PCE Instruments PCE-WP 21 User manual
PCE Americas Inc.
711 Commerce Way
Suite 8
Jupiter, FL 33458 USA
From outside US: +1
Tel: (561) 320-9162
Fax: (561) 320-9176
info@pce-americas.com
PCE Instruments UK Ltd.
Units 12/13
Southpoint Business Park
Ensign Way
Hampshire / Southampton
United Kingdom, SO31 4RF
From outside UK: +44
Tel: (0) 2380 98703 0
Fax: (0) 2380 98703 9
info@pce-instruments.com
www.pce-instruments.com/english
www.pce-instruments.com
PCE-WP 21
USER MANUAL
2
1. Description and applications
PCE- WP-21 is an electronic instrument used for measuring the moisture content of concrete. It is widely
used for measuring the moisture content of concrete floors before painting or applying tiles, parquets,
carpets, etc.
The final reading provided by this device is the average moisture level in a layer of concrete 50 mm thick.
PCE-WP-21 measures the dielectric constant (SIC).
2. Technical data
Range 1.0 % - 8.0 %
Thickness of layer measured About 50 mm
Display type LCD
Accuracy ± 0.7 %
Resolution 0.1
Power 9V, (1 battery 6F22)
Battery life About 5000 measurements
Low power indication Yes
Size 165 x 80 x 33 mm device
270 x 180 x 55 mm case
3. Preparing the instrument
Before conducting any measurements, you should do the following:
a) When measuring a lightweight type of concrete (density between 1.6 and 1.8 kg/dm3):
i. Set the switch to LIGHT CONCRETE.
ii. While holding the device in the air, press the POWER ON button (ON/OFF) and use the
CALIBRATION knob to set the device to the value indicated below the LIGHT
CONCRETE sign (-3.7).
b) When measuring a normal type of concrete (density between 1.8 and 2.4 kg/dm3):
i. Set the switch to NORMAL CONCRETE.
ii. While holding the device in the air, press the POWER ON button (ON/OFF) and use the
CALIBRATION knob to set the device to the value indicated below the NORMAL
CONCRETE sign (-5.6).
4. Measurements
The measurements should be conducted in several places. These places should be flat, smooth and
clean. The actual result of the measurements is the arithmetic average of all the measurements.
Hold the device as shown in Fig. 1. Use your right thumb to press the POWER ON button (ON/OFF).
Press the electrodes hard against the concrete. Read the result. If the result is out of range (below 1% or
above 8%), the measurement should be considered approximate. All results below 1% (for example: -1.2,
0.6) indicate only that the moisture content is below 1%. All results above 8% (for example: 8.3, 9.6)
indicate only that the moisture content is above 8%. In both of these cases, the numbers displayed on the
LCD CANNOT be considered as moisture content values.
Fig. 1
3
5. Remarks
Besides the moisture content, the results are also influenced by:
• Bulk density of the concrete
• Graining and type of aggregate
• Use of admixtures
• Temperature of the concrete
• Value of the water-cement indicator (W/C)
• Water chemical constitution
• Salinity of the concrete (in case of old concrete)
• Smoothness of the surface
In case a very high accuracy of measurement is required, the device should be calibrated to compensate
for the influence of the factors listed above. Such calibration should be done using the dry oven test.
During normal use it is enough to compensate only for the bulk density of the concrete.
The device cannot be used to measure the moisture content of concrete that is densely reinforced or
contains admixtures that conduct electricity. The measurement should not be done closer than 50 mm
from the nearest reinforcement.
The results of the measurement can be totally distorted by the occurrences of stray currents (for example:
those coming from a malfunctioning electrical installation). The accuracy of the device can also be very
low while measuring very fresh or recently dampened concrete. This is due to the interference from the
very moist top layer of the concrete.
6. Changing the battery and storage
The device is equipped with a power level control circuit. When the power drops below the acceptable
level, a LO BAT sign appears on the left side of the LCD. This indicates that the battery has expired and
should be replaced with a new one.
To replace the battery, unscrew the screw on the back of the instrument and carefully remove the back
panel.
Store the device in a dry place.
7. Terms and conditions
Please find PCE Instruments’ general terms and conditions at https://www.pce-
instruments.com/english/terms#AGB.
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