RKI Instruments HS-94 - Manual (Page 12)

• O
2
Sensor
Replace the O
2
sensor when:
1. The O
2
circuit cannot be set to 0 on an oxygen-free sample.
2. The OXY (O
2
) display does not show 20.9% immediately after the start-up
sequence and after the Auto Zero command (AIR adjust).
3. The O
2
reading tends to drift with instrument position.
• H
2
S and CO Sensors
Replace the sensor when:
1. The detection circuit cannot be calibrated correctly.
2. The display does not show “0” immediately after the start-up sequence and
cannot be set to zero by performing an Air adjust.
Sensor Replacement
1. Take the instrument to a non-hazardous location and turn the power off.
2. Remove the instrument from the carrying case.
3. Remove the screw from the top of the instrument and remove the blue plastic
cover case section over the sensor area.
4. Unplug the sensor from the PCB sockets, and install the new sensor.
5. Re-install the blue plastic sensor cover, and screw it in place.
6. Turn on the instrument and verify the display is normal.
7. Calibrate the detection circuit to work correctly with the new sensor (see
Calibration).
For issues not covered in this manual, or for any questions or problems, please contact
RKI Instruments, Inc., at 800-RKI-5165.
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