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Non-destructive measurement mode
1. Press the key to power up. With no RH probe or pin
probe connected the last used scale will be displayed on
the LCD. Press key again to power off.
2. To change scale, press key to select the wood scale
or the comparative material scales. Select the required
material scale using the or key.
3. Hold your MRH directly on the wood, roof, masonry,
drywall or other material being tested, ensuring both
conductive-rubber electrodes are fully in contact with
the surface.
4. For the Roof, Masonry, Drywall and Laminate scales
the readings are comparative from 0 to 99. A visual
indication is also given by the bar display on the bottom
line of the LCD. The display also shows low (LO),
medium (MD) and high (HI) readings for these scales.
LO is displayed for readings from 0 to 30, MD for
readings from 31 to 70 and HI for readings from 71 to 99.
5. The readings on these scales are not to be interpreted as
a measurement of percentage moisture content (% MC)
or relative humidity (RH). It is not a relative humidity
reading and it does not have any linear correlation with
Relative Humidity measurements. This scale should be
regarded as a comparative or qualitative scale only.
6. When the Wood Scale is selected the moisture content
(MC) in percent of wood is shown on the right-hand
side of the bottom line of the display. The left-hand side
of this line shows the specific gravity (SG) being used.
The SG is changed by using the or key to adjust
to the required SG value. The range of SG covered is
0.30 to 0.80. The S.G. increases and decreases in
increments of 0.01
7. A chart showing the approximate specific gravity of a
wide range of different species is shown on pages 22
These do not necessarily indicate low, medium or high
levels of moisture but indicate the area of the 0-100
comparative scale where the reading lies.
MRH III User Guide
www.calcert.com sales@calcert.com1.800.544.2843 0
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