Troubleshooting for gas inlet pressure faults

Diagnostic codes 768 – 771

Diagnostic codes 768 – 771 occur when gas inlet pressure is less than the permitted pressure level.

Use extreme caution if you do diagnosis or maintenance tasks when the plasma power supply is connected to electricity and the panels on the plasma power supply are removed.

Decreases in gas pressure are more likely to occur if the supply gas hoses are long. For more information, refer to:

Symptoms

Code Symptoms XPR® models XPR action Code cancels with...
768 Line A O2 inlet pressure (P2) is less than 5.52 bar (80 psi) or more than 9.31 bar (135 psi). All models None
  • Set process
  • Remote on-off
769 Line B Argon inlet pressure (P1) is less than 5.52 bar (80 psi) or more than 9.31 bar (135 psi).
770 Line B N2 inlet pressure (P1) is less than 5.52 bar (80 psi) or more than 9.31 bar (135 psi).
771 Line A Air inlet pressure (P2) is less than 5.52 bar (80 psi) or more than 9.31 bar (135 psi).

Corrective action

  1. Use the Computer Numerical Control (CNC) or XPR web interface to select Test Cutflow to start the gas flow.
  2. Make sure that the gas inlet pressures are in the permitted range.

    Refer to Process-gas requirements for all gas connect consoles.

  3. If the gas inlet pressure is not in the permitted range, adjust it.
    1. Use a 2-stage regulator that can supply the necessary gas flow and can keep consistent gas pressure with high-pressure gas cylinders.
    2. Look at the diagnostic code history for pressure-related codes that can identify where to look for flow or pressure problems.
    3. If you identify a code for a pressure transducer (P1 or P2), interchange the transducers.
    4. Identify if the diagnostic code aligns with the transducer change.
    5. Replace the bad transducer if necessary.

      For instructions, refer to Replace a pressure transducer in the XPR Replacement Parts Procedures Field Service Bulletin (809970).

  4. If your cutting system has an OptiMix™ gas connect console, refer to Troubleshooting for process-gas inlet pressure faults in the console for systems.
  5. If you cannot find or correct the problem, speak to your cutting machine supplier or regional Hypertherm® Technical Service team.