What to do if the FBI Security System shows “NOT RDY: ZN #” and “SYSTEM NOT READY”?
- MMatthew Lopez Jr.Aug 3, 2025
If the “ARM” light is ON and the “READY” light is OFF, accompanied by the messages “NOT RDY: ZN #” and “SYSTEM NOT READY”, it indicates that a zone is faulted, preventing the system from being armed. This could be due to an open or short in the loop wiring, a bad resistor, or an incorrect resistor value. Inspect the loop wiring for any opens or shorts and repair them. Also, check the resistor and its value. Alternatively, the keypad or the panel might be faulty. Check zone terminals for 3.3 VDC, bypass the zone temporarily, or replace the keypad or panel.