User Guide

32
with your finger as this will damage the
membrane.
• Make sure that the rubber O-ring sits
properly inside the membrane cap.
• With the sensor facing down, slowly
screw the membrane cap clockwise.
Some electrolyte will overflow.
The Platinum cathode (#8 in the Functional
Description at page 3) should always be
bright and untarnished. If it is tarnished or
stained, which could be due to contact with
certain gases or extended use with a loose
or damaged membrane, the cathode should
be cleaned. You can use a clean lint-free
cardboard or cloth. Rub the cathode very
gently side to side 4-5 times. This will be
enough to polish and remove any stains
without damaging the platinum tip. After-
wards, rinse the probe with deionized or
distilled water and install a new membrane
cap using fresh electrolyte and follow the
steps above. Re-calibrate the instrument.
Important: in order to have accurate and
stable measurements, it is important that
the surface of the membrane is in perfect
condition. This semipermeable membrane
isolates the sensor elements from the envi-
ronment but allows oxygen to enter. If any
dirt is observed on the membrane, rinse
carefully with distilled or deionized water. If
any imperfections still exist, or any dam-
age is evident (such as wrinkles or tears-
holes), the membrane should be replaced.
Make sure that the O-Ring sits properly in
the membrane cap.