88 1100 Series FD Reference Manual
4 Troubleshooting and Test Functions
Fan Failed
The cooling fan in the detector has failed.
The hall sensor on the fan shaft is used by the FLM board to monitor the fan
speed. If the fan speed falls below two revolutions/second for more than five
seconds, the error message is generated.
Probable Causes
• Fan cable disconnected.
• Defective fan.
• Defective FLM board.
Suggested Actions
✔ Ensure the fan is connected correctly.
✔ Exchange fan.
✔ Exchange the FLM board.