNING:Do not use appliance if the switch trigger
does not turn the appliance on or off. Any appliance that can not be
controlled with the switch trigger is dangerous and must be repaired.
WARNING: Some dust created by this product contains
chemicals known to the State of California to cause cancer, birth defects
or other reproductive harm. Some examples of these chemicals are:
• compounds in fertilizers
• compounds in insecticides, herbicides and pesticides
• arsenic and chromium from chemically treated lumber
To reduce your exposure to these chemicals, wear approved safety
equipment such as dust masks that are specially designed to filter out
microscopic particles.
WARNING: This product is not an edger and is not
intended to be used for edging.
• The label on your appliance may include the following symbols. The
symbols and their definitions are as follows:
V................... volts A......................amperes
Hz................. hertz W.....................watts
min ............... minutes or AC..........alternating
or DC... direct current ........................current
................. Class I Construction no....................no load
(grounded) speed
................. Class II Construction
(double insulated) …/min..............per minute
RPM ............. revolutions per .....................earthing
..................... minute ........................terminal
.................. safety alert symbol
Important Safety Instructions for All Battery
Packs
When ordering replacement battery packs, be sure to include the
catalog number and voltage. Consult the chart at the end of this
manual for compatibility of chargers and battery packs.
for damage and have any damage repaired before further operation
is attempted. Do not operate with a broken hub or spool.
• REMOVE BATTERY – when not in use, when replacing line, or
prior to cleaning.
• AVOID DANGEROUS ENVIRONMENTAL CONDITIONS – Do
not use electric appliances in damp or wet locations. Follow all
instructions in this Instruction Manual for proper operation of your
appliance. Don’t use the appliance in the rain.
• DO NOT OPERATE portable electric appliances in gaseous or
explosive atmospheres. Motors in these appliances normally spark,
and the sparks might ignite fumes.
• STORE IDLE APPLIANCES INDOORS – When not in use, appliances
should be stored indoors in a dry, locked-up place out of reach of children.
• STAY ALERT – Do not operate this unit when you are tired, ill, or
under the influence of alcohol, drugs, or medication.
• MAINTAIN APPLIANCES WITH CARE – Follow instructions in
maintenance section. Keep handles dry, clean and free from oil
and grease.
• CHECK DAMAGED PARTS – Before further use of the appliance,
a guard or other part that is damaged should be carefully checked
to determine that it will operate properly and perform its intended
function. Check for alignment of moving parts, binding of moving
parts, breakage of parts, mounting, and any other condition that
may affect its operation. A guard or other part that is damaged
should be properly repaired or replaced by an authorized service
center unless otherwise indicated elsewhere in this manual.
• DO NOT immerse appliance in water or squirt it with a hose. DO
NOT allow any liquid to get inside it.
• DO NOT store the appliance on or adjacent to fertilizers or chemicals.
• DO NOT clean with a pressure washer.
• Keep guards in place and in working order.
• Keep hands and feet away from cutting area.
• Do not charge appliance in rain, or in wet locations

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battery terminals. For example, do not place the battery pack in
aprons, pockets, appliance boxes, product kit boxes, drawers, etc.,
with loose nails, screws, keys, etc. Transporting batteries can
possibly cause fires if the battery terminals inadvertently come
in contact with conductive materials such as keys, coins, hand
appliances and the like. The US Department of Transportation
Hazardous Material Regulations (HMR) actually prohibit transporting
batteries in commerce or on airplanes (e.g., packed in suitcases and
carry-on luggage) UNLESS they are properly protected from short
circuits. So when transporting individual battery packs, make sure that
the battery terminals are protected and well insulated from materials
that could contact them and cause a short circuit.
SPECIFIC SAFETY INSTRUCTIONS FOR LITHIUM ION (Li-Ion)
• Do not incinerate the battery pack even if it is severely
damaged or is completely worn out. The battery pack can
explode in a fire. Toxic fumes and materials are created when
lithium ion battery packs are burned.
• If battery contents come into contact with the skin,
immediately wash area with mild soap and water. If battery
liquid gets into the eye, rinse water over the open eye for 15
minutes or until irritation ceases. If medical attention is needed,
the battery electrolyte is composed of a mixture of liquid organic
carbonates and lithium salts.
• Contents of opened battery cells may cause respiratory irritation.
Provide fresh air. If symptoms persist, seek medical attention.
WARNING: Burn hazard. Battery liquid may be
flammable if exposed to spark or flame.
The RBRC™ Seal
The RBRC™ (Rechargeable Battery Recycling
Corporation) Seal on the nickel cadmium, nickel metal
hydride or lithium ion batteries (or battery packs) indicate
that the costs to recycle these batteries (or battery packs)
The battery pack is not fully charged out of the carton. Before using
the battery pack and charger, read the safety instructions below and
then follow charging procedures outlined.
READ ALL INSTRUCTIONS
• Do not charge or use the battery pack in explosive
atmospheres, such as in the presence of flammable liquids,
gases or dust. Inserting or removing the battery pack from the
charger may ignite the dust or fumes.
• Never force the battery pack into the charger. Do not modify
the battery pack in any way to fit into a non-compatible
charger as battery pack may rupture causing serious
personal injury. Consult the chart at the end of this manual for
compatibility of batteries and chargers.
• Charge the battery packs only in designated DeWalt chargers.
• DO NOT splash or immerse in water or other liquids.
• Do not store or use the appliance and battery pack in
locations where the temperature may reach or exceed
105 °F (40 °C) (such as outside sheds or metal buildings in
summer). For best life store battery packs in a cool, dry location.
NOTE: Do not store the battery packs in a appliance with the
trigger switch locked on. Never tape the trigger switch in the
ON position.
WARNING: Fire hazard. Never attempt to open the
battery pack for any reason. If the battery pack case is cracked or
damaged, do not insert into the charger. Do not crush, drop or damage
the battery pack. Do not use a battery pack or charger that has
received a sharp blow, been dropped, run over or damaged in any way
(e.g., pierced with a nail, hit with a hammer, stepped on). Damaged
battery packs should be returned to the service center for recycling.
WARNING Fire hazard. Do not store or carry
the battery pack so that metal objects can contact exposed

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dust, metal chips, steel wool, aluminum foil or any buildup of metallic
particles should be kept away from the charger cavities. Always
unplug the charger from the power supply when there is no battery
pack in the cavity. Unplug the charger before attempting to clean.
•DO NOT attempt to charge the battery pack with any
chargers other than the ones in this manual. The charger and
battery pack are specifically designed to work together.
• These chargers are not intended for any uses other than
charging DeWALT rechargeable batteries. Any other uses
may result in risk of fire, electric shock or electrocution.
• Do not expose the charger to rain or snow.
• Pull by the plug rather than the cord when disconnecting the
charger. This will reduce the risk of damage to the electric plug and cord.
• Make sure that the cord is located so that it will not be
stepped on, tripped over or otherwise subjected to damage
or stress.
• Do not use an extension cord unless it is absolutely
necessary. Use of improper extension cord could result in risk of
fire, electric shock or electrocution.
• When operating a charger outdoors, always provide a dry
location and use an extension cord suitable for outdoor use. Use
of a cord suitable for outdoor use reduces the risk of electric shock.
• An extension cord must have adequate wire size (AWG or
American Wire Gauge) for safety. The smaller the gauge number
of the wire, the greater the capacity of the cable, that is, 16 gauge
has more capacity than 18 gauge. An undersized cord will cause a
drop in line voltage resulting in loss of power and overheating. When
using more than one extension to make up the total length, be sure
each individual extension contains at least the minimum wire size.
The following table shows the correct size to use depending on
cord length and nameplate ampere rating. If in doubt, use the next
heavier gauge. The lower the gauge number, the heavier the cord.
at the end of their useful life have already been paid by DeWALT. In some
areas, it is illegal to place spent nickel cadmium, nickel metal hydride or
lithium ion batteries in the trash or municipal solid waste stream and the
RBRC program provides an environmentally conscious alternative.
RBRC™, in cooperation with DeWALT and other battery users, has
established programs in the United States and Canada to facilitate
the collection of spent nickel cadmium, nickel metal hydride or lithium
ion batteries. Help protect our environment and conserve natural
resources by returning the spent nickel cadmium, nickel metal hydride
or lithium ion batteries to an authorized DeWALT service center or
to your local retailer for recycling. You may also contact your local
recycling center for information on where to drop off the spent battery.
RBRC™ is a registered trademark of the Rechargeable Battery
Recycling Corporation.
Important Safety Instructions for All Battery
Chargers
SAVE THESE INSTRUCTIONS: This manual contains important
safety and operating instructions for battery chargers.
• Before using the charger, read all instructions and cautionary
markings on the charger, battery pack and product using the
battery pack.
WARNING: Shock hazard. Do not allow any liquid to
get inside the charger. Electric shock may result.
CAUTION: Burn hazard. To reduce the risk of injury,
charge only DeWALT rechargeable battery packs. Other types of
batteries may overheat and burst resulting in personal injury and
property damage.
NOTICE: Under certain conditions, with the charger plugged into the
power supply, the charger can be shorted by foreign material. Foreign
materials of a conductive nature, such as, but not limited to, grinding

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Chargers
Your appliance uses a DeWALT charger.
J
FIG. 1
Be sure to read all safety instructions before
using your charger. Consult the chart at the
end of this manual for compatibility of
chargers and battery packs.
Charging Procedure (Fig. 1)
1. Plug the charger into an appropriate outlet
before inserting the battery pack.
2. Insert the battery pack (J) into the charger,
as shown in Figure 1, making sure the
pack is fully seated in charger. The red
(charging) light will blink continuously, indicating that the charging
process has started.
3. The completion of charge will be indicated by the red light
remaining ON continuously. The pack is fully charged and may be
used at this time or left in the charger.
Indicator Light Operation
PACK CHARGING
PACK CHARGED
x
HOT/COLD DELAY
PROBLEM PACK OR CHARGER
PROBLEM POWERLINE
Charge Indicators
This charger is designed to detect certain problems that can arise.
Problems are indicated by the red light flashing at a fast rate. If this
occurs, remove and then reinsert the battery pack into the charger.
Minimum Gauge for Cord Sets
Ampere Rating
Volts Total Length of Cord in Feet (meters)
120V 25 (7.6) 50 (15.2) 100 (30.5) 150 (45.7)
240V 50 (15.2) 100 (30.5) 200 (61.0) 300 (91.4)
More
Than
Not More
Than AWG
0 6 18 16 16 14
610 18 16 14 12
10 12 16 16 14 12
12 16 14 12 Not Recommended
• Do not place any object on top of the charger or place the
charger on a soft surface that might block the ventilation
slots and result in excessive internal heat. Place the charger
in a position away from any heat source. The charger is ventilated
through slots in the top and the bottom of the housing.
• Do not operate the charger with a damaged cord or plug.
• Do not operate the charger if it has received a sharp blow,
been dropped or otherwise damaged in any way. Take it to an
authorized service center.
• Do not disassemble the charger; take it to an authorized
service center when service or repair is required. Incorrect
reassembly may result in a risk of electric shock, electrocution or fire.
• Disconnect the charger from the outlet before attempting
any cleaning. This will reduce the risk of electric shock.
Removing the battery pack will not reduce this risk.
• NEVER attempt to connect 2 chargers together.
• The charger is designed to operate on standard 120V
household electrical power. Do not attempt to use it on any
other voltage.

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temperature below +40°F (+4.5°C), or above +105°F (+40.5°C).
This is important and will prevent serious damage to the battery pack.
2. The charger and battery pack may become warm to the touch
while charging. This is a normal condition, and does not indicate
a problem. To facilitate the cooling of the battery pack after use,
avoid placing the charger or battery pack in a warm environment
such as in a metal shed or an uninsulated trailer.
3. A cold battery pack will charge at about half the rate of a warm
battery pack. The battery pack will charge at that slower rate
throughout the entire charging cycle and will not return to
maximum charge rate even if the battery pack warms.
4. If the battery pack does not charge properly:
a. Check operation of receptacle by plugging in a lamp or other appliance;
b. Check to see if receptacle is connected to a light switch which
turns power off when you turn out the lights;
c. Move the charger and battery pack to a location where the
surrounding air temperature is approximately 65 °F–75 °F
(18°–24°C);
d. If charging problems persist, take the appliance, battery pack
and charger to your local service center.
5. The battery pack should be recharged when it fails to produce
sufficient power on jobs which were easily done previously. DO
NOT CONTINUE to use under these conditions. Follow the
charging procedure. You may also charge a partially used pack
whenever you desire with no adverse effect on the battery pack.
6. Foreign materials of a conductive nature such as, but not limited to,
grinding dust, metal chips, steel wool, aluminum foil, or any buildup of
metallic particles should be kept away from charger cavities. Always
unplug the charger from the power supply when there is no battery
pack in the cavity. Unplug the charger before attempting to clean.
7. Do not freeze or immerse the charger in water or any other liquid.
WARNING:Shock hazard. Don’t allow any liquid
to get inside the charger. Electric shock may result.
If the problem persists, try a different battery pack to determine if the
charger is working properly. If the new pack charges correctly, then the
original pack is defective and should be returned to a service center
or other collection site for recycling. If the new battery pack elicits
the same trouble indication as the original, have the charger and the
battery pack tested at an authorized service center.
HOT/COLD DELAY
This charger has a hot/cold delay feature: when the charger detects a
battery that is hot, it automatically starts a delay, suspending charging
until the battery has cooled. After the battery has cooled, the charger
automatically switches to the pack charging mode. This feature
ensures maximum battery life. The red light flashes long, then short
while in the hot/cold delay mode.
LEAVING THE BATTERY PACK IN THE CHARGER
The charger and battery pack can be left connected with the charge
indicator showing Pack Charged.
WEAK BATTERY PACKS: Weak batteries will continue to function
but should not be expected to perform as much work.
FAULTY BATTERY PACKS: This charger will not charge a faulty
battery pack. The charger will indicate faulty battery pack by refusing
to light or by displaying problem pack or charger.
NOTE: This could also mean a problem with a charger.
PROBLEM POWER LINE
Some chargers have a problem powerline indicator. When the charger
is used with some portable power sources such as generators or
sources that convert DC to AC, the charger may temporarily suspend
operation, flashing the red light with two fast blinks followed by a pause.
This indicates the power source is out of limits.
Important Charging Notes
1. Longest life and best performance can be obtained if the battery
pack is charged when the air temperature is between 65 °F and
75 °F (18 °–24 °C). DO NOT charge the battery pack in an air

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L
FIG. 2
I
M
E
J
F
G
D
H
C
A
B
K
N
ASSEMBLY (FIG. 3 - 5)
Assembling the Pole
1. To assemble the pole, line up the upper trimmer pole (F) and the
lower trimmer pole (G) as shown in figure 3. Press down the
latching button (O) and slide the upper pole into the lower pole.
Ensure the latching button engages the latch hole (P).
2. Secure the poles by tightening the middle bolt (Q) with the supplied
wrench (R) as shown in figure 4.
WARNING:Burn hazard. Do not submerge the battery
pack in any liquid or allow any liquid to enter the battery pack. Never
attempt to open the battery pack for any reason. If the plastic housing of
the battery pack breaks or cracks, return to a service center for recycling.
Storage Recommendations
1. The best storage place is one that is cool and dry, away from direct
sunlight and excess heat or cold.
2. For long storage, it is recommended to store a fully charged battery
pack in a cool dry place out of the charger for optimal results.
NOTE: Battery packs should not be stored completely depleted of
charge. The battery pack will need to be recharged before use.
SAVE THESE INSTRUCTIONS
COMPONENTS (Fig. 2)
INTENDED USE
This string trimmers is designed for professional trimming applications
DO NOT use under wet conditions or in presence of flammable
liquids or gases.
This string trimmer is a professional appliance. DO NOT let children
come into contact with the tool. Supervision is required when
inexperienced operators use this appliance.
A. Variable speed trigger H. Pole bracket
B. Lock-off lever I. Guard
C. Speed control switch J. Spool housing
D. Auxiliary handle K. Battery housing
E. Motor housing L. Battery pack (may not be
included)
F. Upper trimmer pole M. Battery release button
G. Lower trimmer pole N. Handle

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WARNING: NEVER F
FIG. 6
6A
D
OPERATE APPLIANCE WITHOUT
GUARD FIRMLY IN PLACE. The guard
must always be properly attached on
the appliance to protect the user.
The trimmer comes fully assembled.
The auxiliary handle (D) is positioned
to maximize balance. However, if
adjustment is necessary, loosen the four
bolts (6A) with a hex wrench and slide the
auxiliary handle up or down the upper
trimmer pole (F) as shown in figure 6.
OPERATION
WARNING: To reduce the risk of serious
personal injury, turn appliance off and remove battery before
making any adjustments or removing/installing attachments or
accessories.
WARNING: Always use proper eye protection that
conforms to ANSI Z87.1 (CAN/CSA Z94.3) while operating this appliance.
WARNING: Remove the battery before making any
assembly, adjustments, or changing accessories. Such preventive safety
measures reduce the risk of starting the
TRIMMER accidentally.
CAUTION: Before you begin trimming, only use the
appropriate type of cutting line.
CAUTION: Inspect area to be trimmed and remove
any wire, cord, or string-like objects which could become entangled in
the rotating line or spool. Be particularly careful to avoid any wire which
FIG. 3
O
P
FIG. 4
Q
R
Attaching the Auxiliary Handle
1. Slide the auxiliary handle (D) into the top FIG. 5
T
S
hole of the handle base (S).
2. Hold the auxiliary handle in place and
thread the handle bolt (T) into the handle
from the bottom of the handle base.
3. Tighten the handle bolt with the supplied
wrench (R). Ensure the handle is securely
attached.
4. Repeat for the other side of the auxiliary
handle.
Adjustment (Fig. 6)
WARNING:To reduce the risk of serious
personal injury, turn appliance off and remove battery before
making any adjustments or removing/installing attachments
or accessories.
WARNING: Never remove the guard. Damage or
personal injury could result.

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of charge in the battery is below the usable limit, the fuel gauge will not
illuminate and the battery will need to be recharged.
NOTE: The fuel gauge is only an indication of the charge left on the battery
pack. It does not indicate appliance functionality and is subject to variation
based on product components, temperature and end-user application.
For more information regarding fuel gauge battery packs, please call
1-800-4-DeWALT (1-800-433-9258) or visit our website www.dewalt.com.
Switching Trimmer On and Off (Fig. 2)
To turn the appliance on, squeeze the lock-off lever (B) and then the
variable speed trigger (A). To turn the appliance off, release the variable
speed trigger and the lock-off lever.
WARNING: Never attempt to lock the trigger in the
on position.
Speed Control Switch (Fig. 2)
This string trimmer gives you the choice to operate at a more efficient
speed to extend the runtime for larger jobs, or accelerate the trimmer
speed for high-performance cutting.
To extend runtime, push the speed control switch (C) forward toward
the auxillary handle (D) into the "LO" position. This mode is best for
larger projects that require more time to complete.
To accelerate the trimmer, pull the speed control switch back toward
the battery housing (I) into the "HI" position. This mode is best to cut
through heavier growth and for applications that need higher RPM.
NOTE: When in "HI" mode, runtime will be decreased as compared to
when trimmer is in "LO" mode.
Trimming (Fig. 10, 11)
With the trimmer on, angle it and swing side to side as shown in
Figure10.
might be bent outwardly into the path of the appliance, such as barbs
at the base of a chain link fence.
Installing and Removing the Battery Pack
(Fig. 7, 8)
WARNING:Before removing or installing battery, make
certain the lock-off lever is not engaged to prevent trigger actuation.
To install battery pack: Insert battery pack (L) into battery housing
(K) as shown in Figure 7 until fully seated and an audible click is heard.
FIG. 7
L
K
FIG. 8
M
Make sure battery pack is fully seated and fully latched into position.
To remove battery pack: Depress the battery release button (M) on
the battery and pull battery pack out of appliance as shown in Figure 8.
Fuel Gauge Battery Packs (Fig. 9)
Some DeWALT battery packs include
9A
FIG. 9
a fuel gauge which consists of three
green LED lights that indicate the
level of charge remaining in the
battery pack.
To actuate the fuel gauge, press and
hold the fuel gauge button (9A). A
combination of the three green LED
lights will illuminate designating the level of charge left. When the level

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• Wire and picket fences cause extra string wear, even breakage.
Stone and brick walls, curbs, and wood may wear string rapidly.
• Do not allow spool cap to drag on ground or other surfaces.
• In long growth, cut from the top down and do not exceed
12 inches (304.8 mm) high.
• Keep trimmer tilted toward the area being cut; this is the best
cutting area.
• The trimmer cuts when passing the unit from the left to right. This
will avoid throwing debris at the operator.
• Avoid trees and shrubs. Tree bark, wood moldings, siding, and
fence posts can easily be damaged by the string.
Replacement Accessories
WARNING:To reduce the risk of serious
personal injury, turn appliance off and remove battery before
making any adjustments or removing/installing attachments
or accessories.
WARNING:Theuseofanyaccessorynotrecommended
by DeWALT for use with this appliance could be hazardous.
WARNING:Do not use any blades, or any accessory
or attachment other than those recommended by DeWALT on this
trimmer. Serious injury or product damage may result.
UseDeWALT replacementlineModelNo.DWO1DT801orDWO1DT802.
• When replacing the line, use only .080 inches (2.032 mm)
diameter line (MODEL NO. DWO1DT801 OR DWO1DT802 are is
recommended). Other sizes may degrade performance or cause
damage to the trimmer.
Maintain a minimum distance of 24 inches (610 mm) between the
guard and your feet as shown in Figure 11.
FIG. 10 FIG. 11
MINIMUM
24INCHES
(610mm)
WARNING: Keep the rotating string roughly parallel
with the ground (tilted no more than 30 degrees). This trimmer is not
an edger. DO NOT TILT the trimmer so that the string is spinning near
a right angle to the ground. Flying debris can cause serious injury.
Bump Feed Trimmer Line Feed
Your trimmer uses 0.080 inches (2.032 mm) diameter nylon line.
Cutting line will wear faster and require more feeding if the cutting is
done along sidewalks or other abrasive surfaces or heavier weeds are
being cut.
As you use the trimmer, the string will get shorter due to wear. Gently
bump the trimmer on the ground while running at normal speed and
the line will feed.
NOTE: Extending nylon line beyond the 13 inch (330 mm) swath will
negatively affect performance, runtime, and the life of the trimmer due to
potential of damaging motor. Doing so may void the warranty.
Helpful Cutting Tips
• Use the tip of the string to do the cutting; do not force string head
into uncut grass.

11
English
6. Place the end of the cutting line FIG. 14
(13A) into the retaining hole
(13B).
7. Wind the cutting line onto the
spool in the direction of the
arrow on the bottom of the
spool. Make sure to wind the
line on neatly and in layers. Do
not crisscross (Fig.14).
8. When the wound cutting line
reaches the beginning of the
holding slots (13C), cut the line
approximately 4 inches (106mm).
9. Push the line in the holding slots on one side of the spool to hold
the first line while you wind the second line.
10. Repeat the above procedure for the second cutting line on the
lower section of the spool.
CAUTION: Before you begin trimming, only use the
appropriate type of cutting line. Ensure that cutting line is present in
both sections of the spool as shown in Figure 14.
11. Once both lines are wrapped around
15A
15B
15C
FIG. 15
the spool (12A), place your thumb and
finger on the holding slots to further
secure the string and feed the end of
each line through the two holes (15A)
on either side of the head in the spool
housing (H) as shown in Figure 15.
12. Line up the white nubs (15B) inside
the spool housing with the recesses
(15C) of the spool. Align the holding
slots (13C) with the two holes (15A) as
close as possible.
Replacing the Cutting Line (Fig. 2, 12–15)
CAUTION:To avoid appliance damage, if the cutting
line protrudes beyond the trimming blade, cut it off so that it just
reaches the blade.
1. Remove battery.
2. Turn spool (12A) clockwise to unlock as shown in Figure 12. The
white nub (15B) inside the spool will rotate away from the spool
window (12B) to indicate it is unlocked.
12A
12B
FIG. 12
13A
13C
FIG. 13
13B
3. Pull the spool straight out to remove.
4. Remove any dirt and grass from the spool and housing.
5. First, wind new line in the channel of the spool closest to the
holding slots (13C) as shown in Figure 13.

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chemicals may weaken the plastic materials used in these parts. Use a
cloth dampened only with water and mild soap. Never let any liquid get
inside the appliance; never immerse any part of the appliance into a liquid.
CHARGER CLEANING INSTRUCTIONS
WARNING: Shock hazard. Disconnect the charger
from the AC outlet before cleaning. Dirt and grease may be removed
from the exterior of the charger using a cloth or soft non-metallic
brush. Do not use water or any cleaning solutions.
Replacing Spool Housing (Fig. 17–18)
1. Rotate the spool housing (H) until the hole (17A) in the spindle (17B)
lines up with notch (17C) in the guard (I). A third hole in the motor
housing (17D) will be visible as shown in Figure 14. Insert screwdriver
through each all three holes to prevent the spool housing from turning.
2. Turn the spool housing clockwise as shown in Figure 18.
3. Insert a screwdriver back through the three holes (17A, 17C, and
17D) and thread the new spool housing counterclockwise and
securely tighten onto the bolt (18A) protruding from the trimmer.
17A
17D 17B
17C
H
I
FIG. 17 FIG. 18
18A
13. Push the spool into the spool housing and turn counterclockwise
to lock the spool in place. Ensure the white nub (15B) appears in
the spool window (12B). Make sure the line doesn't unravel and
wrap around the shaft below the spool.
14. Pull both ends of the cutting line to release them from the
holding slots. If the line extends past the cutting blade on the
guard cut the line so it just reaches the blade.
MAINTENANCE
WARNING:To reduce the risk of serious personal
injury, turn appliance off and remove battery before making any
adjustments or removing/installing attachments or accessories.
1. Keep the air intake slots (16A) clean
16A
FIG. 16
to avoid overheating.
2. Your trimmer line can dry out over
time. To keep your line in top condition,
store spare line in a plastic, sealable
bag with a tablespoon of water.
3. Plastic parts may be cleaned by
using a mild soap and a damp rag.
4. The line cutter on the edge of the guard can dull over time. It is
recommended you periodically touch-up the sharpness of the
blade with a file.
Cleaning
WARNING: Blow dirt and dust out of all air vents
with clean, dry air at least once a week. To minimize the risk of
eye injury, always wear ANSI Z87.1 approved eye protection when
performing this.
WARNING:Never use solvents or other harsh
chemicals for cleaning the non-metallic parts of the appliance. These

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Accessories
WARNING: Since accessories, other than those
offered by DeWALT, have not been tested with this product, use of
such accessories with this appliance could be hazardous. To reduce
the risk of injury, only DeWALT recommended accessories should be
used with this product.
Recommended accessories for use with your appliance are available
at extra cost from your local service center. If you need any assistance
in locating any accessory, please contact DeWALT Industrial Tool Co.,
701 East Joppa Road, Towson, MD 21286, call 1-800-4-DeWALT
(1-800-433-9258) or visit our website: www.dewalt.com.
Repairs
The charger and battery pack are not serviceable. There are no
serviceable parts inside the charger or battery pack.
To assure product SAFETY and RELIABILITY, repairs, maintenance
and adjustments (including brush inspection and replacement) should
be performed by a DeWALT factory service center, a DeWALT
authorized service center or other qualified service personnel. Always
use identical replacement parts.
Register Online
Thank you for your purchase. Register your product now for:
• WARRANTY SERVICE: Registering your product will help you
obtain more efficient warranty service in case there is a problem
with your product.
• CONFIRMATION OF OWNERSHIP: In case of an insurance
loss, such as fire, flood or theft, your registration of ownership will
serve as your proof of purchase.
• FOR YOUR SAFETY: Registering your product will allow us to
contact you in the unlikely event a safety notification is required
under the Federal Consumer Safety Act.
Register online at www.dewalt.com/register.
Replacing Guard (Fig. 19–20)
WARNING: Never operate appliance without guard
firmly in place.
1. Remove the spool housing as described in the "Replacing Spool
Housing" section.
2. Remove the 4 guard screws (19A) shown in Figure 19.
3. Lift the guard off at an angle as shown in Figure 20.
19A
19A
FIG. 19 FIG. 20
FIG. 21
21A
21B
4. To attached a new guard, slide the
tab (21A) of the new guard under the
lip (21B) of the motor housing (E),
then lower the back of the guard into
place as shown in Figure 18.
5. Replace and securely tighten the 4
guard screws (19A).
6. Replace the spool housing as
described in the "Replacing Spool
Housing" section.

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Three Year Limited Warranty
DeWALT will repair, without charge, any defects due to faulty materials or
workmanship for three years from the date of purchase. This warranty does
not cover part failure due to normal wear or appliance abuse. For further
detail of warranty coverage and warranty repair information, visit www.
dewalt.com or call 1-800-4-DeWALT (1-800-433-9258). 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.
In addition to the warranty, DeWALT appliances are covered by our:
1 YEAR FREE SERVICE
DeWALT will maintain the appliance and replace worn parts caused
by normal use, for free, any time during the first year after purchase.
DeWALT BATTERY PACKS
Product warranty voided if the battery pack is tampered with in any
way. DeWALT is not responsible for any injury caused by tampering and
may prosecute warranty fraud to the fullest extent permitted by law.
90 DAY MONEY BACK GUARANTEE
If you are not completely satisfied with the performance of your
DeWALT Power Tool, Laser, or Nailer for any reason, you can return it
within 90 days from the date of purchase with a receipt for a full refund
– no questions asked.
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 in the packaging, call the local
company or see website for warranty information.
FREE WARNING LABEL REPLACEMENT:
If your warning labels become illegible or are missing, call
1-800-4-DeWALT (1-800-433-9258) for a free replacement.
DCST920
STRING TRIMMER
WARNING
TO REDUCE THE RISK OF INJURY,
USER MUST READ INSTRUCTION MANUAL. USE PROPER EYE
AND RESPIRATORY PROTECTION. KEEP AWAY FROM ROTATING
LINE. TO REDUCE RISK OF INJURY TO PERSONS REMOVE
BATTERY PACK BEFORE REPLACING OR ADJUSTING LINE. TO
REDUCE RISK OF INJURY TO PERSONS DO NOT OPERATE WITHOUT
GUARD IN PLACE. STORE UNIT INDOORS ONLY. USE WITH DEWALT
20V MAX BATTERY. USE ONLY 0.080" (2MM) LINE.
AVERTISSEMENT
AFIN DE RÉDUIRE LE RISQUE DE
BLESSURES, L’UTILISATEUR DOIT LIRE LE MODE D’EMPLOI. UTILISER
UNE PROTECTION OCULAIRE ET RESPIRATOIRE ADÉQUATE. GARDER
SES DISTANCES DU FIL ROTATIF. POUR RÉDUIRE LE RISQUE DE
BLESSURES CORPORELLES, RETIRER LE BLOC-PILES AVANT DE
REMPLACER OU D’AJUSTER LE FIL. POUR RÉDUIRE LE RISQUE DE
BLESSURES CORPORELLES, NE PAS UTILISER SANS LE PARE-MAIN EN
POSITION. RANGER L’APPAREIL UNIQUEMENT À L’INTÉRIEUR.
UTILISER UNIQUEMENT AVEC UN BLOC-PILES DE DEWALT DE 20 V
MAX. À UTILISER AVEC LA LIGNE DE 2MM (0,080PO) UNIQUEMENT.
ADVERTENCIA
PARA REDUCIR EL RIESGO DE
LESIONES, EL USUARIO DEBE LEER EL MANUAL DE INSTRUCCIONES.
UTILICE PROTECCIÓN ADECUADA PARA LOS OJOS Y VÍAS
RESPIRATORIAS. MANTÉNGASE ALEJADO DE LA CUERDA
GIRATORIA. PARA REDUCIR EL RIESGO DE LESIONES A PERSONAS,
RETIRE EL PAQUETE DE BATERÍAS ANTES DE REEMPLAZAR O
AJUSTAR LA CUERDA. PARA REDUCIR EL RIESGO DE LESIONES A
PERSONAS, NO USE LA HERRAMIENTA SIN EL PROTECTOR EN SU
LUGAR. GUARDE LA UNIDAD EN EL INTERIOR SOLAMENTE.
UTILIZAR ÚNICAMENTE CON UNA BATERÍA DEWALT DE 20 V
MAX. USE SOLAMENTE CON UNA LÍNEA DE 0,080" (2 MM).
MADE IN CHINA / FABRIQUÉ EN CHINE / HECHO EN CHINA
DEWALT INDUSTRIAL TOOL CO., BALTIMORE, MD 21286 USA
FOR SERVICE INFORMATION, CALL 1-800-4-DEWALT
www.DEWALT.com

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TROUBLESHOOTING
Problem Solution
Unit will not start. • Check battery installation.
• Check battery charging requirements.
• Check that lock off is fully pulled back prior to moving main trigger.
Unit shuts down in use. • Charge battery.
• Clear debris around spool.
• Reduce/limit swath to 13 inches (330mm) MAX.
• Reinstall guard if it has been removed.
Battery won’t charge. • Insert battery into charger until red charging light illuminates. Charge up to 8 hours if battery is
totally drained.
•
Plug charger into a working outlet. Refer to Important Charging Notes for more details.
• Check current at receptacle by plugging an appliance.
• Check to see if receptacle is connected to a light switch which turns power off when you turn
out the lights.
• Move charger and appliance to a surrounding air temperature of above 40°F (4.5°C) or below
105°F (40.5°C).
Appliance runs slowly. • Fully depress the variable speed trigger. The level of trigger depression affects speed.
• If appliance still runs slowly, remove battery from appliance.
• Check that the spool housing can rotate freely. Carefully clean it if necessary.
• Check that the cutting line does not protrude more than approximately 4-13/16" (122 MM) from
the spool. If it does, cut it off so that it just reaches the line trimming blade.
Trimmer is vibrating. • Make sure both cutting lines are the same length.
• Check to see if the spool is properly wound. If spool is broken then replace spool.