Installation And Operating Instructions; Maintenance; Recalibration; Maintenance Of The Measuring Cell - Grundfos Conex DIA-1-A PA/HP Montage- Und Betriebsanleitung

13. Maintenance

Functional testing
• Every week at least.
Intervals for cleaning and maintenance
• In case of operational faults.
Service life of electrolyte and diaphragm
• Electrolyte: about half a year, depending on the concentration
of peracetic acid or hydrogen peroxide.
• Diaphragm: about one year, depending on the water quality.
The calibration must always be repeated after
Caution
cleaning or maintenance!

13.1 Recalibration

Intervals for recalibration
• Every week at least.
• Repeat the calibration with the analytically measured value.
See section 10.6 Calibration of the measuring system
installation and operating instructions for the Conex
®
Conex DIA-2Q!

13.2 Maintenance of the measuring cell

In case of failure, the cap must be removed in order to check the
electrolyte level or the degree of furring or soiling.
Follow the procedure described in the following exactly!
13.2.1 Unscrewing the diaphragm cap
1. Loosen the connecting cable, and remove the measuring cell
from the flow armature.
It is very important to aerate the cap before
unscrewing the diaphragm cap.
Caution
Uncover the valve by lifting the tubular ring (rubber
band) at the black marking, so that the valve opening
is uncovered.
Fig. 8 Unscrewing the diaphragm cap
If the valve at the diaphragm cap remains covered,
the diaphragm can be damaged by the
underpressure that builds up while unscrewing the
Caution
cap!
Make sure that the thumb does not touch the
diaphragm!
• Unscrew the diaphragm cap with uncovered valve.
– Air flows through the valve opening.
16
13.2.2 Cleaning of the diaphragm cap
In case of furring:
1. Put the diaphragm cap into hydrochloric acid of about 1 % for
several hours.
2. After that, wash the cap with clean water.
Caution
and the
®
DIA-1 /
Fig. 9
13.2.3 Cleaning of the electrode
In case of a large amount of soiling, the electrode must be
cleaned.
1. Unscrew the diaphragm cap as described above.
Caution
2. Rinse the electrode with clean water, and dry it with dry
disposable paper tissue.
3. Carefully clean the tip of the electrode with the enclosed
special emery paper.
– Place the special emery paper on disposable paper tissue,
and hold one of the edges.
– Hold the measuring cell vertically, and move the electrode
tip over the emery paper two or three times.
Caution
Never remove the metallic diaphragm holder from the
plastic part (diaphragm cap)!
Otherwise, the diaphragm may not function correct!
Cleaning the diaphragm cap
Strictly observe the following precautions for
unscrewing the diaphragm cap and for the cleaning
procedure!
Otherwise, the diaphragm and the electrode may be
damaged!
Do not sand the metallic coating of the electrode!
Clean the tip of the electrode carefully. No other parts
must be cleaned!