Safety-Chain Circuit Open

What does F405 mean?

This fault is triggered when the Safety-Chain circuit, which is critical for safe operation, becomes open at any point during an elevator run or is not closed at startup. An open Safety-Chain immediately disables the drive, causes the loop contactor to drop, and halts all motor activity.

• A safety device (e.g., door interlock, limit switch, emergency stop button) in the Safety-Chain has opened.
• Breakage or loose connection in the wiring of the Safety-Chain circuit.
• The Safety-Chain circuit was not fully closed before the drive was commanded to start operation.

Click steps to track your progress.

1. 1

   Inspect all safety devices included in the Safety-Chain circuit (e.g., car door contacts, hoistway door contacts, emergency stop buttons) to ensure they are in their closed state.

2. 2

   Trace the entire Safety-Chain circuit wiring to identify any open circuits, loose terminals, or damaged cables.

3. 3

   Verify the continuity of the Safety-Chain circuit from start to finish using a multimeter at appropriate test points.

4. 4

   Confirm that all safety inputs required for the Safety-Chain to close are met before enabling the drive to run.