Xylem handylab pH 11 - Manual (Page 38)

What to do if... handylab pH 11
38 ba75366e04 01/2011
No stable mea-
sured value
LoBat display
Buffer solutions
– Incorrect buffer solutions – Change calibration procedure
– Buffer solutions too old – Use only once.
Note the shelf life
– Buffer solutions depleted – Change solutions
Cause Remedy
pH electrode:
– Diaphragm contaminated – Clean diaphragm
– Membrane contaminated – Clean membrane
Test sample:
– pH value not stable – Measure with air excluded if
necessary
– Temperature not stable – Adjust temperature if
necessary
Electrode + test sample:
– Conductivity too low – Use suitable electrode
– Temperature too high – Use suitable electrode
– Organic liquids – Use suitable electrode
Cause Remedy
– Batteries almost empty – Replace batteries
(see section 5.1 M AINTENANCE )