Hilti DD 120 Mode D'emploi page 19

1. Install the water collection system → page 10 and connect the wet-type industrial vacuum extractor.
2. Switch on the wet-type industrial vacuum extractor; do not use automatic mode.
3. Slowly open the water flow regulator until the water flows at the desired rate.
4. Push the ON/OFF switch to the "I" position.
5. Release the carriage lock.
6. Turn the hand wheel until the diamond core bit is in contact with the work surface.
7. When you start drilling apply only light pressure until the core bit has centered itself and only then,
increase the pressure against the working surface.
8. Observe the drilling performance indicator.
Initially, the drilling performance indicator shows orange. Optimum drilling performance is achieved
when the drilling performance indicator shows green. Reduce the pressure against the work
surface if the drilling performance indicator shows red.
6.6 Procedure in the event of the core bit jamming
If the bit jams the safety clutch disengages. The electronic control system then switches the motor off and
subsequently on again; this is done twice without manual intervention by the user. If this does not free the
core bit, the electronic control system switches the motor off for 90 seconds. You can free a jammed bit
manually, as follows:
6.6.1 Using an open-end wrench to free the core bit
1. Unplug the supply cord from the power outlet.
2. Grip the diamond core bit with a suitable open-end wrench close to the connection end and turn the
diamond core bit to free it.
3. Plug the supply cord into the power outlet.
4. Resume the drilling operation.
6.6.2 Using the hand wheel to free the core bit
1. Unplug the supply cord from the power outlet.
2. Free the core bit from the base material by turning the hand wheel.
3. Plug the supply cord into the power outlet.
4. Resume the drilling operation.
6.7 Switching off the diamond core drilling machine
WARNING
Risk of personal injury and material damage The diamond core bit fills with water during overhead drilling.
The diamond core drilling machine may become damaged and the risk of electric shock is increased.
▶ As a first step, carefully allow the water to drain away after completing overhead drilling. This is done
by disconnecting the water supply from the water flow regulator and draining the water by opening the
water flow regulator. Do not allow the water to run over the motor and cover.
1. Connect the water flow regulator to the diamond core drilling machine.
2. Remove the diamond core bit from the hole.
3. Lock the diamond core drilling machine with the carriage lock.
4. Switch off the diamond core drilling machine.
5. Switch off the wet-type industrial vacuum extractor, if used.
6.8 Removal of the diamond core drilling machine
1. Unplug the supply cord from the power outlet.
2. See the section headed "Removing the diamond core bit" → page 11 for instructions on removing the
diamond core bit.
3. Remove the core, if necessary.
4. Remove the diamond core drilling machine from the working surface.
If you remove the system as a complete unit, after setting it down it is advisable to run the machine
all the way down the rail until the core bit is in contact with the floor. This will help prevent the
diamond core drilling machine from toppling over.
*2215140*
Printed: 09.08.2019 | Doc-Nr: PUB / 5431632 / 000 / 02
2215140
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English 13