Controller shows F18 Fuel Pressure Low; engine may stall or fail to start.

Safety first: Shut off fuel supply before opening any fuel lines. Ventilate the area and avoid ignition sources.

• Check shutoff valves: Verify that all manual fuel shutoff valves between the supply and the generator are fully open.
• Replace fuel filter: Locate the primary and secondary fuel filters on the generator. Close upstream valves, remove the filters, and install new Siemens-approved elements. Prime the system if required.
• Inspect fuel pump operation: During a start attempt, listen for the fuel pump running. Use a pressure gauge on the test port (if provided) to confirm pressure meets Siemens specifications. Replace the pump if pressure is low or absent.
• Check gas regulator (NG/LPG): Ensure the regulator vent is not blocked and that inlet pressure from the gas meter or tank is within range. A gas technician may be required to adjust or replace the regulator.
• Retest: Clear F18 and attempt a start. If pressure remains low, further diagnostics by a technician are recommended.