Legal notice
This is a publication by Conrad Electronic SE, Klaus-Conrad-Str. 1, D-92240 Hirschau (www.conrad.com).
All rights including translation reserved. Reproduction by any method, e.g. photocopy, microfilming, or the capture in electronic data
processing systems require the prior written approval by the editor. Reprinting, also in part, is prohibited. This publication represent the
technical status at the time of printing.
© Copyright 2016 by Conrad Electronic SE.
G
Zero point calibration
Take some pH7 buffer solution in a small container. The glass electrode should be completely covered
during immersion.
Turn on the meter by pressing the power button (3).
Wait a while until the display has stabilised and then dip the electrode head in the buffer solution. Stir
slowly with the meter in the buffer solution until the reading has stabilised. Leave the meter immersed and
set the reading to a pH 7.00 using a calibration control “ZERO” (12). To do this, use the small alignment
screwdriver.
The pH changes slightly at a temperature deviation of 25 °C. The corresponding pH value is
specified on the buffer solution container for the different temperatures. Use the corresponding
value for alignment.
Rinse the electrode with distilled water, rinse and pat the replaceable electrode dry.
Reference point calibration
The reference point shall always be close to the measured pH of the liquid. Select the reference point pH4
if you want to measure acidic liquids (< pH7), and the reference point pH10 for alkaline liquids (> pH7).
The reference buffer solution pH4 is supplied with the meter.
Take some pH4 or pH10 buffer solution in a small container. The glass electrode should be completely
covered during immersion.
Wait a while until the display has stabilised and then dip the electrode head in the buffer solution. Stir
slowly with the meter in the buffer solution until the reading has stabilised. Leave the meter immersed and
set the reading to a pH 4.00 (or pH 10.00) using the calibration control “SPAN” (10). To do this, use the
small alignment screwdriver.
The pH changes slightly at a temperature deviation of 25 °C. The corresponding pH value is
specified on the buffer solution container for the different temperatures. Use the corresponding
value for alignment.
Rinse the electrode with distilled water, rinse and pat the replaceable electrode dry.
Place the alignment screwdriver in the holder (11) within the battery compartment and close the battery
compartment carefully.
MEASURING
Perform a calibration if the meter is not used for a long time or a electrode was changed.
Proceed as follows for measuring:
Pull the protective cap (8) off the device. This cap is merely plugged.
Screw the moistening cap (7) of the replaceable electrode (5) and check the liquid. The electrode must be
moist.
Clean the electrode with distilled water and tap it dry. Never touch the glass electrode (6) while doing so as
this may damage it.
Turn off the device by pressing the power button (3).
Dip the electrode into the liquid to be measured. The glass electrode has to be completely covered by the
liquid.
Stir slowly with the meter in the buffer solution until a stable reading is displayed. Read this from the
display.
Turn off the device after the measurement by pressing the power button (3).
Clean the electrode and screw the moistening cap onto the device. If necessary, add a little soaking solu-
tion into the moistening cap.
Replace the protective cap (8) on the meter and stow it away carefully in the plastic box.
Measurements in hot liquids cause the electrode to wear much faster.
CHANGING THE ELECTRODE
The electrode is a wear part. Worn electrodes are not covered by the warranty/guarantee.
If measurement is not possible or calibration cannot be carried out, the electrode is usually worn and must
be replaced.
To replace, proceed as follows:
Make sure that the meter is switched off and the battery compartment is closed.
Remove the protective cap (8) from the device.
Loosen the screw fitting (4) of the electrode and take it off.
Carefully pull the replaceable electrode (5) off the meter without turning the
electrode.
Insert the new replaceable electrode into the meter. Please note the notch in
the plug region. This fits correctly on the meter only on the right side.
Screw the replaceable electrode again with the screw fitting (4).
Check the liquid in the moistening cap and refill the soaking solution, if neces-
sary.
Turn on the meter and check the operational readiness. A reading must be
displayed. If no reading is displayed, please check the plug connection. Turn
the device off.
Perform a calibration before the first measurement.
Replace the protective cap (8) on the meter and stow it away carefully in the
plastic box.
TROUBLESHOOTING
In purchasing the measuring instrument, you have acquired a product with state-of-the-art design that is
operationally reliable. Nevertheless, problems or faults may occur. Which is why we would like to describe
here how you can solve any problems:
Always follow the safety instructions!
Error
Possible cause
Remedy
The meter cannot be
switched on
The batteries are flat.
Change the batteries.
Incorrect readings
The temperature of the liquid is
out of the allowable range of 0 to
+ 50 °C.
Bring the liquid within the given
temperature range.
The device has not been calibrated.
Perform a calibration.
Calibration is not
possible
The electrode is dirty.
Clean the electrode.
The buffer solutions are used.
Use new buffer solutions.
The electrode has dried up.
Recover the electrode.
The electrode is used up.
Replace the electrode.
Repairs other than described above are carried out exclusively by authorised specialist staff. If
you have questions concerning the use of the meter, please contact our technical support team.
CLEANING AND MAINTENANCE
Maintenance is limited to changing of batteries and electrodes.
Use a clean, lint-free, antistatic and slightly damp cloth to clean the device. Do not use any abrasive or
chemical agents or detergents containing solvents.
The electrode must be cleaned after each measurement. Distilled water is sufficient for normal cleaning.
A pepsin-cleaning fluid is required for measurements in protein-containing liquids (e.g. milk). Leave the
electrode in the pepsin-cleaning fluid for about 5 minutes and then rinse thoroughly with distilled water.
Pat the electrode dry and screw the moistening cap onto the electrode.
All screw-fitted parts are protected from infiltration of water using rubber seals. Make sure that
the seals are not pinched or damaged. Regular use of silicone grease is recommended.
Recovery of the glass electrode
A dried glass electrode has a negative effect on the service life. Dried electrodes may be recovered to
render the open-pore glass layer permeable again.
Dip the dried electrode in plenty of soaking solution (3 mol KCl solution) for min. 24 hours and then try
re-calibrate. If this is not successful, extend the time again by 24 hours. Then, a measurement should be
possible; if not, the electrode must be replaced.
DISPOSAL
Electronic products are raw material and do not belong in the household waste. When the
device has reached the end of its service life, please dispose of it, according to the current
statutory requirements, at your local collecting site. It is prohibited to dispose of the device with
domestic waste.
Disposal of used batteries!
As the end user, you are required by law (Battery Ordinance) to return all used batteries/re-
chargeable batteries; disposal of them in the household waste is prohibited!
Batteries/rechargeable batteries containing harmful substances are marked with the following
symbols, which indicate that disposal in the household waste is prohibited. The symbols of the
critical heavy metals are: Cd = Cadmium, Hg = Mercury, Pb = Lead. You can return your used
batteries/rechargeable batteries free of charge at the official collection points in your community,
in our stores, or at places where batteries or rechargeable batteries are sold!
You thereby fulfil your statutory obligations and contribute to the protection of the environment!
TECHNICAL DATA
Display ...........................................................LCD
Measuring range ............................................0.01 - 14.00 pH
Accuracy ........................................................±0.01 + 1 count
Temperature compensation ...........................automatic, 0 to +50 °C
Power supply .................................................2 Lithium batteries (CR2032)
Weight ...........................................................approx. 85 g
Dimensions (H x Ø) in mm ............................168 x 37
Weight ...........................................................approx. 85 g
