Commissioning Of The Measuring Cell; Calibration; Photometrical Measurement; Calibration 12 - Grundfos AQC-D5 Installation And Operating Instructions Manual

9.10 Commissioning of the measuring cell

Before starting, the buffer solution must be sucked up to the
measuring cell in order to shorten the running-in period.
Ensure that the pump is switched off for these steps.
For that purpose, take out the sample water
Note
deficiency sensor (loosen the screw, and pull out the
sample water deficiency sensor).
1. Place the tank with the buffer under the peristaltic pump and
insert the suction line.
2. Open the cover of the tube at the pump.
3. Connect a syringe to the suction tube of the tap (pos. c).
4. Turn the three-way tap (pos. c) in order to open the line to the
syringe.
5. Carefully suck the buffer solution until the syringe is filled.
to measuring cell
Fig. 13 Sucking in buffer solution, part 1
6. Turn the three-way tap in order to open the line from the
syringe to the measuring cell.
7. Carefully press the buffer solution into the line until it reaches
the measuring cell.
Fig. 14 Sucking in chemicals, part 2
8. Remount the cover of the pump.
9. Turn the three-way-tap in order to open the line from the pump
to the measuring cell.
Fig. 15 Sucking in buffer solution, part 3
12
from pump

10. Calibration

At first start-up or after long-term stop, let the system
Caution
run for at least two hours to avoid faulty
measurements and calibration!
Due to the electro-chemical behaviour of the measuring cell, no
zero-point adjustment is necessary. Only the rate of rise
(sensitivity) must be adjusted during calibration.
During calibration, keep the sample water flow rate
Caution
and water temperature constant.
Check the calibration after 24 hours and repeat, if necessary!

10.1 Photometrical measurement

1. Take a water sample at the sample water tap (pos. a).
2. Determine the concentration of the measuring parameter
photometrically, for instance using the Grundfos DIT
photometer.
Observe the installation and operating instructions of
Caution
the photometer!
10.2 Calibration
1. Select the calibration function using the [Cal] button. The LED
lights up.
2. Press [OK] to select the "Calibration" menu.
3. Select "Chlorine", and confirm using [OK].
Chlorine
Cal. meas. value
Cal result
Cal. cycle
4. Enter the reference value (for instance the value measured
photometrically using the DIT).
– The measured signal is read in automatically and compared
with the reference value.
– The calibration result is displayed: sensor slope.
CALDATA chlorine
Slope
34.67 µA / ppm
Reading calibration data in the "Service" diagnostics menu
• Select "Service" in the main menu using the [Up] or [Down]
button, and press [OK].
– The data of the last 10 calibrations can be read.
CALDATA chlorine
Slope
34.67 µA / ppm