54
NRG 26-61 - Installation & Operating Manual -
819874-00
System malfunctions
Common application and usage errors
The 0 % and 100 % measuring range limits are obviously outside the sight glass level.
Possible causes if no error messages appear
Remedy
The measuring range is incorrectly set.
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Check the measuring range calibration.
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Repeat calibration if necessary.
The characteristic of the measurement signal in the measuring range is reproducible, but not linear.
Possible causes if no error messages appear
Remedy
The level electrode was installed without a protective
tube.
The protective tube is required as a counter electrode.
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Install a protective tube.
The characteristic of the displayed reading appears implausible compared with the tendency of the level in
the sight glass.
Possible causes if no error messages appear
Remedy
The pressure relief hole is clogged or flooded, or may
even be missing completely.
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Check the protective tube
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If necessary, add a pressure relief hole.
The shut-off valves of an externally mounted measur-
ing cylinder (option) are closed.
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Inspect the shut-off valves, open if necessary.
A correctly set electrode that has been in operation for a long period delivers increasingly imprecise readings.
Possible causes if no error messages appear
Remedy
Increasing soiling due to build-up of deposits on the
electrode rod.
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Remove the level electrode and clean the electrode rod
with a damp cloth.
A control unit, e.g. NRR2-60, indicates a MIN or MAX alarm even though the level visible in the sight glass
remains within the admissible measuring range limits.
Possible causes if no error messages appear
Remedy
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The measuring range is incorrectly set.
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The electrode or protective tube is soiled.
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Calibrate the measuring range at the operating point.
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Inspect the electrode and protective tube for soiling and
clean if necessary.