Hach ORBISPHERE 3654 Basic User Manual page 29

9.2.2 Diagnostics messages
The following are warning messages that may appear on the instrument LCD in place of the gas
concentration.
Message Meaning
This message appears on the LCD if the purge gas supply fails. To detect this condition, the voltage
signal from the TC sensor is measured. This is normally between 1-3 volts, depending which gas is
Pur being measured.
If the flow of purge gas stops, the sensor voltage wanders outside the permitted range of 100mV to
4 V. Refer to
This message appears if the sensor is unplugged from its correct position, or if the temperature is
Out
outside the range -5°C to 100°C.
During start-up, this message indicates the instrument cannot complete the start-up tests
successfully. Refer to
Hach Lange service representative for assistance.
Err
During calibration, this message indicates that the partial pressure of gas is below the acceptable
range (<5 mbar), or that you have pressed a wrong key. Refer to
Bat The batteries charge are too low for a correct operation of the instrument. Replace the batteries.
9.2.3 Continuous purge
It may be useful, particularly when seeing a [Pur] error message on your display, to view the purge
voltage of the TC sensor in a continuous purge mode. In this mode, there is no purge/measurement
cycle, as the purge gas is flowing through the sensor continuously.
To start continuous purge mode, put the instrument into standby, then hold down the Down Arrow
button while switching the instrument back on again. The instrument displays [Pur], followed by the
purge gas voltage. At 20-25°C, this voltage should be about 1.0V (± 200 mVolt) for N
measurements.
To exit from continuous purge mode, put the instrument in standby, then switch back on again
without holding any keys.
9.2.4 Troubleshooting table
Symptom
Unstable measurement
Table 4 Diagnostic messages
Continuous purge on page 29.
Taking measurements
Cause
Degassing
Flow chamber and/or membrane
not clean
Sensor's membrane not tight
smooth and wrinkle free
Leaking solenoid valve
An external power supply is used
but the power supply is not clean
on page 14. If the problem persists, contact your local
Sensor calibration
Possible Solution
Adjust sample flow rate
Clean system
Replace membrane and recalibrate
No gas bubbles should escape from the purge
gas outlet during measurement. If the solenoid
leaks (more than 1 bubble in 15 seconds) contact
your Hach Lange representative
Switch to battery power
on page 21.
/H
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