Generator starts to crank but stalls or runs rough, then shuts down with LOW FUEL PRESSURE or FUEL SUPPLY error.

Safety first: Turn the controller to OFF, open the main breaker, and close the gas shutoff valve. Work only in a well-ventilated outdoor area. Do not smoke or create sparks near fuel.

• Check fuel source: Verify LP tank level is adequate and that the main tank valve is fully open. For NG, confirm gas service is active and sized per Guardian installation requirements.
• Inspect fuel piping: Look for crushed, kinked, or sagging flexible fuel lines. Correct any mechanical damage and ensure proper support.
• Replace fuel filter: If equipped, replace the in-line fuel filter with a Guardian-approved part to remove restrictions.
• Check regulator vent: Ensure the regulator vent is not blocked by insects, dirt, or ice. Clear obstructions carefully.
• Test run: Reopen the gas valve, leak-test connections with a soap solution, then reset the controller and perform a manual start. If LOW FUEL PRESSURE persists, the regulator or gas supply sizing must be evaluated by a licensed gas technician.