Hach-Lange H-Series Meters Basic User Manual User Manual
Page 18
Problem
Possible cause
Solution
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 correctly
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.
The meter continually
shows –2.00 or 19.99 with an
electrode attached. The "ISFET" icon
does not show when ISFET probe is
attached.
The ISFET probe is not sensed
by the meter or the probe.
Set the meter power to off. If the
"ISFET" icon does not show, replace
the ISFET probe.
Out of calibration
on page 16.
The probe is not in the solution.
Put the probe in liquid. Carefully
shake the probe to make sure that air
bubbles are not caught on the sensor
surface.
No probe is connected to the
meter.
Set the meter power to off. Connect
the pH probe. Set the meter power to
on.
The probe is dirty.
Clean the probe.
The probe is damaged.
Replace the probe. Contact technical
support.
Screen flashes during calibration.
The probe sensor surfaces are
dirty or it is necessary for the
probe to be conditioned again.
Clean and condition the probe again.
No flow in the reference junction
Clean the warm buffer.
The buffers are contaminated or
expired.
Calibrate with new buffers again.
Interference from other devices in
the solution
Remove all devices from the solution.
The battery is low.
Replace the batteries if the battery
icon shows low battery power.
Interference from direct sunlight
Use protection for the probe from
direct sunlight.
The probe is too old.
Replace the probe.
18 English