–Without turning the tool, position it close to wall B. Switch the tool on and allow it to level in.
–Align the height of the tool (using a tripod or by underlaying, if required) in such a manner that the cross point of the laser lines is projected against the previously marked point II on the wall B.
A | 180˚ B |
d 
–Without changing the height, turn around the tool by 180°. Direct it against the wall A in such a manner that the vertical laser line runs through the already marked point I.
Allow the tool to level in and mark the the cross point of the laser lines on the wall A (point III).
–The difference d of both marked points I
and III on wall A indicates the actual height deviation of the tool.
The maximum permitted deviation dmax is calculated as follows:
dmax = double distance of the walls x 0.0036 mm/m Example: With a 26 ft distance between the walls, the maximum deviation must not exceed dmax = 2 x 26 ft x 0.0036 in/ft = 3/16 In. (0.188in) Thus, the marks must not be more than 3/16 of an inch apart.
Checking the Leveling Accuracy of the Horizontal Line
For the check, a free surface of approx. 26 x 26 ft is required.
–Set up the tool on a firm, level surface between both walls A and B. Allow the tool to level in while in horizontal operation.
A
| 26ft |
ft |
|
13 | B |
|
–At a distance of 13 ft from the measuring tool, mark the centre of the laser line (point I on wall A and point II on wall B) on both walls.
A
d
| ft | |
26 | 13 | |
ft | ||
|
B
–Set up the tool 26 ft away turned by 180° and allow it to level in.
–Align the height of the tool(using a tripod or by underlaying, if required) in such a manner that the center of the laser line is projected exactly against the previously marked point II on wall B.
–Mark the center of the laser line as point III (vertically above or below point I) on the wall A.
–The difference d of both marked points I and III on wall A indicates the actual deviation of the tool from the level plane.
The maximum permitted deviation dmax is calculated as follows:
dmax = double distance of the walls x 0.3 mm/m
Example: With a 26 ft distance between the walls, the maximum deviation must not exceed dmax = 2 x 26 m x 0.0036 in/ft = 3/16 in. Thus, the marks must not be more than 3/16 in apart.