RKI Instruments GX-82 - Manual (Page 17)

Model GX-82 Instruction Manual Maintenance • 13
O
2
sensor
Replace the O
2
sensor when:
• the O
2
circuit cannot be set to 0 on an oxygen-free sample
• the OXY (O
2
) display does not show 20.9% immediately after the start-up sequence
and after the Auto Zero command
• the O
2
reading tends to drift with instrument position
H
2
S and CO sensors
Replace the sensor when:
• the detection circuit cannot be calibrated correctly
• the display does not show 00 for H
2
S or 000 for CO immediately after the start-up
sequence and cannot be set to zero by the Auto zero command
NOTE: Allow up to 1/2 hour after the H
2
S or CO sensors have been replaced to show a
normal response, then calibrate.
Sensor Replacement
1. Place the GX-82 in a non-hazardous area.
2. Verify that the GX-82 is turned off.
3. Press in the cover latch and slide the sensor cover down and away from the
instrument case.
4. Open the spring clips, then unplug the sensor block (pull straight out).
5. Press the sensor down and turn counter-clockwise, then pull the sensor out of the
block.
6. Insert the replacement sensor into the block and turn clockwise. Make sure you use
the correct socket for the sensor type; sensors are not interchangeable between
sockets.
7. Reinstall the sensor block and cover.
8. Start-up the GX-82 and verify operation as described in “Start-up” on page 5.
9. Calibrate the new sensor as described in “Calibration” on page 9.