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10 Troubleshooting
Specific errors for RTD temperature probes
General errors for thermometers
Common causes of errors can be avoided by following the explanations in this operating manual as well
as the product-specific data sheets and manuals.
In particular, it is important to consider the specific installation situation in each case. It may be necessary
or advisable to consult qualified personnel and the Technical Support team from JUMO.
The contact addresses and telephone numbers can be found on the last page
Error Possible cause Remedy
Temperature indicator is too high Self-heating Improve the heat conduction
Influence of the measuring line Minimize the supply power
Incorrect measured value Parasitic thermoelectric voltage Eliminate the parasitic voltages
or replace the thermometer
Heat conduction error Increase the immersion depth or
use a contact agent
Measured value drops over time Sensor aging Replace the measuring insert,
check the temperature range
Differing temperature indicators Power supply is not constant Replace the power supply unit
Two-wire circuit with fluctuating
temperature in the area of the
supply line
Switch to a three-wire circuit
Error Possible cause Remedy
Time behavior is very slow or
measured values are delayed
Deposits on the protection tube Clean the protection tube
Protection tube diameter is too
large
Modify the protection tube design
Heat conduction error Increase the mounting depth or
use a contact agent
Protection tube is located in a
"shadow" area with little flow
Change the installation site
Incorrect measured value Influence of an additional heat
source
Optimize the installation situation
Measuring circuit is interrupted
by vibrations, etc.
Change the installation location,
use vibration-damping measures
on the plant, modify the design
Protection tube broken Solids in the measurement medi-
um, flow velocity too high, etc.
Minimize the immersion depth,
change the installation location,
modify the design, or replace the
protection tube
Corrosion The protection tube material and
the medium have not been coor-
dinated with one another
Change the protection tube ma-
terial, check the medium
Temperature indicator is too low Poor-quality insulation resistance
or drift caused by moisture
Carry out an insulation test and, if
necessary, improve the insula-
tion or replace the probe
Thermometer cannot be inserted
into the protection tube
The protection tube or probe is
bent
Replace the bent part
Foreign bodies in the protection
tube (such as pollutants)
Clean the protection tube or re-
move the foreign bodies
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