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Xylem Lab 850, up to serial number 09470314 User Manual

Page 44

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What to do if...

Lab 850

44

ba75553e03

01/2006

No stable measured

value

CalClock expired

Display,

LoBat

– Incorrect buffer solutions

– Change calibration

procedure

– Buffer solutions too old

– Use only once.

Note the shelf life

– Buffer solutions depleted

– Change solutions

Cause

Remedy

Cause

Remedy

pH electrode:

– Junction contaminated

– Clean junction

– 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 a suitable electrode

– Temperature too high

– Use a suitable electrode

– Organic liquids

– Use a suitable electrode

Cause

Remedy

– Calibration interval expired

– Recalibrate the measuring

system

Cause

Remedy

– Batteries almost empty

– Replace the batteries (see

page 41)