Hilti DX 351-CT User manual

DX 351-CT
English 1
Français 15
Español 30
Português 44

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DX 351-CT
en Originaloperatinginstructions....................................... 1
fr Noticed'utilisationoriginale ....................................... 15
es Manualdeinstruccionesoriginal .................................... 30
pt Manualdeinstruçõesoriginal ...................................... 44

*388037* 388037 English 1
Original operating instructions
1 Information about the operating instructions
1.1 About these operating instructions
• Read these operating instructions before the product is used or operated for the first time. This is a
prerequisite for safe, trouble-free handling and use of the product.
• Observe the safety instructions and warnings in these operating instructions and on the product.
• Always keep the operating instructions with the product and make sure that the product is accompanied
by these operating instructions only, when the product is given to other persons.
1.2 Explanation of symbols
1.2.1 Warnings
Warnings alert persons to hazards that occur when handling or using the product. The following signal words
are used:
DANGER
DANGER !
▶Draws attention to imminent danger that will lead to serious personal injury or fatality.
WARNING
WARNING !
▶Draws attention to a potential threat of danger that can lead to serious injury or fatality.
CAUTION
CAUTION !
▶Draws attention to a potentially dangerous situation that could lead to personal injury or damage to the
equipment or other property.
1.2.2 Symbols in the operating instructions
The following symbols are used in these operating instructions:
Comply with the operating instructions
Instructions for use and other useful information
Dealing with recyclable materials
Do not dispose of electric equipment and batteries as household waste
1.2.3 Symbols in illustrations
The following symbols are used in illustrations:
These numbers refer to the illustrations at the beginning of these operating instructions.
The numbers in illustrations refer to important work steps or to components important for the
work steps. In the text, the corresponding numbers draw attention to these work steps or compo-
nents, e.g. (3).
Item reference numbers are used in the overview illustration and refer to the numbers used in
the key in the product overview section.
This symbol is intended to draw your special attention to certain points for handling the product.

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1.3 Product-dependent symbols
1.3.1 Warning symbols
Warning symbols are warnings of hazards.
Warning: Hot surface
1.3.2 Obligation symbols
Obligation symbols indicate "must do" actions.
Wear eye protection
Wear head protection
Wear ear protection
1.4 Product information
products are designed for professional users and only trained, authorized personnel are
permitted to operate, service and maintain the products. This personnel must be specifically informed about
the possible hazards. The product and its ancillary equipment can present hazards if used incorrectly by
untrained personnel or if used not in accordance with the intended use.
The type designation and serial number are printed on the rating plate.
▶Write down the serial number in the table below. You will be required to state the product details when
contacting Hilti Service or your local Hilti organization to inquire about the product.
Product information
Cartridge fastening tool DX 351-CT
Generation 01
Serial no.
2 Safety
2.1 Safety instructions
Basic safety precautions
WARNING! Read all safety instructions and other instructions. Failure to comply with the safety
instructions and instructions can cause serious injuries.
Keep all safety instructions and instructions for future reference.
▶Do not tamper with or modify the fastening tool in any way.
▶Use only fastening tools and items of equipment that are compatible with each other (base plates,
fastener guides, magazines, pistons and accessories) and consumables (fasteners and cartridges).
▶Check the fastening tool and accessories for damage.
▶Moving parts must be in full working order; make sure that they cannot jam. Comply with the
instructions on cleaning and oiling in these operating instructions → page 11.
▶All parts must be correctly installed to ensure faultless operation of the fastening tool. Damaged
parts must be properly repaired or replaced by Hilti Service unless otherwise stated in the operating
instructions.
▶Use only Hilti DX cartridges, or other suitable cartridges that meet the minimum safety requirements.
→ page 4
▶Use the fastening tool only for the applications defined in the section headed "Intended use" → page 4.
Do not attempt to drive fasteners into unsuitable base materials, for example material that is too thin, too
hard, or too brittle. Driving a fastener into these materials can cause the fastener to break, splinter the
material or be driven right through. Examples of unsuitable materials are:
▶Weld seams in steel, cast iron, glass, marble, plastic, bronze, brass, copper, insulating material,
hollow brick, ceramic brick, thin sheet metal (< 4 mm) and cellular concrete.
▶Comply with the Hilti 'Direct Fastening Technology Manual' or the corresponding local Hilti 'Technical
Guide to Fastening Technology'. Always also comply with the operating instructions of the fastener
to be used.

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Requirements to be met by users
▶Only appropriately trained persons who have been duly authorized and informed of the possible hazards
are allowed to operate or service this fastening tool.
▶Wear your personal protective equipment while the tool is in use.
▶Wear suitable eye protection and a hard hat.
▶Wear protective gloves. The fastening tool can get hot in use.
▶Wear ear protectors. The ignition of a propellant charge can damage the hearing.
▶Wear non-skid shoes.
Safety at the workplace
▶Keep the workplace tidy. Objects which could cause injury should be removed from the working area.
Disorder in the working zone can lead to accidents.
▶Make sure that the working area is well lit and, when working in an enclosed space, make sure it is
adequately ventilated.
Personal safety
▶Never press the nosepiece of the fastening tool against your hand or any other part of the body! Never
point the fastening tool toward other persons! → page 8
▶Do not compress the fastening tool with your hand on the magazine or fastener guide, piston or piston
guide or a loaded fastener. Compressing the fastening tool by hand can make the fastening tool ready
to fire, even without a fastener guide installed. This gives rise to a risk of serious injury for yourself and
others.
▶Everyone in the vicinity must wear ear protection, eye protection and a hard hat.
▶Stay alert, watch what you are doing and use common sense when operating a direct fastening tool. Do
not use the fastening tool when you are tired or under the influence of drugs, alcohol or medication. Stop
working if you experience pain or feel unwell. A moment of inattention while operating the fastening tool
can result in serious injury.
▶Avoid working in awkward body positions. Make sure you work from a safe stance and stay in balance
at all times.
▶Keep the arms slightly bent while operating the fastening tool, do not straighten the arms.
▶Keep other people away from the working area, especially children.
Use and care of direct fastening tools
▶Use the fastening tool only for its intended use and only when it is in faultless condition. Do not attempt
to use the tool for purposes for which it is not intended.
▶Do not use the fastening tool in places where there is a risk of fire and explosion.
▶Before driving fasteners, check behind the object to make sure that no-one is present in line with the
fasteners to be driven. Danger of fasteners penetrating right through!
▶Make sure that the nosepiece of the fastening tool is never pointed toward yourself or other persons.
▶Hold the fastening tool only by the gripping surfaces provided for the purpose.
▶Keep the gripping surfaces dry, clean and free from oil and grease.
▶Pull the trigger only when the fastening tool is at right angles to and pressed fully against the work
surface.
▶Before starting work, check the selected energy setting.
▶Carry out a test by driving fasteners into the base material you are working on.
▶When driving fasteners, always hold the fastening tool at right angles to the work surface. This reduces
the risk of a fastener being deflected by the base material.
▶Do not drive fasteners into existing holes except in situations where this is recommended by Hilti.
▶Do not re-use a fastener that was used beforehand - risk of injury! Use a new fastener.
▶Do not attempt to re-drive a fastener that was not driven in deeply enough! The fastener could break.
▶Never leave a loaded fastening tool unattended.
▶Always unload the fastening tool (remove cartridges and fasteners) before cleaning, maintenance and
care, changing the fastener guide, before work breaks and before storing the tool.
▶Transport and store the fastening tool in the Hilti case intended for the purpose.
▶Store fastening tools that are not in use in a dry, secure place where they are inaccessible to children.
▶Always position the nosepiece of the fastening tool on smooth, flat surfaces free of obstructions and fully
supported by the sub-structure.
▶Comply with the specifications for distances from edges and spacing between fasteners (see the section
headed "Minimum distances").

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▶Before driving fasteners, check that there is no electrical wiring, water piping or gas piping behind the
surface into which you want to drive them.
▶For detailed information, request a copy of the Hilti 'Direct Fastening Technology Manual' or the
corresponding local Hilti 'Technical Guide to Fastening Technology' from your Hilti Store.
Thermal safety rules
▶Do not exceed the maximum fastener driving rate recommended in the section headed "Technical data".
▶If the fastening tool overheats or if the cartridge strip deforms or melts, remove the cartridge strip and
allow the fastening tool to cool down.
▶Do not dismantle the fastening tool while it is hot. Allow the fastening tool to cool down.
Risk of explosion with cartridges
▶Use only cartridges that are suitable and approved for use with the fastening tool.
▶Remove the cartridge strip when you are going to take a break and when you have finished the job, and
before you transport the fastening tool.
▶Do not use force to remove fasteners and/or cartridges from the magazine strip or the fastening tool.
▶Store unused cartridges in accordance with the storage specifications for cartridges for powder-actuated
fastening tools (e.g. dry, temperature between 5 °C and 25 °C) in a locked storage facility.
▶Do not leave unused or partly used cartridge strips lying around. Collect the used cartridge strips and
store the cartridge strips at a suitable location.
▶Follow all instructions relating to safety, handling and storage in the safety data sheet of the cartridges.
3 Description
3.1 Product overview 1
@Piston
;Piston guide
=Power-tool housing
%Switchgear box
&Latching pawl
(Locking sleeve
)Cartridge barrel (ejection)
+Cartridge barrel (insertion)
§Adjusting knob for driving energy
/Indicator for driving energy
:Air vents
∙Switchgear box
$Thread for extension rod
£Trigger mechanism (extension)
3.2 Intended use
The product described is a cartridge-actuated fastening tool for driving fasteners into steel and concrete and
it is designed for use on ceilings. The product can be used only with the appropriate X-PT-CT extensions
and grip sections.
Use the product only in combination with the equipment designed for use with the fastening tool. Fastener
guides, pistons and fasteners must be compatible with one another.
Use the product only with spare parts and accessories from Hilti and with cartridges and fasteners from
Hilti, or other suitable cartridges and fasteners.
3.3 Requirements to be met by cartridges
WARNING
Risk of injury by unexpected explosion! Use of cartridges that do not meet the minimum safety
requirements can lead to a build-up of unburned powder. A sudden explosion and severe injuries to the
operator and bystanders can result.
▶Use only cartridges that meet the minimum safety requirements of your local statutory regulations!
▶Adhere to the maintenance intervals as stated and have the fastening tool cleaned regularly by Hilti-
Service!
Use only the Hilti DX cartridges listed in this table, or other suitable cartridges that are compliant with the
minimum safety requirements:
• It is a requirement for EFTA countries that the cartridges must be CE-compliant and must bear the CE
mark of compliance.
• It is a requirement for the United Kingdom that the cartridges must be UKCA-compliant and must bear
the UKCA mark of compliance.

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• It is a requirement for the USA that the cartridges must be compliant with the stipulations set out in
ANSI A10.3-2020.
• It is a requirement for the non-European member states of the C.I.P. that the cartridges must have C.I.P.
approval for the DX fastening tool used.
• It is a requirement for the remaining countries that the cartridges must have passed the firing-residues
test in accordance with EN 16264 and must have a manufacturer's declaration to this effect.
Compatible cartridges
Ordering designation Color Power level
6.8/11 M green green Weak
6.8/11 M yellow yellow Medium
6.8/11 M red red Strong
3.4 Information about the field of applications
See the Hilti product page for more information about the areas of application.
4 Technical data
4.1 Product properties
DX 351-CT
Weight (basic tool) 2.7 kg
(6.0 lb)
Length (fastening tool) 545 mm
(21.5 in)
Recommended maximum fastening
rate
700 fastener driving operations/h
Required contact pressure 140 N … 320 N
(31 lbf… 72 lbf)
Compression stroke 62 mm
(2.4 in)
Ambient temperature (storage and
use)
−15 ℃ … 45 ℃
(5 ℉ … 113 ℉)
4.2 Minimum distances and edge distances
You must always observe certain minimum distances and spacing when driving fasteners. They can differ,
depending on the product.
Comply with the instructions for use in the operating instructions of the fastener used, in the Hilti
Direct Fastening Technology Manual or the corresponding local Hilti 'Technical Guide to Fastening
Technology'.
Concrete Steel supporting structures
Min. distance to edge
(base-material edge to fastener)
≥ 70 mm
(≥ 2.8 in)
≥ 15 mm
(≥ 0.6 in)
Min. center-to-center distance
(between fasteners)
≥ 80 mm
(≥ 3.1 in)
≥ 20 mm
(≥ 0.8 in)
Min. base material thickness ≥ 100 mm
(≥ 3.9 in)
Follow the instructions in the
operating instructions of the
fastener!

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4.3 Product properties (extensions)
DX 351-CT
Weight (grip section) 0.9 kg
(2.0 lb)
Weight (extension, 1 ft) 0.2 kg
(0.4 lb)
Weight (extension, 3 ft) 0.5 kg
(1.1 lb)
Length (grip section) 935 mm
(36.8 in)
Length (short extension) 288 mm
(11.3 in)
Length (long extension) 915 mm
(36.0 in)
4.4 Noise and vibration information
General conditions for noise measurements
The noise values listed were determined under the following conditions:
Boundary conditions:
cartridge Caliber 6.8/11 red
Energy setting 3
Application Fastening 0.75 mm sheet steel to concrete (B35) with XU 27 P8
Technical data, noise and vibration values
Noise information
DX 351-CT
Sound power level (LWA)110 ±2 dB
Sound pressure level (LpA)97 ±2 dB
Peak sound pressure level (LpC,peak)127 ±2 dB
Total vibration
The value that must be specified in accordance with 2006/42/EC
does not exceed the limit value of:
< 2.5 m/s²
(< 8.2 ft/s²)
5 Preparations at the workplace
▶Before you start driving fasteners, always check that you are using the correct combination of fastener
guide, piston, fasteners and cartridge.
▶Before commencing work, check that all safety devices are fitted and that they are functioning correctly.
In order to ensure faultless operation of the fastening tool, all parts must be fitted correctly and must
meet the necessary requirements.
▶Check correct installation of all installed accessories.
Read and observe the instructions on safety, installation and use in the operating instructions of
the accessory.
5.1 Assembling the fastening tool 2
1. Push the locking sleeve on to the piston guide from the rear.
2. Bring the mark on the piston guide (1) into alignment with the mark on the metal housing (2).
3. Press and hold down the locking sleeve against the spring and insert the piston guide fully into the
power-tool housing.
4. Squeeze the two latching pawls (3) together and tighten the locking sleeve by screwing it clockwise as
far as it will go.
5. Open the piston stop by turning the locking sleeve one full turn counter-clockwise.

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6. Insert the piston as far as it will go into the piston guide.
7. Fully tighten the locking sleeve by screwing it as far as it will go clockwise.
▶The locking sleeve engages with an audible click.
8. Install a fastener guide. → page 7
5.2 Disassembling the fastening tool 3
1. Remove the fastener guide. → page 7
2. Open the piston stop by turning the locking sleeve one full turn counter-clockwise.
3. Pull the piston out of the piston guide.
4. Completely unscrew the locking sleeve from the thread of the power-tool housing.
The locking sleeve sits on a preloaded spring on the piston guide. Hold the piston guide firmly
while unscrewing.
5. Pull the piston guide with locking sleeve out of the power-tool housing.
6. Pull the locking sleeve to the rear and off the piston guide.
5.3 Changing fastener guide 5,6
Removing fastener guide
1. Release the fastener guide by unscrewing the union nut counter-clockwise.
2. Pull the fastener guide out of the piston guide.
Installing fastener guide
3. Check that piston brake (1) is present and correctly installed.
4. Position the fastener guide on the piston guide.
5. Push the fastener guide over the protective sleeve into the piston guide as far as it will go.
▶The piston guide retracts fully into the power-tool housing.
▶The fastener guide is seated correctly on the piston guide.
6. Secure the fastener guide by screwing union nut (2) clockwise until it is tight.
▶The annular spring engages with an audible click in the arbor hole of the fastener guide.
7. Check that the annular spring is correctly seated in the arbor hole (3).
5.4 Installing X-PT CT-351 grip 4
Unless national or local regulations specify a shorter length, a maximum of 3 extensions (3 ft and/or 1 ft
extensions) can be installed between grip and fastening tool to reach high ceilings. The maximum permitted
length of all extensions (not including the grip) is 3 m (9 ft).
Be sure to position your hands correctly when you operate the fastening tool. Always hold the fastening tool
with your hand centered on the grip (see illustration).
1. Screw the grip and extensions, if any, on to the back of the fastening tool.
2. Check that all extensions and the grip are correctly installed.
5.5 Loading the single-fastener tool 7
▶Push the fastener into the fastener guide from the front until the plastic washer of the fastener is held in
place in the fastener guide.
5.6 Loading cartridge strips 8
1. Push the cartridge strip, narrow end first, into the cartridge barrel (insert) until the full length of the
cartridge strip is inside the grip.
2. If you wish to use a cartridge strip in which some of the cartridges have already been used, pull the strip
up and out the top of the fastening tool by hand until the first unused cartridge is in place in the cartridge
chamber.

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6 Operation
WARNING
Risk of injury by accidental triggering! A loaded fastening tool can be made ready to fire at any time.
Accidental triggering can endanger you and others.
▶Always unload the fastening tool (cartridges and fasteners) whenever you interrupt work with the fastening
tool.
▶Before all maintenance, cleaning and setup activities, always make sure that there are no cartridges and
no fasteners in the fastening tool.
WARNING
Hazard due to hot surfaces! The fastening tool can become hot in use.
▶Wear protective gloves.
If resistance is unusually high when you insert the cartridge strip, check whether the cartridge strip is
compatible with this fastening tool.
Observe the safety instructions and warnings in these operating instructions and on the product.
Safety-related instructions for use
Illustration showing
example
Description
Do not press the nosepiece of the fastening tool against any part of the
body!
Pressing the nosepiece against a part of the body (a hand, for example) can
make the fastening tool ready to fire. As a result, there would be the risk of a
fastener being fired into a part of the body.
Do not pull back the magazine or other fastener guides by hand!
Pulling the magazine or another fastener guide back by hand can make the
fastening tool ready to fire. As a result, there would be the risk of a fastener
being fired into a part of the body.
6.1 Setting driving energy
Select the energy setting that suits the application. If no empirical values are available, always start with the
minimum driving energy.
6.2 Driving a fastener 9
CAUTION
Risk of injury due to electric shock! Driving fasteners into concealed electrical wiring leads to the risk of
an electric shock.
▶Check that there is no concealed electrical wiring in the work area.
▶Always hold the fastening tool by the black parts of the grip section.
▶Check the insulated gripping surfaces for damage at regular intervals.

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Before starting work, familiarize yourself with the characteristics of the fastener to be used and with the
technical specifications for the application. Read the operating instructions of the relevant fastener.
1. Position the fastening tool.
2. Hold the fastening tool straight against and perpendicular to the work surface.
3. Compress the fastening tool against the surface.
▶The fastener is driven.
4. Lift the fastening tool away from the working surface.
5. Load a fastener into the fastening tool.
6. Position the fastening tool at the next point and repeat the steps.
7 Troubleshooting
DANGER
Risk of injury by unsecured fastening tool! If the fastening tool jams in the compressed state or if a
cartridge does not fire, the fastening tool might be loaded with the safety off. Unintentional triggering can
cause severe injuries.
▶At all times, make sure that the fastening tool is not pointing toward you or anyone else.
▶Make sure that the fastening tool cannot be fired accidentally and do not hold your hand in front of the
muzzle of the fastener guide.
▶Keep a fastening tool with the safety off under observation at all times.
▶Free the jammed components. → page 9
▶After 2-3 misfires, i.e. no clearly audible firing sound and fasteners are not driven or not driven adequately,
please proceed as follows: → page 10
▶If a cartridge does not fire, proceed as follows: → page 9
7.1 Fastening tool jams and does not extend
DANGER
Risk of injury by unsecured fastening tool! If the fastening tool jams in the compressed state or if a
cartridge does not fire, the fastening tool might be loaded with the safety off. Unintentional triggering can
cause severe injuries.
▶At all times, make sure that the fastening tool is not pointing toward you or anyone else.
▶Make sure that the fastening tool cannot be fired accidentally and do not hold your hand in front of the
muzzle of the fastener guide.
▶Keep a fastening tool with the safety off under observation at all times.
1. Keep the fastening tool pressed against the work surface for at least 30 seconds and trigger the fastening
tool again.
2. Lift the fastening tool away from the working surface.
▶Be sure not to point it toward yourself or other persons!
3. Try to pull the fastener guide to its initial position by hand.
▶Take your hand off the trigger and do not hold your hand in front of the muzzle!
4. Immediately pull the cartridge strip out of the fastening tool.
▶If the cartridge strip cannot be removed:
▶Allow the fastening tool to cool down at a safe location under observation.
▶At all times, make sure that the fastening tool is not pointing toward you or anyone else.
▶Contact Hilti Service.
5. Service the tool. → page 11
7.2 Cartridge does not fire when fastening tool is above operating temperature
At all times, make sure that the fastening tool is not pointing toward you or anyone else!
If a cartridge does not fire, proceed as follows:
1. Keep the fastening tool pressed against the work surface for at least 30 seconds and trigger the fastening
tool again.

10 English 388037 *388037*
2. If the cartridge still does not fire, wait for 30 seconds and then lift the fastening tool away from the work
surface.
3. Immediately pull the cartridge strip out of the fastening tool.
▶If the cartridge strip cannot be removed:
▶Allow the fastening tool to cool down at a safe location under observation.
▶Contact Hilti Service.
4. Service the tool. → page 11
5. Move the cartridge to a safe location.
6. Dispose of the cartridges that have not fired.
▶Comply with the locally applicable disposal regulations.
7. Allow the fastening tool to cool down and resume work with a new cartridge strip.
7.3 The cartridge does not fire when the fastening tool is at operating temperature
After 2-3 misfires, i.e. no clearly audible firing sound and fasteners are not driven or not driven adequately,
please proceed as follows:
1. Keep the fastening tool pressed against the work surface for at least 30 seconds and trigger the fastening
tool again.
2. If the cartridge still does not fire, wait for 30 seconds and then lift the fastening tool away from the work
surface.
3. Stop using the tool immediately and remove the cartridge strip.
4. Disassemble the fastening tool. → page 7
5. Check that you are using the correct combination of fastener guides, piston, fasteners and cartridge.
6. Check piston brake and piston for wear; replace the components as necessary. → page 11
7. Clean and oil the fastening tool. → page 11
▶If the problem persists after the measures described above have been taken, further use of the
fastening tool is not permissible.
▶Have the fastening tool checked and, if necessary, repaired by Hilti Service.
Dirt and residues build up in the tool under normal operating conditions and functional parts are
also subject to wear.
Service the tool at regular intervals → page 11. Check the piston and piston brake daily if the
fastening tool is used intensively, or at the latest after every 2500 to 3000 fasteners. The interval
corresponds to the regular cleaning cycle of the fastening tool. The service and cleaning cycles
are based on typical tool use.
When 30,000 fasteners have been driven, have the tool fully serviced by Hilti Service.
8 Care and maintenance
8.1 Care of the fastening tool
For cleaning, use only the cleaning accessories supplied by Hilti, or material of equivalent quality. Do not,
under any circumstances, use spray cleaning equipment, compressed air, high-pressure cleaning equipment,
solvents or water for cleaning.
For maintenance and lubrication of the fastening-tool components, always use Hilti spray. Never use
greases, because the use of greases can lead to malfunctions of the fastening tool.
Do not apply oil to the switchgear box. Prevent oil and Hilti spray from entering the switchgear box.
Lubricant penetrating inside the switchgear box can lead to malfunctions.
CAUTION
Risk of damage to the fastening tool! Foreign bodies can jam in the fastening tool and damage the
fastening tool when a cartridge is fired.
▶Prevent foreign bodies from penetrating into the interior of the fastening tool.
▶Clean the exterior of the fastening tool with a slightly damp cloth at regular intervals.
▶Keep the air vents clear and operate the fastening tool only with clear air vents.

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8.2 Maintenance
WARNING
Dangerous substances! The deposits inside DX tools contain substances that may present a health hazard.
▶Do not inhale dust or dirt while cleaning.
▶Keep dust and dirt away from foodstuffs.
▶Wash your hands after cleaning the fastening tool.
▶Clean the fastening tool and use Hilti spray as stated in the operating instructions. This will help prevent
malfunctions.
1. Regularly check all external parts of the fastening tool for damage.
2. Regularly check all operating controls to ensure that they work properly.
3. Use the fastening tool only with suitable cartridges and the recommended energy setting.
▶Use of the wrong cartridges or incorrect driving-energy settings can lead to premature failure of the
fastening tool.
8.3 Servicing the tool
Service the tool in the following situations:
▶If energy fluctuations occur (evidenced by irregularities in fastener penetration depth).
▶If cartridge misfires occur (the cartridge is not fired).
▶If the tool becomes noticeably less easy to operate:
▶If the required contact pressure increases noticeably.
▶If triggering resistance increases.
▶If the adjuster for driving energy is stiff.
▶If the cartridge strip is difficult to remove.
8.4 Cleaning fastening tool 10,11
1. Disassemble the fastening tool. → page 7
2. Clean the fastener guide (bore and thread of the locking sleeve).
3. Clean the cartridge barrel with the cleaning rod supplied for the purpose.
4. Clean the outside and inside of the piston guide (rear of the piston guide), cartridge chamber (1) and hole
for power regulation (2) in the end face of the piston guide.
Do not use a metal brush to clean the O-ring and do not accidentally remove the O-ring. Metal
brushes can damage the O-ring.
5. Lightly oil the inside of the piston guide.
6. Check O-ring (3) for wear and damage and check that the O-ring is correctly seated.
7. Oil the outside of the piston guide or alternatively oil the inside of the locking sleeve.
8. Clean the inside and outside of the power-tool housing.
Prevent oil and Hilti spray from entering the switchgear box. Lubricant penetrating inside the
switchgear box can lead to malfunctions.
8.5 Additional checks in the course of the tool service
WARNING
Risk of injury! A faulty piston brake, piston or fastener guide leads to an increased risk of malfunctions.
▶Check the piston brake and piston for wear and replace them if damaged.
▶Do not tamper with or modify the piston.
▶Do not attempt to repair a faulty piston yourself, for example by grinding the tip.
1. Replace the piston if you establish that any one of the following points applies:
▶The piston is broken.
▶The piston is badly worn or chipped (e.g. a segment of more than 90° of the circumferential
ring-shaped elevation at the piston tip broken away)
▶The piston is bent (check by rolling the piston on a smooth, flat surface).

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2. Replace the piston brake if you establish that any one of the following points applies:
▶The metal ring of the piston brake is broken or detached.
▶The piston brake no longer holds on the fastener guide.
▶The rubber is badly worn at certain points under the metal ring.
▶Piston jams in piston brake.
8.6 Final check of the fastening tool
▶After carrying out care and maintenance, check that all protective and safety devices are fitted and that
they function faultlessly.
9 Troubleshooting
9.1 Problems with the fastening tool
Before you start troubleshooting, make sure there are no cartridges and no fasteners in the fastening
tool. If the cartridges cannot be removed, contact Hilti Service.
If the trouble you are experiencing is not listed in this table or you are unable to rectify the problem by
yourself, please contact Hilti Service.
Trouble or fault Possible cause Action to be taken
Higher force required to press
the tool against the surface
Build-up of combustion residues. ▶Service the tool.
▶Insert new cartridge strip.
Triggering resistance
increases
Build-up of combustion residues. ▶Service the tool. → page 11
▶Contact Hilti Service.
Adjusting knob for driving
energy is difficult to turn
Build-up of combustion residues. ▶Service the tool. → page 11
Fastening tool cannot be fired Fastening tool was not pressed
fully against the working surface.
▶Press the fastening tool fully
against the working surface.
Piston incorrectly installed. ▶Check installation and, if nec-
essary, repeat the installation
procedure. → page 6
Fastening tool is faulty. ▶Contact Hilti Service.
Fastener guide not correctly
screwed on.
▶Turn the fastener guide until it
engages with an audible click.
→ page 6.
Piston bounce because driving
energy is too high.
▶Reduce driving energy.
The piston jams in the fas-
tener guide
Piston and/or piston brake dam-
aged.
▶Check piston brake and piston
for wear; replace the compo-
nents as necessary. → page 11
Too much driving energy ▶Turn the adjusting knob for
driving energy to reduce driving
energy.
Piston bent because tool fired
without fastener
▶Avoid firing the tool without a
fastener loaded.
▶Check the straightness of the
piston; replace if necessary.
9.2 Problems with fasteners
Malfunction Possible cause Action to be taken
Fastener driving depth varies Incorrect piston position ▶Check piston brake and piston
for wear; replace the compo-
nents as necessary. → page 11
Piston bounce because driving
energy is too high.
▶Reduce driving energy.

*388037* 388037 English 13
Malfunction Possible cause Action to be taken
The fastener bends Hard material (steel, concrete). ▶Turn the adjusting knob for
driving energy to increase
driving energy.
▶Use a shorter nail.
▶Use a nail with a higher
application limit.
A rebar is located just below the
concrete surface.
▶Drive the fastener at a different
position.
The fastener is not driven
flush
Wrong fastener. ▶Match the length of the fastener
to the thickness of the compo-
nent.
Wrong power setting. ▶Change the energy setting on
the fastening tool.
A rebar is located just below the
concrete surface.
▶Drive the fastener at a different
position.
Hard material (steel, concrete). ▶Turn the adjusting knob for
driving energy to increase
driving energy.
▶Use a shorter nail.
▶Use a nail with a higher
application limit.
Damaged fastener head Too much driving energy. ▶Turn the adjusting knob for
driving energy to reduce driving
energy.
The wrong piston has been fitted. ▶Make sure that the correct
piston / fastener combination is
used.
The piston is damaged. ▶Change the piston.
The nail doesn’t penetrate
deeply enough
Driving energy too low ▶Increase driving energy.
▶Use a more powerful cartridge.
The application limits have been
exceeded (very hard material).
▶Use a nail with a higher
application limit.
The system is unsuitable. ▶Use a more powerful system,
e.g. DX 6.
The fastener doesn’t hold in
the base material
Thin supporting steel (45 mm) ▶Use a different energy setting.
▶Use a nail suitable for thin
supporting steel.
Fastener breakage
(shear breakage)
Driving energy too low ▶Increase driving energy.
▶Use a more powerful cartridge.
The application limits have been
exceeded (very hard material).
▶Use a more powerful system,
e.g. DX 6, with corresponding
suitable fasteners.
Fastener breakage
(with deformation)
Driving energy too low ▶Increase driving energy.
▶Use a more powerful cartridge.
The application limits have been
exceeded (very hard material).
▶Use a more powerful system,
e.g. DX 6, with corresponding
suitable fasteners.
Too much driving energy. ▶Turn the adjusting knob for
driving energy to reduce driving
energy.
The head of the nail punches
through the material fastened
Too much driving energy ▶Turn the adjusting knob for
driving energy to reduce driving
energy.
▶Use a less powerful cartridge.

14 English 388037 *388037*
9.3 Problems with the cartridges
Malfunction Possible cause Action to be taken
The cartridge strip doesn’t
advance
The cartridge strip is damaged. ▶Change the cartridge strip.
Fastening tool damaged. ▶Contact Hilti Service.
Wrong cartridge strip used ▶Use only cartridge strips of a
type intended for use with the
fastening tool.
Fastening tool not fully pressed ▶After positioning the fastening
tool, press it against the base
material and fire the fastener
right away.
Cartridge strip is difficult to
remove.
Fastening tool overheated. ▶Allow the fastening tool to
cool down under constant
observation.
▶Subsequently, carefully remove
the cartridge strip from the
fastening tool.
Build-up of combustion residues. ▶Service the tool.
▶Insert new cartridge strip.
The cartridge doesn’t fire Bad cartridge. ▶Pull the cartridge strip through
to the next cartridge.
Fastening tool dirty. ▶Service the tool.
Fastening tool was not pressed
fully against the working surface.
▶Press the fastening tool fully
against the working surface.
Wrong combination of fastener,
fastener guide, etc.
▶Check that the combination of
fastener, fastener guide, etc. is
correct for your application.
The cartridge strip melts Fastening tool was pressed against
the surface for too long without a
fastener being fired.
▶After positioning the fastening
tool, press it against the base
material and fire the fastener
right away.
Fastener driving rate too high (fas-
tening tool overheated).
▶Stop using the tool immediately.
▶Remove cartridge strips and
allow the fastening tool to cool
down.
▶Do not exceed the recom-
mended maximum fastener
driving rate (see the section
headed "Technical data").
A cartridge detaches itself
from the cartridge strip
Fastener driving rate too high (fas-
tening tool overheated).
▶Stop using the tool immediately.
▶Remove cartridge strips and
allow the fastening tool to cool
down.
▶Do not exceed the recom-
mended maximum fastener
driving rate (see the section
headed "Technical data").
10 Disposal
Most of the materials from which Hiltiproducts are manufactured can be recycled. The materials must be
correctly separated before they can be recycled. In many countries, your old tools, machines or appliances
can be returned to Hilti for recycling. Ask Hilti Service or your Hilti representative for further information.