Hach-Lange ORBISPHERE 31xxx Basic User Manual - Manual (Page 17)

Hydrogen sensor
Problem Probable cause Possible solution
Sensor won't calibrate, even after
thorough servicing. Repeated calibrations go beyond
"expected limits" of instrument.
MOCA 3600 only: Select membrane
from "Options/Membrane" menu.
Then, calibrate the sensor.
"0000" H
2
levels displayed.
Wrong reading scale "XXXX"
selected for display unit. Change reading scale by selecting
"X.XXX, XX.XX or XXX.X".
Shorter than expected sensor
operation in relatively high H
2
concentration.
High H
2
concentrations require
more work from electrochemical
sensor. Shut off analyzer when not needed.
Unexpected or inaccurate H
2
readings.
High residual current.
If concentration is significantly
higher than low limit, try a sensor
service.
Ozone sensor
When the O
3
sensor has been properly calibrated using the ORBISPHERE measuring instrument,
the sensor has to settle down for up to 24 hours when used in very low O
3
concentration conditions.
Problem Probable cause Possible solution
Sensor won't calibrate, even after
thorough servicing.
Repeated calibrations go beyond
"expected limits" of instrument.
MOCA 3600 only: Select membrane
from "Options/Membrane" menu.
Then, calibrate the sensor.
Instrument internal barometric
pressure sensor needs calibration.
Calibrate internal barometer against
a certified barometer. Do not correct
for sea level !
Wet membrane interface.
Wipe dry with a tissue and re-
calibrate.
"0000" O
3
levels displayed.
Wrong reading scale "XXXX"
selected for display unit. Change reading scale by selecting
"X.XXX, XX.XX or XXX.X".
Unexpected or inaccurate dissolved
O
3
readings.
High residual current.
If concentration is significantly
higher than low limit, try a sensor
service.
Insufficient flow rate.
Regulate flow equivalent to
membrane specified levels.
Length of sample line allows O
3
time to react.
Reduce length of sample tubing.
Doesn't match lab samples.
Take samples at close proximity to
sensor.
English 17