What the hell happened in my computer room this afternoon?

[Feek]

I've just installed a Netbotz monitoring system in one of our racks, the unit itself is sitting in the middle of the rack at the back.

Earlier today my Blackberry bleeped and I had a warning that the internal temperature had reached 30.1C. I was in the middle of a BBQ at the time so it wasn't easy to get away but although 30C is high, I wasn't too worried providing it got no higher.

I wanted to get a plot of how the temp had gone over the previous 12 hours so at just after 21:00 I logged on and checked. It was as follows.



Yikes, still over 30C. But nothing I can do about it from here, it'll have to be looked at in the morning.

Then I checked the external sensor. It's on a cable hanging out of the top of the rack and over the edge so not in any direct airflow out of the rack.



WTF? As the internal one went up, the external dropped.

I need to pull the logs to see whether the room was accessed around those times and check the airconditioning as well. We've got a door sensor but it's not fitted yet. It will go on this week!

Any thoughts as to what could have caused the above? it's very strange.