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6.    The screen shown below is displayed upon successful zeroing. Select Done to exit the 
zeroing screen. 
 
 
6.3.4.3 Zeroing Failure Troubleshooting 
If the zeroing fails, perform the following steps to locate and rectify the fault. 
1.    Disconnect the gas supplies, exhaust the gas inside the machine, and perform zeroing again. 
2.    If the zeroing is successful, it is concluded that the previous zeroing failure is caused by a 
mechanical failure in the pilot valve or faults in the proportional valves. Replace the pilot 
valve assembly and proportional valve assemblies. 
3.    If the zeroing still fails, it is concluded that the cause is the fault in the Sensirion differential 
pressure sensors or the high-flow O2 supply board. Replace the Sensirion differential 
pressure sensor assemblies and high-flow O2 supply board.