Astec 49DV events in memory description

Hi all,

I was away at the weekend and when I came back the alarm in my house was going off. It's an Astec 49DV. It was strange because I had forgotten to set the alarm before I left, 100% certain it wasn't armed. I checked the memory and it showed the following events:

13th July - Mains Fault at 19:03
13th July - On at 20:09
14th July - Tamper Panel 1 Call Engineer (Code 14) at 11:33

I think the power went to my house which caused the mains fault because the cooker clock had been reset too. ESB has confirmed that there was a power outage in my area on the 13th so I know nobody was messing with wiring or whatever on Saturday but 2 things I'd like to know:

1. When these alarms come on after a mains fault to they arm themselves even if they weren't armed before the fault?
2. What could cause error 14 to display the following day? The error displayed would indicate someone was tampering with the panel but there is no sign that anyone was in the house.

I also noticed that one of the trip switches on the main board was down, but I haven't yet found what it's used for, still investigating. I doubt that it's anything related to the alarm though.

I'd appreciate any input you may have. Many thanks.