Bosch GCL 2-160 Operating/Safety Instructions Manual page 21

This can be caused by placing the measuring tool on a surface that
deviates by more than 4° from the horizontal plane. In this case, bring
the measuring tool to the level position and wait for the self-levelling
to take place.
In case of ground vibrations or position changes during operation, the
measuring tool is automatically levelled in again. To avoid errors by
moving the measuring tool, check the position of the laser beams with
regard to the reference points upon re-levelling.
Working without Automatic Levelling (see figure F1)
– For work without automatic levelling, slide the On/Off switch 2 to po-
sition " ". When automatic levelling is switched off, the laser lines
flash continuously.
When automatic levelling is switched off, you can hold the measuring
tool freely in your hand or place it on an inclined surface. The laser
beams no longer necessarily run perpendicular to each other.
Levelling Accuracy
Influences on Accuracy
The ambient temperature has the greatest influence. Temperature dif-
ferences occurring from the ground upward, especially, can divert the
laser beam.
In addition to external influences, device-specific influences (e.g. falls
or heavy impacts) can also lead to deviations. For this reason, check
the levelling accuracy each time before beginning work.
First, check both the height as well as the levelling accuracy of the hori-
zontal laser line, then the levelling accuracy of the vertical laser line.
Should the measuring tool exceed the maximum deviation during one
of the tests, please have it repaired by a Bosch after- sales service.
Checking the Height Accuracy of the Horizontal Line
For this check, a free measuring distance of 16 ft (5 m) on a firm sur-
face between two walls A and B is required.
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