Mindray WATO EX-55Pro, Service Manual

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6.6.7 Check the Electronic Flowmeter Accuracy
NOTE

When a great measurement deviation occurs to the electronic flowmeters, checkthe
electronic flowmeter accuracy so as to determine whether to calibrate the
electronic flowmeters again.
This test is to check if the measurement by the electronic flowmeter is normal. Do this test after
calibration to check the calibration effect.
6.6.7.1 Check the O2/Air Electronic Flowmeter Accuracy
To check the measurement accuracy of O2 or Air electronic flowmeters:
1. When the flowmeter tubes are correctly configured, if alarms related to flowmeter
calibration data error occur, re-calibration is necessary.
2. Adjust the needle valve of the flowmeter of the supply gas under test (O2 or Air).
Compare the measured value by the electronic flowmeter and that by the float flowmeter.
If a great deviation occurs between the value displayed by electronic flowmter LED and
the reading on the float flowmeter, such as more than 1 L/min, you may need to
calibrate again (this method is suitable for comparison of more than 3 L/min flow due to
low accuracy).
3. Use the anesthesia machine calibration device to check the accuracy of electronic
flowmeter further. Connect the low flow (0 to 15 L/min) inlet of the calibration device
to the fresh gas port of the breathing system and position the low flow (0 to 15 L/min)
outlet of the calibration device to the air.
4. Select the same gas for the anesthesia machine calibration device to that under test, O2 or
Air.
5. Adjust the electronic flowmeter, causing the measured flow value by the calibration
device to fall within the setting range, such as (3.0±1) L/min, (5.0±1) L/min, (8.0±2.0)
L/min. Record the displayed value by the electronic LED to which each setting
corresponds respectively.
6. Make sure that the deviation between the reading on the calibration device and that on
the electronic flowmeter must not exceed 10% of the reading on the calibration device.
Otherwise, you need to calibrate the electronic flowmeter again.