Troubleshooting the Anesthetic Gas Module 9 Anesthetic Gas Module
217
O
2
Assembly Diagnostic Checks
Symptom Possible Cause Corrective Action
O
2
Assy shows
Problem
O
2
jumpers incorrectly
set
Check if the O
2
jumpers are correctly set.
O
2
sensor failed Zero/
Span calibration
See calibration checks.
Defective O
2
sensor If two solenoids are installed, disconnect
cable of solenoid #2 (near O
2
sensor).
Go into Gas Analyzer Calibration window
Start a zero calibration to get the actual
barometric pressure reading.
Note the measured barometric pressure in
mmHg displayed in the Calibration window
Using a voltmeter, check the O
2
sensor
voltage as follows:
Connect voltmeter ground to TP1.
Measure TP8 voltage. 1% O
2
is
approximately equal to 10mV.
As the O
2
measurement is influenced by the
barometric pressure, the correct voltage must
be calculated as follows:
O
2
concentration of gas in mV multiplied by
the measured barometric pressure in mmHg
and divided by 760 mmHg.
For example, correct calculated voltage for
room air (20.9% O
2
) and barometric
pressure of 720 mmHg is: 209 mV x 720
mmHg / 760 mmHg = 198mV.
If the voltage is not within ±10% of
calculated value, proceed to adjust O
2
Zero
and Span potentiometers in the following
order:
Table continued on next page.