Control panel shows E18, generator shuts down shortly after transfer to load

Safety first: Immediately open the main utility breaker and the generator breaker. Backfeeding can be deadly. Only qualified personnel should work inside the ATS.

• Inspect ATS wiring: With all power off, open the ATS and verify that utility, generator, and load conductors are landed on the correct terminals per the DuroMax wiring diagram.
• Check contactor operation: Manually operate the ATS contactor (if possible) and ensure it fully transfers between utility and generator positions without bridging both sources.
• Test for welded contacts: Use a meter to confirm that when in generator position, there is no continuity between utility and load terminals. Replace the ATS contactor if contacts are welded.
• Verify phase rotation (3‑phase units): Ensure phase sequence from generator matches the ATS and load. Incorrect rotation can cause protection trips.
• Controller check: If wiring and ATS hardware are correct, the reverse power sensing circuit in the controller may be faulty and require professional diagnosis.