Correcting Start-Up Error on Pellistor (Catalytic Bead) Cartridge

Customers using a pellistor (catalytic bead) cartridge may experience a negative baseline reading upon starting up EXO. This may show as a negative Under Limit (UL). 

If a sensor has drifted too far into the negatives, it will trigger an Under Limit (UL) alarm on EXO. 

NOTE: Mute the alarm by pressing and holding the up and down arrow buttons.  


Before zeroing the sensors, make sure you are in a clean atmosphere with no ambient gas levels.  

NOTE: If you are unable to move EXO (example: if the device is mounted to a wall), a trained technician should zero the sensors using a cylinder of clean air. 

  1. Press the OK button to open Main menu. 
  2. Use the up or down arrow button to navigate to Gas options. 
  3. Navigate to Zero sensors. 
  4. Select Yes to continue with zero sensors. The screen will indicate when the zero is complete.