Page 27 - WM E-Learning Handbook
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Slide Topic                     Content                                 Notes

Depressurizing High-Pressure   Fuel Systems with Defueling
Components (Excluding             Port and/or Bleed Valve
Cylinders, Valves, or PRDs)        Always follow
                                       manufacturer’s
                                       procedures
                                   Generic description of
                                       procedure
                                        Close cylinder valve
                                            or disconnect electric
                                            solenoid valves
                                        Use defueling port or
                                            bleed valve to
                                            depressurize the
                                            remainder of the
                                            high-pressure fuel
                                            system

                               Fuel Systems without
                                  Defueling Port or Bleed Valve
                                   Always follow
                                       manufacturer’s
                                       procedures
                                   Generic description of
                                       procedure
                                        Close cylinder valves
                                            or disconnect electric
                                            solenoid valves
                                        Perform rundown
                                            procedures to
                                            depressurize

Rundown Procedure              Shut off all cylinder valves or
                                  disconnect electric solenoid
                                  valves

                               Start the engine

                               Run until it stalls or shuts off

                               Wait 1-2 minutes; attempt to
                                  re-start engine

                               When engine will not run,
                                  the high-pressure fuel system
                                  should have low pressure
                                   Check pressure gauges to
                                       confirm

                               Open bleed valve or use two
                                  wrenches to open a fitting
                                  just to the point where gas
                                  begins to flow

Technician Safety and Awareness Training for NGVs  © 2018 NGVi All Rights Reserved         Page 25
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