Stihl SG 21 User manual

SG 21
Instruction Manual2 - 13

Contents
1 Guide to Using this Manual.........................2
2 Safety Precautions and Working Techni‐
ques............................................................ 2
3 Assembling the Unit.................................... 6
4 Controls.......................................................6
5 Preparing Unit for Operation....................... 7
6 Filling the Container.................................... 8
7 Spraying......................................................8
8 After Spraying............................................. 9
9 Storing the Machine.................................... 9
10 Inspection and Maintenance by User..........9
11 Maintenance and Care..............................11
12 Main Parts.................................................11
13 Specifications............................................11
14 Troubleshooting........................................ 12
15 Maintenance and Repairs......................... 12
16 Disposal.................................................... 12
17 EC Declaration of Conformity................... 12
Dear Customer,
Thank you for choosing a quality engineered
STIHL product.
It has been built using modern production techni‐
ques and comprehensive quality assurance.
Every effort has been made to ensure your satis‐
faction and trouble-free use of the product.
Please contact your dealer or our sales company
if you have any queries concerning this product.
Your
Dr. Nikolas Stihl
1 Guide to Using this Manual
1.1 Pictograms
All the pictograms attached to the machine are
shown and explained in this manual.
1.2 Symbols in text
WARNING
Warning where there is a risk of an accident or
personal injury or serious damage to property.
NOTICE
Caution where there is a risk of damaging the
machine or its individual components.
1.3 Engineering improvements
STIHL's philosophy is to continually improve all
of its products. For this reason we may modify
the design, engineering and appearance of our
products periodically.
Therefore, some changes, modifications and
improvements may not be covered in this man‐
ual.
2 Safety Precautions and
Working Techniques
This instruction manual covers a STIHL sprayer
which is also referred to as the unit in the
descriptions.
Special safety precautions must be
observed when working with this
sprayer.
It is important that you read the
instruction manual before first use
and keep it in a safe place for future
reference. Non-observance of the
instruction manual may result in seri‐
ous or even fatal injury.
2.1 General
Observe all applicable local safety regulations,
standards and ordinances.
If you have not used this model before: Have
your dealer or other experienced user show you
how it is operated or attend a special course in
its operation.
Minors should never be allowed to use this prod‐
uct.
Keep bystanders, especially children, and ani‐
mals away from the work area.
When the sprayer is not in use, put it in a place
where it does not endanger others. Secure it
against unauthorized use.
English
2 0458-583-0121-B
© ANDREAS STIHL AG & Co. KG 2022
0458-583-0121-B. VA0.B22.
Printed on chlorine-free paper Printing inks contain vegetable oils, paper can be recycled.
Original Instruction Manual 0000007179_009_GB

The user is responsible for avoiding injury to third
parties or damage to their property.
Do not lend or rent your sprayer without the
instruction manual. Be sure that anyone using it
understands the information contained in this
manual.
Do not operate your sprayer if any of its compo‐
nents are damaged. Make sure that all compo‐
nents are properly sealed – no leaks.
Pressurize the tank only with the pump that is
installed in the sprayer.
Operate the sprayer only if it is complete and
properly assembled.
To operate this sprayer you must be rested, in
good physical condition and mental health.
Do not operate the sprayer if you are under the
influence of any substance (drugs, alcohol)
which might impair vision, dexterity or judgment.
2.2 Intended use
The sprayer is suitable for spraying chemicals
and other liquids to control pests and weeds.
Typical areas of application are in fruit and vege‐
table growing, horticulture, plantations, grassland
and the forestry industry.
Only use plant protection products that are spe‐
cifically approved for use in sprayers.
Do not use your sprayer for any other purpose
because of the increased risk of accidents and
damage to the sprayer. Never attempt to modify
your sprayer in any way since this may result in
accidents or damage to the sprayer.
2.3 Clothing and Equipment
Wear proper protective clothing and equipment
when using, filling and cleaning the sprayer. Fol‐
low the chemical manufacturer's instructions with
respect to protective equipment.
Clothing must be snug-fitting but allow complete
freedom of movement.
Immediately change work clothes contaminated
with plant control chemicals.
For some chemicals it is necessary to
wear impermeable coveralls.
If you are spraying overhead, wear impermeable
head covering.
Wear impermeable safety boots with
a non-slip sole which are resistant to
plant control chemicals.
Do not wear sandals or go barefoot.
Wear impermeable gloves resistant to
plant control chemicals.
WARNING
To reduce the risk of eye injuries,
wear snug-fitting safety glasses in
accordance with European Standard
EN 166. Make sure the safety
glasses are a good fit.
Wear a suitable respirator.
Inhaling plant control chemicals may endanger
your health. Always wear a suitable respirator to
protect yourself against health risks and allergic
reactions. Observe warnings in the directions for
use of the plant protection product and all appli‐
cable local safety regulations, standards and
ordinances.
2.4 Transport
Transporting in a vehicle:
–Properly secure the sprayer to prevent turn‐
over and damage.
–The tank must be de-pressurized, empty and
clean.
2.5 Cleaning
Clean plastic surfaces with a cloth. Do not use
aggressive detergents. They may damage the
plastic.
Do not use a pressure washer to clean the unit.
The solid jet of water may damage parts of the
unit.
2.6 Accessories
Only use parts and accessories that are explicitly
approved for this tool by STIHL or are technically
identical. If you have any questions in this
respect, consult a servicing dealer. Use only high
quality parts and accessories in order to avoid
the risk of accidents and damage to the tool.
STIHL recommends the use of genuine STIHL
replacement parts. They are specifically
designed to match your model and meet your
performance requirements.
2 Safety Precautions and Working Techniques English
0458-583-0121-B 3

Never attempt to modify your tool in any way
since this may increase the risk of personal
injury. STIHL excludes all liability for personal
injury and damage to property caused while
using unauthorized attachments.
2.7 Handling Chemicals
Read the instructions supplied with the plant pro‐
tection chemical prior to use. Follow the instruc‐
tions with respect to mixing, using, personal pro‐
tection equipment, storage and disposal.
Observe legal requirements for handling plant
protection chemicals.
Plant protection chemicals may contain substan‐
ces that are harmful to humans, animals, plants
and the environment – risk of poisoning and risk
of serious or fatal injuries!
Avoid contact with plant protection chemicals.
Plant protection chemicals may be used only by
persons trained in their handling and the appro‐
priate first-aid measures.
Keep instructions or label of the plant protection
chemical available at all times in order to inform
the doctor about the chemical concerned in an
emergency. In an emergency, follow the chemi‐
cal manufacturer's instructions provided or on
the label. Observe manufacturer's safety data
sheets.
2.7.1 Mixing plant protection chemicals and
filling tank
Use plant protection chemicals only as specified
by the manufacturer.
–Before filling the tank with chemicals, carry out
a test with fresh water and check all parts of
the sprayer for leaks.
–Never apply undiluted liquid concentrates of
plant protection products.
–Mix the plant protection chemical and fill the
tank outdoors only or in well-ventilated loca‐
tions.
–Only mix sufficient solution for the job in hand
so that nothing is left over.
–Do not mix different plant protection products
unless such a mixture is approved by the man‐
ufacturer.
–Mix different chemicals only in accordance
with the manufacturer's instructions – incorrect
mixtures may produce toxic fumes or explo‐
sive solutions.
–Stand the sprayer on a level surface – do not
fill the tank above the maximum mark.
–When filling from central water supply, do not
immerse the end of the hose in the solution –
sudden low pressure in the system may cause
the solution to be sucked back into the water
supply.
–To reduce the risk of injury, do not fill the
sprayer while carrying it.
–Close the tank tightly after filling.
2.7.2 Application
–Work only in the open or in very well ventilated
locations, e.g. open greenhouses.
–Do not eat, drink or smoke while working with
plant control chemicals.
–Never blow through nozzles or other compo‐
nents by mouth.
–Do not spray in windy conditions.
Too high or too low a spray pressure or unfavor‐
able weather conditions can result in the wrong
solution concentration. Overdosing may damage
plants and the environment. Under-dosing may
result in unsuccessful plant treatment.
To reduce the risk of damage to plants and the
environment, do not operate the sprayer:
–if pressure is too high or too low
–in windy conditions
–at temperatures above 30 °C in the shade
–in direct sunlight
In order to reduce the risk of accidents and dam‐
age to the sprayer, never operate the sprayer
with:
–flammable liquids
–viscous or sticky liquids
–caustic or corrosive chemicals
–liquids hotter than 30 °C
2.7.3 Storage
–During work breaks, do not leave the sprayer
in the hot sun or near any heat source.
–Do not store plant protection chemical in the
sprayer for longer than one day.
–Store and transport plant protection products
only in approved containers.
–Never store the plant protection products in
containers intended for foods, drinks or animal
feed.
–Do not store plant protection products with
foods, drinks or animal feed.
–Keep plant protection products out of the
reach of children and animals.
–Store the sprayer empty and clean. It must not
be under pressure.
–Store plant protection products and power tool
in a place secured against unauthorized use.
English 2 Safety Precautions and Working Techniques
4 0458-583-0121-B

–Store the unit in a dry place protected from
frost.
2.7.4 Disposal
Dispose of plant protection chemicals in accord‐
ance with environmental requirements – follow
instructions of chemical manufacturer.
Never dispose of residual plant protection prod‐
ucts or contaminated rinsing solutions in water‐
ways, drains, sewers, street gutters or manholes.
–Dispose of residual chemicals and used con‐
tainers in accordance with local waste dis‐
posal regulations.
2.8 Holding and Controlling the
Unit
0000-GXX-0010-A0 KN
Put the strap over your left shoulder so that the
unit hangs at your side. To ensure the unit can
be quickly thrown off in an emergency, do not
wear the strap across your chest.
Hold the sprayer with your right hand on the
spray gun and your left hand on the pump han‐
dle.
Walk slowly forwards as you work – observe the
nozzle outlet at all times – do not walk back‐
wards – risk of stumbling.
To reduce the risk of spillage and injury, hold the
sprayer upright.
2.9 During Operation
Never spray in the direction of bystanders – risk
of injury.
Take special care in slippery conditions – damp,
snow, ice, on slopes or uneven ground.
Watch out for obstacles: Be careful of refuse,
tree stumps, roots and ditches which could
cause you to trip or stumble.
To reduce the risk of accidents, take a break in
good time to avoid tiredness or exhaustion.
Work calmly and carefully – in daylight conditions
and only when visibility is good. Stay alert so as
not to endanger others.
Never work on a ladder or any other insecure
support.
When working in open ground and gardens take
special care to avoid harming small animals.
To reduce the risk of electrocution, never work in
the vicinity of live wires or power cables.
Always clean the sprayer before changing to a
different plant protection product.
2.10 After Finishing Work
Check all parts of the unit for leaks.
After finishing work, thoroughly clean the unit
and wash your hands, face and, if necessary,
your clothes.
Keep other persons and animals away from the
areas that have been sprayed and do not walk
on them until the plant protection chemical has
dried.
2.11 Maintenance and Repairs
Do not attempt any maintenance or repair work
not described in the instruction manual. Have all
other work performed by a servicing dealer.
STIHL recommends that you have servicing and
repair work carried out exclusively by an author‐
ized STIHL servicing dealer. STIHL dealers are
regularly given the opportunity to attend training
courses and are supplied with the necessary
technical information.
Only use high-quality replacement parts in order
to avoid the risk of accidents and damage to the
unit. If you have any questions in this respect,
consult a servicing dealer.
STIHL recommends the use of genuine STIHL
replacement parts. They are specifically
2 Safety Precautions and Working Techniques English
0458-583-0121-B 5

designed to match your model and meet your
performance requirements.
Always clean and empty the tank and release
pressure in the sprayer before carrying our any
maintenance or repair work.
When cleaning the tank, tube and hose system,
make sure that other persons are not endan‐
gered by escaping liquid – risk of injury.
3 Assembling the Unit
1
1
2
3
0000-GXX-0011-A0 KN
► Connect the hose (1) to the spray gun (2).
► Connect the hose (1) to the tank (3).
2
4
0000-GXX-0012-A0 KN
► Connect the wand (4) to the spray gun (2).
3.1 Shoulder Strap
► Pull the buckle off the shoulder strap.
6159BA004 KN
► Ease the housing outwards and thread the
strap through the openings from below.
6159BA005 KN
► Thread the ends of the strap through the
buckle.
4 Controls
Make yourself familiar with how the components
function before using your sprayer for the first
time.
4.1 Pump
Locking the pump handle
6159BA006 KN
► Push the pump handle downwards and turn it
until it engages.
Lock the pump handle:
–during operation
–when screwing the pump into the tank – rotate
clockwise
–to unscrew the pump from the tank – rotate
counterclockwise
Unlocking the pump handle
6159BA007 KN
English 3 Assembling the Unit
6 0458-583-0121-B

► Rotate the pump handle about a quarter turn
until it disengages and can be moved up and
down freely.
Unlock the pump handle:
–to pressurize the tank
4.2 Tank
Pressurizing the tank
1
6159BA008 KN
► Move the pump handle up and down several
times – the pressure in the tank rises.
The scale on the piston manometer (1) shows
the pressure in the tank.
The higher the pressure in the tank, the higher
the piston manometer rises – maximum operat‐
ing pressure is 3 bar (43.5 PSI).
If the maximum operating pressure is exceeded,
the relief valve in the piston manometer releases
the excess pressure.
Depressurize the tank
6159BA010 KN
► Pull the piston manometer up all the way –
pressure is released – wait until tank is com‐
pletely depressurized.
Pressure must be released:
–before filling the tank
–after spraying
–to drain and clean the tank
–before carrying out maintenance work
4.3 Operating the Spray Gun
0000-GXX-0013-A0 KN
► Pull the trigger – solution flows from nozzle
► Release the trigger – solution flow stops
5 Preparing Unit for Opera‐
tion
5.1 Visual Inspection
Do not operate your unit if any of its components
are damaged. It is particularly important to check
the tank and hose connection for leaks.
5.2 Checking for Leaks
Carry out test with the tank empty.
5 Preparing Unit for Operation English
0458-583-0121-B 7

2
6159BA009 KN
1
► Pressurize the tank – move the unlocked
pump handle (1) up and down several times
until piston manometer (2) shows a pressure
of 2 bar (29 PSI).
The pressure in the tank must not drop any more
than 0.5 bar (7.25 PSI) within the next 30
minutes.
► Operate spray gun trigger – pressure must
escape.
► Release spray gun trigger – pressure must not
escape.
► Pull out piston manometer – pressure must
escape audibly.
► Completely depressurize the tank.
6 Filling the Container
The tank must not be under pressure.
► Unscrew the pump from the tank.
► Stand the tank securely on a level surface.
0000-GXX-0014-A0 KN
► Pour thoroughly mixed spray solution through
the opening (arrow) – do not exceed maximum
capacity (check max mark on scale).
► Screw the pump into the tank.
7 Spraying
7.1 Visual Inspection
Do not operate your unit if any of its components
are damaged. It is particularly important to check
the tank and hose connection for leaks.
7.2 Spraying
► Build up pressure – move the pump handle up
and down several times until the piston man‐
ometer shows the required working pressure –
see “Pressures / Spray Rates”
► Lock the pump handle.
Working pressures / spray rates – see "Specifi‐
cations".
English 6 Filling the Container
8 0458-583-0121-B

0000-GXX-0010-A0 KN
► Put the strap over your left shoulder so that
the unit hangs at your side.
► Operate the gun and always pay attention to
the optimal working pressure while spraying.
► If the working pressure drops more than
0.5 bar (7.25 PSI) , restore it by operating the
pump handle.
8 After Spraying
► Completely depressurize the tank.
► Unscrew the pump from the tank.
► Drain the tank in a well-ventilated location –
collect remaining solution in a suitable con‐
tainer.
Dispose of any residual spray solution in accord‐
ance with environmental requirements – follow
instructions of chemical manufacturer.
► Rinse the tank with clean water.
► Fill the tank with clean water, pump and spray
until the tank is empty and completely depres‐
surized.
► Wipe down the whole unit with a damp cloth.
9 Storing the Machine
► Keep tank and pump separate for drying and
storage.
► Dry the unit and store it in a place protected
from direct sunlight and frost.
10 Inspection and Mainte‐
nance by User
10.1 Pump
Removing
► Unscrew the pump from the tank.
► Hold pump firmly by the cylinder barrel and
unlock the pump handle.
6159BA015 KN
2
3
4
1
► Pull the pump handle (1) out of the cylinder
barrel (2) as far as stop.
► Pull pump handle and rotate it counterclock‐
wise until the gland (3) is released from the
cylinder barrel.
► Pull the piston rod (4) out of the cylinder bar‐
rel.
6159BA016 KN
► Lubricate the piston cup seal and O-ring with a
food-safe grease.
8 After Spraying English
0458-583-0121-B 9

Installing
6159BA017 KN
1
2
3
► Push gland (1) with piston cup seal (2) into the
cylinder barrel (3).
► Hold the gland (1) steady with your thumb and
push it into the cylinder barrel.
6159BA018 KN
1
2
► Pull the pump handle (1) upwards as far as
stop.
► Rotate the pump handle (1) clockwise until
gland (2) engages the cylinder barrel.
► Push the pump handle (1) downwards and
lock it in position.
► Screw the pump into the tank.
10.2 Cleaning the Filter and Nozzle
1
3
0000-GXX-0015-A1
2
► Unscrew the hollow cone nozzle (1) with spin‐
ner insert (2) from the wand.
0000-GXX-0016-A0 KN
► Rinse out all parts under running water and
then reassemble.
English 10 Inspection and Maintenance by User
10 0458-583-0121-B

11 Maintenance and Care
The following intervals apply to normal operating
conditions only. If your daily working times are lon‐
ger, shorten the specified intervals accordingly.
before starting work
after finishing work or daily
weekly
monthly
every 12 months
if problem
if damaged
as required
after 50 refills
Complete unit Visual inspection
(condition, leaks)
X
Clean X
Tank, hose system, wand Drain X
Clean X
Nozzle Clean X X
Filter Clean X X X
Piston cup seal Lubricate with
grease
X X X
O-ring Lubricate with
grease
X X
Safety labels Replace X
12 Main Parts
5
5
9
6
7
1
2
3
0000-GXX-0017-A1
19
8
4
20
18
10
15
16
11
13
14
17
12
1 Hollow cone nozzle
2 Spinner insert
3 Filter
4 Elbow
5 Union nut
6 Spray wand
7 Spray gun
8 Lever
9 Hose
10 Pump handle
11 Piston rod
12 Latch on pump cylinder
13 Gland
14 O-ring
15 Pump barrel
16 Piston cup seal
17 Valve disk
18 Piston manometer / relief valve
19 Tank
20 Shoulder strap
13 Specifications
13.1 Working Pressures / Spray
Rates
Working pressure Flow rate with hollow cone
nozzle
11 Maintenance and Care English
0458-583-0121-B 11

1.5 bar (21.75 PSI) 0.49 l/min (29.9 cu.in/min)
2.0 bar (29.0 PSI) 0.56 l/min (34.2 cu.in/min)
3.0 bar (43.5 PSI) 0.69 l/min (42.1 cu.in/min)
13.2 Specifications
Working pressure, max.: 3 bar
(43,5 PSI)
Flow volume, max.: 1.0 l/min
(61 cu. in./min)
Solution capacity, max.: 3 l
(0.8 US gals)
Total capacity: 4.2 l
(1.1 US gals)
Operating temperature, max.: 30°C
(86°F)
Residual solution in tank: <0.04 l
(1.4 fl.oz)
Recoil force: <5 N
(1.1 lbf)
Dry weight: 1.2 kg
(2.6 lbs)
14 Troubleshooting
Before starting any service work, operate the sprayer until it is no longer under pressure – if pressure
is not released, chemical may escape unexpectedly when working on the sprayer.
After servicing, carry out test run with clean water.
Condition Cause Remedy
Pumping action produces no
pressure
Pump not tightened down properly Lock the pump handle and
tighten down the pump
O-ring on pump damaged Install new O-ring
Piston cup seal damaged Install new piston cup seal
Jet only – spray not atomized Spinner insert in nozzle missing Fit spinner insert in the nozzle
Nozzle does not spray – pres‐
sure in tank OK
Nozzle / spinner insert and/or filter
blocked
Clean nozzle / spinner insert
and/or filter
Liquid entering the pump Valve disk dirty or damaged Clean or replace valve disk
Piston manometer indicates
no tank pressure; relief valve
operates too soon
Piston manometer faulty Replace the sprayer.
15 Maintenance and Repairs
Users of this machine may only carry out the
maintenance and service work described in this
user manual. All other repairs must be carried
out by a servicing dealer.
STIHL recommends that you have servicing and
repair work carried out exclusively by an author‐
ized STIHL servicing dealer. STIHL dealers are
regularly given the opportunity to attend training
courses and are supplied with the necessary
technical information.
When repairing the machine, only use replace‐
ment parts which have been approved by STIHL
for this power tool or are technically identical.
Only use high-quality replacement parts in order
to avoid the risk of accidents and damage to the
machine.
STIHL recommends the use of original STIHL
replacement parts.
Original STIHL parts can be identified by the
STIHL part number, the { logo and the
STIHL parts symbol K (the symbol may appear
alone on small parts).
16 Disposal
Contact the local authorities or your STIHL serv‐
icing dealer for information on disposal.
Improper disposal can be harmful to health and
pollute the environment.
000BA073 KN
► Take STIHL products including packaging to a
suitable collection point for recycling in accord‐
ance with local regulations.
► Do not dispose with domestic waste.
17 EC Declaration of Con‐
formity
ANDREAS STIHL AG & Co. KG
Badstr. 115
English 14 Troubleshooting
12 0458-583-0121-B

D-71336 Waiblingen
Germany
declare under our sole responsibility that
Designation: Sprayer
Make: STIHL
Series: SG 21
Serial identification number: 4255
conforms to the relevant specifications of Direc‐
tive 2006/42/EC.
Technical documents deposited at:
ANDREAS STIHL AG & Co. KG
Produktzulassung
Done at Waiblingen, 03.02.2020
ANDREAS STIHL AG & Co. KG
pp
Dr. Jürgen Hoffmann
Director Product Certification & Regulatory
Affairs
17 EC Declaration of Conformity English
0458-583-0121-B 13

English 17 EC Declaration of Conformity
14 0458-583-0121-B

17 EC Declaration of Conformity English
0458-583-0121-B 15

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