Specifications

MODEL 300 COMBUSTION ANALYZER
4-14 Instruction 24-9223
4.5 OXYGEN SENSOR CALIBRATION
The oxygen sensor does not require manual calibration. Automatic
calibration to an oxygen level of 20.9% occurs each time the combustion
analyzer runs through its calibration cycle – the microprocessor assumes
fresh air is being sampled during calibration.
During the calibration cycle, the middle display shows the millivolt
output of the oxygen sensor. If this output indication is below 18, the
oxygen sensor is nearing the end of its useful life and should soon be
replaced.
If the microprocessor senses that the oxygen sensor’s output is less than
15.1 mV or greater than 65.9 mV during calibration, the first display will
show an E*O2 error after the conclusion of the calibration cycle. Also, if
the oxygen cell’s output exceeds 74.4 mV during calibration or during a
combustion efficiency run, the first display will shown an OR/O over-
range and stop the instrument. Refer to Section 3.5 for information on
what to do if an E*O2 or OR/O message appears.