ℹ
info Honeywell
Status Three short beeps
System has been armed in STAY, NIGHT-STAY, or INSTANT mode, or a zone opened while the system is in chime mode.
? What Causes This
User armed system in STAY mode or a door/window was opened while chime mode is on.
ⓘ What This Means
No action needed for normal arming. If a zone opened during chime mode, investigate the open zone and close it if necessary.
Source: page 50 of the official manual
From the manual
This error code appears in:
Honeywell Vista-20P Security System