Hilti DD 120 Original Operating Instructions

36 English 274865
*274865*
Malfunction Possible cause Action to be taken
The diamond core drilling
machine doesn’t achieve full
performance.
Supply network fault – undervolt-
age occurred.
▶ Check whether other power
consumers are disrupting the
power supply from the network
or generator.
▶ Check the length of the exten-
sion cord used.
The diamond core bit doesn’t
rotate.
The gear selector isn’t engaged. ▶ Operate the gear selector until
it engages.
The diamond core bit has become
jammed in the base material.
▶ 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.
The gearing is defective. ▶ Have the machine repaired by
Hilti Service.
The drilling speed is decreas-
ing.
Maximum drilling depth has been
reached.
▶ Remove the core and use a core
bit extension.
The core is stuck in the diamond
core bit.
▶ Remove the core.
Wrong core bit specification for the
base material.
▶ Select a more suitable diamond
core bit specification.
High steel content (indicated by
clear water containing metal cut-
tings).
▶ Select a more suitable diamond
core bit specification.
The diamond core bit is defective. ▶ Check the diamond core bit
for damage and replace it if
necessary.
Wrong gear selected. ▶ Select the right gear.
Contact pressure is too low. ▶ Increase the contact pressure.
The machine has too little power. ▶ Select the next lower gear.
The diamond core bit is polished. ▶ Sharpen the diamond core bit
by drilling into a sharpening
plate.
The water flow rate is too high. ▶ Reduce the water flow rate
by adjusting the water flow
regulator.
The water flow rate is too low. ▶
Check the water supply to
the diamond core bit or,
respectively, increase the water
flow by adjusting the water flow
regulator.
The brake has been applied. ▶ Release the brake.
Safety clutch disengages too soon
or is slipping.
▶ Have the machine repaired by
Hilti Service.
The handwheel can be turned
without resistance.
The split pin is broken. ▶ Replace the split pin.
Printed: 09.08.2019 | Doc-Nr: PUB / 5069516 / 000 / 07

Hilti DD 120 Specifications

General

Brand	Hilti
Model	DD 120
Category	Drill
Language	English