CAUTION
Hot surfaces
Risk of burns during maintenance work on parts having surface temperatures exceeding
70 °C (158 °F).
● Take corresponding protective measures, for example by wearing protective gloves.
● After carrying out maintenance, remount touch protection measures.
6.3.1.1
Checking the gaskets
Inspect the seals at regular intervals
Note
Incorrect seal changes
Incorrect measured values will be displayed. Changing the seals in a process flange of a
differential pressure measuring cell can alter the start-of-scale value.
● Changing seals in devices with differential pressure measuring cells may only be carried
out by personnel authorized by Siemens.
Note
Using the wrong seals
Using the wrong seals with flush-mounted process connections can cause measuring errors
and/or damage the diaphragm.
● Always use seals which comply with the process connection standards or are
recommended by Siemens.
1. Clean the enclosure and seals.
2. Check the enclosure and seals for cracks and damage.
3. Grease the seals if necessary.
- or -
4. Replace the seals.
6.3.1.2
Diagnostics messages
Device diagnostics (e.g. sensor break) detected by the internal self-test are signaled as follows:
● Display: NE107 symbol and diagnostics ID
● Current output (4-20 mA): Fault current
● HART: Diagnostic alarm via the remote operation
In case of a defect, you can replace the transmitter electronics with observation of the warning
notes and the operating instructions.
Service and maintenance
6.3 Maintenance and repair work
SITRANS TH320/TH420/TR320/TR420/TF320/TF420
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Compact Operating Instructions, 03/2018, A5E41865021-AA
