Hach-Lange H170 User Manual - Manual (Page 17)

BNC electrode maintenance
Prevent unstable readings:
• Keep the probe in an electrode storage solution.
• Start measurements with at least a 2-point calibration. Update often with 1, 2 or 3-point
calibrations.
• Use new buffers and new deionized rinse solution.
• Use buffer solutions with pH values no larger than 3 pH units apart. Ideally, the buffers bracket the
anticipated pH values of the unmeasured samples.
• Use deionized water to rinse residual buffer and sample solutions from the probe after calibration
and measurement.
• Calibrate at the same temperature as the sample solution. Although the meter has an ATC, get the
best results when the calibration buffers and the sample are the same temperature.
• Keep the connectors clean and dry. Dirty or damp connectors can cause unstable readings.
Troubleshooting
Problem Possible cause Solution
No display Automatic shutdown set the
power to off. Set the power to on again.
There is no power. Replace the batteries.
Unstable reading The probe is dirty. Clean the probe.
The probe or the meter
connectors are dirty. Clean the probe contacts on the
cable connector. Clean the meter
with methanol on a cotton swab. Let
dry completely. Connect the probe to
the meter again.
No flow in the reference junction Clean the warm buffer.
ISFET probe is not properly
hydrated. Soak the probe for at least 5 minutes
in a pH 7.00 buffer.
Interference from other devices Remove other devices from the
solution.
Interference from direct sunlight Use protection for the probe from
direct sunlight.
The probe is in a very low ionic
strength solution. A stable reading is not possible.
The pH or temperature of the
solution changes. A stable reading is not possible until
pH and temperature are constant.
English 17