Section 9 Troubleshooting
9.1 General troubleshooting
Problem
Probable cause
The sample temperature is very different
from the ambient temperature, e.g. 6 °C
(43 °F) in water and 35 °C (95 °F) in air will
cause a measurement drift.
There is an electrolyte leak through the
membrane. The current is too high because
of an excessive penetration of oxygen.
There is pollution of the electrolyte due to a
loose filling screw.
The electrode is not correctly mounted in
the sensor body causing an excessive gap
between the membrane and the cathode.
Excessive time for
The membrane is incorrectly installed
stabilization or no
causing a risk of electrolyte pollution.
stabilization during
calibration in air.
Lack of humidity due to high temperature.
There is water or humidity in the sensor
cable connector.
The gold surface is scratched or damaged.
Sludge or particles on the cathode.
Cable or connections damaged when the
sensor has been removed.
The sensor is incorrectly positioned. The
electrolyte has leaked and air bubbles have
entered the cathode.
There is pollution of the electrolyte due to a
loose filling screw.
There is pollution of the electrolyte due to a
leaking membrane.
The membrane is torn.
No significant
current increase
The electrode is not correctly mounted in
when the sensor is
the sensor body causing an excessive gap
in the air for the
between the membrane and the cathode.
calibration.
Cable or connections damaged when the
sensor has been removed.
The membrane is worn.
There is a dark green deposit of silver
bromide (AgBr) on the silver tube.
Resolution
Do not wait till the sensor temperature
equals the external temperature (use
temperature compensation).
Change the membrane.
Change the electrolyte. Check there is a
gasket in place and tighten the screw using
a screwdriver but without using excessive
force.
Tighten the electrode holding nut.
Change the electrolyte and reinstall the
membrane onto the sensor body as far as it
will go finger tight.
Use a calibration cap (see
parts and accessories
on page 20).
Dry the sensor cable connector inside and
out, and install finger tight.
Change the electrode.
Clean the cathode with a soft and
absorbent tissue. Rinse the membrane.
Check the sensor connection to the
controller module. If correct check the
connections to the sensor cable connector.
Put the sensor in the correct position, head
down.
Change the electrolyte. Check there is a
gasket in place and tighten the screw using
a screwdriver but without using excessive
force. Check the sensor is not damaged.
Change the electrolyte and the membrane.
Change the membrane.
Tighten the electrode holding nut.
Check the connection to the controller
module. If correct check the connections to
the sensor cable connector.
Change the membrane.
Polish the tube with a soft abrasive (N°
400 to 600) and replace the membrane.
Replacement
English 17