KROHNE OPTISENS ORP 8590 EN - Manual (Page 22)

4
OPERATION
22
OPTISENS ORP 8590
www.krohne.com 01/2014 - 4001933801 MA OPTISENS ORP 8590 R01 en
4.3 Troubleshooting
Problem Possible cause Remedy
The ORP sensor
does not deliver a
signal.
Mechanical damage of the
platinum electrode, e.g.
scratches.
Exchange sensor.
Moisture inside the
sensor connector.
Clean the connector (sensor/cable) with pure water
and dry with air (e.g. hair blower).
The ORP sensor
delivers a bad
signal.
Coated/abraded platinum
electrode.
Clean the platinum electrode by using aqua regia (this
procedure uses hazardous chemicals and should only
be performed by a qualified person), HCl
concentrated/HNO3 concentrated (1/1).
The ORP electrode
delivers an
unstable signal.
The diaphragm in the
reference half-cell does
not provide good contact
to the process medium
due to drying up or
coatings.
• Clean the diaphragm with hot soap or acid using a
soft tissue (details on page 23).
• Submerge sensor in water and increase the
temperature to 50...60°C / 122...140°F.
• Submerge sensor in 3 molar KCl solution at ambient
temperature. The decrease in temperature will cause
the reference half cell to suck in KCl solution through
the diaphragm and regenerate the diaphragms
functionality.
.book Page 22 Friday, January 24, 2014 11:29 AM