Hilti DD 120 Mode D'emploi page 42

Malfunction
The diamond core drilling
machine doesn't achieve full
performance.
The diamond core bit doesn't
rotate.
The drilling speed is decreas-
ing.
The handwheel can be turned
without resistance.
36 English
Possible cause
Supply network fault – undervolt-
age occurred.
The gear selector isn't engaged.
The diamond core bit has become
jammed in the base material.
The gearing is defective.
Maximum drilling depth has been
reached.
The core is stuck in the diamond
core bit.
Wrong core bit specification for the
base material.
High steel content (indicated by
clear water containing metal cut-
tings).
The diamond core bit is defective.
Wrong gear selected.
Contact pressure is too low.
The machine has too little power.
The diamond core bit is polished.
The water flow rate is too high.
The water flow rate is too low.
The brake has been applied.
Safety clutch disengages too soon
or is slipping.
The split pin is broken.
Action to be taken
▶ Check whether other power
consumers are disrupting the
power supply from the network
or generator.
▶ Check the length of the exten-
sion cord used.
▶ Operate the gear selector until
it engages.
▶ Use an open-end wrench to
release the diamond core bit:
Disconnect the supply cord plug
from the power outlet. Grip the
diamond core bit with a suitable
open-end wrench close to the
connection end and release the
diamond core bit by rotating it.
Stand-guided drilling
▶ Turn the handwheel and try to
release the diamond core bit
by moving the carriage up and
down.
▶ Have the machine repaired by
Hilti Service.
▶ Remove the core and use a core
bit extension.
▶ Remove the core.
▶ Select a more suitable diamond
core bit specification.
▶ Select a more suitable diamond
core bit specification.
▶ Check the diamond core bit
for damage and replace it if
necessary.
▶ Select the right gear.
▶ Increase the contact pressure.
▶ Select the next lower gear.
▶ Sharpen the diamond core bit
by drilling into a sharpening
plate.
▶ Reduce the water flow rate
by adjusting the water flow
regulator.
▶ Check the water supply to
the diamond core bit or,
respectively, increase the water
flow by adjusting the water flow
regulator.
▶ Release the brake.
▶ Have the machine repaired by
Hilti Service.
▶ Replace the split pin.
274865
*274865*