Advanced Micro Instruments, Inc.
Page 23
The sensor is provided in a special sealed bag. Do not open this until you are ready to install the sensor.
Before installing sensor, turn ON power.
1.
Connect a low level gas like nitrogen to the sample inlet.
2. Turn the On/Off selector valve to Off if it isn’t already there.
3. Adjust the flow of nitrogen to 2 SCFH using the metering needle valve.
4. Unscrew the cell cap, being careful not to lose the O ring.
5. Carefully remove the old cell by pulling on the little handle provided.
6. Inspect the cell block cavity, and if any sign of moisture clean it out with a Q tip or similar. Make sure that
the contact springs inside the block are intact. Be careful not to snag them with the Q tip.
7. Carefully open the bag using a pair of scissors or a knife. Make sure you don’t cut yourself or stab the
sensor! Make sure that there is no sign of any liquid in the bag, if so do not proceed, you need a new
sensor
8. Quickly install the sensor, membrane side down, into the cell block (gold plated contact side of sensor
should be facing up touching the cell block contacts).
9. Remove the shorting tab from the little socket on the sensor. You may also want to write down the
serial number.
10. Verify that the sealing O ring is in place in the cell cap groove. Verify that the O ring and the cap are clean
and free of any particulate deposits (dirt).
11. Allow the sensor to sit for about 30 seconds and adjust the reading to 20.9% using the span
adjustment.
12. Carefully replace the cap, making sure that you do not cross thread it, and tighten firmly by hand.
Do not over tighten.
13. Turn the On/Off selector valve to the On position.
14. Allow the gas to flow until the reading has dropped to the low ppm range – ideally to less than 10 ppm.
15. Turn the On/Off selector valve to the Off position, and disconnect the nitrogen.
16. If desired, use a suitable 80-100ppm span gas to calibrate the unit per the calibration procedure above.
Common Calibration Errors:
Common errors when spanning the analyzer are as follows:
•
Leaky gas fittings.
•
Incorrect regulator, or regulator with non-metallic diaphragm.
•
Regulator and gas line not properly bled.
•
Not allowing long enough for the sensor to come down to its reading from air exposure.
•
Use of any plastic tubing (should be the special AMI tubing or stainless steel tubing).
