TO RESET METER
h
Press and release
the calibration check key
@
.
h
Within one second
press the scale key
#
.
h
The meter will reset itself
the default setting of Scale #1
(wood) and 15% set-point, and clear all the readings
stored in memory.
h
Resetting the meter
will erase any previously stored readings.
SECTION B
PRACTICAL APPLICATIONS
TESTING WOOD
h
Set the scale
to #1 Wood
h
Align the contact pins
^
parallel to the grain and push
them into the wood to their full penetration, if possible. If
using an external electrode, attach it to the connector
&
and also align the pins parallel to the grain before driving
them into the wood.
h
Press the read key
!
. The meter displays the %MC for
two seconds.
If the displayed reading is above the set-point value the set-
point buzzer will sound. Also, one of the LEDs on the front
panel will light up as follows:
Wood Scale #1
Green
- 6% to 15%
Yellow
- 15% to17%
Red
- > 17%
The LEDs are a visual aid to help quickly determine the
moisture level that each reading indicates. Readings that
activate the green light indicate a sufficiently dry moisture
level, those that activate the yellow light indicate a borderline
situation, and those that activate the red light indicate
material that is too wet for most appliations. Use the color-
coded ranges a a guideline. Specific applications may require
different MC thresholds.
Meter readings taken on construction-grade lumber material
can be taken at face value, without “corrections” for many
applications.
If your application requires a higher level of accuracy (ex.
finish flooring, furniture-making) Delmhorst recommends
applying the following corrections:
6
Temperature
–As wood temperature increases, its electrical
resistance decreases and indicated moisture content rises.
Lower wood temperatures result in lower indicated moisture
content. If the wood temperature, which is typically the
ambient temperature, is between 50˚F/10˚C and 90˚F/32˚C,
there is no need to apply a correction. Refer to the
temperature correction table at the end of the manual.
Pin (insulated vs non-insulated)
– The reference calibration of
the meter was made with non-insulated pins that penetrate
5/16 inch. Insulated pins read slightly lower than non-
insulated ones. When using an electrode with insulated pins,
such as the 26-ES, refer to the correction at the end of the
manual.
Specie
s – Delmhorst uses Douglas Fir, the USDA standard, as
the basis for all wood calibrations. Because the electrical
characteristics of different species vary, all species read
differently at the same moisture content. For this reason, a
species correction is required. Refer to the species correction
table at the end of the manual.
Paint Failure and Moisture
Moisture is by far the most frequent cause of paint failure.
The key to preventing paint failure is to make certain that
moisture is not absorbed through the wood to the back of
the paint film. In order to insure quality paint jobs, wood
must remain dry after the application of paint.
Outdoor wood can be safely painted without danger of
peeling if the %MC is 15% or less. In drier climates, the
maximum reading should be 10% to 11%. Indoor wood
should be between 7% to 8% prior to painting.
The following conditions may cause high moisture content
in wood:
h
Leaky gutters and down spouts
h
Leaky pipes or condensation on cold water lines in attic
or hollow walls
h
Faulty flashing around windows, doors and where porch
and dormer roofs meet sidings
h
End-grain wood that is not sealed with paint at all joints
around windows, corners, and butt joints
h
Porch columns that do not have good drainage and
ventilation where they rest on porch floors
h
Siding or any other wood that is in contact with the
ground
7
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