22
| English
Close the water cutoff valve
(5)
. Once work is complete, dis-
connect the valve adapter
(4)
from the water supply. Open
the water cutoff valve
(5)
and drain off the residual water.
Starting current limitation
The electronics of the power tool make the motor start
softly, therefore preventing the starting current from being
too high.
Restart protection
The restart protection feature prevents the power tool from
uncontrolled starting after the power supply to it has been
interrupted.
To restart the tool, press the
RESET
button on the portable
residual current device (PRCD)
(1)
. Set the on/off
switch
(2)
to the off position and then switch the power tool
on again.
Preselecting speed
Three speeds can be preselected using the gear selector
switch
(3)
.
The gears are recommended for the following drilling dia-
meters:
– 1st gear: 165–350 mm
– 2nd gear: 80–160 mm
– 3rd gear: 55–105 mm
Working advice
u
Pull the plug out of the socket before carrying out any
work on the power tool.
To drill, loosen the locking brake
(16)
until the star
handle
(15)
is easy to move. When doing so, hold the star
handle in place to prevent the power tool from sliding down
in an uncontrolled manner.
Start drilling in 1st gear with low speed until the core bit ro-
tates in the material without vibrating. Then switch to 2nd or
3rd gear if necessary.
During drilling, adapt the feed pressure to the material you
are drilling. Drill with consistent pressure. If necessary, pull
the core bit gently out of the drill hole to remove the wet
drilling debris from the diamond segments.
Use the star handle
(15)
to turn the power tool down to the
required drilling depth. Then turn it back until the core bit is
completely visible.
To reach the maximum possible working length, you will
need to remove the drill core once it completely fills the core
bit. Then insert the core bit back into the drilled hole and
drill to the maximum depth.
Overload clutch
If a core bit jams or snags, the power transmission to the drill
spindle will be interrupted. If this happens, switch the power
tool off immediately to prevent wear and heat build-up.
Dislodge the core bit by turning it to the right and left using a
suitable open-ended spanner. Carefully pull the power tool
out of the bore hole as you do so.
Overload protection
If the overload threshold is exceeded, the power tool will
start noticeably pulsating. Reduce the contact pressure until
the power tool starts working normally again.
If the contact pressure is not reduced, the power tool will
switch off. You will be able to switch the power tool on again
straight away, but you should now continue working with a
lower contact pressure.
Removing the core
Once drilling is complete, allow the water to keep flowing for
a short while to rinse out the debris between the core bit and
the core itself.
If the drill core is tightly seated in the core bit, hit the core bit
with a piece of soft wood or plastic to loosen the drill core. If
necessary, push the drill core out through the shank of the
core bit using a rod.
Note:
Do not hit the core bit with hard objects, as this may
damage or deform it.
Maintenance and Service
Maintenance and Cleaning
u
Pull the plug out of the socket before carrying out any
work on the power tool.
u
To ensure safe and efficient operation, always keep
the power tool and the ventilation slots clean.
Keep the rack
(22)
and the guide surfaces of the drill
column
(21)
clean at all times.
Clean the drill spindle
(7)
once the work is complete. Regu-
larly spray the drill spindle and the core bit
(6)
with corro-
sion inhibitor.
In order to avoid safety hazards, if the power supply cord
needs to be replaced, this must be done by
Bosch
or by an
after-sales service centre that is authorised to repair
Bosch
power tools.
Readjusting guide rollers (see figure G)
Over time, the guide rollers can wear down, resulting in play
between the guide rollers and the drill column. To eliminate
this play, you must readjust both guide rollers on the side
with the locking brake
(16)
.
Loosen both hex nuts
(36)
using a socket spanner (size
17 mm).
1 609 92A 4NK | (21.01.2021)
Bosch Power Tools
