A5/A3™ Service Manual 046-001141-00 5 - 27
Repair and Troubleshooting Pneumatic Circuit System Problems
5.3.2.1 Test the Pipeline Pressure Gauge and Correct the Regulator 
Use the following tools to test the pipeline pressure gauge and regulator of the pipeline gas supply 
inlet assembly:
• 1 MPa (10bar) test pressure gauge (before the test, make sure that the 1 MPa (10bar) test pressure 
gauge is in good condition) (quantity: 1)
• 3106-04-06 adapter connector (quantity: 1)
• PU tube (4X200) (quantity: 1)
• PU tube (6X200) (quantity: 1)
Test procedures:
I O2 supply inlet assembly: 
1. Turn off the pipeline gas supply and bleed the residual pressure through O2 flushing.
2. Disconnect tube 57. The end of the tube which connects the auxiliary O2 supply is not pulled 
out but the end to Y piece is pulled out.Connect 1MPa test pressure gauge to the above Y piece 
through “3106-04-06 adapter connector”.
The readings on the 
pipeline pressure gauge 
fluctuate greatly.
The filter of pipeline gas 
supply inlet assembly or 
the PU tube of the pipeline 
pressure gauge is 
occluded or the pressure 
gauge is damaged. 
1. After confirming that the pipeline gas pressure is 
stable, check the PU tube of the pipeline pressure 
gauge and filter of the pipeline gas supply inlet 
assembly. If the tube or the filer is occluded, 
replace it.
2. If the problem persists, replace the pipeline 
pressure gauge.
No “O2 Supply Failure” 
alarm occurs when the 
O2 pressure is low or 
this alarm occurs when 
the O2 supply pressure 
is within specifications.
The gas pressure switch of 
the O2 supply inlet 
assembly is ineffective.
Adjust the pressure switch of the O2 supply inlet 
assembly to cause O2 supply pressure to approach 
0.2 MPa as much as possible within the range of 
0.15 to 0.25 MPa when this alarm occurs. If the 
adjustment fails, replace the pressure switch (refer 
to “Adjust the Pressure Switch” on page 5-34.).
No “Drive Gas Pressure 
Low” alarm occurs when 
the drive gas pressure is 
low or this alarm occurs 
when the drive gas 
pressure is within 
specifications.
The pressure switch on the 
integrated pneumatic 
circuit of the expiratory 
valve assembly or the PEEP 
safety valve is ineffective. 
Or, the filter on the 
integrated pneumatic 
circuit of the expiratory 
valve assembly is 
occluded. 
Adjust the pressure switch on the integrated 
pneumatic circuit of the expiratory valve assembly 
to cause drive gas pressure to approach 0.14 MPa 
as much as possible within the range of 0.05 to 0.2 
MPa when this alarm occurs. If the adjustment fails, 
replace the pressure switch. If the problem persists 
after the pressure switch is replaced, replace the 
integrated pneumatic circuit of the expiratory 
valve assembly (refer to ‘‘Adjust the Pressure 
Switch’’ on page 5-34)
Failure description Possible cause Recommended action