Service manual

30 Functional Verification Welch Allyn Propaq Encore Vital Signs Monitor
12. Disconnect the CO
2
sensor from the monitor.
13. Turn off the monitor.
14. Log the test date and results in your department log.
Sidestream CO
2
Verification Procedure
The following procedures verify the operation of the sidestream CO
2
(SCO
2
) option.
1. Allow the monitor to warm-up for 3 minutes before performing the SCO
2
tests.
2. If present, disconnect the mainstream sensor from the monitor.
3. If installed, remove the water tap from the receiver on the front left panel of the
expansion module
4. Determine the local barometric pressure (“CO2 Verification Preparation” on page 26),
steps 1-3.
5. Select the SIDE TST screen through SETUP > MORE > MORE > SERVICE > YES >
CO
2
TEST
WARNING Eliminate all the possibilities causing errors shown in the following
table before performing the calibration procedure (“MSP Board (MCO2)
Calibration” on page 42). Recalibrating the altimeter, as described in that
procedure, without adequately eliminating all other possible faults may result in
inaccurate EtCO
2
readings.
Table 9. Possible Sources of CO
2
Verification Test Errors
Error Specification Correction
Incorrect/unknown calibration
gas concentration
4 to 10% certified to within ±0.01% Verify gas supply. Gas must be between 4% and
10%. Once known, convert percentage to partial
pressure (mmHg) (“Partial pressure of test gas
source” on page 27).
Insufficient/excessive gas
flow rate
Between 60 and 200 ml/min Verify with flow meter.
Excessive back pressure in
cuvette
Back pressure should not exceed
1þmmHg
Connect gases as instructed in verification test.
Air mixed with standard gas Check integrity of test setup.
Gas temperature Gas temperature entering airway
adapter should be at room
temperature
Store gas at room temperature.
Cuvette error Results should not vary more than
0.5 mmHg due to cuvette tolerances
Use another cuvette (airway adapter).
Thermal equilibrium error Sensor not warmed up Allow sensor/system to operate for a 15 minute
warm-up period.
High CO
2
reading with sensor
subject to room air only
CO
2
forced outside of airway adapter
into sensor. This is possible during
demonstration if exhaled gases are
blown through hands cupped around
cuvette and exhaled gases are
forced into sensor.
Contain exhaled breath through the inside of
cuvette only. Do not allow gases to be forced
outside of cuvette and into sensor housing. If
CO
2
has been forced into sensor allow 24 to 48
hours for the CO
2
to dissipate.