wtw pH 7310, Operating Manual

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pH 7310 What to do if...
ba75929e02 10/2011
59
12 What to do if...
12.1 pH/ORP
Error message
OFL, UFL
The measured value is outside the measuring range.
Error message,
Error
More information and instructions on cleaning and exchange of
sensors are given in the documentation of your sensor.
Cause Remedy
pH electrode:
– Air bubble in front of the junction – Remove air bubble
– Air in the junction – Extract air or moisten junction
– Cable broken – Replace electrode
– Gel electrolyte dried out – Replace electrode
– Measured value outside the mea-
suring range of the meter
– Use suitable electrode
Cause Remedy
pH electrode:
– The values determined for zero
point and slope of the electrode
are outside the allowed limits.
– Recalibrate
– Junction contaminated – Clean junction
– Electrode broken – Replace electrode
Buffer solutions:
– Wrong buffer solutions – Change calibration procedure
– Buffer solutions too old – Use only once.
Note the shelf life
– Buffer solutions depleted – Change solutions