Velly Velly intelestink. I will investigate this as a potential possibility.

If our system runs in a similar fashion, I could see this being the very problem. Our server room AC uses a heat exchanger located on the roof. And based on where we live, it wouldn't surprise me if we lost water pressure when the power to this neighborhood went out. It would make sense that if we lost water pressure, the safety circuits would shut down the heat exchanger on the roof. Which would explain why, when they deliberately killed the power to the heat exchanger and the AC unit, they were unable to reproduce the problem: They still had water pressure.