Hilti DD 350 Mode D'emploi Original page 27

Malfunction
The service indicator blinks.
The drilling speed is decreas-
ing.
The diamond core bit doesn't
rotate.
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.
Printed: 18.10.2017 | Doc-Nr: PUB / 5236054 / 000 / 02
Possible cause
Service interval exceeded.
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 volume of water is too high.
The water flow rate is too low.
The carriage lock is engaged.
The diamond core bit has become
jammed in the base material.
The shear pin is broken.
The core bit connection end or
chuck is dirty or damaged.
The water pressure is too high.
Action to be taken
▶ Bring the diamond core drilling
machine to Hilti.
▶ 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 volume of water us-
ing the water volume regulator
(ensure that the volume of water
is at least 0.5 l/min as required).
▶ Check the water supply to
the diamond core bit or,
respectively, increase the water
flow by adjusting the water flow
regulator.
▶ Release the carriage locking
mechanism.
▶ 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.
▶ Replace the shear pin.
▶ Clean and grease the connec-
tion end and/or the chuck or
replace these parts.
▶ Reduce the water pressure.
English 17