Welch Allyn PROPAQ CS Service Manual page 39

Service Manual
Table 10. Possible sources of CO
Error
Incorrect/unknown calibration gas
concentration
Insufficient/excessive gas flow rate
Excessive back pressure in cuvette
Air mixed with standard gas
Gas temperature
Cuvette error
Thermal equilibrium error
High CO
2
to room air only
WARNING Eliminate all the possibilities causing errors shown in the following
table before performing the calibration procedure
calibration" on page 54). Recalibrating the altimeter as described in that
procedure, without adequately eliminating all other possible faults, may result in
inaccurate EtCO readings.
2
verification test errors
2
Specification
4 to 10% certified to within ±0.01%
Between 60 and 200 ml/min
Back pressure should not exceed
1 mmHg
Gas temperature entering airway
adapter should be at room
temperature
Results should not vary more than
0.5 mmHg due to cuvette tolerances
Sensor not warmed up
reading with sensor subject CO
into sensor. This is possible during
demonstration if exhaled gases are
blown through hands cupped around
cuvette and exhaled gases are forced
into sensor.
forced outside of airway adapter
2
Functional verification
("MSP Board (MCO2)
Correction
Verify gas supply. Gas must be
between 4% and 10%. Once known,
convert percentage to partial pressure
(mmHg) as instructed in "Partial
pressure of test gas source"
page 31.
Verify with flow meter.
Connect gases as instructed in
verification test.
Check integrity of test setup.
Store gas at room temperature.
Use another cuvette (airway adapter).
Allow the sensor/system to warm up
for 15 minutes.
Contain exhaled breath through the
inside of the cuvette only. Do not allow
gases to be forced outside of the
cuvette and into the sensor housing. If
CO has been forced into the sensor,
2
allow 24 to 48 hours for the CO
dissipate.
35
on
to
2