• Make sure that the rubber O-ring is seated
properly inside the membrane cap.
• With the sensor facing down, screw the
membrane cap clockwise. Some electro-
lyte will overflow.
The Platinum cathode sensor (#8 in the Func-
tional Description on page 2) 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 sensor
should be cleaned. Use a clean, lint-free card-
board or cloth. Rub the cathode very gently
side to side 4-5 times. This will be enough to
polish and remove any stains without damag-
ing the platinum tip. Then, rinse the probe with
deionized or distilled water. Install a new mem-
brane and fill it with fresh electrolyte following
the instructions above. Recalibrate the instru-
ment.
Important: In order to have accurate and
stable measurements, it is important that the
surface of the membrane is in perfect condi-
tion. This permeable membrane isolates the
sensor elements from the environment but
allows oxygen to enter. If any dirt is deposited
on the membrane, rinse it carefully with dis-
tilled or deionized water. If any imperfections
are observed, or any damage is evident (such
as wrinkles, tears or holes), the membrane
should be replaced. Make sure that the O-Ring
is properly seated in the membrane cap.
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