Okuma Alarm A-8646 – Fire Extinguishing Unit Power OFF or Error

Alarm A-8646 indicates that the machine has detected a problem with the fire extinguishing system.

This alarm appears when:

• The fire extinguishing unit is switched OFF

• Power supply to the unit is interrupted

• The unit reports an internal fault

• The extinguishing agent is empty or pressure is too low

• A communication or monitoring signal from the unit is missing

The CNC monitors the fire protection system as a safety interlock. If the fire suppression unit is not ready or reports an error, the machine may block operation to prevent unsafe machining conditions.

Possible causes:

• Main power to the fire extinguishing unit is OFF

• Blown fuse or tripped breaker

• Empty extinguishing cartridge

• Pressure sensor fault

• Faulty wiring or loose connector

• Communication signal between unit and CNC interrupted

Recommended actions:

1. Check whether the fire extinguishing unit is powered ON.

2. Inspect status LEDs or display on the unit.

3. Verify pressure and extinguishing agent level.

4. Check electrical connections and fuses.

5. Reset the fire extinguishing unit if required.

This is a safety-related alarm and should not be bypassed without verifying the system condition.