Homelite ZR31810 User manual

OPERATOR'S MANUAL
18V CORDLESS STRING TRIMMER
MODEL NO. ZR31810
THANK YOU FOR BUYING A HOMELITE CORDLESS STRING TRIMMER
YournewcordlessstringtrimmerhasbeenengineeredandmanufacturedtoHomelite'shighstandardfor
dependability, ease of operation, and operator safety. Properly cared for, it will give you years of rugged, trouble-free
performance.
SAVE THIS MANUAL FOR FUTURE REFERENCE
Pay close attention to the Rules for Safe Operation, Warnings, and Cautions. If you use your string
trimmer properly and only for what it is intended, you will enjoy years of safe, reliable service.
Thank you again for buying Homelite products.
CAUTION: Carefully read through this entire operator's manual before using your new cordless string
trimmer.
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Rules for Safe Operation................................................................................................................................2 - 5
Safety Symbols .................................................................................................................................................... 6
Features ................................................................................................................................................................ 7
Assembly .............................................................................................................................................................. 8
Operation .......................................................................................................................................................9 - 12
Maintenance and Repair ............................................................................................................................13 - 15
Troubleshooting................................................................................................................................................. 16
Product Specifications...................................................................................................................................... 16
Warranty ............................................................................................................................................................. 17
TABLEOFCONTENTS
WARNING:
Whenusing batterypowered stringtrimmers, basic
safety precautions should always be followed to
reduce the risk of fire, electric shock, and personal
injury.Carefullyreadandunderstandtheentire
Operator’sManualbeforeusingyourstringtrimmer.
Pay close attention to the Operating Instructions
andRules for Safe Operation.
WARNING:
Failure to obey Rules for Safe Operation can result
in injury to yourself and others. Always follow the
safety precautions to reduce the risk of fire, electric
shock, and personal injury.
RULESFORSAFEOPERATION
The purpose of safety symbols is to attract your attention to possible dangers. The safety symbols, and the
explanations with them, deserve your careful attention and understanding. The safety warnings do not by
themselves eliminate any danger. The instructions or warnings they give are not substitutes for proper
accidentpreventionmeasures.
SYMBOL MEANING
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
serious injury.
CAUTION: Indicates a potentially hazardous situation which, if not avoided, may result in
minor or moderate injury. It may also be used to alert against unsafe practices that may cause
property damage.
NOTE: Advises you of information or instructions vital to the operation or maintenance of the equipment.

Page 3
READ ALL INSTRUCTIONS
BEFORE OPERATING
• Read the instructions carefully. Be familiar with the
controls and proper use of the unit.
• Do not operate this unit when tired, ill, or under the
influence of alcohol, drugs, or medication.
• Inspect the unit before use. Replace damaged
parts. Check for battery pack leaks. Make sure all
fasteners are in place and secure. Replace string
head or any other parts that are cracked, chipped,
or damaged. Make sure the string head is properly
installed and securely fastened. Be sure the grass
shield is properly attached, and positioned as
recommended. Failure to do so can result in
personal injury to the operator and bystanders, as
well as damage to the unit.
• Use the right tool. Only use this string trimmer for
the purpose intended.
• Do not use string trimmer if switch will not turn the
unit on or off. A unit that cannot be controlled with
the switch is dangerous and must be repaired.
• Clear the area to be cut before each use. Remove
all objects such as rocks, broken glass, nails, wire,
or string which can be thrown or become en-
tangled in the string head.
• Clear the area of children, bystanders, and pets.
At a minimum, keep all children, bystanders and
pets outside a 50 feet (15 m) radius; there still may
be a risk to bystanders from thrown objects.
Bystanders should be encouraged to wear eye
protection. If you are approached, stop the motor
and make sure the string head stops immediately.
• To avoid the risk of electric shock, do not operate
unit in damp or wet locations.
• Do not handle the unit with wet hands.
• Use only 0.065 in (1.65 mm) diameter genuine
Homelite replacement line. Never use metal-
reinforced line, wire, or rope, etc. These can break
off and become a dangerous projectile. Do not use
any other attachment on this unit.
• Do not allow children under the age of 15 or
untrained individuals to use this string trimmer.
• To reduce the risk of injury, always wear full eye
protection when using this string trimmer.
RULESFORSAFEOPERATION
• Wear a face or dust mask if the operation is dusty.
• Dressproperly. Donot wearloose clothingor
jewelry; they can be caught in moving parts. Use of
rubberglovesandsubstantialfootwear is recom-
mendedwhenworkingoutdoors.
• Topreventhairfrom being drawnintonearby air
ventsand becoming entangled in moving parts,
wearprotective hair covering to contain long hair or
securecoveredhairaboveshoulderlevel.
• Do not use electric or battery operated units in rain
or damp weather.
WHILE OPERATING
• Do not use trimmer without front handle in place.
Keep both hands on handles when unit is in use.
• To avoid accidental starting, never carry your unit
with your finger on the trigger.
• Wear safety glasses or goggles that are marked to
comply with ANSI Z87.1-1989 standards when
operating this unit.
• Stay alert and pay attention to what you are doing.
Use common sense when using this string trim-
mer.
• Wear heavy, long pants, substantial footwear and
well fitting gloves. Do not wear short pants,
sandals or go barefoot.
• Do not operate in poor lighting. Use the unit only in
daylight or good artificial light.
• Do not overreach or stand on unstable support.
Keep good footing and balance at all times. Do not
use on ladder.
• Do not force the trimmer. It will do the job better
and with less likelihood of a risk of injury at the
rate for which it was designed.
• Always hold the unit with both hands when operat-
ing. Keep a firm grip on both the rear handle and
the front handle.
• Release the trigger, allow the motor to stop, and
remove the battery pack before performing mainte-
nance, repair or making adjustments.
• This cordless string trimmer is intended only for
cutting grass, light weeds and for decorative
trimming. Do not use this string trimmer as an
edger.

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• Before starting the unit, make sure the string head
will not come in contact with anything.
• If you strike or become entangled with foreign
objects, stop the unit immediately, remove the
battery pack and check for damage. Do not
operate before repairing damage. Do not operate
the unit with loose or damaged parts.
• Keep all body parts away from string head and
other moving parts. Do not touch or try to stop the
string head when it is rotating.
• Keep string head below waist level.
• Always stop the motor when cutting is delayed or
when walking from one cutting location to another.
• The grass shield must always be in place while
operating the unit. Do not operate unit without the
cutting line extended, and the proper line installed.
Do not extend the cutting line beyond the length of
the shield.
• Keep unit clean of grass clippings and other
materials. They may become lodged between the
string head and shield.
• Store the unit inside in a dry place, either locked
up or up high to prevent unauthorized use or
damage. Keep out of the reach of children or
untrained individuals.
• Never douse or squirt the unit with water or any
other liquid. Keep handles dry, clean and free from
debris. Clean after each use, see Cleaning and
Storage instructions.
• Be sure to secure the unit while transporting.
• Keep these instructions. Refer to them often and
use them to instruct other users. If you loan
someone this unit, also loan them these instruc-
tions.
SERVICE
• Service on unit must be performed only by quali-
fied repair personnel. Service or maintenance
performed by unqualified personnel could result in
a risk of injury to the user, or damage to the unit. It
may also void your warranty.
• When servicing a unit, use only identical replace-
ment parts. Follow instruction in the Maintenance
section of this manual. Use of unauthorized parts
or failure to follow Maintenance Instructions may
create a risk of shock or serious injury to the user,
or damage to the unit. It may also void your
warranty.
RULESFORSAFEOPERATION
BATTERY SAFETY
• Battery operated units do not have to be plugged
into an electrical outlet; therefore, they are always
in operating condition. Be aware of possible
hazards even when unit is not operating.
• Remove the battery pack before making any
adjustments, cleaning, storing, or removing
material from the unit, or when not in use.
• A battery pack must be recharged only with the
specified charger for the battery pack. A charger
that may be suitable for one type of battery pack
may create a risk of fire when used with another
battery pack. Use battery pack only with charger
listed.
BATTERY PACK: 1323701
CHARGER: 1425701
• To reduce the risk of explosion and possible injury,
DO NOT place battery units or their batteries near
fire or heat.
• Do not open or mutilate the battery pack. Re-
leased electrolyte is corrosive and may cause
damage to the eyes or skin. It may be toxic if
swallowed.
• A damaged battery pack is subject to explosion. To
avoid serious personal injury, properly dispose of a
damaged battery pack.
• Batteries vent hydrogen gas and can explode in the
presenceofasourceofignition,suchasapilotlight.
To reduce the risk of serious personal injury, never
use any cordless product in the presence of open
flame. An exploded battery pack can propel debris
andchemicals.If exposed, flushwithwater immedi-
ately.
• Do not charge unit in a damp or wet location.
Following this rule will reduce the risk of electric
shock.
• For best results, your battery unit should be
charged in a location where the temperature is
more than 50°F (10°C) but less than 100°F (38°C).
Do not store outside or in vehicles.
• Under extreme usage or temperature conditions,
battery pack leakage may occur. If liquid comes in
contact with your skin, wash immediately with
soap and water, then neutralize with lemon juice
or vinegar. If liquid gets into your eyes, flush them
with clean water for at least 10 minutes, then seek
immediate medical attention.

Page 5
b. That extension cord is properly wired and in
good electrical condition; and
c. That wire size is large enough for AC ampere
rating of charger as specified below:
Cord Length (Feet) 25' 50' 100'
Cord Size (AWG) 16 16 16
NOTE: AWG = American Wire Gage
• Do not operate charger with a damaged cord or
plug. If damaged, have replaced immediately by a
qualified serviceman.
• Do not operate charger if it has received a sharp
blow, been dropped, or otherwise damaged in any
way; take it to a qualified serviceman.
• Do not disassemble charger; take it to a qualified
serviceman when service or repair is required.
Incorrect reassembly may result in a risk of
electric shock or fire.
• To reduce risk of electric shock, unplug the
charger from outlet before attempting any mainte-
nance or cleaning. Turning off controls will not
reduce this risk.
• Disconnect charger from power supply when not
in use.
• Risk of electric shock. Do not touch uninsulated
portion of output connector or uninsulated battery
terminal.
• Save these instructions. Refer to them frequently
and use them to instruct others who may use this
unit. If you loan someone this unit, loan them
these instructions also.
RULESFORSAFEOPERATION
• Do not dispose of batteries in a fire. The cell may
explode. Batteries should be recycled, consult
your local waste authority for information regarding
available recycling and/or disposal options.
• When battery pack is not in use, keep it away from
other metal objects like: paper clips, coins, keys,
nails, screws, or other small metal objects that can
make a connection from one terminal to another.
Shorting the battery pack terminals together may
cause sparks, burns, or a fire.
CHARGER SAFETY
• Save these instructions. This manual contains
important Rules for Safe Operation and operating
instructions for charger.
• Before using battery charger, read all instructions
and cautionary markings in this manual, on battery
charger, and product using battery charger.
• To reduce risk of injury, charge only nickel-
cadmium type rechargeable batteries. Other types
of batteries may burst, causing personal injury and
damage.
• Do not expose charger to wet or damp conditions.
• Use of an attachment not recommended or sold by
the battery charger manufacturer may result in a
risk of fire, electric shock, or injury to persons.
• To reduce risk of damage to charger body and
cord, pull by charger plug rather than cord when
disconnecting charger.
• Make sure cord is located so that it will not be
stepped on, tripped over, or otherwise subjected to
damage or stress.
• An extension cord should not be used unless
absolutely necessary. Use of improper extension
cord could result in a risk of fire and electric shock.
If extension cord must be used, make sure:
a. That pins on plug of extension cord are the
same number, size and shape as those of
plug on charger.

Page 6
SAFETYSYMBOLS
SAFETYALERTSYMBOL
Indicates danger, warning, or caution. Attention is required in order to avoid serious personal
injury. May be used in conjunction with other symbols or pictographs.
WARNING:READOPERATOR’SMANUAL
Failure to follow operating instructions and rules for safe operation in the operator’s manual can
result in serious injury. Read the operator’s manual before starting or operating this unit.
FORSERVICEINFORMATION,CALL:
1-800-chainsaw(1-800-242-4672)
WEAREYEPROTECTION
WARNING: Thrown objects can cause severe eye injury. Wear eye protection marked to comply
withANSIZ87.1-1989 standardswhen operating thisunit.
KEEPBYSTANDERSAWAY
WARNING: Keep all bystanders, especially children and pets, at least 50 feet (15 m.) from the
operatingarea.
DANGEROFRICOCHET
WARNING: Do not operate without the grass shield in place. Keep away from the rotating
string head.
SHARP BLADE
WARNING: Sharp blade on grass shield. To prevent serious injury, do not touch line cutting
blade.
Advises you of information or instructions vital to the operation or maintenance of the equip-
ment.
The purpose of safety symbols is to attract your attention to possible dangers. The safety symbols, and their
explanations, deserve your careful attention and understanding. The safety warnings do not by themselves
eliminate any danger. The instructions or warnings they give are not substitutes for proper accident prevention
measures.
SYMBOL MEANING
NOTE:
SAVE THESE INSTRUCTIONS

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18.0v
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MODEL UT31810 - 18V CORDLESS STRING TRIMMER
FEATURES
BATTERY
PACK
TRIGGER
FRONT
HANDLE
TRIGGER LOCK
BUTTON
SHAFT
ADJUSTIMENT
COLLAR
GRASS
SHIELD
CUTTING LINE
MOTOR HOUSING
REAR
HANDLE
Fig. 1
ANCHOR SCREW
CUT OFF BLADE

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ASSEMBLY
INSTALLING GRASS SHIELD
Remove both screws on the motor housing. Orient
grass shield on the motor housing and twist to lock in
place as shown. Re-install screws to secure grass
shield in place. See Figure 2.
ADJUSTING THE SHAFT
• Rotate the lower portion of the shaft adjustment
collar to the “Unlock” position. See Figure 3 .
Fig. 2
Fig. 3
Fig. 4
• Lower shaft should now be free to slide down from
inside the upper shaft. Make sure the shaft is
pulled out to the desired position. See Figure 4 .
SHAFT
ADJUSTMENT
COLLAR
SLIDE OUT TO
DESIRED POSITION
LOWER PORTION
OF SHAFT
ADJUSTMENT
COLLAR
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Fig. 5
TO
UNLOCK
COLLAR
TO
LOCK
COLLAR
• Rotate shaft adjustment collar to the “Lock”
position and tighten securely. See Figure 5 .
GRASS
SHIELD
MOTOR
HOUSING
LOWER PORTION
OF SHAFT
ADJUSTMENT
COLLAR
SHAFT
ADJUSTMENT
COLLAR
RE-INSTALL
BOTH SCREWS
REMOVE
BOTH
SCREWS

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OPERATION
LED FUNCTIONS OF CHARGER
See Figure 6 .
LED WILL BE ON TO INDICATE STATUS
OF CHARGER AND BATTERY PACK:
• Red LED on = Fast charging mode.
• Green LED on = Fully charged battery pack.
• Yellow and Green LEDs on = Control charge or
defective battery pack.
• No LED on = Defective charger or battery pack.
CAUTION: To prevent damage to battery pack,
remove battery pack from charger immediately if no
LED comes on. Return battery pack and charger to
your nearest Homelite Authorized Service Center for
checking or replacing. Also, if you are removing
battery pack from charger and no LEDs are on, return
both battery pack and charger to your nearest
Homelite Authorized Service Center. Do not insert
another battery pack into charger. A damaged charger
may damage a battery pack.
CHARGING YOUR BATTERY PACK
The battery pack for this unit has been shipped in a
low charge condition to prevent possible problems.
Therefore, you should charge it prior to use.
NOTE: Batteries will not reach full charge the first
time they are charged. Allow several cycles (trimming
followed by recharging) for them to fully charge.
TO CHARGE
• Charge battery pack only with the charger pro-
vided.
•Make sure power supply is normal household
voltage, 120 volts, 60 Hz, AC only.
• Connect charger to power supply.
• Place battery pack in charger. See Figure 6 . Align
raised rib on battery pack with groove in charger.
• When charger is properly connected, red light will
turn on. Press down on battery pack to be sure
contacts on battery pack engage properly with
contacts in charger.
WARNING:
If any parts are missing, do not operate unit until
the missing parts are replaced. Failure to do so
could result in possible serious personal injury.
• Normally, the yellow and green lights on the
charger will come on. This indicates charger is in
control charge mode and should switch to fast
charge mode within 5 minutes. When charger is in
fast charge mode the yellow and green lights will
go off and the red light will come on. If after a
period of 15 minutes the yellow and green lights
remain on, remove the battery pack, wait 1 minute
and reinsert battery pack in charger. If the yellow
andgreen lights continueto remainon an additional
15 minutes, the battery pack is damaged and will
not accept charge.
• When your battery pack becomes fully charged,
the red light will turn off and the green light will turn
on.
• After normal usage, 1 hour of charge time is
required to be fully charged. A minimum charge
time of 1 to 1-1/2 hours is required to recharge a
completelydischarged battery pack.
• The battery pack will become slightly warm to the
touch while charging. This is normal and does not
indicateaproblem.
•DO NOT place charger in an area of extreme heat
or cold. It will work best at normal room tempera-
ture.
Fig. 6
BATTERY
CHARGER
BATTERY
PACK
GREEN
LIGHT
YELLOW
LIGHT
RED LIGHT

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18.0V
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TO INSTALL BATTERY PACK
• Place the battery pack in the string trimmer. Align
raised rib on battery pack with groove in string
trimmer's battery port. See Figure 7 .
• Make sure the latches on each side of the battery
pack snap in place and that battery pack is secured
instringtrimmerbeforebeginningoperation.
CAUTION:
When placing battery pack in your string trimmer,
be sure raised rib on battery pack aligns with
groove in string trimmer's battery port and latches
snap in place properly. Improper assembly of
battery pack can cause damage to internal
components.
OPERATION
IMPORTANT INFORMATION FOR
RECHARGING HOT BATTERY PACK
When using your string trimmer continuously, the
batteries in your battery pack will become hot. You
should let a hot battery pack cool down for approxi-
mately 30 minutes before attempting to recharge.
NOTE: This situation only occurs when continuous use
of your string trimmer causes the batteries to become
hot. It does not occur under normal circumstances.
Referto“CHARGINGBATTERYPACK”fornormal
recharging of batteries. If the charger does not charge
yourbattery pack under normal circumstances,return
both the battery pack and charger to your nearest
HomeliteAuthorizedServiceCenter for electrical
check.
IMPORTANT INFORMATION FOR
RECHARGING COOL BATTERY PACK
If battery pack is below normal temperature range, the
green LED on charger will come on. Allow battery pack
toreach normal temperature,then the red LED will
comeon.
NOTE:Referto “CHARGING BATTERYPACK”for
normal recharging of batteries. If the charger does not
chargeyour battery pack under normal circumstances,
returnboth the battery pack and charger to your
nearestHomeliteAuthorizedServiceCenterfor
electrical check.
Fig. 8
TRIGGER LOCK
BUTTON
TRIGGER
STARTING THE STRING TRIMMER
•Press and hold the trigger lock button.
See Figure 8 . This makes the trigger operational.
•Release the trigger lock button and continue to
squeezethetriggerforextendedoperation.
STOPPING THE STRING TRIMMER
• Release the trigger to stop the string trimmer.
• Upon release of the trigger, the trigger lock button
will be automatically reset to the lock position.
Fig. 7
TO REMOVE BATTERY PACK
• Locate latches on side of battery pack and depress
both sides to release the battery pack from the
string trimmer. See Figure 7 .
• Remove battery pack from the string trimmer.
LATCHES
BATTERY PACK
BATTERY
PORT

Page 11
OPERATION
USING THE STRING TRIMMER
ADVANCING LINE
Your string trimmer is equipped with a string head,
which allows the operator to release more cutting line
without stopping the motor. As the line becomes worn
or frayed, additional line can be released by lightly
tapping the string head on the ground while operating
the string trimmer at full throttle. See Figure 10 . For
best results, tap the head on bare ground or hard soil.
If line release is attempted in tall grass, the motor may
overheat.
• Hold the string trimmer as shown. See Figure 9 .
Right arm is slightly bent, the right hand holding the
rear handle. Left arm is straight, the left hand
holding the front handle. The unit should be slightly
below waist level.
• The string head on your string trimmer should be
parallel to the ground and should easily contact
the material being cut without the operator having
to bend over. A simple shaft adjustment accom-
modates most user's heights.
Fig. 9
Fig. 10
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Approximately 1 inch (25.4 mm) of cutting line is
released each time the head is tapped on the ground.
Always keep the cutting line fully extended. If the
string is worn too short you may not be able to ad-
vance the string by tapping the head on the ground. If
this occurs, stop the motor, remove the spool as
described in the following section, feed the cutting line
throughtheopeninginspoolhousingandreassemble
the spool to the string head.
HOLDING THE STRING TRIMMER
WARNING:
Dress properly to reduce the risk of injury when
operating this unit. Do not wear loose clothing or
jewelry.Wear eye protection. Wear heavy,long
pants, boots and well fitting gloves. Do not wear
short pants, sandals or go barefoot.

Page 12
OPERATION
OPERATING TIPS
• Clear the area to be cut before each use. Remove
all objects such as rocks, broken glass, nails, wire,
orstringwhich can bethrown or becomeentangled
in the string head.
• Keepthe string trimmer tilted toward the area being
cut. Avoid digging into grass.
• Slowly move the string trimmer in and out of the
areabeingcut.
•Use the tip of line to do the cutting - do not force
string head into uncut grass.
• Cut tall grass from the top down. This will prevent
grassfromwrappingaroundthestringhead that
may cause damage from overheating. If grass or
otherdebrisbecomeswrappedaroundthestring
head,STOP THE MOTOR byreleasing the trigger
and allow the string head to stop spinning. Remove
the battery pack and then remove the grass or
debris.
Fig. 12
30°
CUTTING LINE
This string trimmer is equipped with a string cut off
blade on the grass shield. See Figure 11 . For best
cutting, advance line until it is trimmed to length by the
string cut-off blade. Advance line whenever you hear
the motor running faster than normal. This will main-
tain best performance and keep the cutting line long
enough to advance properly.
Fig. 11
CUT OFF BLADE
Avoid using solvents when cleaning plastic parts.
Most plastics are susceptible to damage from various
types of commercial solvents and may be damaged
by their use. Use a clean cloth to remove dirt, oil,
grease, etc.
WARNING:
Whenservicinguse onlyidentical Homelite replace-
ment parts. Use of any other parts can create a
hazardorcauseproductdamage.
• Wire and picket fences cause extra line wear,
even breakage. Stone and brick walls, curbs, and
wood may wear line rapidly. Walk around trees
and shrubs. Tree bark, wood moldings, siding, and
fence posts can easily be damaged by the line.
• Keepthe string trimmer tilted toward the area being
cut. To trim around trees, posts, fences, etc., keep
the string trimmer at a 30-degree angle. See
Figure12 .

Page 13
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MAINTENANCEANDREPAIR
CUTTING LINE REPLACEMENT
Thecutting line may be replaced by either rewinding
theexisting spoolor installinga convenientprewound
spool.
REWINDING THE EXISTING SPOOL
SeeFigure13 .
• Remove the battery pack from the string trimmer.
• Press in the tabs on each side of the spool cap.
• Remove the spool cap and spool. Discard any
remainingline on thespool.
NOTE: If the spring falls off the spool housing
duringthisprocedure,reinstallthespringbefore
installing the spool and spool cap.
• Inspect the string head for damaged or worn parts
andcleanthoroughly.
• Using approximately 10 feet (3 m) of new cutting
line, insert one end of the line into the slot on the
spool. Ensure the end of the line is pushed all the
way towards the inner side of slot.
NOTE: No more than 1/8 in. of the line is to
protrude from the slot.
• Wind the line, in even and tight layers, onto the
spool. Line should be wound in the direction of the
arrowindicatedonthespool.
• Unwind approximately 4 in. (102 mm) of the line
from the spool. Hold the line and spool firmly to
keep it from unwinding then place the spool cap
onto the spool.
• Holding the spool cap and spool by the bump knob,
place into the spool housing and insert cutting line
intothe opening in spool housing.
NOTE: Tabs on the spool cap should be aligned
with the slots in the spool housing.
SLOT ON
SPOOL
TABS
SPOOL
CAP
BUMP KNOB
SPOOL
SPRING
SPOOL
HOUSING
SLOT
OPENING IN
SPOOL HOUSING
SPOOL
HOUSING
Fig. 13
• While pressing in the tabs, push down the spool
cap and spool to lock in place.
• Completely assembled string head should appear
as shown. See Figure 14 .
WARNING:
Useonly 0.065 in (1.65 mm)diameter genuine
Homelitereplacementline.Neverusemetal-
reinforced line, wire, or rope, etc. These can break
off and become a dangerous projectile. Do not use
any other attachment on this unit.
CAUTION:
Do not at any time let brake fluids, gasoline,
petroleumbased products, penetrating oils, etc.,
come in contact with plastic parts. They contain
chemicals that may damage, weaken, or destroy
plastics.

Page 14
MAINTENANCEANDREPAIR
INSTALLING A PREWOUND SPOOL
SeeFigure13 .
• Remove the battery pack from the string trimmer.
• Press in the tabs on each side of the spool cap.
• Remove the spool cap and spool.
NOTE: If the spring falls off the spool housing
duringthisprocedure,reinstallthespringbefore
installing the spool and spool cap.
• Inspect the string head for damaged or worn parts
andcleanthoroughly.
• Unwind approximately 4 in. (102 mm) of the line
fromthe prewoundspool. Holdthe lineand spool
firmly to keep it from unwinding then place the
spool cap onto the spool.
• Holding the spool cap and spool by the bump knob,
place into the spool housing and insert cutting line
intothe opening in spool housing.
NOTE: Tabs on the spool cap should be aligned
with the slots in the spool housing.
• While pressing in the tabs, push down the spool
cap and spool to lock in place.
• Completelyassembledstringheadshouldappear
as shown. See Figure 14 .
Fig. 14
BATTERIES
Yourbatterypack isequipped with Nickel-Cadmium
rechargeablebatteries.Lengthofservice from each
charging will depend on the type of work you are doing.
The batteries in this unit have been designed to
providemaximumtrouble-free life. However,like all
batteries, they will eventually wear out. DO NOT
disassemble battery pack and attempt to replace the
batteries. Handling of these batteries, especially when
wearing rings and jewelry, could result in serious burn.
To obtain the longest possible battery pack life, we
suggestthefollowing:
• Store and charge your batteries in a cool area.
Temperaturesaboveorbelownormalroomtem-
perature will shorten battery pack life.
• Neverstore batteries in a dischargedcondition.
Wait for battery pack to cool and charge immedi-
ately.
• Allbatteries graduallylose theircharge. Thehigher
the temperature, the quicker they lose their charge.
If you store your unit for long periods of time
without using it, recharge the batteries every month
or two. This practice will prolong battery pack life.
WARNING:
Do not attempt to disassemble the battery pack.
Fire or injury can result.

Page 15
DISPOSAL OF THE EXHAUSTED
BATTERY PACK
MAINTENANCEANDREPAIR
WARNING:
Do not attempt to modify this unit or create or
mount any accessory not specifically recom-
mended in this manual for use with this string
trimmer. Any such alteration or modification is
misuse and could result in a hazardous condition
leadingto possibleserious personal injury.
CAUTION:
Anyrepairs requiring disassemblyshould only be
performedbya Homelite Authorized Service
Center. For the repair center nearest you, call
1-800-chainsaw(1-800-242-4672).
WARNING:
Upon removal, cover the battery pack’s terminals
with heavy duty adhesive tape. Do not attempt to
destroy or disassemble battery pack or remove any
of its components. Also, never touch both terminals
with metal objects and/or body parts, as short
circuit can result. Keep away from children. Failure
to comply with these warnings could result in fire
and/orseriousinjury.
CLEANING THE STRING TRIMMER
• Remove the battery pack.
• Clean the unit using a damp cloth with a mild
detergent.
• Do not use any strong detergents on the plastic
housingor the handle. They can be damaged by
certain aromatic oils such as pine and lemon, and
by solvents such as kerosene.
• Moisture can cause a shock hazard. Wipe off any
moisture with a soft dry cloth.
• Use a small brush or the air discharge of a small
vacuum cleaner brush to clean the air vents on the
batterypack housingand motorhousing.
• Keep the air vents free of obstructions.
STORING THE STRING TRIMMER
• Cleanthestringtrimmerthoroughlybeforestoring.
Store the string trimmer in a dry, well-ventilated
place that is inaccessible to children. Keep away
from corrosive agents such as garden chemicals
and de-icing salts.
• Store and charge your batteries in a cool area.
Temperaturesaboveorbelownormalroomtem-
perature will shorten battery pack life.
• Neverstore batteries in a dischargedcondition.
Wait for battery pack to cool and charge immedi-
ately.
• Allbatteries graduallylose theircharge. Thehigher
the temperature, the quicker they lose their charge.
If you store your unit for long periods of time
without using it, recharge the batteries every month
or two. This practice will prolong battery pack life.
WARNING:
Battery units do not have to be plugged into an
electrical outlet; therefore, they are always in
operatingcondition.Topreventseriouspersonal
injury, always remove the battery pack and take
extraprecautionsandcarewhenperforming
maintenance, cleaning or servicing the unit.
WARNING:
Toprevent serious personalinjury, remove the
batterypack before servicing, cleaning, or removing
material from the unit.
R
E
C
Y
C
L
E
1
.
8
0
0
.
8
2
2
.
8
8
3
7
RBRC
Ni Cd
BATTERYPACKPREPARATIONFORRECYCLING
Topreservenaturalresources,please
recycle or dispose of properly. This
productcontainsnickel-cadmium
battery pack. Must be disposed of
properly. Local, state, or federal laws
may prohibit disposal of Nickel-
Cadmiumbatteriesinordinarytrash.
Consult your local waste authority for information
regardingavailablerecyclingand/ordisposal
options. For more information on battery pack
recyclingcall1-800-8BATTERY.
WARNING:
Examine string trimmer frequently to assure all
partsare unbroken and securely attached.Make
sure all screws and fasteners are securely tight-
ened to prevent the risk of serious personal injury.

Page 16
BATTERY PACK WILL NOT CHARGE
POSSIBLE CAUSE POSSIBLE SOLUTION
No power to charger or battery pack. Check charger.
Battery pack has failed. Replace battery pack.
MOTOR OPERATES SLOWLY OR WILL NOT OPERATE
POSSIBLE CAUSE POSSIBLE SOLUTION
Battery pack is not charged. Chargebatterypack.
STRING HEAD WILL NOT ADVANCE LINE
POSSIBLE CAUSE POSSIBLE SOLUTION
Stringheadboundwith grass. Stop the unit and clean string head.
String head out of line. Refill withnew line.
Spoolboundup. Replacethespool.
Stringhead dirty. Cleanspoolandspoolhousing.
Linewelded. Disassemble, removethewelded section and
rewindtheline.
Linetwistedwhenrefilled. Disassembleandrewindtheline.
Notenough lineis exposed. Push the bump knob and pull out line until 4 inches
(102 mm.) of line is outside of the string head.
TROUBLESHOOTING
If the above solutions don't solve the problem, take the unit to your nearest Homelite Authorized Service
Center for service or repair. Do not return the unit to the retailer.
UT31810 STRING TRIMMER SPECIFICATIONS
Motor ..................................................................................................................................................... 18 Volt DC
Battery Pack............................................................................................. Nickel-Cadmium rechargeable, 18 Volt
Charge Rate................................................................................................................................... 1 to 1-1/2 hour
String Head ......................................................................................................................................... Bump Head
Cutting Line Diameter ............................................................................................................ 0.065 in. (1.65 mm.)
Cutting Path Diameter..................................................................................................................... 9 in. (229 mm)
Weight with Battery pack...............................................................................................................5.5 lbs. (2.6 kg.)
PRODUCTSPECIFICATIONS

Page 17
Homelite Products Limited Warranty
Homelite Consumer Products, Inc. warrants to the original retail
purchaserthatthisHOMELITE®Productisfreefromdefect inmaterial
andworkmanshipandagreestorepairorreplace,atHomeliteConsumer
Products,Inc.'sdiscretion, anydefective Productfree ofcharge within
these time periods from the date of purchase:
• One Year for all other Homelite Products, if the Product is used
for personal, family, or household use;
• 90 days, if any of the above Products are used for any other
purpose, such as commercial or rental.
This warranty extends to the original retail purchaser only and
commences on the date of original retail purchase.
Any part of the HOMELITE Product manufactured or supplied by
HOMELITE and found in the reasonable judgement of HOMELITE to
bedefectiveinmaterialorworkmanshipwillberepairedorreplacedby
an authorized HOMELITE service dealer without charge for parts and
labor.
TheHOMELITEProductincludinganydefectivepartmustbereturned
to an authorized service dealer within the warranty period. The
expenseofdeliveringtheHOMELITEProducttothedealerforwarranty
work and the expense of returning it back to the owner after repair or
replacementwillbepaidforbytheowner. HOMELITE'S responsibility
in respect to claims is limited to making the required repairs or
replacements and no claim of breach of warranty shall be cause for
cancellation or rescission of the contract of sale of any HOMELITE
Product.Proofofpurchasewillberequiredbythedealertosubstantiate
any warranty claim. All warranty work must be performed by an
authorized HOMELITE service dealer.
This warranty is limited to ninety (90) days from the date of original
retail purchase for any HOMELITE Product that is used for rental or
commercial purposes, or any other income-producing purpose.
This warranty does not cover any HOMELITE Product that has been
subject to misuse, neglect, negligence, or accident, or that has been
operatedinanywaycontrarytothe operatinginstructionsas specified
inthe HOMELITE Operator'sManual. Thiswarranty doesnot applyto
any damage to the HOMELITE Product that is the result of improper
maintenance or to any HOMELITE Product that has been altered or
modifiedsoastoadverselyaffecttheproductsoperation,performance
or durability or that has been altered or modified so as to change its
intendeduse.Thewarrantydoesnotextendtorepairsmadenecessary
by normal wear or by the use of parts or accessories which are either
incompatible with the HOMELITE Product or adversely affect its
operation, performance or durability.
In addition, this warranty does not cover:
A.Tune-ups – Spark Plugs, Carburetor Adjustments, Filters
B.WearItems–BumpKnobs,OuterSpools,CuttingLine,InnerReels,
Starter Pulley, Starter Ropes, Drive Belts.
HOMELITEreserves the right to change or improve the design of any
HOMELITE Product without assuming any obligation to modify any
product previously manufactured.
ALL IMPLIED WARRANTIES ARE LIMITED IN DURATION TO THE
STATED WARRANTY PERIOD. ACCORDINGLY, ANY SUCH
IMPLIEDWARRANTIESINCLUDINGMERCHANTABILITY,FITNESS
FOR A PARTICULAR PURPOSE, OR OTHERWISE, ARE
DISCLAIMED IN THEIR ENTIRETY AFTER THE EXPIRATION OF
THE APPROPRIATE TWO-YEAR, ONE-YEAR, OR NINETY DAY
WARRANTY PERIOD. HOMELITE'S OBLIGATION UNDER THIS
WARRANTY IS STRICTLY AND EXCLUSIVELY LIMITED TO THE
REPAIR OR REPLACEMENT OF DEFECTIVE PARTS AND
HOMELITE DOES NOT ASSUME OR AUTHORIZE ANYONE TO
ASSUME FOR THEM ANY OTHER OBLIGATION. SOME STATES
DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED
WARRANTYLASTS,SOTHEABOVELIMITATIONMAYNOTAPPLY
TO YOU.
HOMELITE ASSUMES NO RESPONSIBILITY FOR INCIDENTAL,
CONSEQUENTIAL OR OTHER DAMAGES INCLUDING, BUT NOT
LIMITEDTOEXPENSEOFRETURNINGTHEHOMELITEPRODUCT
TO AN AUTHORIZED SERVICE DEALER AND EXPENSE OF
DELIVERING IT BACK TO THE OWNER, MECHANIC'S TRAVEL
TIME, TELEPHONE OR TELEGRAM CHARGES, RENTAL OF A
LIKE PRODUCT DURING THE TIME WARRANTY SERVICE IS
BEINGPERFORMED,TRAVEL,LOSSORDAMAGETOPERSONAL
PROPERTY,LOSSOFREVENUE,LOSSOFUSEOFTHEPRODUCT,
LOSS OF TIME, OR INCONVENIENCE. SOME STATES DO NOT
ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR
EXCLUSION MAY NOT APPLY TO YOU.
This warranty gives you specific legal rights, and you may also have
other rights which vary from state to state.
This warranty applies to all HOMELITE Products manufactured by
HOMELITE and sold in the United States and Canada.
To locate your nearest service dealer, dial
1-800-242-4672 or log on to our website at www.homelite,com.
CALIFORNIA EMISSION CONTROL LIMITED WARRANTY STATEMENT
YOUR WARRANTY RIGHTS AND OBLIGATIONS
HOMELITE® CONSUMER PRODUCTS, INC.
The U.S. Environmental Protection Agency (EPA), the California Air Resources Board (CARB), and Homelite Consumer Products, Inc. are
pleased to explain the Emission Control System Warranty on your utility/lawn/garden equipment engine. The California, new 1995 and later
utility/lawn/gardenequipment enginesmustbedesigned,builtandequippedtomeet thestate'sstringentanti-smogstandards. Inotherstates,
new 1997 and later model year utility/lawn/garden equipment engines must be designed, built and equipped, at the time of sale, to meet the
U.S. EPA regulations for small non-road engines. The equipment engine must be free from defects in material and workmanship which cause
it to fail to conform with U.S. EPA standards for the first two years of engine use from the date of sale to the ultimate purchaser. Homelite
ConsumerProducts,Inc.must warranty the emission control system onyourutility/lawn/gardenequipmentenginefortheperiodoftimelisted
above provided there has been no abuse, neglect, or improper maintenance of your utility/lawn/garden equipment engine.
Your emission control system may include parts such as the carburetor or fuel injection system, the ignition system, the catalytic converter.
Also included may be hoses, belts, and connectors and other emission-related assemblies.
Where a warrantable condition exists, Homelite Consumer Products, Inc. will repair your utility/lawn/garden equipment engine at no cost to
you, including diagnosis (if the diagnostic work is performed at an authorized dealer), parts, and labor.

SERVICE
Now that you have purchased your unit, should a need ever exist for repair parts or service, simply contact your
nearest Homelite Authorized Service Center. Be sure to provide all pertinent facts when you call or visit. Please
call1-800-chainsaw(1-800-242-4672)foryournearestHomeliteAuthorizedServiceCenter.Youcanalsocheck
our web site at www.homelite.com for a complete list of Authorized Service Centers.
MODEL NO. AND SERIAL NO.
The model number of this unit will be found on a label attached to the motor housing.
Please record the model number and serial number in the space provided below.
HOW TO ORDER REPAIR PARTS
WHENORDERINGREPAIRPARTS,
ALWAYSGIVETHEFOLLOWINGINFORMATION:
•MODEL NUMBER
• SERIAL NUMBER
HOMELITE CONSUMER PRODUCTS, INC.
1428PearmanDairyRoadAnderson,SC29625
PostOffice Box 1207,Anderson, SC 29622-1207
Phone1-800-chainsaw(1-800-242-4672)
www.homelite.com
OPERATOR'S MANUAL
18V CORDLESS STRING TRIMMER
MODEL NO. ZR31810
983000-013
2-03
SAVE THIS MANUAL FOR FUTURE REFERENCE
ZR31810