Hilti DD 120 Original Bedienungsanleitung Seite 42

Malfunction
The diamond core bit doesn't
rotate.
The drilling speed is decreas-
ing.
The handwheel can be turned
without resistance.
The diamond core bit can't be
fitted into the chuck.
Water escapes at the water
swivel or gear housing.
Water escapes from the
chuck during operation.
36 English
Printed: 11.06.2018 | Doc-Nr: PUB / 5069516 / 000 / 06
Possible cause
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.
The core bit connection end or
chuck is dirty or damaged.
The water pressure is too high.
The diamond core bit isn't securely
tightened in the chuck.
The core bit connection end /
chuck is dirty.
The seal at the chuck or at the
connection end is defective.
Action to be taken
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.
▶ Clean and grease the connec-
tion end and/or the chuck or
replace these parts.
▶ Reduce the water pressure.
▶ 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.
▶ Clean and grease the connec-
tion end and/or the chuck.
▶ Check the seal and replace it if
necessary.
274865
*274865*