Hitachi System Messages

Meaning & Quick Troubleshooting Guide

Air Quality & Maintenance Messages
E1
Filter Replacement Required
  • Check air filter condition.
  • Clean or replace filter as needed.
  • Reset filter indicator after maintenance.
  • Ensure proper airflow after replacement.
E2
Air Quality Sensor Fault
  • Clean air quality sensor area.
  • Inspect sensor wiring connection.
  • Restart system to reset readings.
  • Replace sensor if issue persists.
System Errors
E3
Motor Failure
  • Check motor wiring connections.
  • Inspect fan or blower for obstruction.
  • Test motor operation.
  • Replace motor if not functioning.
E4
Overheat Protection Activated
  • Turn off unit and allow cooling.
  • Check ventilation and airflow paths.
  • Inspect fan operation.
  • Restart after temperature normalizes.
E5
Power Failure Detected
  • Check household power supply.
  • Inspect circuit breaker.
  • Reset unit after power stabilizes.
  • Verify consistent voltage supply.
Control Messages
RESET
System Restart Required
  • Disconnect power for a few minutes.
  • Reconnect and restart system.
  • Check if error returns.
  • Inspect control board if persistent.
LOCK
Child Lock Active
  • Press and hold lock button to disable.
  • Check control panel settings.
  • Refer to model-specific instructions.
  • Power reset if lock remains active.
Important: If system messages repeatedly appear, it may indicate a control board or sensor issue requiring professional service.