4-25 
 
NOTE 
  In case of leak test failure, check all of the possible leak sources, including bellows, 
breathing system tubes and CO2 absorbent canister. Check that they are correctly 
connected and their connectors are not damaged. 
  If there is indeed a leak, check the pneumatic circuit system for leakage and 
troubleshoot the problems as described in section 8.3 Leak and Compliance Tests. 
  After leak failure is troubleshot, do the leak test again and make sure the test is 
passed. 
 
 
4.11.4.2 Commonly-encountered Problems and Recommended Actions 
The following table lists the commonly-encountered problems and recommends actions for 
breathing system leak test in mechanical ventilation mode. 
 
Failure description  Possible cause  Recommended action 
Leak test failure is 
prompted 
immediately after 
[Start] is selected 
(typically, the leak 
test requires at least 3 
minutes). 
The bag/vent switch is set to the bag 
position and the message [Manual 
Vent.] is prompted. 
Set the bag/vent switch to the 
mechanical ventilation position. 
The reading on the drive gas (O2) 
pressure gauge indicates drive gas 
pressure low (lower than 200 kPa) 
and the alarm of [Drive Gas 
Pressure Low] is produced. 
Replace or connect gas supplies 
and make sure that the drive gas 
pressure is at 280 to 600 kPa. 
The ACGO switch is turned on and 
the screen displays prompt message 
of ACGO. 
Turn off the ACGO switch. 
The airway pressure 
does not drop during 
the test but test 
failure is prompted. 
Fresh gas is not turned off.  Turn off the fresh gas. 
During leak test, the 
pressure indicated by 
the airway pressure 
gauge fails to reach 
30 cmH2O. 
1. Before the leak test, the bellows 
is not fully inflated. 
2. The Y piece on the breathing tube 
is not connected to the test plug. 
3. The bellows housing is not 
properly installed. 
4. The CO2 absorbent canister is not 
installed in place. 
Check the pneumatic connections 
and re-install the pneumatic 
circuit. 
During leak test, the 
pressure indicated by 
the airway pressure 
gauge reaches 30 
cmH2O but then falls 
rapidly. 
1. The bellows housing may not be 
installed properly. 
2. The expiratory valve assembly is 
leaky. 
3. The circuit is not tightly 
connected to the circuit adapter. 
4. The connection between the 
sampling line of the sensor and the 
board is leaky. 
Check the pneumatic connections 
and re-install the pneumatic 
circuit. 
After the leak test, 
the alarm of 
[Ventilator Hardware 
Error 11] occurs. 
Control of safety valve by the 
auxiliary control board fails. 
Restart the machine. Verify if the 
safety valve is controllable by 
using the safety valve control 
command of the monitor board. If