Product Manual

4.3 Valve Boxes and Covers
Valve Boxes and/or Covers made of ferrous
materials can provide excellent signal response.
Based on the size of the Valve Box you may experi-
ence a wider signal peak than with smaller objects like
a property pin.
Plastic valve boxes may have a strong magnet inside
to make them easy to locate. In this situation you
should use caution because the magnet will produce
weak signals to each side of the box and a stronger
peak signal over the center of the box. (See Sketch in
Section 4.2) Turning the sensitivity down as you begin
to detect the magnetic marker will help you eliminate
the unwanted signals.
You can trace the outline of the cover by reducing the
sensitivity control to the lowest setting that will detect
the cover. As you sweep 360
o
around the cover, the
signal will peak each time you pass over the outer rim
of the cover. Mark each of these peak signals to detail
the cover dimensions.
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