Chapter 3: Fault finding – ECU faults
ZP3-ECU Extinguishing Control Unit Maintenance Manual
21
Fire bell fault
Indications
• The Fire Bell Fault LED on the ECU main board illuminates (see Figure 1 on
• The Fault LED on the ECU front panel illuminates.
• A GNFLT fault message is displayed on the fire alarm control panel and the
panel buzzer sounds. The Fault LED on the fire alarm control panel also
illuminates.
GNFLT Zone 001 Dev 5001 Event 002
Possible causes
The EOL resistor across the fire bell is not inserted or the monitored circuit wiring
is open or short-circuited. Faulty fire bell fuse, replace if necessary.
Corrective actions
1. Press the Accept/Panel Silence button to silence the buzzer to acknowledge
the fault.
2. Inspect the EOL resistor. If missing, insert one between terminals 4 and 5 of
TB1 on the ECU main board.
3. Check continuity of the monitored circuit wiring.
4. Reset the panel.
