Cause : External fault comes when external fault at multi-function input terminal or faults comes from external control circuit.

"Err15" fault indicate an external device tripped an alarm function or wiring is incorrect or multi-function contact input setting is incorrect.

1. Remove the cause of the external fault and reset the fault.
2. Properly connect the signal lines to the terminals assigned for external fault detection.
3. Reconnect the signal line.
4. Change the terminal settings.