Fault
Possible cause
Remedy
Tensides in the water (membrane is
transparent!)
Remove tensides and
replace membrane cap;
allow the sensor to run in
and calibrate, possibly
use a CDP sensor
pH value > pH 8.0
Lower pH value (pH
5.5-8.0)
No electrolyte in the membrane cap
Fill with new electrolyte
further information on page 39
Electrolyte pushed out by gas bubbles in
the sample water
Contact ProMinent
Display of reading shows
"""zero"""
Only bonded chlorine present
If chloramine is present
(DPD 4 test) then perform
shock chlorination or
replace the water
Chlorine content below the lower limit of
the measuring range
Add chlorine and then
repeat calibration or use
a suitable sensor
Sensor incorrectly connected to the con‐
troller
Connect the sensor cor‐
rectly to the controller
Run-in time too short
Allow to run-in for 3 hours
Sensor defective
Replace sensor
Reading display unsteady Air bubbles on the outside of the mem‐
brane
Remove air bubbles by
tapping and increase flow
rate if necessary
Membrane damaged
Replace membrane cap,
allow sensor to run in,
calibrate
Reason lies with control device
Eliminate cause
Troubleshooting / Maintenance: When you have tried everything: Check whether the reference elec‐
trode at the end of the electrode shaft is silvery-white instead of brownish-grey. It is then worn out
and can be replaced by ProMinent.
Troubleshooting
45
