Pr
o
Minent
®
Page 42
Sensor:
Troubleshooting
For troubleshooting, the entire sensor is to be considered. The sensor consists of
1)
Measuring/control
unit
2) Electrical lines and connections
3) In-line probe and hydraulic connections
4)
Sensor
The possible causes listed in the following table predominantly refer to the sensor. Before
troubleshooting, ensure that the operating conditions are observed:
a) ozone content 0.02 - 2 mg/l
b) pH value in the stability range ozone and constant
c) temperature 5 - 45 °C and constant
d)
fl ow rate 30 - 60 l/h
For locating the failure in the measuring and control unit, the sensor simulator (DULCOMETER
®
Simulator order no. 1004042) can be used. A detailed troubleshooting at the measuring and
control unit is described in the operating instructions of DULCOMETER
®
D1C, Ozone.
In case of excessive deviations of the sensor readings from the result of the DPD method, fi rst all
possible error causes of the photometric DPD method should be considered. If required, the DPD
measurement is to be repeated several times.
Ozone
Fault
Sensor cannot
be calibrated -
Reading
measuring/
control device
greater
than
DPD-4
measurement
Sensor cannot
be calibrated -
Reading
measuring/
control device
smaller
than
DPD-4
measurement
Possible cause
Running-in period too low
Diaphragm cap damaged
Interfering substances in water
Short in the measuring line
Distance between diaphragm and
diaphragm cap too large
DPD chemicals past shelf life
Running-in period too low
Deposits on the diaphragm cap
Sample water fl ow rate too low
Air bubbles on the exterior of
the diaphragm
Interfering substances in the
sample water (surfactants, oils,
alcohol, corrosion inhibitors)
Surfactants in water (diaphragm
is transparent)
No electrolyte in diaphragm cap
Electrolyte displaced by gas
bubbles in sample water
Remedy
see “Running-in period”
Replace diaphragm cap; run in
sensor, calibrate
Check water for interfering
substances and remedy
Locate short and remedy
Tighten diaphragm cap up to
stop
Use new DPD chemicals,
repeat calibration
see “Running-in period”
Remove deposits see “Mainte-
nance”; replace diaphragm cap;
run-in sensor, calibrate
Adjust fl ow rate
Remove air bubbles by
tapping and increase fl ow rate,
if required
Contact ProMinent
Remove surfactants and replace
diaphragm cap; run-in sensor
and calibrate
Fill in new electrolyte see
“Assembly”, “Running-in period”
and “Calibration”)
Contact ProMinent
BA_DR_002_02_09_GB_Cooling.indd 42
BA_DR_002_02_09_GB_Cooling.indd 42
24.02.2009 11:56:05 Uhr
24.02.2009 11:56:05 Uhr