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9.2 Redox Troubleshooting
Symptom
Possible Causes
Remedy
Span calibration
fails (insufficient
range with
SPAN
control).
1.
ATC probe connected.
2.
Platinum tip not clean.
3.
Redox electrode is aged.
4.
Redox standard is
inaccurate.
Redox does not require an ATC
probe. The Span range will be
reduced if an ATC probe is
fitted. Ensure that there are no
connections to terminals 1 and 2
(see section 3.4).
Clean platinum tip as per
instructions supplied with the
electrode.
Attempt rejuvenation, as per
instructions supplied with the
electrode. If not successful,
replace electrode.
Replace Redox standard.
Unstable readings.
1.
Solution guard not fitted.
2.
Reference junction blocked.
3.
Platinum tip not clean.
4.
Reference junction not
immersed.
5.
KCl crystals around
reference junction, inside
the electrolyte chamber.
Connect a solution guard rod, to
terminal 3 (see section 3.4).
Clean reference junction, as per
instructions supplied with the
electrode.
Clean platinum tip as per
instructions supplied with the
electrode.
Ensure that the platinum tip
AND the reference junction are
fully immersed (see diagram in
section 4.1)
Rinse electrolyte chamber with
warm distilled water until
dissolved. Replace electrolyte.
Inaccurate readings,
even when
calibration is
successful.
Reference junction blocked.
Clean reference junction, as per
instructions supplied with the
electrode.
Displays around 0
mV in all solutions
Electrical short inside electrode
or in cable.
Test system with a new
electrode and replace if
necessary.
