!!
critical Honeywell
Error Code Loud, interrupted alarm
Fire alarm or carbon monoxide alarm condition.
? What Causes This
Smoke or heat detected by fire detectors or high level of carbon monoxide detected.
✓ How to Fix It
Evacuate the premises immediately. Move to fresh air. Contact fire department or emergency services from a safe location. Do not re-enter the building.
Source: page 51 of the official manual
From the manual
This error code appears in:
Honeywell Vista-20P Security System