72
8024252/AE00/V1-0/2020-07| SICK
O P E R A T I N G I N S T R U C T I O N S | ZIRKOR200 Ex-D
Subject to change without notice
11
TROUBLESHOOTING
11.4
O
2
display on 0%, although the operating mode indicates a higher O
2
value
Possible cause
Notes
Probe heater defective (resistance
must be approx. 37.5...47.5 Ohm;
disconnect on the probe and check)
Attention: Disconnect the probe from
the power supply beforehand
Query the measuring cell temperature (setpoint 800 °C or
840 °C depending on the setting).
A cell temperature lower than 800 °C or 840 °C can cause
a display of 0%.
Thermoelement defective (check
resistance, approx. 2...80 Ohm)
Replace the inner part of the probe.
Fuse of the heating voltage defective
Replace the fuse.
Transformer (230/115 V) defective
Check voltages.
Line short-circuit
Electronics inlet defective
Wire break
– Check wiring.
– Measure the probe cable
mV-tap in the probe (measuring signal
wire) is not available or interrupted
Check the inner part of the probe for good contact.
Combustible components in flue gas
Check that the probe reacts to test gas. When the probe
reacts to the test gas, there may be a high percentage of
combustible gases in the flue gas. In this case, reducing
conditions prevail on the O
2
measuring cell, which reduce
the O
2
content on the cell surface.
Measuring cell defective
Replace the measuring cell.
