What causes an alarm to cleared by System.Alarm_AgeOut?
This is a feature inside of Spectrum called "Age Out Alarms".
Release : 10.3
Component : Spectrum Core / SpectroSERVER
Go to the VNM Model in OneClick
Click Information Tab
Expand Alarm Management
Here is where it can be set to age out alarms with certain pcause IDs.
After the time chosen expires, the alarms listed will be auto cleared.