10
©2017 Johnson Level & Tool
Checking Level Accuracy
• Set the instrument on a level surface such as a tripod, located
between two walls (labeled Wall 1 and Wall 2), located a minimum
of 25
′
apart (see Fig 1). The laser should be as close as possible
to Wall 1.
• Point the instrument at Wall 1. Turn the laser
on, and mark the beam as Point A. Rotate the
instrument 180 degrees so the laser is pointed
at Wall 2. Mark the beam on Wall 2 as Point B.
• Move the instrument and the tripod so the
laser is positioned as close as
possible to Wall 2 near Point B (see
Fig 2). Level the tripod and position the
instrument on the tripod facing Wall 2. Turn the
laser on, and mark the beam as Point C. Point C should be directly
above or below Point B.
• Turn the laser off and rotate the laser 180 degrees so that it is
facing directly to Wall 1.Turn on the laser, and mark the beam as
Point D. Point D should be directly above or below Point A.
• Measure the vertical distance between Points A and D.
• Measure the vertical distance between Points B and C.
• If the larger of the two differences measured above is less than
1/4
″
at 25
′
, your instrument is within tolerance.
Note:
This accuracy checking method doubles the error. For example,
if the difference between Point A and Point D is 1/4
″
at 25
′
, your
laser is accurate to 1/8
″
at 25
′
.
Wall 1
Wall 2
Fig 1
Fig 2
1836i-English_Manuals 3/15/17 11:36 AM Page 10
