7-4 
No. Calibration 
Item 
Function 
Description 
Calibration Occasion 
5 EFCS 
flowmeter 
zeroing (user) 
Zeros the EFCS 
flowmeter.  
There is deviation between the zero point of flow 
and actual zero points on the EFCS flowmeter. 
After the fresh gas is turned off, the EFCS 
flowmeter displays non-zero values.   
6 O2 sensor 
calibration 
(user) 
Calibrates the 
measurement 
accuracy of the O2 
sensor in 21% O2 
concentration and 
100% O2 
concentration.  
1. The measured value of the O2 sensor deviates 
from that of the actual value. The deviation is 
greater than 3% in both air (21% O2 concentration) 
and pure O2 (100% O2 concentration) 
environment.  
2. The O2 sensor is replaced.   
3. The VCM is replaced.   
7 CO2 sensor 
calibration 
(service) 
Calibrates the 
module to make it 
work more 
accurately.  
The deviation between measured value and the 
actual value exceeds the standard accuracy range.   
8 AG 
concentration 
calibration 
(service) 
Calibrates the 
module to make it 
work more 
accurately.  
The deviation between measured value and the 
actual value exceeds the standard accuracy range.   
9 O2 module 
calibration 
Calibrates the 
module to make it 
work more 
accurately.  
1. The deviation between measured value and the 
actual value exceeds the standard accuracy range.   
2. The O2 module is replaced.   
 
 
7.3.1 Flow Calibration (User) 
 
NOTE 
  A new flow sensor must be calibrated. 
  The measurement accuracy of flow sensors may be affected by the operating 
environment, especially when they have been used for a long time, and the tidal 
volume control may also experience a great deviation correspondingly. After-sales 
engineers can call users to help them resolve the deviation problem through 
calibration. 
  Before a calibration, perform the auto circuit leak test and ensure that no leak 
exists. 
  During a calibration, ensure that the drive gas pressure is within the specified 
range. Otherwise, the calibration may fail. 
  When the altitude changes significantly, there may be sensor measurement errors. 
In this case, errors can be corrected only by performing the flow calibration 
(service).