Methods; Important Notes; Guidelines For Photometric Measurements; Method Notes - Grundfos DIT-L Bedienungsanleitung

A separate calibration of the chlorine dioxide and
ozone measuring ranges is not possible.
Caution
The calibration of the chlorine measuring range is
used as a reference.
6.8.5 Resetting to factory calibration
Resetting the user calibration to the original
factory calibration will reset all methods and
ranges.
Store Date
A user-calibrated method is indicated by an
Cal
RESULT
arrow pointing to "Cal" while the test result is
displayed.
Time Cal
To reset the calibration, proceed as follows:
Press both the [Mode] and [Zero/Test] keys and
Zero/Test
Mode
hold.
Switch on the photometer using the [On/Off] key.
On/Off
Release the [Mode] and [Zero/Test] keys after
approx. 1 second.
The following messages will appear in the
display alternately:
SEL
The factory setting is active.
("SEL" means select.)
CAL
or:
Calibration has been set by the user. (If the user
SEL
calibration is to be retained, switch the unit off
cAL
using the [On/Off] key).
To reset the calibration to the factory setting,
Mode press the [Mode] key for all methods
simultaneously.
SEL
"SEL" and "CAL" appear in the display
alternately.
CAL
Switch the unit off using the [On/Off] key.
On/Off

7. Methods

7.1 Important notes

7.1.1 Guidelines for photometric measurements

• Vials, caps and stirring rods should be cleaned thoroughly
after each analysis to prevent interferences. Even minor
reagent residues can cause errors in the test result.
• The outside of the vial must be clean and dry before starting
the analysis. Fingerprints or other marks on the vials will lead
to incorrect measurements.
• Zero setting and test must be carried out with the same vial, as
there may be slight differences in optical performance
between vials.
• The vials must be positioned in the sample chamber for
zeroing and test with the mark on the vial (white triangle)
aligned with the mark on the photometer. See fig. 3.
• Always perform zeroing and test with the vial cap tightly
closed. Only use cap with gasket (fig. 3) in order to avoid light
entering the sample chamber.
• Bubbles on the inside wall of the vial lead to incorrect
measurements. To prevent this, remove the bubbles by
swirling the vial before performing the test.
• Avoid spillage of water into the sample chamber as this can
lead to incorrect test results.
• Contamination of the transparent cell chamber can result in
wrong readings. Check at regular intervals and, if necessary,
clean the transparent cell chamber using a moist cloth or
cotton buds.
8
• Large temperature differences between the photometer and
the environment can lead to errors, e.g. due to the formation of
condensation in the cell chamber or on the vial.
• To avoid errors caused by stray light, do not use the
photometer in bright sunlight.
• Always add the reagent tablets to the water sample straight
from the foil without touching them with the fingers.
• The reagents must be added in the correct sequence.

7.1.2 Method notes

• Prior to measurement, ensure that the sample is suitable for
analysis (no major interferences) and does not require any
preparation such as pH adjustment, filtration etc.
• Reagents are designed for use in chemical analysis only and
should be kept well out of the reach of children.
• Ensure proper disposal of reagent solutions.
• Material Safety Data Sheets are available on request.
(Internet: www.grundfos.com)
7.1.3 Correct position of the vial (∅24)
Fig. 3 Correct position of the vial

7.1.4 Correct filling of the vial

CORRECT
Fig. 4 Correct filling of the vial
WRONG