Hazardous Area
X-STREAM O
2
Transmitter
6-2
Instruction Manual
IM-106-910C, Rev. 1.0
November 2009
MAINTENANCE
INTERVALS
The maintenance interval required is quite variable, depending on the type of
service the analyzer is placed into. The zirconium oxide sensing cell is
non-depleting, and has no specific shelf life or a defined life in flue gas
operation. The cell of a probe that is mounted inside a boiler that is burning
natural gas may shift very little over several years. Acidic compounds are the
main aggressors to the sensing cell, typically SO
2
resulting from sulfur
contained in coal and heavy oil fuels, and also HCl from the combustion of
plastics in municipal incinerators and in industrial thermal oxidizers. Sensing
cells may experience significant degradation and signal shift in this type of
service, particularly if the operating levels of O
2
are very low (below 1% O
2
).
A calibration check is generally recommended on a quarterly basis (every 3
months) by flowing bottled gas to the probe. (Make sure that the operations
personnel are notified when doing this, and also make sure that the O
2
control
loop is placed in manual mode). If the probe readings vary significantly from
the bottle values, then a formal calibration should be conducted as noted in
Section 4: Startup and Operation.
The Xi enhanced electronics offers a "calibration recommended" diagnostic
that will indicate when the probe needs to be calibrated.
Combustion processes that have a high level of ash or other particulate
content will cause the diffusion element on the end of the probe to plug off. A
badly plugged diffuser will cause a slower speed of response to changing O
2
levels in the process. This can usually be seen on the recorded trends in the
control room.
When performing a calibration check or actual calibration, the calibration flow
meter may read lower if the diffuser is badly plugged. (Never increase the flow
rate back up, however, as this can cause a shifted calibration. Adjust the
calibration flow rate only when a new diffuser is installed). Always record the
response time back to the process after the calibration gases are removed, as
noted on the calibration record at the end of this section. Diffuser pluggage
can be tracked through this record.
A visual inspection of the probe sensor core should be conducted during plant
outages, paying particular attention to condensed components. Condensation
can be reduced or eliminated by insulating the probe installation, including the
probe mount, flange, and dual blue housings.
CALIBRATION
The Hazardous Area X-STREAM O
2
Transmitter can be calibrated manually
through the handheld 375 Field Communicator, or automatically through the
SPS 4001B Single Probe Autocalibration Sequencer or the IMPS 4000
Intelligent Multiprobe Test Gas Sequencer and the Xi Enhanced Interface.
Automatic Calibration
Contact from the Xi Enhanced Interface to an SPS 4001B (one per probe) or
IMPS 4000 (up to four probes) provides the ability to manually initiate a
calibration at any time from the control room. The Xi Enhanced Interface must
be used with the SPS 4001B or IMPS 4000 in order to perform an auto /
semi-auto calibration.
Refer to the SPS 4001B or IMPS 4000 Instruction
Manual for further details on how to configure and perform an automatic
calibration.
Manual Calibration
Refer to the "Calibration - General" in Section 4: Startup and Operation to
perform a manual calibration.
