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bottle that was originally included with the sensor. This can be filled
with buffer 4 solution. If you no longer have the storage bottle, simply
place the sensor in a buffer 4 solution.
When storing the dissolved oxygen sensor for more than 30 days,
remove the cap membrane and thoroughly rinse the dissolved
oxygen sensor with distilled or deionized water. Once the sensor
has been rinsed either blow it dry with compressed air or allow to air
dry completely. Next, install a new, clean, dry cap membrane onto
the sensor. This will keep the sensor dry and protect the anode and
cathode during storage. After storing for a long period of time, it is
necessary to “condition” the dissolved oxygen sensor by installing a
new membrane with electrolyte solution.
Long Term Storage Temp: -5 to 70°C (23 to 158°F) without pH
0 to 30°C (32 to 86°F) with pH or ORP*
*Operating temperature range for pH sensor is -5 to 60°C (23 to 140°F)
and operating temperature range for the ORP sensor is 0 to 60°C (32
to 140°F)
T R O U B L E S H O O T I N G
Symptom
Possible Solution
Instrument will
not turn on, a
battery symbol
appears, or “Critical
Shutdown” displays
on the screen.
1. Low battery voltage, replace batteries.
2. Batteries installed incorrectly,
check battery polarity.
3. Return system for service.
Temperature values
display Over or Undr
on Run screen.
1. Sample temperature is less than -5° C or more
than +55°C. Increase or decrease the sample
temperature to bring within the allowable
range.
2. Contact YSI Tech Support. Possible temperature
sensor failure.
Barometer reads
over/undr and
calibrating DO results
in a Barometric
Pressure Over/Undr
error message.
1. Barometer failure, return system for service
Symptom
Possible Solution
Instrument will not
calibrate pH or ORP;
instrument displays
“Calibration Over”,
“Calibration Under”,
or “Unstable Reading”
during calibration.
1. Verify correct ISE sensor type selection
in the System Setup menu.
2. Verify the calibration solution is accurate.
3. If calibrating pH, make sure you
are calibrating buffer 7 first.
4. Clean the pH or ORP sensor.
5. Contact YSI Tech Support.
pH or ORP readings
are inaccurate.
1. Verify correct ISE sensor type selection
in the System Setup menu.
2. Verify temperature readings are accurate.
3. Recalibrate the pH or ORP sensor.
4. Clean the pH or ORP sensor.
5. Contact YSI Tech Support.
pH values display
Over or Undr on
Run screen.
1. Verify correct ISE sensor type selection
in the System Setup menu.
2. Verify temperature readings are accurate.
3. Recalibrate the pH sensor.
4. Clean the pH sensor and recalibrate.
5. Contact YSI Tech Support.
ORP values display
Over or Undr on
Run screen.
1. Verify correct sensor type selection
in the System Setup menu.
2. Sample ORP value is outside the
measurement range of -1500 to 1500 mV.
3. Verify temperature readings are accurate.
4. Recalibrate the ORP sensor.
5. Clean the ORP sensor and recalibrate.
6. Contact YSI Tech Support.
Instrument will not
calibrate dissolved
oxygen; instrument
displays “Calibration
Over”, “Calibration
Under”, or “Unstable
Reading” during
calibration.
1. Verify barometer reading.
2. Verify correct DO sensor and DO membrane
type selection in the System Setup menu.
3. Calibrations cup may not be 100%
water saturated, see DO Calibration.
4. Ensure adequate sample movement if
performing mg/L or ppm calibration.
5. Allow sufficient stabilization time for
dissolved oxygen and temperature AND
wait at least 3 seconds before confirming
a DO% or DO Local% calibration.
6. Replace membrane and electrolyte.
7. Clean sensor electrodes.
8. Contact YSI Tech Support.
