Operating Instruction DD 250-CA

*2279864*
2279864 English 25
Malfunction Possible cause Action to be taken
Water escapes from the
chuck during operation.
The core bit connection end /
chuck is dirty.
▶ Clean and grease the connec-
tion end and/or the chuck.
The seal at the chuck or at the
connection end is defective.
▶ Check the seal and replace it if
necessary.
No water is flowing. The water channel is blocked. ▶ Increase the water pressure or
flush the water channel clear
from the opposite direction.
▶ Clean the water inlet and outlet
apertures.
The drilling system has too
much play.
The diamond core bit isn’t securely
tightened in the chuck.
▶ Tighten the diamond core bit
securely.
▶ Remove the core bit. Rotate the
diamond core bit approx. 90°
about its own axis. Refit the
diamond core bit.
The core bit connection end /
chuck is defective.
▶ Check the connection end and
chuck and replace them if
necessary.
The carriage has too much play. ▶ Adjust the play between the rail
and carriage.
Screws / bolts on the drill stand are
loose.
▶ Check the security of screws
/ bolts on the drill stand and
tighten them if necessary.
The drill stand is inadequately fas-
tened.
▶ Fasten the drill stand more
securely.
The connection between the dia-
mond core drilling machine and the
carriage or spacers is loose.
▶ Check the connection and,
if necessary, refasten the
diamond core drilling machine.
9.2 The diamond core drilling machine is not in working order
Malfunction Possible cause Action to be taken
The multifunction display is
not showing anything.
The PRCD isn’t switched on. ▶ Check that the PRCD is
functioning and switch it on.
Interruption in the electric supply. ▶ Plug in another electric tool or
appliance and check whether it
works.
▶ Check the plug connections,
supply cord, power supply line
and main supply fuse.
Water in the motor. ▶ Allow the diamond core drilling
machine to dry out completely
in a warm, dry place.
▶
Switch the diamond core drilling
machine off and then on again.
Service required.
The carbon brushes are worn out. ▶
Replace the carbon brushes.
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Water in the motor. ▶ Allow the diamond core drilling
machine to dry out completely
in a warm, dry place.
▶ Switch the diamond core drilling
machine off and then on again.
10 Disposal
Most of the materials from which Hilti tools and appliances are manufactured can be recycled. The
materials must be correctly separated before they can be recycled. In many countries, your old tools,