Generator shuts down during operation and the display shows E04 with no AC output to the home.

Safety first: Set the generator to OFF and disconnect battery negative. Ensure the automatic transfer switch (ATS) is in the NORMAL/UTILITY position if utility power is available.

• Reduce load: Turn off high-demand appliances (HVAC, electric water heater, ovens) at the home breaker panel. Firman standby generators have a rated continuous kW; ensure your total load does not exceed this rating.
• Inspect generator main breaker: Open the Firman enclosure and locate the main AC breaker. If tripped, switch it fully OFF then back ON. If it trips immediately with no load, suspect a short or faulty breaker.
• Check output connections: With power OFF, inspect the output lugs and wiring inside the generator for signs of overheating, melted insulation, or loose connections. Tighten lugs to the torque specified in the Firman manual.
• Inspect ATS wiring: At the automatic transfer switch, visually inspect for burned contacts or loose lugs. Do not work inside a live ATS; if unsure, call a licensed electrician.

After reducing load and confirming connections, clear the E04 code and restart. If overload trips continue at modest loads, have a technician test the main breaker and alternator windings.