Hilti DD 30-W Original Operating Instructions page 51

8.1 The diamond core drilling machine is in working order
Malfunction
The service indicator lights.
The diamond core drilling
machine doesn't achieve full
performance.
The diamond core bit doesn't
rotate.
The drilling speed is decreas-
ing.
The diamond core bit can't be
fitted into the chuck.
Printed: 20.12.2016 | Doc-Nr: PUB / 5283477 / 000 / 03
Possible cause
The carbon brush wear limit has
almost been reached. The diamond
core drilling machine will continue
to run for a few hours until it shuts
down automatically.
The carbon brushes have been
changed and must be run in.
Supply network fault – undervolt-
age occurred.
The diamond core bit has become
jammed in the base material.
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.
The diamond core bit is polished.
The water flow rate is too high.
The water flow rate is too low.
The connection end is dirty or not
secured in the chuck correctly.
The core bit connection end or
chuck is dirty or damaged.
Action to be taken
▶ Have the carbon brushes
replaced at the next opportunity.
▶ Run in the carbon brushes by
letting the machine run under
no load for at least 1 minute
without interruption.
▶ Check whether other power
consumers are disrupting the
power supply from the network
or generator.
▶ Check the length of the exten-
sion cord used.
▶ Guide the diamond core drilling
machine in a straight line.
▶ Use an open-end wrench to
release the diamond core bit:
Disconnect the mains 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.
▶ Remove the core and use a
longer core bit.
▶ 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.
▶ 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.
▶ Check the filter element at the
water connection.
▶ Clean the connection end and fit
the diamond core bit correctly.
▶ Clean the connection end
and/or the chuck or replace
these parts.
English 43