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SENSOR MAINTENANCE - TEMPERATURE
You must keep the temperature sensor free of build up. No additional
maintenance is required. A toothbrush can be used to scrub the
temperature sensor if needed.
SENSOR MAINTENANCE - pH AND ORP
CAUTION
: When using a cotton swab, be careful NOT to wedge
the swab between the guard and the glass sensor. If necessary,
remove cotton from the swab tip, so that the cotton can reach
all parts of the sensor tip without stress. You can also use a pipe
cleaner for this operation if more convenient.
Cleaning is required whenever deposits or contaminants appear on
the glass or platinum sensor surfaces or when the sensor’s response
slows. The cleaning can be chemical and/or mechanical.
Removing the sensor from the cable may make cleaning easier. Initially,
use clean water and a soft clean cloth, lens cleaning tissue, or cotton
swab to remove all foreign material from the glass bulb or platinum
button. Then use a moistened cotton swab to carefully remove any
material that may be blocking the reference electrode junction of the
sensor.
If good pH or ORP response is not restored, perform the following
additional procedure:
1. Soak the sensor for 10-15 minutes in clean water containing a
few drops of commercial dish washing liquid.
2. GENTLY clean the glass bulb and platinum button by rubbing
with a cotton swab soaked in the cleaning solution.
3. Rinse the sensor in clean water (not DI water), wipe with a cotton
swab saturated with clean water, and then rerinse with clean
water.
If good pH or ORP response is still not restored, perform the following
additional procedure:
1. Soak the sensor for 30-60 minutes in one molar (1 M) hydrochloric
acid (HCl). This reagent can be purchased from most lab supply
distributors. Be sure to follow the safety instructions included
with the acid.
2. Rinse the sensor in clean water, wipe with a cotton swab
saturated with clean water (not DI water), and then rerinse with
clean water. To be certain that all traces of the acid are removed
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from the sensor crevices, soak the sensor in clean water for
about an hour with occasional stirring.
CAUTION
: Do NOT mix the acid from the previous step with the
chlorine bleach in the following step. Toxic gaseous products
can be formed from the reaction between acid and chlorine
bleach. Be certain to copiously rinse the sink and drain system
of acid after its disposal and before disposal of the chlorine
bleach.
If biological contamination of the reference junction is suspected or if
good response is not restored by the above procedures, perform the
following additional cleaning step:
1. First, be sure all HCl acid from the previous cleaning step has
been rinsed from the probe, sink and drain!
2. Soak the sensor for approximately 1 hour in a 1:1 dilution of
commercially-available chlorine bleach.
3. Rinse the sensor with clean water (not DI water) and then soak
for at least 1 hour in clean water with occasional stirring to
remove residual bleach from the junction. (If possible, soak the
sensor for a period of time longer than 1 hour in order to be
certain that all traces of chlorine bleach are removed.) Then
rerinse the sensor with clean water and retest.
Dry the port and sensor connector with compressed air and
apply a very thin coat of o-ring lubricant to all o-rings before
reinstallation.
If this procedure is unsuccessful, as indicated by improper sensor
performance, contact YSI Technical Support or the YSI authorized
dealer where you purchased the instrument.
SENSOR MAINTENANCE - DISSOLVED OXYGEN
Membrane Cap Installation
The DO sensor (Polarographic or Galvanic) is shipped with a protective
red cap that needs to be removed before using. Remove the red
protective cap or used cap membrane and replace it with a new cap
membrane following these instructions:
Remove the sensor guard to access the sensor.
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