ProMinent DULCOTEST CLO 1 Guide D'utilisation page 29

Error description:
Sensor display << DPD 1 value
No calibration possible (gradient too low)
Measure/Remedy
1. Check that the flow rate at the
sensor is at least 30 l/h
2. Check whether there are air bub‐
bles on the electrodes. If yes then
the flow rate must be increased
through the flow gauge housing
ð As an immediate measure, you
can remove the air bubbles by
knocking against the flow
gauge housing.
3. Check whether the electrodes are
dirty/soiled
ð If yes, then clean the sensor
Ä further information on page 33
as described.
4. Is the chlorine concentration out‐
side of the measuring range indi‐
cated on the sensor?
ð If yes, reduce the chlorine con‐
centration until it is within the
measuring range and then
clean the sensor
Ä further information on page 33
as described.
5. Clarify whether there might be trou‐
blesome substances (e.g. tensides/
oils) in the sample water
ð If there are then contact ProMi‐
nent.
6. Check whether the conductivity of
the water is at least 50μS/cm
ð Type CLO sensors cannot be
used in completely desalinated
water.
7. Check whether there is cyanuric
acid in the water (e.g. using the DT
1 photometer)
NOTICE!
Cyanuric acid
Cyanuric acid is often con‐
tained in chlorine tablets; never
use any chlorine tablets if you
want to use type CLO sensors.
ð If there is cyanuric acid in the
water then sensor types CLO 1
and CLO 2 cannot be used.
Contact ProMinent.
8. Check the age of your DPD chemi‐
cals
ð If there is doubt, repeat the
DPD measurement with new
chemicals and then re-cali‐
brate.
9. When directly connecting the
sensor to external devices (e.g.
PLC), make sure that the sensor is
galvanically isolated from all other
devices/consumers
ð Always use a separating trans‐
former for the supply.
10. Foreign (stray) potentials on the
water (e.g. due to defective rotary
pump)
11. If the reason for this disturbance
cannot be determined we recom‐
mend you clean the sensor as
described in
Ä further information on page 33 .
Troubleshooting
29