Owner's manual

Advanced Instruments Inc.
29
6 Maintenance
With exception of components related to optional equipment and charging the battery of portable analyzers, cleaning the
electrical contacts when replacing the sensor is the extent of the maintenance requirements of this analyzer as there are no
serviceable parts in the analyzer given the nature of the solid state electronics and sensor.
Serviceability: Except for replacing the oxygen sensor, there are no parts inside the analyzer for the operator to service. Only
trained personnel with the authorization of their supervisor should conduct maintenance.
Sensor Replacement
Periodically, the oxygen sensor will require replacement. The operating life is determined by a number of factors that are
influenced by the user and therefore difficult to predict. The Specifications found in section 4 define the normal operating
conditions and expected life of the oxygen sensors utilized by the analyzer. Expected sensor life is inversely proportional to
changes in oxygen concentration, pressure and temperature.
Caution: DO NOT open the oxygen sensor. The sensor contains a corrosive liquid
electrolyte that could be harmful if touched or ingested, refer to the Material
Safety Data Sheet contained in the Owner’s Manual.
Procedure:
1. Regardless of the type of sensor the analyzer is equipped with, the procedure
for replacing an oxygen sensor is the same. Note: Pico-Ion MS sensor cannot
be calibrated with air.
2. Determine your calibration requirements by reviewing the Calibration
discussion in section 5 Operation, pay particular attention to the recovery
times and span gas available.
3. Remove the bolts and open the door of the enclosure.
4. Using the 5/16 wrench supplied loosen but do not remove the clamp bolt
located in the center of the bracket attached to bottom section with the elbow fittings.
5. Rotate the upper section of the sensor housing 90º to disengage from the clamp.
6. Remove the upper section by pulling it straight up and place it on a smooth surface.
7. Remove the old oxygen sensor and dispose of it as you would a battery.
8. Remove the o-ring from the bottom section of the sensor housing.
9. Wipe the o-ring with a damp lint free cloth.
10. Lightly lubricate the o-ring with vacuum grease for
optimal seal.
11. Reinstall the o-ring into the bottom section of the
sensor housing.
12. Place the analyzer in the OXYGEN mode.
13. Advance the red LED to the 0-25% RANGE.
14. Connect zero gas or low oxygen content sample gas
line to purge the lines and the sensor of oxygen to
the appropriate range for zero and/or span
calibration.
15. Caution: Minimize the time the new sensor is
exposed to ambient air.
16. The flow rate should already be set to 2 SCFH.
17. Remove the new oxygen sensor from the shipping bag.
18. Remove the red label and the gold ribbon (shorting device) from the PCB at the rear of the sensor.
19. Place the new sensor in the bottom section of the sensor housing with the PCB facing up.
20.
Place the upper section of the sensor housing over the sensor.
21. Gently push the upper section downward and rotate 90º to engage the clamp.
22. Finger tighten the clamp bolt and one full turn with the 5/16 wrench to com
pressed the o-ring seal.
23. Expect the analyzer reading to recover to ppb levels as described in the analyzer specification.
24. Perform the desired calibration(s). Note: Manually turn the RANGE selector switch to follow the progress of the sensor’s
recovery from exposure to air during installation. Begin sampling once the analyzer has reached the value of the purge gas.