Operating Instruction DD 250-CA

*2279864*
2279864 English 19
WARNING
Risk of injury due to electric shock! Do not continue operating the diamond core drilling machine if the
indicator on the ground fault circuit interrupter does not go out when the 0 or the TEST button is pressed.
▶ Have your diamond core drilling machine repaired by Hilti Service.
4. Press the "I" or "RESET" button on the PRCD.
▶ The indicator lights up.
6.6 Operating the diamond core drilling machine
WARNING
Risk of personal injury and material damage The diamond core drilling machine may become damaged
and the risk of electric shock is increased.
▶ Use of the water collection system in conjunction with a wet-type industrial vacuum cleaner is a mandatory
requirement for wet drilling overhead.
DANGER
Risk of personal injury and material damage The wet-type industrial vacuum cleaner switches on and off
with a delay. This allows water to run over the diamond core drilling machine. The diamond core drilling
machine may become damaged and the risk of electric shock is increased.
▶ When drilling in an upward direction, the wet-type industrial vacuum cleaner must be switched on
manually before opening the water supply valve and switched off again manually after closing the water
supply valve.
DANGER
Risk of personal injury and material damage The diamond core drilling machine may become damaged
and the risk of electric shock is increased.
▶ When drilling in an upward direction, stop working if the suction removal system stops working (e.g. the
wet-type industrial vacuum cleaner is full).
WARNING
Risk of personal injury and material damage The water collector cannot function correctly during drilling
in an upward direction at an angle. The diamond core drilling machine may become damaged and the risk
of electric shock is increased.
▶ Do not drill in an upward direction at an angle.
Pressing the button for the hole-starting mode (when the machine is idling or operating under no load)
reduces the speed for starting holes. This makes it possible for diamond core bits of large diameters
to start holes with greater ease and less vibration. Pressing the button for the hole-starting mode
again deactivates this function and the diamond core drilling machine adjusts up to the preset speed.
If the function for starting holes is not deactivated before a maximum of two minutes has expired, the
diamond core drilling machine automatically switches off.
1. Slowly open the water flow regulator until the desired volume of water is flowing.
2. Press the On/Off switch on the diamond core drilling machine to "I".
3. Release the carriage locking mechanism.
4. Turn the hand wheel until the core bit is in contact with the base material.
5. When beginning drilling, apply only light pressure, until the core bit has centered itself. Only increase the
pressure afterwards.
6. Regulate the contact pressure while observing the drilling performance indicator.