A5/A3™ Service Manual 046-001141-00 4 - 5
Calibration System Calibration
4.3 System Calibration
NOTE: The anesthesia machine drive gas and calibration device drive gas type 
setttings should be consistent with the actual drive gas type configured 
for the anesthesia machine.
NOTE: Perform the corresponding calibration if any test item of the system 
test about measurement accuracy is failed.
NOTE: Fluke VT Plus: The zero reading (offset) of the pressure measurements 
may drift slightly with time and temperature. A zeroing function is 
provided for the user to zero the offset drift. Typically, this is done 
when a non-zero reading occurs when there is zero applied pressure. 
However, it is good practice to zero the respective signal before any 
measurement is taken.
NOTE: You can select VT Plus to perform automatic calibration of pressure 
sensors or flow sensors, or any other calibration devices that fulfills the 
accuracy requirements to perform manual calibration.
The anesthesia machine provides the function of monitoring volume, pressure, FiO2 and etc. When 
these measured values have great deviations, it is very likely that measurement offset occurs to the 
relevant measurement parts. In this case, you need to perform calibration again. After equipment 
service, such as replacing the ventilator control board, expiratory valve assembly or solenoid valve 
assembly, you need to calibrate the flow sensors or pressure sensors.
The following table lists the possible calibration items and calibration time.
SN Calibration item Functional description Calibration time 
1
Flow calibration 
(user)
Calibrate the flow sensors of 
the breathing system.
1. The TV measurement deviation is greater 
(more than 9% compared with the setting value) 
after the flow sensors in the patient circuit have 
been used for a long time.
2. The flow sensor in the patient circuit has been 
replaced.
2
Flow calibration 
(Service)
Calibrate the flow sensors 
and inspiratory valve of the 
anesthesia machine.
1. The expiratory valve assembly is replaced.
2. The ventilator control board is replaced.
3. The deviation between the measured value of 
the ventilator flow sensor and that of the flow 
measurement device exceeds more than 5% of 
the reading or 1 L/min, whichever is greater.
3
Pressure 
calibration 
(Service)
Calibrate the pressure 
sensors and PEEP valve of 
the anesthesia machine.
1. The ventilator control board is replaced.
2. The expiratory valve assembly is replaced.
3. The deviation between the measured value of 
the machine's pressure sensor and that of the 
standard pressure gauge exceeds more than 5% 
of the reading or 2 cmH2O, whichever is greater.
4
Pressure and flow 
zeroing (Service)
Calibrate the deviation from 
zero point of the ventilator 
control board and auxiliary 
ventilator control board.
Flow or Paw waveforms deviates from the 
baseline.