Maintenance And Cleaning; Faults - WIKA TR10-B Operating Instructions Manual

7. Maintenance and cleaning / 8. Faults

7. Maintenance and cleaning

7.1 Maintenance
This resistance thermometer is maintenance-free.
Repairs must only be carried out by the manufacturer.
7.2 Cleaning
CAUTION!
Clean the instrument with a moist cloth.
■
Electrical connections must not come into contact with moisture.
■
Wash or clean the dismounted instrument before returning it, in order to
■
protect personnel and the environment from exposure to residual media.
Residual media in dismounted instruments can result in a risk to persons, the
■
environment and equipment. Take sufficient precautionary measures.
For information on returning the instrument see chapter "9.2 Return".

8. Faults

Faults
No signal/ line breakage Mechanical load too high or
Erroneous measured
values
Erroneous measured
values (too low)
Erroneous measured
values and response
times too long
Measurement signal
"comes and goes"
Corrosion
Signal interference
WIKA operating instructions resistance thermometers per EN 14597
Causes
overtemperature
Sensor drift caused by
overtemperature
Sensor drift caused by chemical
attack
Entry of moisture into cable or
measuring insert
Wrong mounting geometry, for
example mounting depth too deep or
heat dissipation too high
Deposits on the sensor or thermowell
Cable break in connecting cable or
loose contact caused by mechanical
overload
Composition of the medium not
as expected or modified or wrong
thermowell material selected
Stray currents caused by electric
fields or earth loops
Earth circuits
Measures
Replace probe or measuring insert with
a suitable design
Replace probe or measuring insert with
a suitable design
Use a design with thermowell
Replace probe or measuring insert with
a suitable design
The temperature-sensitive area of the
sensor must be inside the medium,
and surfaces must be isolated
Remove deposits
Replace probe or measuring insert
with a suitable design, for example
equipped with a strain relief or a
thicker conductor cross-section
Analyse medium and then select a
more-suitable material or replace
thermowell regularly
Use shielded connecting cables, and
increase the separation from motors
and power cables.
Eliminate potential differences by
using galvanically isolated transmitter
power supplies or transmitters.
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