Probe And Membrane Maintenance - Hanna Instruments HI2400 Instruction Manual

PROBE AND MEMBRANE MAINTENANCE

The oxygen probe body is made of reinforced plastic for maximum
durability.
A thermistor temperature sensor provides temperature measurements of
the sample. Use the protective probe cap when not in use.
To replace the membrane or refill with electrolyte, proceed as follows:
• Remove the protective cap by gently
twisting and pulling it off the body of
the probe (see fig. 1).
• Unscrew the membrane cap by turning
it counterclockwise (see fig. 2).
• Wet the sensor by soaking the bottom
2½ cm (1") of the probe in electrolyte
(HI7041S) for 5 minutes.
• Rinse the new membrane cap
(HI76407A), supplied with the meter
with electrolyte solution while shaking
it gently. Refill with clean electrolyte
solution.
• Gently tap the sides of the membrane
cap with your finger tip to ensure that
no air bubbles remain trapped. Do not
tap directly the bottom 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 Func‑
tional Description page 4) should always
be bright and untarnished. If it is tarnished
or stained, 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. Afterwards, rinse the probe with deionized or distilled
water and install a new membrane cap using fresh electrolyte and follow
the steps above. Recalibrate the instrument.
UNSCREW
28
TWIST
AND
PULL
fig. 1
fig. 2